Orthopedic Arthroplasty, Fracture, Ankle, Hip MCQs - Part 79

About This Board Review Set

This is Part 79 of the comprehensive OITE and AAOS Orthopedic Surgery Board Review series authored by Dr. Mohammed Hutaif, Consultant Orthopedic & Spine Surgeon.

This set has been strictly audited and contains 100 100% verified, high-yield multiple-choice questions (MCQs) modelled on the exact format of the Orthopaedic In-Training Examination (OITE) and the American Academy of Orthopaedic Surgeons (AAOS) board examinations.

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Two distinct learning modes are available:

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Pro Tip: Use keyboard shortcuts A–E to select options, F to flag a question for review, and Enter to jump to the next unanswered question.

Topics Covered in Part 79

This module focuses heavily on: Ankle, Arthroplasty, Fracture, Hip.

Sample Questions from This Set

Sample Question 1: A 12-year-old child with spina bifida paraplegia requires brace management for ankle stability. Which of the following principles applies to brace management in this individual?...

Sample Question 2: An open biopsy specimen of a radiodense distal clavicle lesion in a 12-year-old girl shows chronic polyclonal inflammatory cells without granuloma formation. Laboratory studies show that bacterial, fungal, and acid-fast bacillus cultures ar...

Sample Question 3: Which of the following findings best describes the acetabular fracture shown in Figure 38?...

Sample Question 4: Porous hydroxyapatite is placed into a bone defect. Incorporation of this bone graft substitute is expected to follow which of the following patterns?...

Sample Question 5: -A patient who had previously undergone a salvage pelvic (Chiari) osteotomy now requires a total hip arthroplasty. The most frequent complication of this procedure is...

Why Active MCQ Practice Works

Evidence consistently demonstrates that active recall through spaced MCQ practice yields substantially greater long-term retention than passive reading alone (Roediger & Karpicke, 2006). All questions in this specific module have been algorithmically verified for clinical integrity and complete explanations.

Comprehensive 100-Question Exam

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Question 1

A 12-year-old child with spina bifida paraplegia requires brace management for ankle stability. Which of the following principles applies to brace management in this individual?

Explanation

DISCUSSION: Bracing for spina bifida paraplegia provides both support and improved function of the movable limb. An orthosis has value in controlling unstable joints. The three-point pressure effect applies a force above and below the joint to prevent it from buckling. A four-point pressure effect is only required for a two-joint system (this patient has problems only at the ankle). A longer lever arm brace and a brace with a greater area of support provide better stability. Finally, a straighter limb, without contracture, applies less pressure to the brace and lessens overload to the skin.
REFERENCES: Gage JR: An overview of normal walking. Instr Course Lect 1990;39:291-303.
Bleck EE: Current concepts review: Management of the lower extremities in children who have cerebral palsy. J Bone Joint Surg Am 1990;72:140-144.
Harris MB, Banta JV: Cost of skin care in the myelomeningocele population. J Pediatr Orthop 1990;10:355:361.

Question 2

An open biopsy specimen of a radiodense distal clavicle lesion in a 12-year-old girl shows chronic polyclonal inflammatory cells without granuloma formation. Laboratory studies show that bacterial, fungal, and acid-fast bacillus cultures are negative. Subsequently, a similar lesion is noted in the fibula. The next most appropriate step in management should consist of

Explanation

DISCUSSION: The most likely diagnosis is chronic multifocal osteomyelitis. This is a culture-negative polyostotic disease that is most commonly found in young people. The treatment of choice is anti-inflammatory drugs. The pathology does not suggest eosinophilic granuloma. Antiviral therapy, broad-spectrum antibiotics, and surgical resection are not indicated for this disease.
REFERENCE: Carr AJ, Cole WG, Roberton DM, Chow CW: Chronic multifocal osteomyelitis. J Bone Joint Surg Br 1993;75:582-591.

Question 3

Which of the following findings best describes the acetabular fracture shown in Figure 38?

Explanation

DISCUSSION: The CT scan shows a posterior wall fracture with impaction of the articular surface and a free fragment within the joint. Proper treatment of this injury requires not only reduction and fixation of the posterior wall fragment but also removal of the free fragment and elevation of the depressed articular segment.
REFERENCES: Letournel E, Judet R: Fractures of the Acetabulum, ed 2. Berlin, Germany, Springer Verlag, 1993.
Matta J: Surgical treatment of acetabular fractures, in Browner BD, Jupiter JB, Levine AM, et al (eds): Skeletal Trauma, ed 3. Philadelphia, PA, WB Saunders, 2003, vol 1, pp 1109-1149.

Question 4

Porous hydroxyapatite is placed into a bone defect. Incorporation of this bone graft substitute is expected to follow which of the following patterns?

Explanation

Porous hydroxyapatite is created via a hydrothermal chemical exchange with phosphate of the calcium carbonate exoskeleton of ocean corals. This process converts the original exoskeleton into an inorganic replica of hydroxyapatite. The porous structure allows neovascularization and new bone is deposited on the macrostructure via appositional bone deposition. The hydroxyapatite does not dissolve and is not removed via creeping substitution. Creeping substitution relies on osteoclastic resorption creating a cutting cone followed by osteoblastic bone formation. The macrostructure of porous hydroxyapatite allows full penetration of osteoblasts and vascularization, not just to the periphery. Inorganic hydroxyapatite does not induce an inflammatory response.

Question 5

A patient who had previously undergone a salvage pelvic (Chiari) osteotomy now requires a total hip arthroplasty. The most frequent complication of this procedure is

Explanation

The Chiari osteotomy is recommended for patients with inadequate femoral head coverage and an incongruous joint. The osteotomy shortens the affected leg. It also medializes the hip's center of rotation. The osteotomy involves cutting the ileum at a spot above the acetabulum, which in effect abducts the acetabulum into a more vertical and medial position. The iliac wing then serves as a superior buttress. Answer #1 makes no sense. Answer #2 is wrong because the articular portion of the acetabulum remains unchanged. Answer #3 is incorrect because inferior coverage remains unchanged. Answer #4 is completely incorrect because superior coverage INCREASES with a Chiari osteotomy.

Question 6

Figure 1 is the ultrasound of a 23-year-old patient who has had a volar radial 1.5-cm tender and painful wrist mass for 6 months. The additional workup prior to surgery should consist of

Explanation

EXPLANATION:
The ultrasound shows a homogeneous anechoic mass consistent with a ganglion cyst. As a benign lesion, no further workup or biopsy is required prior to a marginal surgical excision other than age-appropriate laboratory studies. An MRI study with contrast would provide no diagnostic benefit.

Question 7

A 51-year-old woman with no preoperative neurologic deficit is undergoing elective anterior cervical diskectomy and fusion (ACDF) with plating and fusion for a C5-6 disk herniation with right-sided neck pain. Thirty minutes into the surgery the neurophysiologic monitoring shows a rapid drop and then loss of amplitude in the right cortical somatosensory-evoked potential waveform. All other waveforms remained normal and unchanged, including right-sided cervical (subcortical) and peripheral (Erb’s point), and those from the left-sided upper extremity and both lower extremities. What is the most likely cause of the change?

Explanation

DISCUSSION: The change noted is focal and confined to the cortex, sparing the opposite side, both lower extremities, and the subcortical waveforms, making all the choices unlikely with the exception of carotid compression with focal cortical ischemia. This may be associated with poor collateral flow from the opposite hemisphere due to an incomplete circle of Willis.
REFERENCES: Drummond JC, Englander RN, Gallo CJ: Cerebral ischemia as an apparent complication of anterior cervical discectomy in a patient with an incomplete circle of Willis. Anesth Analg 2006;102:896-899.
Yeh YC, Sun WZ, Lin CP, et al: Prolonged retraction on the normal common carotid artery induced lethal stroke after cervical spine surgery. Spine 2004;29:E431-E434.

Question 8

A 35-year-old woman undergoes an L4-5 anterior fusion via a left retroperitoneal approach. Postoperative examination reveals that her right foot is cool and pale. Her neurologic examination is normal, and her pedal pulses are asymmetric. What is the most likely reason for the right foot finding?

Explanation

DISCUSSION: The lower extremity symptoms are consistent with a sympathectomy that is the result of an injury to the sympathetic chain, ipsilateral to the approach along the anterior border of the lumbar spine. This results in a warm, red foot, which creates the appearance that the normal cooler foot may have compromised circulation. The latter generally attracts greater attention because of the risks associated with limb ischemia. The condition usually is self-limited and does not require any specific treatment.
REFERENCES: Rothman RH, Simeone FA (eds): The Spine, ed 4. Philadelphia PA, WB Saunders, 1999, p1550.
Benzel EC (ed): Spine Surgery Techniques, Complication Avoidance and Management. New York, NY, Churchill Livingstone, 1999, p 190.

Question 9

Which of the following findings is likely to be pathologic in a thin, well-conditioned endurance athlete?

Explanation

DISCUSSION: Left ventricular hypertrophy by voltage is a nonspecific diagnosis, especially in athletes with an asthenic body habitus. High vagal tone in endurance athletes may result in first degree or even type I second degree (ie, Wenckebach) AV block in endurance athletes. High vagal tone results in resting sinus bradycardia in many trained athletes. A I-II/IV systolic ejection murmur is occasionally found in healthy athletes; however, when the murmur increases in intensity with maneuvers that decrease ventricular filling, such as standing or the Valsalva maneuver, dynamic obstruction that is the result of hypertrophic obstructive cardiomyopathy should be suspected. Nonspecific STT wave changes in the lateral leads on ECG are not uncommon in highly trained athletes; thus, they are nonspecific for ischemic heart disease.
REFERENCES: Pelliccia A, Maron BJ, Culasso F, DiPaolo FM, et al: Clinical significance of abnormal electrocardiographic patterns in trained athletes. Circulation 2000;102:278-284.
Maron BJ, Thompson PD, Puffer JC, McGrew CA: Cardiovascular preparticipation screening of competitive athletes: A statement for health professionals from the Sudden Death Committee (Clinical Cardiology) and Congenital Cardiac Defects Committee (Cardiovascular Disease in the Young), American Heart Association. Circulation 1996;94:850-856.

Question 10

With increasing abduction in the scapular plane, maintaining neutral rotation, contact area, and contact pressure per unit area between the humeral head and glenoid follows what pattern if the total load across the joint is held constant?

Explanation

DISCUSSION: The glenohumeral joint becomes more congruent at higher levels of abduction. As a consequence, contact area increases. As the load is spread more evenly across the joint, contact pressure per unit area decreases as long as the total load across the joint is held constant.
REFERENCES: Warner JJP, Bowen MK, Deng XH, et al: Articular contact patterns of the normal glenohumeral joint. J Shoulder Elbow Surg 1998;7:381-388.
Greis PE, Scuderi MG, Mohr A, et al: Glenohumeral articular contact areas and pressures following labral and osseous injury to the anteroinferior quadrant of the glenoid. J Shoulder Elbow Surg 2002;11:442-451.

Question 11

A 26-year-old professional rodeo bull rider sustained a grade III midshaft femoral fracture after being thrown from his bull. He underwent closed interlocking intermedullary nailing with a titanium rod, and his recovery was uneventful. Prior to returning to competition, the patient must

Explanation

DISCUSSION: While it is recommended that a patient gain full range of motion, pain-free function, and symmetric strength prior to returning to vigorous activities, it is absolutely essential that radiographs of the fracture site reveal a circumferential external bridging callus to prevent refracture. This is particularly important for comminuted femoral fractures with various sized fragments. It is also recommended that a return to rodeo riding be postponed for at

least 1 year.
REFERENCES: Brumback RJ, Ellison TS: Intermedullary nailing of femoral stress fractures. J Bone Joint Surg Am 1992;74:106-112.
Bucholz RW, Jones A: Fractures of the shaft of the femur. J Bone Joint Surg Am

1991;73:1561-1566.
Butler MS, Brumback RJ: Interlocking nailing for ipsilateral fractures of the femur, femoral shaft, and distal part of the femur. J Bone Joint Surg Am 1991;73:1492-1502.

Question 12

While lifting weights, a patient feels a pop in his arm. He has the deformity shown in Figure 30. If left untreated, the patient will have the greatest deficiency in

Explanation

DISCUSSION: The patient has a distal biceps rupture. While the distal biceps contributes to elbow flexion, its main function is forearm supination.
REFERENCES: Baker BE, Bierwagen D: Rupture of the distal tendon of the biceps brachii: Operative versus non-operative treatment. J Bone Joint Surg Am 1985;67:414-417.
D’Arco P, Sitler M, Kelly J, et al: Clinical, functional, and radiographic assessments of the conventional and modified Boyd-Anderson surgical procedures for repair of distal biceps tendon ruptures. Am J Sports Med 1998;26:254-261.
Pearl ML, Bessos K, Wong K: Strength deficits related to distal biceps tendon rupture and repair: A case report. Am J Sports Med 1998;26:295-296.

Question 13

Figure 14 is a sagittal-cut MR image from the hindfoot of a 54-year-old woman who has had plantar heel pain for 3 months. There is no history of trauma. Her pain is worse when she rises and at the end of the day. Upon examination she has localizable tenderness over the plantar medial tubercle of the calcaneus. The Achilles is intact and nontender, and subtalar joint motion is full and painless. A Tinel test result is negative. What is the most likely diagnosis?

Explanation

DISCUSSION
Plantar fasciitis is inflammation of the plantar fascia at its insertion onto the medial calcaneus. The T2-weighted sagittal MR image reveals thickening of the plantar fascia with no evidence of a calcaneal stress fracture, coalition, or inflammation of the insertion of the Achilles tendon.
RECOMMENDED READINGS
Lareau CR, Sawyer GA, Wang JH, DiGiovanni CW. Plantar and medial heel pain: diagnosis and management. J Am Acad Orthop Surg. 2014 Jun;22(6):372-80. doi: 10.5435/JAAOS-22-06-

Question 14

A 72-year-old woman who fell on her right shoulder while using a treadmill is now unable to elevate her right arm. An MRI scan is shown in Figure 7. What is the most likely diagnosis?

Explanation

DISCUSSION: The MRI scan reveals a large chronic rotator cuff tear with retraction and fatty infiltration atrophy of the supraspinatus and infraspinatus tendons. This tear is responsible for the patient’s severe weakness and inability to elevate the arm.
REFERENCE: Gerber C, Myer DC, Schneeberger AG, et al: Effect of tendon release and delayed repair on the structure of the muscles of the rotator cuff: An experimental study in sheep. J Bone Joint Surg Am 2004;86:1973-1982.

Question 15

Which of the following treatments of polyethylene results in the highest amount of oxidative degradation?

Explanation

DISCUSSION: Oxidative degradation of polyethylene occurs as a function of time in an air environment. In an environment such as argon, nitrogen, or a vacuum, the process is reduced. Ethylene oxide is an alternative for sterilization in which the cross-link degradation is minimized because of the absence of oxidative interactions. Gamma sterilization or use of ethylene oxide gas is the industry standard; however, oxygen concentrations are now reduced to a minimal level to retard the oxidation phenomenon.
REFERENCES: Sanford WM, Saum KA: Accelerated oxidative aging testing of UHMWPE. Trans Orthop Res Soc 1995;20:119.
Sun DC, Schmidig G. Stark C, et al: On the origins of a subsurface oxidation maximum and its relationship to the performance of UHMWPE implants. Trans Soc Biomater 1995;18:362.
Callaghan JJ, Dennis DA, Paprosky WA, Rosenberg AG (eds): Orthopaedic Knowledge Update: Hip and Knee Reconstruction. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1995, pp 35-41.
McKellup HA: Bearing surfaces in total hip replacement: State of the art and future developments. Instr Course Lect 2001;50:165-179.

Question 16

A 70-year-old man with primary osteoarthritis undergoes a primary cementless total hip arthroplasty (THA). His history includes pelvis irradiation for prostate carcinoma (6000 rads). He is at increased risk for which complication?

Explanation

DISCUSSION
The complication associated with pelvic radiation prior to cementless THA is loosening of the acetabular component or postsurgical noningrowth of the component. Although scarring from radiation may put the hip at increased risk for arterial or nerve damage or infection, this risk has not been associated with pelvic radiation. Cementless acetabular components with porous metal surfaces such as trabecular metal should be considered.

Question 17

A 62-year-old woman with a bone mass density (BMD) T-score of -2.0 sustained a subcapital fracture of her hip. She is an avid tennis player, and history reveals no previous fractures. What is the most appropriate follow-up care?

Explanation

DISCUSSION: A DEXA scan is most appropriately used to establish a baseline score. Even if the bone mineral density is not within the osteoporotic range (T-score less than -2.5), a prior fragility fracture is a strong risk factor for a second fracture as a result of factors other than bone density, such as worsening vision or balance, confusion, or other predispositions to falls. The guidelines of the National Osteoporosis Foundation indicate that, following a fragility hip fracture, active anti-osteoporotic medication should be initiated, whether or not a DEXA scan is performed. A recent study showed that antiresorptive therapy following a hip fracture reduces not only the risk of a second fracture but also overall mortality.
REFERENCE: Gardner MJ, Brophy RH, Demetrakopoulos D, et al: Interventions to improve osteoporosis treatment following hip fracture: A prospective, randomized trial. J Bone Joint Surg Am 2005;87:3-7.

Question 18

They used three outcome tools, SF-36, WOMAC, and Modified Boston Children's Hospital Grading System to evaluate the the two groups at a minimum of 2 years from injury. The foot injury group, including all types of foot fractures, had a poor outcome when using any of these measures. Turchin concludes that “Foot injuries cause significant disability to multiply injured patients. More attention should be given to these injuries, and more

Explanation

This patient with hemophilia A is presenting with an intramuscular hematoma surrounding the iliacus muscle which is likely to cause femoral nerve compression. Paresthesias would be expected in the L4 nerve distribution.
Excessive bleeding into joints and muscles is a common manifestation of hemophilia. The iliacus muscle is a frequent site of hemorrhage in patients with severe or moderate hemophilia. Intramuscular hematoma of the iliacus muscle is likely to occur following play or sporting events that include forceful contraction of the hip flexor muscles. As the hematoma expands, it may
compress the adjacent femoral nerve, potentially resulting in complete femoral nerve palsy. Femoral nerve compression typically includes paresthesias in the distribution of the terminal saphenous nerve branch.
Gilbert et al. review the complex relationship between recurrent bleeding, synovitis, and the development of arthritis in the patient with hemophilia. They discuss both conservative and surgical treatment modalities in these patients and recommend arthroscopic synovectomy for the knee and ankle joints. They conclude that the greatest risk to these procedures is a decreased range of motion.
Kuo et al. reports on a fourteen-year-old healthy boy with an 11-day history of pain and weakness in the right lower limb following a fall. They report pain in the right lower extremity, numbness of the anterior aspect of the right thigh and medial border of the right leg and foot, inability to ambulate and
weakened quadriceps muscle strength. MRI revealed an iliacus hematoma with a complete femoral nerve palsy. He underwent CT-guided percutaneous drainage for decompression with complete resolution of the palsy.
Illustration A is a diagram of dermatomal distribution. Illustration B shows the lumbar plexus demonstrating the intimate relationship of the femoral nerve to the iliacus muscle.
Incorrect Answers:
A 45-year-old male trauma patient presents with multiple extremity injuries including the foot injury shown in Figure A. The foot fracture is treated surgically, and heals without any initial complications. At a minimum of 12 months, this patient will be expected to have which of the following scores compared to a
Patients with pauciarticular juvenile rheumatoid arthritis (JRA), specifically the subgroup with elevated antinuclear antibody (ANA) titers, are associated with the highest incidence (~75%) of anterior uveitis. As a result, referral for an ophthalmology consultation is recommended.
Pauciarticular JRA is the most common subgroup of JRA and typically presents between the ages of 2 to 4 years with mild swelling of one to four joints. The diagnosis is typically one of exclusion as laboratory studies, including erythrocyte sedimentation rate and rheumatoid factor, are usually within normal limits. In JRA, iridocyclitis, a type of anterior uveitis typically occurs following the onset of synovitis but may precede the joint symptoms. This iridocyclitis is frequently indolent but requires immediate ophthalmologic consultation for a slit-lamp examination because if left untreated, anterior uveitis may progress to loss of vision.
Foeldavri et al. review JRA anterior uveitis. They report an overall incidence of
10%, but this is dependent on the JRA subtype. They noted that a large proportion of children with JRA develop uveitis in the first year of disease and
90% after 4 years. They state that early age of JRA onset, oligoarticular subtype, and ANA reactivity are the main risk factors for the development of uveitis. They conclude that JRA-associated uveitis is important to recognize and treat early to prevent any visual damage.
Hawkins et al. review bilateral chronic anterior uveitis in JRA. They report that female gender, oligoarthritis, and presence of antinuclear antibodies are risk factors.
They report on treatment options, including the use of biologics. They conclude that stepwise immunomodulatory therapy is indicated, with new biologic drugs being used in cases of refractory uveitis.
Incorrect Answers:
Anterior 4: Pompe disease is a glycogen storage disease which may lead to ptosis (drooping of the upper eyelid), not anterior uveitis
A 9-year-old male with hemophilia A presents with severe groin pain, parasthesias over the medial aspect of the distal tibia, and difficulty ambulating several hours after a soccer game. He is believed to have an intramuscular hematoma surrounding the iliacus muscle. Which nerve is MOST likely to be compressed?
Which of the following conditions places the patient at highest risk for anterior uveitis and necessitates referral to an ophthalmologist?
Salmonella is a classic cause of osteomyelitis in patients with sickle cell disease.
Sickle cell disease is a genetic disorder of hemoglobin synthesis. The disease occurs in two phenotypes: sickle cell anemia (most severe) and sickle cell trait (most common). The two most common causes of osteomyelitis in children with sickle cell disease are
Staphylococcus aureus and Salmonella. Although S. aureus is the most common cause of osteomyelitis in the general population, the literature varies on which is the most common in patients with sickle cell disease. The increased risk in these patients may be associated with gastrointestinal microinfarcts, poor circulation of blood in bone, and splenic infarcts that predispose patients to infection by encapsulated bacteria (i.e., Salmonella).
Piehl et al. analyzed records of seven hundred seventeen patients with sickle cell disease treated over a thirteen-year period. They identified and retrospectively reviewed sixteen cases of osteomyelitis in fifteen patients. The authors found Salmonella to be the causative organism in thirteen cases with Proteus mirabilis, Escherichia coli, and Staphylococcus aureus all affecting one patient each. The authors report the annual incidence of osteomyelitis in their series as 0.36%.
Givner et al. reviewed sixty-eight cases of osteomyelitis in children with sickle cell disease and positive cultures over a ten year period. Of the sixty-eight, 50 (75%) yielded Salmonella and Staphylococci was isolated 7 (10%). In
addition, the authors report non-speciated gram-positive cocci were isolated in
11 (16%), non-speciated gram-negative rods in 5 (7%), and non-specified bacteria in 2 (3%). The authors conclude Salmonella is the most common pathogen causing osteomyelitis in patients with major sickle hemoglobinopathies.
Epps et al. reviewed fifteen patients with sickle cell disease and osteomyelitis. Staphylococcus aureus was isolated in eight cases (53%), Salmonella in six (40%), and Proteus mirabilis in one (7%). The authors conclude S. aureus, not Salmonella, may be the most common cause of osteomyelitis associated in patients with sickle-cell disease.
Figure A demonstrates an osteolytic lesion of the distal tibia and Figure F demonstrates sickle-shaped erythrocytes.
Incorrect Answers
Low toughness is a disadvantage of ceramic bearings in total hip arthroplasty.
Ceramic is a non-metal that demonstrates excellent wear characteristics when used with polyethylene in total hip arthroplasty. Although it has a high Young's modulus, it has a low fracture toughness. Subsequently, ceramic is poorly resistant to crack formation. In contrast, UHMWPE has a high fracture toughness because of the presence of very long hydrocarbon chains.
Santavirta et al. review alternative bearing materials to improve wear in total hip arthroplasty. Alumina ceramics are noted to be biostable and bioinert. The best wear properties are noted with ceramic-on-ceramic bearings. For current ceramic constructs, fracture risk is less than 1 per 1000.
Lang et al. review the use of ceramics in total hip replacement. The authors note that ceramic has high compressive strength and high wettability. Low fracture toughness and linear elastic behavior increase the risk of breakage of ceramic components under stress. Processing improvements, enhanced head- neck interfaces and liner modifications have lead to a decrease in the rate of ceramic fracture.
Illustration A shows a compromised ceramic head as a manifestation of the low fracture toughness of the material.
Incorrect Answers:
An 8-year-old African American female presents with lower extremity pain and subjective fever. On exam there is tenderness about the distal tibia. Further workup reveals elevated inflammatory markers and a lytic lesion (Figure A). An aspirate is obtained and cultures grow Salmonella. Additional investigation is most likely to reveal which of the following findings (Figure B-F)?
An ideal fluid film lubrication regime minimizes friction. A larger head size results in a greater development of full-film lubrication due to the increased relative sliding velocity of the larger bearing surfaces. Increased surface roughness inhibits the formation of the film lubrication. The most important factor influencing the predicted lubrication film thickness
has been found to be the radial clearance between the ball and the socket.
Jin et al report that slight clearance, not complete congruence, is optimal for formation of the optimal fluid film lubrication. They note that full fluid film lubrication may be achieved in these hard/hard bearings provided that the surface finish of the bearing surface and the radial clearance are chosen correctly and maintained.
Dumbleton reviewed the literature of metal-on-metal THA and concluded that the current literature does not show any clinical benefit of metal-on-metal compared to metal on poly. Metal-on-metal has been shown to have higher metal ion level in blood, and measurement of these levels is recommended to help identify those at risk of adverse effects from metal on metal prostheses.
Low toughness is a disadvantage of which of the following bearing surfaces used in total hip arthroplasty?
This attending did not fully disclose that the resident would be performing the cementing portions of the case unsupervised. This represents an ethically unsound scenario as the patient was misled regarding involvement of the resident in their surgery.
The informed consent process is grounded in the ethical principle of autonomy. Informed consent represents a shared decision making process where a
patient understands all the risks and benefits of a surgery fully and makes an informed decision. However, the patient's choice of surgeon is felt to be critical
to the informed consent process and any variation from that surgeon performing the surgery should be discussed explicitly. A surgeon who performs surgery or part of surgery on the patient without prior consent may be held liable for battery.
Kocher presents three cases demonstrating the spectrum of "ghost surgery". They state the substitution of an authorized surgeon with an unauthorized surgeon or allowing surgical trainees to operate without appropriate guidance constitutes "ghost surgery".
Deviation from what is explicitly discussed has been justified in an emergency scenario or if the treatment is aimed at an overall condition.
Bhattacharyya et al reviewed malpractice claims for factors that positively correlated with successful defense. They found that those who performed informed consent in the office had lower risk of malpractice payment. They conclude surgeons can decrease their risk of malpractice claims by performing informed consent in the office and documenting the discussion.
Incorrect Answers:
Which of the following features of metal-on-metal total hip arthroplasty does not allow for improved fluid film lubrication between the components?
The patient sustained a fragility fracture with lab work consistent with primary hyperparathyroidism.
Hyperparathyroidism is commonly caused by increased activity of the parathyroid glands resulting in high levels of PTH. Increased circulating levels of PTH leads to calcium being "sucked" out of bone and into the serum. This
alteration in calcium hemostasis leads to low-density bone and a predisposition to fragility type fractures. When present, lab values are much different from standard age-related osteoporosis. Furthermore, referral to medical and surgical endocrinology specialists for directed treatments may improve overall bone quality and prevent further fragility fractures.
Fraser summarizes primary and secondary hyperparathyroidism. He describes the normal physiologic response to low calcium of an increase in PTH. Increased PTH has three downstream effects of increased tubular resorption of calcium by the kidneys, increased osteoclast activity to harvest calcium from bone, and increased active vitamin D levels leading to increased bowel absorption of calcium.
Singhal et al. reviewed hyperparathyroidism and what the orthopedic surgeon should know. They state when a patient presents with a pathologic fracture and elevated serum calcium levels, an appropriate lab workup for hyperparathyroidism should be done. They stated when surgery is needed for hyperparathyroidism and fracture, surgery can safely be performed simultaneously as demonstrated by 3 case examples.
Figure A exhibits a left femoral neck fracture, which is a fragility fracture associated with poor bone density. Illustration A is a figure from Fraser's article exhibiting the
feedback loop from the hypothalamus, pituitary, adrenal/glandular axis.
Incorrect answers:
Prior to undergoing a total knee arthroplasty at an academic medical center a patient is told during informed consent by the attending surgeon that resident involvement in the case will be limited to retracting. During the case the attending is present up to trialing of the selected components. The surgeon leaves prior to cementing to start trialing components in another case while the chief resident remains alone in the room for the completion of the case. Which of the following is true regarding the ethics of this practice?
Patients in factorial randomized control trials (RCT) are assigned to groups that receive a specific combination of interventions and non-interventions.
In factorial RCTs, patients are randomized to groups receiving treatment A and B, treatment A or control, treatment B or control, or no treatment. This study design is useful because two interventions can be assessed with the same
study population and any interaction between the treatments can be determined (for example, does treatment A work differentially when combined with treatment B). Other randomized control trial designs include parallel, cluster, and crossover. Parallel studies are performed by having two or more groups that exclusively have one intervention without group overlap.
Crossover studies have each group receive each intervention in a random sequence. Cluster design studies have pre-existing groups of participants
(such as schools, or cities) that are randomly selected to receive or not receive an intervention.
Karlsson and the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine published an exhaustive guide to research for evidence-based medicine in a step-wise fashion. They cover levels of evidence, design for randomized control trials and the CONSORT checklist. They also describe proper study design of cohort, case- control, case series, systematic review, meta-analysis studies. The second half of the guide discusses appropriate outcome measures, statistical analyses, and data interpretation, reporting complications, and concludes with steps to writing a scientific article.
Incorrect Answers:
A 66-year-old woman falls from standing and sustains the injury shown in Figure A. Her most recent T score was -1.9, 3 months prior to presentation. Preoperative lab work reveals elevated serum calcium, elevated alkaline phosphatase, decreased serum phosphorus, and elevated parathyroid hormone (PTH). Which of the following correctly describes the underlying etiology of her osteopenia?
The most recent update of the CDC guidelines for the prevention of SSI issues a category IA strong recommendation stating that "in clean and clean- contaminated procedures, do not administer additional antimicrobial prophylaxis doses after the surgical incision is closed in the operating room, even in the presence of a drain."
The previous 2002 CDC guidelines for the prevention of SSI focused on three performance parameters: (1) initiation of parenteral antibiotics within 1 hour of the surgical incision, (2) selection of an appropriate antibiotic, and (3) discontinuation of antibiotics within 24 hours. The most recent updated 2017
CDC guidelines for the prevention of SSI has several notable changes with an emphasis that additional doses of antibiotics after initial prophylaxis are no longer recommended.
Berrios-Torres et al. review the 2017 updates to the CDC guidelines for prophylaxis against SSI. Strong recommendations include that in clean and clean-contaminated cases, additional antimicrobial prophylaxis should not be administered after the surgical incision is closed in the operating room, even in the presence of a drain. Furthermore, the authors discuss that there is no evidence that re-dosing intraoperative antibiotics or continuation of antibiotics until surgical drains have been removed provides any additional protection against surgical site infection.
O'Hara et al. highlights the key updates in the most recent CDC guidelines for prevention of SSI. The authors present specific suggestions for translating these recommendations into evidence-based policies and practices. They conclude that the implementation of new and existing guidelines in SSI prevention requires thoughtful and careful collaboration with several inter- professional and interdisciplinary teams.
Incorrect Answers:
Which of the following study designs describes a randomized controlled trial in which two interventions are applied separately or in combination to study groups?
The patient has an allergy to cephalosporins and a history of an MRSA infection. Of the choices listed, vancomycin is the best preoperative antibiotic for this patient.
The choice of preoperative antibiotics is of great interest given the large
medical and economic cost of periprosthetic infections. Standard preoperative prophylaxis in patients undergoing total joint arthroplasty consists of cefazolin or cefuroxime. In patients with beta-lactam allergies, the treatment options include clindamycin or vancomycin. Vancomycin is often the antibiotic of choice given it's higher efficacy with regard to MRSA prevention. In those patients who are considered at risk for MRSA infection and a beta-lactam allergy, vancomycin can be supplemented with an aminoglycoside (gentamicin) or aztreonam.
Bratzler et al. review antimicrobial prophylaxis for surgery and state for orthopedic joint replacement procedures cefazolin or cefuroxime is the recommended antibiotic. For patients with a confirmed beta-lactam allergy, they recommend vancomycin or clindamycin. They also state antibiotics should be stopped within 24hrs after surgery.
Dellinger et al. review antibiotics for surgical prophylaxis. They state the standard antibiotics for orthopedic procedures are cefazolin or cefuroxime. They state if there is also a concern for MRSA infection vancomycin can be added in addition to the above antibiotics.
Incorrect Answers:
Which of the following is STRONGLY recommended by the most recent (2017) Centers for Disease Control and Prevention (CDC) Guidelines with regard to antimicrobial prophylaxis for the prevention of surgical site infection (SSI)?
Clindamycin is a bacterial protein synthesis inhibitor by inhibiting ribosomal translocation at the 50S subunit.
Clindamycin is primarily bacteriostatic but may be bactericidal at higher concentrations.
Side effects of clindamycin may include a hypersensitivity reaction and pseudomembranous colitis. Resistance to clindamycin is conferred by a plasmid that alters the 50s ribosome binding site for clindamycin. The D- zone test is used to determine whether an organism has inducible resistance
to clindamycin.
Marcotte and Trzeciak published a review on community-acquired methicillin- resistant Staphylococcus aureus (CA-MRSA). They reported that CA-MRSA
does not have predictable susceptibility to clindamycin. They conclude that clindamycin also presents a risk for the development of Clostridium difficile colitis and inducible clindamycin resistance for which a D-zone test should be performed when culture results reveal erythromycin resistance.
Steward et al. performed a lab study to determine the efficacy of testing for induced clindamycin resistance in erythromycin-resistant Staphylococcus aureus. They reported that resistance to erythromycin and clindamycin can occur through methylation of their ribosomal target site (50s), which is mediated by erm genes. They conclude that disk diffusion is the preferred method for testing S. aureus isolates for inducible clindamycin resistance.
Incorrect Answers:
A 68-year-old man is scheduled to undergo total hip arthroplasty. He states he had an anaphylactic reaction after taking cefazolin for an MRSA hand infection 10 years ago. Which of the following best describes the preoperative antibiotic that should be administered for this patient?
Advanced glycation end-products (AGEs) cause excessive cross-linking of collagen in aging articular cartilage. As a result, the stiffness is increased.
AGEs are produced by spontaneous nonenzymatic glycation of proteins when sugars (glucose, fructose, ribose) react with lysine or arginine residues. The most abundant matrix protein in cartilage is Type II collagen. AGEs cause changes to the aging cartilage matrix and the aging chondrocyte. The increased cross-linking of Type II collagen results in an increase in cartilage stiffness (i.e. increase in the modulus of elasticity) and an increase in brittleness (i.e. less strain needed to go from the yield point to the fracture point on the stress-strain curve). As a result of the change in the aging cartilage’s biomechanical properties, it's susceptible to fatigue failure. Additionally, AGEs decrease the anabolic response of chondrocytes from autocrine signaling via TGF-beta, IGF-1, BMP-7, and OP-1. These two initial mechanisms contribute to aging cartilage to eventually lead to the development of osteoarthritis.
Li et al. reviewed age-related changes in cartilage and seek to define the different
mechanisms between aging cartilage and osteoarthritis. They state that with AGEs, there is excessive collagen cross-linking increases cartilage stiffness, while shortening/degradation of aggrecan leads to loss of sugar side chains and water-binding ability. Additionally, increased levels of AGEs are associated with a decline in anabolic activity. They state that these changes to cartilage make it more vulnerable to damage and therefore the onset of osteoarthritis. This is contrast to the initial steps in the mechanism of osteoarthritis which is characterized by cell proliferation, formation of chondrocyte clusters, increased synthesis of irregular cartilage matrix, and eventually a pro-catabolic and pro-inflammatory state that results in an imbalance in cartilage homeostasis and cartilage matrix breakdown.
Anderson et al. reviewed the relationship between osteoarthritis and aging.
They state that knee cartilage thins with aging, especially on the femoral and patellar sides, suggesting a gradual loss of cartilage matrix. AGEs formation leads to modification of type II collagen by cross-linking of collagen molecules, increasing stiffness and brittleness and increasing susceptibility to fatigue failure. Furthermore, describe the senescent phenotype of the chondrocyte
and its similarities with osteoarthritic chondrocyte phenotype.
Incorrect Answers:
Which of the following antibiotics works by binding to the 50S ribosomal subunit?
The patient has clinical signs and symptoms of gout. Figure D would correspond to this diagnosis as it shows negatively birefringent needle-shaped monosodium urate crystals.
Gout is an idiopathic disorder of nucleic acid metabolism that leads to hyperuricemia and deposition of monosodium urate crystals, most commonly in the joints of the lower limb (knee, ankle, and classically the 1st metatarsophalangeal joint). Diagnosis can be confirmed with joint arthrocentesis revealing negatively birefringent needle-shaped crystals. Treatment of acute gout flares is generally comprised of NSAIDs and colchicine, and chronic gout is treated with allopurinol to prevent the build-up
of uric acid.
Shmerling et al. prospectively analyzed the synovial fluid test results of 100 consecutive patients undergoing diagnostic arthrocentesis. They noted that synovial fluid white blood cell count (WBC) and the percentage of polymorphonuclear cells performed well as discriminators between inflammatory and noninflammatory diseases. Given the diagnostic value of synovial WBCs, the authors concluded that ordering of chemistry studies of synovial fluid should be discouraged because they are likely to provide misleading or redundant information.
Chiodo et al. review the use of intra-articular aspiration and injections for both diagnosis and treatment of disorders of the lower extremity such as infectious arthritis, gout, pigmented villonodular synovitis (PVNS), rheumatoid arthritis, and hemophilia. The authors discuss the importance of knowledge of regional anatomy, procedural indications, and appropriate techniques for successful aspiration/injection. The authors review safe and effective aspiration and injection techniques for the lower extremity, including the hip, knee, foot, and ankle.
Figure A reveals hemosiderin stained multinucleated giant cells consistent with PVNS. Figure B is a gram stain revealing gram-positive cocci in clusters consistent with Staphylococcus aureus. Figure C reveals rhomboid-shaped, positively birefrigerant crystal consistent with calcium pyrophosphate/pseudogout. Figure D reveals negatively birefringent needle- shaped crystals of monosodium urate/gout. Figure E reveals a collection of histiocytes and inflammatory cells around prominent intimal hyperplasia.
Incorrect Answers
An increase in advanced glycation end-products (AGEs) is characteristic of which of the following clinical conditions and results in which pathologic process?
Regardless of the number of level I studies included in a systematic review, having one study with <80% follow-up decreases the level of evidence for this review from level I to level II.
After classifying the type of study (e.g. therapeutic study, prognostic study, diagnostic study, economic analysis, or decision analysis) the “level of evidence” is then determined. The level of evidence (on a scale of I through V) for medical research is determined. It is important to consider the characteristics of a study’s design. This would include the percent follow-up, utilization of a control group, presence of blinding, heterogeneity of results, and process of randomization. Specific to meta-analyses and systematic reviews, it is important to know that the lowest quality study used in the review determines the level of evidence. In evidence-based medicine, higher levels of evidence have a larger impact on clinical recommendations.
Bhandari et al. analyzed the interobserver agreement among reviewers in categorizing the type of study, level of evidence, and subclassification for different clinical studies. The authors had 6 different surgeons with different levels of training in epidemiology analyzed 51 separate papers published in JBJS. The results demonstrated that the interobserver absolute agreement for the type of study and the level evidence was 82% and 67%, respectively. The epidemiology-trained reviewers had nearly perfect agreement in categorizing the type of study, level of evidence, and subclassification.
Wright et al. published an editorial introducing the different types of study designs and defined the different levels of evidence. Illustration A is a figure from this editorial.
Incorrect Answers:
A 55-year-old male, alcoholic, presents to the ER with acute right knee swelling and pain x 3 days. He admits to prior episodes of this pain that resolve after a few days. Serum labs reveal an ESR of 40 mm/hr and CRP of 5 mg/dl. He undergoes right knee aspiration and based on the results, he is discharged home on colchicine with the presumed diagnosis of gout. Which of the following images of the aspiration results are consistent with this diagnosis?
conclude that the patient populations and outcomes measure are homogenous and you do not have any concerns with randomization. You notice one of
the studies included had 70% follow-up, yet the remaining studies had
>80% follow-up. Knowing this, you appropriately assign what level of evidence to the systematic review?
The correct sequence of events should be the surgeon reads the surgical information on the consent to the patient, then the surgeon marks the surgical site with the patient’s assistance, then allows the anesthesia team to perform their procedure, and then performs a final Time-Out with the surgical team immediately prior to the surgical incision.
Orthopedic surgical patients are at risk of surgical errors due the number of procedures that can be performed on the bilateral extremities. The responsibility to identify the correct surgical procedure at the correct location has expanded beyond only the surgeon. The entire surgical team is
responsible for confirming the patient, surgical site, and surgical procedure. All members on the surgical team should be valued and emboldened to “speak up’ and actively participate. To help improve communication and reduce complications, surgical safety checklists have become common. In a statement
published by the AAOS is 2015, they support the use of standardized surgical systems, including the use checklists, as it is critically important to keep patients safe. In 1998, the AAOS introduced the “Sign Your Site” safety program to reduce wrong-site surgeries through improved site identification. Permanent ink should be used to mark the site(s) with the patient's assistance prior to surgery, and the site(s) should be confirmed by the surgical team during the Time-Out immediately before the start of the surgical procedure.
Singer et al. performed a study to evaluate the association between surgical teamwork and surgery safety checklist performance. Their results emphasized the importance of surgeon buy-in and clinical leadership to initiating and maintaining surgical safety checklists. In addition to surgeon buy-in and clinical leadership, factors that help maintain high-quality and consistent surgical teamwork were communication, coordination, respect, and assertiveness.
Incorrect Answers:
You are reviewing a systematic review on the 90-day complication rate and outcome for same day total joint arthroplasty for publication. After you analyze the methodology of the 6 randomized controlled trials included in the review, you
preoperative paperwork outside the room. The patient is taken to surgery and receives an interscalene block on the left shoulder after sedation. At the final Time- Out, the surgeon realizes a discrepancy with the laterality when the consent is read aloud. The surgeon aborts the case and wakes the patient. What is the correct sequence of events that should have happened to prevent this error? A: The surgeon begins
the surgery B: The surgical team performs a Time-Out C: The surgeon marks the surgical site D: The surgeon reads the surgical information on the consent to the patient E: The anesthesia team administers a local extremity block
Enchondral ossification occurs with relative stability constructs, which is represented by the bridge plate in figure C.
Fracture healing is a complex process that occurs in several key steps. The type of healing that occurs is dependent on the stability and strain of the fracture environment. In constructs with very little strain, also referred to as absolute stability, there is primary bone healing through Haversian remodeling. This produces very little callus and does not rely on a cartilage precursor. Relative stability constructs with higher strains produce a cartilage precursor, which subsequently ossifies in later stages of healing, also referred to as enchondral ossification.
Perren reviewed the biological mechanisms of fracture healing. The author discussed the importance of skeletal stiffness for limb function in addition to the healing process that utilizes soft tissue compensatory mechanisms to aid
in fracture healing. The author concluded that the goal of fracture healing is to obtain a functional limb to allow for daily mobility and activity.
Gerstenfeld et al. investigated the effect of non-selective and COX-2 selective NSAIDs effects on bone healing in a rat model. They reported a significantly higher nonunion rate in valdecoxib treated rats compared to the ketorolac group. They also noted that withdrawal of either drug at six days resulted in prostaglandin E2 levels returning to normal levels after 14 days. The authors concluded that COX-2 specific NSAIDs inhibited bone healing greater than nonspecific NSAIDs with the magnitude of the effect dependent on the duration of treatment, but the effects on prostaglandin E2 levels appear reversible with discontinuation of the drug.
Figure A is the AP radiograph of the left distal tibia with three lag screws through a spiral fracture. Figure B is the lateral radiograph of the right elbow with an olecranon plate.
Figure C is the AP radiograph of the right distal femur with a lateral bridge plate. Figure D is an AP radiograph of the left ankle with a lag screw and neutralization plate on the distal fibula. Figure E is the lateral radiograph of the forearm with a compression plate on the radius.
Incorrect Answers:
A 31-year-old man is scheduled to undergo a right shoulder arthroscopic labral repair. The surgeon is running behind and hurries to the preoperative holding area. The surgeon greets the patient and verbally confirms the operative site with the patient. The surgeon leaves the patient’s room and completes the appropriate
The yield point is the transition point between elastic and plastic deformation. The yield strength is defined as the amount of stress necessary to produce a specific amount of permanent deformation.
Stress is the amount of force applied to a material and strain is the deformation resulting
from that stress. This is graphically depicted as a stress- strain curve, where the X-axis represents strain and the Y-axis represents stress. The elastic modulus of a material is the linear region of the graph (rise over run/stress on strain). Remember, an elastic material is one that resists a change in shape (less strain or deformation under increasing stress). Non- linear regions include the toe region for some materials (tendons/ligaments) and the plastic zone, which occurs after the yield point.
Mantripragada et al. provide a review of recent advances in designing orthopaedic implants. Of note, they discuss modifications to metallic implants to reduce unwanted effects, such as nickel-free stainless steel. They also go over newer alloys with desirable mechanical and biological properties, such as tantalum, niobium, zirconium, and magnesium.
Kennedy et al. provide a classic in-vitro tension study of the human knee ligaments. They used an Instron Tension Analyzer to test the ultimate failure of the medial collateral, lateral collateral, anterior cruciate, and posterior cruciate ligaments at different loading rates. They found that the posterior cruciate ligament was the strongest (the other ligaments were all of
comparable strength) and that microscopic failure occurred before macroscopic failure. Illustration A represents a stress-strain curve.
Incorrect Answers:
is a phenomenon especially associated with a ductile material; the diameter of the material is diminished prior to fracture.
material can absorb before fracture and is the area under the stress-strain curve. Answer 5: The toe region is seen in materials such as ligaments and tendons and represents the straightening of the crimped ligament fibers.
Which of the following fixation constructs would achieve fracture healing through enchondral ossification?
The preosteoclast (precursor to the osteoclast) is the only cell of myeloid origin. The remainder of the cells involved in bone formation, remodeling, and metabolism are of mesenchymal origin.
Osteoclast signaling, function, and biology have grown increasingly well understood over the past few decades. Osteoclast activity is regulated by
osteoblasts, thereby coupling bone formation and resorption. Osteoclast differentiation from myeloid precursor cells is stimulated by key molecules including RANK, PU-1, and CSF-1. An understanding of these molecular pathways is essential to developing effective directed anti-resorptive therapies.
Zaidi et al. present a comprehensive review of proliferation, differentiation, and hormonal regulation of cells of the bone. The authors specifically discuss the unique origin of the osteoclast from the myeloid lineage and conversely the mesenchymal origin of the osteoblast. Furthermore, they highlight the
most recent understanding of the molecular mechanisms involved in osteoclast formation
and signaling, including M-CSF and RANKL.
Caterson et al. discusses mesenchymal differentiation in the context of musculoskeletal regeneration. The authors review the growth factors and bioactive signaling molecules involved in directed differentiation itno the various mesodermal lineages including bone, cartilage, muscle, tendon, marrow, and adipose. They emphasize the importance of understanding these pathways to regenerative medicine.
Illustration A is a diagram illustrating the difference between mesenchymal and myeloid lineages.
Incorrect answers:
The point on a stress-strain curve that separates the plastic and elastic regions is defined as which of the following:
Due to the risk of inducible clindamycin resistance in erythromycin-resistant MRSA, a D-test should be performed.
Isolates of MRSA that are resistant to erythromycin have been shown to become resistant to clindamycin through a process called inducible resistance, which is conferred by a plasmid that alters the 50S ribosome binding site for both clindamycin and erythromycin. Thus, when culture results reveal erythromycin-resistant MRSA, a D-zone test should be performed to check for inducible clindamycin resistance. The D-zone test is performed by
placing an erythromycin disk in proximity to a clindamycin disk on an agar plate inoculated with methicillin-resistant S aureus (MRSA). A zone of inhibition in the shape of the letter "D" is seen with an inducible strain and is considered a positive test. If the D- zone test is positive, then clindamycin should not be used because the strain of MRSA can become resistant to the treatment.
Marcotte et al. published a review on community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). They reported that clindamycin has activity against Streptococcus species, but it is not as predictable against CA- MRSA. Clindamycin also presents a risk for the development of Clostridium difficile colitis and inducible clindamycin resistance. for which a D-zone test should be performed when culture results reveal erythromycin resistance.
Steward et al. performed a study to determine the efficacy of testing for induced clindamycin resistance in erythromycin-resistant Staphylococcus aureus. They reported that resistance to erythromycin and clindamycin can occur through methylation of their ribosomal target site (25), which is typically mediated by erm genes. They found that disk diffusion is the preferred method for testing S. aureus isolates for inducible clindamycin resistance.
Illustration A is an image of a positive D-zone test, which indicates inducible clindamycin resistance.
Incorrect Answers:
Which of the following cells involved in bone metabolism derives from a myeloid origin?
Enoxaparin primarily exerts its effects by inhibiting Factor Xa, which is labeled C in Figure A.
Enoxaparin is a low molecular weight heparin (LMWH) that primarily exerts its effects by inhibiting Factor Xa. It achieves this by binding to antithrombin to form a complex that irreversibly inactivates clotting factor Xa. Enoxaparin has the advantage of not requiring laboratory monitoring and can be reversed with protamine sulfate. However, it is important to note that protamine sulfate is less effective in reversing enoxaparin compared to unfractionated heparin (UFH).
Hyers published a review on the past, present, and future management of venous thromboembolism. He found that, for the most part, LMWH and other newer anticoagulants have been shown to be superior to UFH in terms of the venographic endpoint. He also reports that several meta-analyses have demonstrated that LMWH offers superior benefit to UFH for VTE prevention in hip and knee surgery patients.
Tørholm et al. performed a study to determine outcomes of thromboprophylaxis using LMWH compared to placebo in elective hip surgery. They found that 9 (16%) patients in the treatment group and 19 (35%) in the placebo group developed deep venous thrombosis. The risk of thrombosis in the placebo group was increased with prolonged surgery and occurred more frequently during the first 4 postoperative days. They concluded that LMWH offers safe and easily administered thromboprophylaxis in total hip replacement.
Figure A is an image of the coagulation cascade. Illustration A is an image of the
coagulation cascade with the sites of action of the various anticoagulants labeled.
Incorrect Answers:
A 42-year-old IV drug user presents to the emergency department with a large abscess on his forearm. A bedside I&D is performed and he is started on broad-spectrum IV antibiotics. Initial results from his cultures demonstrate methicillin-resistant Staphlycoccus aureus (MRSA) that is also resistant to erythromycin. The team would like to transition him to oral clindamycin. Prior to transitioning him to clindamycin, which additional laboratory test should be performed?
Teriparatide promotes bone formation in patients at high risk of fractures due to severe osteoporosis that is refractory to multiple treatments, including bisphosphonates and cement augmentation. Teriparatide is a human recombinant N-terminal parathyroid hormone.
Teriparatide administered in daily injections results in bony formation, whereas continuous infusion results in bony resorption. In rat models, teriparatide caused an increase in the incidence of osteosarcoma, and thus should only be prescribed for patients for whom the potential benefits outweigh the potential risk. It can be administered in isolation or as an adjunct treatment during bisphosphonate therapy. However, in patients on long-term bisphosphonate therapy, discontinuation of bisphosphonates are advised to reduce potential complications of atypical femur fractures and jaw osteonecrosis.
Watts et al. published a review article on postmenopausal osteoporosis. They reported that bisphosphonates can accumulate in bone, thus after a period of treatment, lower- risk patients should be offered a drug holiday. Denosumab, on the other hand, is not sustained when treatment is discontinued, so no drug holiday is warranted. They concluded that, although there are safety
concerns regarding atypical femoral fracture and osteonecrosis of the jaw with long term use, the benefit of hip fracture risk reduction far outweighs the risk of these relatively uncommon side effects.
Song et al. performed a meta-analysis to investigate the effect of teriparatide monotherapy and the additive effect of teriparatide on antiresorptive agents in postmenopausal women with osteoporosis. They reported that teriparatide monotherapy significantly improved bone mineral density (BMD) in the lumbar spine, total hip, and femoral neck compared with placebo; the additive effect
of teriparatide over hormone replacement therapy (HRT) and denosumab agents was evident in all 3 skeletal sites; however, teriparatide plus alendronate did not demonstrate additive effect in total hip and femoral neck. They concluded that, for patients with osteoporosis who were at high risk for fracture, BMD increased more in patients receiving teriparatide than in those receiving alendronate.
Saag et al. compared the use of teriparatide or alendronate in the management of glucocorticoid-induced osteoporosis. They reported that BMD had increased more in the teriparatide group than in the alendronate group in the lumbar spine and total hip at 6 and 12 months, respectively. They also reported significantly fewer new vertebral fractures in the teriparatide group compared to the alendronate group. They concluded that in severely osteoporotic patients at high risk for fracture, BMD increased more in patients receiving teriparatide than in those receiving alendronate.
Figure A depicts multiple vertebral insufficiency fractures in the setting of a prior cement augmentation procedure.
Incorrect Answers:
Where in the coagulation cascade shown in Figure A does enoxaparin primarily exert its effects?
This patient is presenting with signs of a septic nonunion after open reduction and internal fixation (ORIF) of a radial shaft fracture. Of the choices listed, C- reactive protein (CRP) is the best predictor of infection in the setting of nonunion.
Nonunions after fracture fixation may occur from infection. The most sensitive and readily-available laboratory marker to detect infection is the CRP. CRP is an acute phase reactant that significantly rises within 6 hours after tissue damage or onset of clinical infection. CRP then peaks 2-3 days later and returns to normal levels 5-21 days after the inciting event if it is treated (e.g. antibiotics for cellulitis). In septic nonunions, the chance of fracture healing is low if the infection is not properly treated, and chronic infection can lead to substantially elevated CRP values.
Wang et al. evaluated the effectiveness of laboratory tests in the diagnosis of
infected nonunion. They reported that the sensitivity and specificity of CRP for detection of infected nonunions are both higher than those of IL-6. They concluded that the diagnostic utility of CRP was superior to IL-6, which is contrary to similar studies comparing these markers in prosthetic joint infection patients.
Stucken et al. performed a study to investigate the utility of a standardized protocol to rule out infection in high-risk patients and to evaluate the efficacy of each component of the protocol. They reported that the ESR and the CRP levels were both independently accurate predictors of infection. They
concluded that their protocol can help surgeons to risk-stratify patients prior to the surgical treatment of a nonunion, allowing them to counsel patients more appropriately.
Figure A depicts a nonunion of a radial shaft fracture after ORIF. Incorrect Answers:
An 85-year-old woman presents with severe back pain and the CT shown in Figure A. Her history is notable for prior vertebral compression fractures for which she underwent a cement augmentation procedure. She has been on bisphosphonates for the last 5 years, without improvement of her osteoporosis. She has no history of malignancy. What is the mechanism of action of the medication that should be prescribed for her refractory osteoporosis?
A receiver operating characteristic (ROC) curve is used to determine responsiveness.
Responsiveness is a measure of the diagnostic ability of different tests. It can be determined by calculating the C-statistic, which represents the area under a
Receiver Operating Characteristic (ROC) curve. On a ROC curve, the false positive rate (1 - specificity) is plotted on the x-axis, while the true positive rate (sensitivity) is plotted on the y-axis. The higher the area under the curve, the more responsive the outcome measure. A value of 0.5 indicates a random chance and a therefore useless test, while values above 0.75 usually are considered to be adequately responsive.
Kocher et al. published a review on clinical epidemiology and biostatistics for orthopaedic surgeons. They reported that the relationship between the sensitivity and specificity of a diagnostic test can be portrayed with use of a receiver operating characteristic (ROC) curve. A ROC graph shows the relationship between the true- positive rate (sensitivity) on the y-axis and the false-positive rate (1 − specificity) on the x-axis plotted at each possible cutoff. Overall diagnostic performance can be evaluated on the basis of the area under the ROC curve.
Hanley et al. published a review on the meaning and use of the area under a receiver operating characteristic (ROC) curve. They reported that it represents the probability that a randomly chosen diseased subject is (correctly) rated or ranked with greater suspicion than a randomly chosen non-diseased subject.
Illustration A is an example of a ROC curve. Illustration B is an example of a funnel plot. Illustration C is an example of a Kaplan-Meier curve. Illustration D is a table outlining the interpretation of the Cronbach alpha coefficient. Illustration E is an example of a forest plot.
Incorrect Answers:
A 32-year-old man underwent open reduction and internal fixation for an open radial shaft fracture 6 months ago. He is now experiencing fevers and chills at night and pain and swelling over the surgical site. A current radiograph is depicted in Figure A. What is the most accurate laboratory test for assessing his most likely diagnosis?
The Patient-Reported Outcomes Measurement Information System (PROMIS) has been shown to have reduced floor and ceiling effects compared to other assessment tools.
The PROMIS system was developed to produce a highly reliable, precise, and versatile assessment of outcomes. When administered in a computerized adaptive mode, each question that is answered is followed with a customized follow-up question based on the previous response, which allows for reduced testing items and time. Further, the results of the assessment are reported in T-scores with 50 being the population norm and with a standard deviation of

Question 19

Figures 1 and 2 are the most recent radiographs of an 18-year-old high school student who sustains an anterior shoulder dislocation playing recreational football. He has a low Beighton score on physical examination. He was closed reduced and underwent a course of physical therapy but had a second dislocation playing recreational basketball. What is the most appropriate course of treatment, with the lowest complication rate, to prevent further dislocation?

Explanation

The patient has recurrent instability and is at a high rate of further dislocations due to his young age. Therefore, therapy and bracing are unlikely to decrease his dislocation rate. The radiographs are normal, and there is no Hill-Sachs lesion or bony Bankart lesion. His instability severity index score is 3, and; therefore, a bony procedure such as Latarjet is not necessary. Furthermore, the rate of complication following a Latarjet procedure, especially nerve
injury and hardware problems, exceeds that of arthroscopic Bankart repair.

Question 20

What is the most common presentation of a benign bone tumor in childhood?

Explanation

DISCUSSION: The most common benign bone tumors in childhood are discovered incidentally and include single bone cysts, fibrous cortical defects, nonossifying fibroma, and osteochondroma. Benign bone tumors can be classified as latent, active, or aggressive. Aggressive bone tumors usually present with pain, whereas active lesions present with pain or pathologic fracture. Only aggressive benign bone tumors are associated with a soft-tissue mass, and they are far less common than indolent bone tumors, especially in children.
REFERENCES: Aboulafia AJ, Kennon RE, Jelinek JS: Benign bone tumors of childhood. J Am Acad Orthop Surg 1999;7:377-388.
Biermann JS: Common benign lesions of bone in children and adolescents. J Pediatr Orthop 2002;22:268-273.

Question 21

5 mm of change in the atlanto-dens interval (ADI) between flexion and extension views

Explanation

The patient has been treated with agents for rheumatoid arthritis (RA) and is developing symptoms concerning for rheumatoid cervical spondylitis. All of the answers are indications for surgical intervention EXCEPT >3.5 mm change in ADI on flexion/extension views.
With the introductions of disease-modifying antirheumatic agents (DMARDs), the incidence of RA patients undergoing cervical spine surgery has decreased significantly. Basilar invagination, atlantoaxial instability, and subaxial subluxation are the three most common manifestations of cervical disease. Multiple studies in RA patients with untreated or poorly controlled disease have led to the development of a set of measurements that identify patients who require surgical intervention and predict outcome after surgery. Additionally, progressive neurological compromise and
refractory
pain
are
indications
for
intervention.
Kim and Hilibrand reviewed management of the rheumatoid cervical spine and outline parameters for surgical intervention. These include a PADI < 14 mm, cervicomedullary angle <135 degrees, progressive neurological deficit, refractory pain, atlantoaxial impaction as determined by migration >5 mm rostral to McGregor's line, and subaxial canal diameter < 14 mm.
Boden et al. analyzed 73 patients followed for rheumatoid cervical spine disease with an average follow up of 7 years. They found that the PADI correlated with paralysis. Patients with PADI less than 10 mm had no recovery, and all patients with PADI greater than 14 mm had full recovery.
Illustration A demonstrates the measurement of the ADI and PADI. Illustration B demonstrates how to measure the cervicomedullary angle (as marked by A), which is typically determined on MRI
Incorrect

Question 22

What are the four most common soft-tissue sarcomas to spread via the lymph node system?

Explanation

DISCUSSION: Soft-tissue sarcomas most frequently metastasize to the lung, but certain histologic types have a predilection for the lymph node system as well. Rhabdomyosarcoma, clear cell sarcoma, epithelioid sarcoma, and synovial sarcoma are four of the most common types to spread in this fashion. Careful evaluation and/or sentinel lymph node biopsy plays a role in disease staging and prognosis.
REFERENCES: Riad S, Griffin AM, Liberman B, et al: Lymph node metastasis in soft-tissue sarcoma in an extremity. Clin Orthop Relat Res 2004;426:129-134.
Blazer DG III, Sabel MS, Sondak VK: Is there a role for sentinel lymph node biopsy in the management of sarcoma? Surg Oncol 2003;12:201-206.

Question 23

Which of the following types of intra-articular pathology is associated with lateral meniscal cysts? Review Topic

Explanation

Lateral meniscal cysts often arise from myxoid degeneration that progresses from the meniscal center and then outside the meniscus. Horizontal cleavage tears are commonly associated with the condition. Cysts of the lateral meniscus are most commonly the consequence of a tear located in the medial third. If the tear communicates with the joint, arthroscopic partial meniscectomy and cyst decompression are indicated. If the tear does not open into the joint, arthroscopy should be followed by an open cystectomy.

Question 24

A 35-year-old active woman with rheumatoid arthritis experiences right shoulder pain following an extended course of corticosteroids (Figures 96a and 96b).

Explanation

DISCUSSION
The indication for anatomic TSA is end-stage glenohumeral arthritis with an intact rotator cuff. For the 62-year-old man, his radiographs reveal osteoarthritis, and his MR image shows an intact rotator cuff. Although humeral head replacement has historically been employed for this disorder, pain relief is not as reliable as with TSA, and the revision rate is higher. rTSA is generally reserved for patients with a nonfunctional rotator cuff.
For this 58-year-old patient with a full-thickness rotator cuff tear, preserved motion, and weakness in forward elevation, a rotator cuff repair is the most appropriate treatment. In the absence of degenerative changes, shoulder hemiarthroplasty or anatomic TSA is not indicated. Although indications for rTSA continue to evolve, well-compensated range of motion and a medium-sized rotator cuff tear in a younger patient are not among them.
rTSA is an emerging treatment for comminuted proximal humerus fractures in elderly patients. Although hemiarthroplasty has been a traditional treatment, current evidence suggests rTSA more reliably restores range of motion, and this 78-year-old patient's CT scan shows a small and comminuted greater tuberosity fragment that is unlikely to heal. ORIF is another option, but the CT scan also shows a small humeral head fragment that suggests osteopenia, making fixation more tenuous and likely less reliable.
A common problem associated with hemiarthroplasty for glenohumeral osteoarthritis is symptomatic glenoid degeneration that necessitates revision. This 55-year-old patient’s images reveal this is the case, although his infection workup is negative. His examination findings suggest an intact subscapularis repair. With a functioning rotator cuff and symptomatic glenoid arthritis, a conversion to anatomic TSA is indicated. In the absence of a functioning rotator cuff in an older patient, an rTSA is a better option.
This 72-year-old patient has classic symptoms and radiographs of cuff tear arthropathy. For patients with massive rotator cuff tear and glenohumeral arthritis, neither anatomic TSA nor rotator cuff repair is indicated. Hemiarthroplasty has historically been indicated for cuff tear arthropathy, but rTSA outcomes for this disorder have been superior and are now the preferred option.
Comminuted proximal humerus fractures in young, active patients are treated primarily with ORIF. The absence of glenohumeral arthritis removes anatomic TSA as a possibility, and concerns about implant longevity in younger, active patients such as this 40-year-old laborer contraindicate rTSA. Hemiarthroplasty is still employed in 3- and 4-part fractures but is generally reserved for subacute presentations or dislocations in which the humeral head is dysvascular and unlikely to survive. In this acute setting, a fixation procedure is preferred.
The 71-year-old patient who has had 2 failed rotator cuff repairs has an MR image that reveals another recurrent tear that is retracted to the glenoid. Her examination findings reveal classic signs
of a decompensated rotator cuff tear with pseudoparalysis and weakness in forward elevation. Although infection is a concern in the setting of multiply failed rotator cuff repair, the workup is negative in this scenario. Because this patient has a dysfunctional rotator cuff and has failed previous attempts at repair, a conversion to rTSA is the better option. In the absence of degenerative changes, hemiarthroplasty and anatomic TSA are not indicated.
The indications for hemiarthroplasty continue to narrow, but it is still a consideration for young patients with unipolar shoulder degeneration. In this 35-year-old patient, her MR image shows avascular necrosis in the humeral head, and her arthroscopy suggests arthritic change only on the humeral side with an uncompromised glenoid. To best treat young and active patients, a hemiarthroplasty that articulates with healthy glenoid cartilage can provide good pain relief and functional outcomes. Anatomic TSA is also reasonable but not an optimal option considering the normal glenoid condition. rTSA is not a consideration when a young patient’s MR images reveal an intact rotator cuff.
RECOMMENDED READINGS
Torchia ME, Cofield RH, Settergren CR. Total shoulder arthroplasty with the Neer prosthesis: longterm results. J Shoulder Elbow Surg. 1997 Nov-Dec;6(6):495-505. PubMed PMID: 9437598. View Abstract at PubMed
Chalmers PN, Slikker W 3rd, Mall NA, Gupta AK, Rahman Z, Enriquez D, Nicholson GP. Reverse total shoulder arthroplasty for acute proximal humeral fracture: comparison to open reduction-internal fixation and hemiarthroplasty. J Shoulder Elbow Surg. 2014 Feb;23(2):197-204. doi: 10.1016/j.jse.2013.07.044. Epub 2013 Sep 27. PubMed PMID: 24076000. View Abstract at PubMed
Groh GI, Wirth MA. Results of revision from hemiarthroplasty to total shoulder arthroplasty utilizing modular component systems. J Shoulder Elbow Surg. 2011 Jul;20(5):778-82. doi: 10.1016/j.jse.2010.09.014. Epub 2011 Jan 13. PubMed PMID: 21232989. View Abstract at PubMed
Orfaly RM, Rockwood CA Jr, Esenyel CZ, Wirth MA. Shoulder arthroplasty in cases with avascular necrosis of the humeral head. J Shoulder Elbow Surg. 2007 May-Jun;16(3 Suppl):S27-32. Epub 2006 Nov 16. PubMed PMID: 17113317. View Abstract at PubMed
Sershon RA, Van Thiel GS, Lin EC, McGill KC, Cole BJ, Verma NN, Romeo AA, Nicholson GP. Clinical outcomes of reverse total shoulder arthroplasty in patients aged younger than 60 years. J Shoulder Elbow Surg. 2014 Mar;23(3):395-400. doi: 10.1016/j.jse.2013.07.047. Epub 2013 Oct 12. PubMed PMID: 24129052. View Abstract at PubMed

Question 25

Which of the following best describes the use of epidural morphine and steroid paste after laminectomy?

Explanation

DISCUSSION: Kramer and associates conducted a retrospective review during an “epidemic” period to identify the risk factors associated with a sudden increase in the rate of surgical site infections. They found in a multivariate analysis that the use of morphine nerve paste resulted in a 7.6-fold increase in postoperative surgical wound debridement, and an 11% rate of surgical site complications.
REFERENCES: Kramer MH, Mangram AJ, Pearson ML, et al: Surgical-site complications associated with a morphine nerve paste used for postoperative pain control after laminectomy. Infect Control Hosp Epidemiol 1999;20:183-186.
Lowell TD, Errico TJ, Eskenazi MS: Use of steroids after discectomy may predispose to infection. Spine 2000;25:516-519.

Question 26

Intrinsic muscles of the foot act on the toes by

Explanation

DISCUSSION: Intrinsic muscles of the foot function to flex the metatarsophalangeal joints and extend the interphalangeal joints.
REFERENCES: Myerson MS, Shereff MJ: The pathologic anatomy of claw and hammertoes.

J Bone Joint Surg Am 1989;71:45-49.
Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 71-80.

Question 27

2010 Pediatric Orthopaedic Examination Answer Book • 9 A 9-year-old girl has had bilateral knee and leg pain for the past 2 years. The family has noted increasing deformity in both lower extremities. She is less than the fifth percentile for height. Examination reveals bilateral femoral bowing, mild medial-lateral laxity of the knees, and the deformities shown in the radiograph seen in Figure 3. What is the most likely diagnosis?

Explanation

DISCUSSION: The widening, bowing, and cupping of the physes indicate some form of metabolic bone disease; therefore, the most likely diagnosis is renal osteodystrophy. The age of onset makes X-linked hypophosphatemic rickets less likely. The ground glass lesions and widening of the medullary canal characteristic of fibrous dysplasia are not present. There are no fractures creating the deformities indicating osteogenesis imperfecta.
There is an asymmetry of the deformities that makes diastrophic dysplasia less likely.
REFERENCES: Goldberg MJ, Yassir W, Sadeghi-Nejad A: Clinical analysis of short stature. J Pediatr Orthop 2002;22:690-696.
Parmar VS, Stanitski DF, Stanitski CL: Interpretation of radiographs in a pediatric limb deformity practice: Do
radiologists contribute? J Pediatr Orthop 1999;19:732-734. Question 4
Patients with slipped capital femoral epiphysis are more likely to experience a delay in definitive diagnosis if they initially present to a physician reporting which of the following problems?
L Limp
Hip pain
Knee pain
Proximal thigh pain
Buttock pain
DISCUSSION: A delay in diagnosis of slipped capital femoral epiphysis (SCFE) can lead to significant worsening of the deformity or even progression from a stable to an unstable SCFE. Those patients that report knee pain as their primary complaint are most likely to experience significant delay. Other variables associated with this delay include Medicaid insurance and stable SCFE.
REFERENCES: Kocher MS, Bishop JA, Weed B, et al: Delay in diagnosis of slipped capital femoral epiphysis.
AL-Madena Copy
10 • American Academy of Orthopaedic Surgeons
Pediatrics 2004;113:e322-e325.
Rahme D, Comley A, Foster B, et al: Consequences of diagnostic delays in slipped capital femoral epiphysis. J Pediatr Orthop B 2006;15:93-97.

Question 28

During a posterior approach to the right Achilles tendon, the surgeon encounters a nerve running with the small saphenous vein as shown in Figure 22. This nerve innervates what part of the foot?

Explanation

DISCUSSION: The sural nerve runs with the small saphenous vein on the posterior leg just lateral to the Achilles tendon. It is formed by contributions from both the tibial and common peroneal nerves and provides sensation on the dorso-lateral aspect of the foot.
REFERENCES: Aktan Ikiz ZA, Ucerler H, Bilge O: The anatomic features of the sural nerve with an emphasis on its clinical importance. Foot Ankle Int 2005;26:560-567.
Lawrence SJ, Botte MJ: The sural nerve in the foot and ankle: An anatomic study with clinical and surgical implications. Foot Ankle Int 1994;15:490-494.

Question 29

A 72-year-old woman falls onto her left hip after tripping over a curb during her daily 3-mile walk. An injury radiograph is shown in Figure A. What is the best long term solution?

Explanation

THA is the best long term solution for displaced femoral neck fractures (FNF) in active elderly patients.
The aims of surgery for FNF in elderly patients are immediate pain relief, rapid mobilization, and low complications and revision. THA has best pain relief, fewer reoperations, best survivorship and is most cost-effective but has longer operative/anesthetic time, blood loss, higher infection rate, and potential instability compared with HA.
Healy and Iorio examined the optimal treatment for elderly FNF. They compared internal fixation (120 patients) with arthroplasty (HA, 43 patients; THA, 23 patients). There was no different in reoperation or mortality rates between the 2 groups, but arthroplasty was more cost effective, had independent living, and longer interval to reoperation/death. THA had less pain, better function, and lower rates of reoperation than HA, and was most cost-effective. They concluded that THA was the best treatment.
Yu et al. performed a meta-analysis of randomized controlled trials to determine whether THA or hemiarthroplasty (HA) was superior. They found that THA had lower risk of reoperation (RR = 0.53), higher risk of dislocation (RR = 1.99), and
higher functional scores at 1 and 4 years. There was no difference in mortality, infection and complication rates.
Figure A shows a displaced left femoral neck fracture. Incorrect Answers:

Question 30

Figure 32 shows the radiograph of a laborer who jammed his thumb in a fall. Examination reveals pain at the base of the thumb and proximal thenar eminence region. Management should consist of

Explanation

DISCUSSION: The radiographs are classic for a Bennett’s fracture, which involves a fracture of the palmar ulnar aspect of the proximal phalanx. This fracture fragment is still attached to the anterior oblique ligament. The deforming forces that cause subluxation of the base of the proximal phalanx include the pull of the abductor pollicis longus as well as the adductor pollicis. Adequate reduction can be achieved by closed reduction, percutaneous pin fixation, and casting. The fragment is too small for secure internal fixation.
REFERENCES: Stern PJ: Fractures of the metacarpals and phalanges, in Green DP, Hotchkiss RN, Pederson WC (eds): Green’s Operative Hand Surgery, ed 4. Philadelphia, PA, 1999, pp 711-771.
Howard FM: Fracture of the basal joint of the thumb. Clin Orthop 1987;220:46-51.

Question 31

A 72-year-old man undergoes an uncomplicated cementless total hip arthroplasty for advanced osteoarthritis. At his 6-week postoperative follow-up, he has minimal pain and is progressing well with his mobility. Radiographs show early formation of Brooker grade III heterotopic bone around his hip. What is the best treatment of the heterotopic bone at this time?

Explanation

DISCUSSION: The development of heterotopic bone occurs early after hip arthroplasty. The process begins within days after surgery; therefore, prophylactic treatment must be in the early postoperative period (preoperative radiation given within 24 hours of surgery, or postoperative radiation given within 72 hours of surgery, or nonsteroidal antiinflammatory drugs (NSAIDs) given postoperatively for 7 to 21 days - longer duration has not been shown to be of any additional benefit). At 6 weeks, prophylactic treatment with NSAIDs or radiation is no longer effective. Surgery at 10 weeks would be premature because the patient is currently asymptomatic with regards to the heterotopic bone, and surgery prior to full maturation of the bone may increase the risk for more abundant recurrence of bone.
REFERENCES: Balboni TA, Gobezie R, Mamon HJ: Heterotopic ossification: Pathophysiology, clinical features, and the role of radiotherapy for prophylaxis. Int J Radiat Oncol Biol Phys 2006;65:1289-1299. Fransen M, Neal B: Non-steroidal anti-inflammatory drugs for preventing heterotopic bone formation after hip arthroplasty. Cochrane Database Syst Rev 2004;3:CD001160.
Neal BC, Rodgers A, Clark T, et al: A systematic survey of 13 randomized trials of non-steroidal antiinflammatory

drugs for the prevention of heterotopic bone formation after major hip surgery. Acta Orthop Scand 2000;71:122-128.

Question 32

In the most common condition causing a winged scapula, which of the following nerves is affected?

Explanation

DISCUSSION: A winged scapula is most often associated with Parsonage-Turner syndrome, a condition thought to be due to an inflammatory or immune-mediated mechanism. Certain muscles are predisposed, particularly the serratus anterior muscle innervated by the long thoracic nerve. Other less common nerve lesions (eg, the spinal accessory and dorsal scapular nerves) may also cause winged scapulae.
REFERENCES: Kline DG, Hudson AR: Nerve Injuries: Operative Results for Major Nerve Injuries, Entrapments and Tumors. Philadelphia, PA, WB Saunders, 1995.
van Alfen N, van Engelen BG: The clinical spectrum of neuralgic amyotrophy in 246 cases. Brain 2006;129:438-450.

Question 33

Spontaneous rupture of the extensor pollicis longus tendon is most frequently associated with which of the following scenarios?

Explanation

DISCUSSION: Rupture of the extensor pollicis longus (EPL) tendon after non operative treatment for a distal radius fracture occurs with a 0.3-3% incidence. The causes of EPL rupture include mechanical irritation, attrition, and vascular impairment leading to delayed rupture. Synovitis of the extensor carpi radialis due to repetitive use may invade the EPL tendon and lead to rupture. Recommended treatment in the pre-rupture setting includs a third dorsal compartment release with or without an extensor retinacular patch graft. Palmaris longus graft or a transfer from the extensor indicis proprius to the EPL tendon are reasonable treatment options. Results of all treatments seem to be
clinically satisfactory.
The referenced article by Gelb is a review of the etiology and treatment of this injury. He reviews the above discussion and findings.

Question 34

A 70-year-old woman had poliomyelitis as a young child, and the residual weakness she has as an adult principally involves the lower extremities. She now notes progressive weakness in both legs and she tires easily. What is the best course of action?

Explanation

DISCUSSION: The most likely diagnosis is postpolio syndrome, which is characterized by increasing weakness in both the paretic and previously normal muscles. Fatigability, joint pain, muscle atrophy, respiratory insufficiency, dysphagia, and sleep apnea are also seen. Gentle exercise and modification in lifestyle demands are generally recommended. Vigorous rehabilitation is likely to be detrimental in this condition. Further diagnostic work-up is not indicated at this time.
REFERENCES: Dalakas MC, Elder G, Hallett M, et al: A long-term follow-up study of patients with post-poliomyelitis neuromuscular symptoms. N Eng J Med 1986;314:959-963.
Kasser JE (ed): Orthopaedic Knowledge Update 5. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1996, pp 683-687.

Question 35

The arrow in the axial T 1 -weighted MRI scan shown in Figure 18 is pointing to which of the following structures?

Explanation

DISCUSSION: The arrow is pointing to the ulnar nerve within Guyon’s canal. Guyon’s canal is approximately 4 cm long, beginning at the proximal extent of the transverse carpal ligament and ending at the aponeurotic arch of the hypothenar muscles. Many structures comprise the boundaries of Guyon’s canal. The floor, for example, consists of the transverse carpal ligament, the pisohamate and pisometacarpal ligaments, and the opponens digiti minimi. Within Guyon’s canal, the ulnar nerve bifurcates into the superficial and deep branches, with the deep branch of the ulnar nerve persisting distal to the canal. The ulnar artery is immediately adjacent and radial to the ulnar nerve. The median nerve is visualized within the carpal tunnel. The radial artery is on the radial side of the wrist. The hook of the hamate is clearly seen in the figure, orienting the observer to the ulnar side of the wrist.
REFERENCES: Goss MS, Gelberman RH: The anatomy of the distal ulnar tunnel. Clin Orthop 1985;196:238-247.
Denman EE: The anatomy of the space of Guyon. Hand 1978;10:69-76.

Question 36

A B C Figures 64a through 64c are the MR images and radiograph of an active 30-year-old man who has been treated for pain in his subtalar joint for 6 months. He has had casting, physical therapy, and bracing but continues to have activity-limiting pain. An injection into the subtalar joint under fluoroscopic guidance temporarily relieved his pain. His best surgical option at this time is

Explanation

DISCUSSION
When contemplating the causes of subtalar joint degeneration in young patients, an unstable tarsal coalition should be considered in the absence of antecedent trauma. Initial treatment with casting is appropriate because this intervention can relieve symptoms for many patients. There are 2 surgical options for a symptomatic tarsal coalition: bar resection or completion fusion. Risk factors for a poor outcome after bar resection are adult age and a bar that encompasses more than 50% of the middle facet of the subtalar joint. Because this patient has both risk factors, the appropriate procedure is a subtalar fusion.
RECOMMENDED READINGS
Comfort TK, Johnson LO. Resection for symptomatic talocalcaneal coalition. J PediatrOrthop. 1998 May-Jun;18(3):283-8. PubMed PMID: 9600549. View Abstract at PubMed
Thorpe SW, Wukich DK. Tarsal coalitions in the adult population: does treatment differ from the adolescent? Foot Ankle Clin. 2012 Jun;17(2):195-204. doi: 10.1016/j.fcl.2012.03.004. Epub 2012 Apr 6. Review. PubMed PMID: 22541520. View Abstract at PubMed

Question 37

A 10-year-old girl is seen in the emergency department after being involved in a motor vehicle accident. She has right hip pain and is unable to bear weight. She has no neurovascular deficits and no other injuries. Radiographs reveal a posterior dislocation of the right hip without apparent fracture. The acetabulum appears to be developing normally. What is the best course of treatment? Review Topic

Explanation

Hip dislocation in the pediatric population is a rare event. However, prompt recognition and rapid care for this injury is imperative to avoid future hip problems including osteonecrosis of the femoral head (a devastating problem for a pediatric patient). Reduction maneuvers can create violent impact between the posterior wall of the (intact) acetabulum and the femoral head, resulting in shearing of the proximal femoral physis and displacement of the epiphysis from the remainder of the femoral head in skeletally immature patients. Therefore, deep sedation with good muscle relaxation, such as that achieved with general anesthetic, is recommended. Reduction is best accomplished with fluoroscopy for a number of reasons, including assessment of concentricity of the hip joint after reduction, and to detect any catastrophic femoral head physeal separation that occurs during the reduction maneuver. Sedation in the emergency department is often insufficient to achieve acceptable muscle relaxation for the patient. Open reduction is only indicated if closed reduction fails completely or if the hip is not concentric after an apparently successful closed reduction

Question 38

The MRI findings shown in Figure 51 would most likely create which of the following signs and symptoms?

Explanation

DISCUSSION: The MRI scan shows a far lateral disk herniation. With the L4-5 disk, a far lateral herniation abuts the left L4 nerve root. The findings would be consistent with those of a left L4 radiculopathy and would include pain or a sensory deficit on the anteromedial aspect of the knee, diminished patellar tendon reflex, and quadriceps weakness, perhaps making it difficult to walk up and down stairs.
REFERENCES: Fardin DF, Garfin SR (eds): Orthopaedic Knowledge Update: Spine 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, p 329.
O’Hara LJ, Marshall RW: Far lateral lumbar disc herniation: The key to the intertransverse approach. J Bone Joint Surg Br 1997;79:943-947.

Question 39

What are the two terminal branches of the lateral cord of the brachial plexus?

Explanation

DISCUSSION: The lateral cord divides into the musculocutaneous and median nerves. The posterior cord terminates into the axillary and radial nerves. The medial cord divides into the ulnar and median nerves.
REFERENCES: Hollinshead WH: Anatomy for Surgeons, ed 3. Philadelphia, PA, Harper and Row, 1982, pp 228-236.
Shin AY, Spinner RJ, Steinmann SP, et al: Adult traumatic brachial plexus injuries. J Am Acad Orthop Surg 2005;13:382-396.

Question 40

In X-linked hypophosphatemic rickets, the gene defect may be found in which of the following?

Explanation

Mutations of PHEX are responsible for X-linked hypophosphatemic rickets. Mutations of CLCN7 and TC1RG1 cause osteopetrosis. COLIA1 or COLIA2 mutations cause osteogenesis imperfecta (OI) which has literally hundreds of genotypes causing a more limited number of phenotypes as described by Silence. GNAS1 is the gene mutation of fibrous dysplasia that results in an activating mutation of the GSalpha1 protein. TGF-BR2 or FBN1 cause Marfan syndrome.

Question 41

A 68-year-old man reports a 1-year history of debilitating neck pain without neurologic symptoms. History reveals a C5-6 anterior diskectomy and bone grafting 10 years ago that provided good relief of arm and neck pain. Radiographs show evidence of fibrous union at C5-6, spondylotic disk narrowing at C4-5 and C6-7, and a fixed 2-mm subluxation at C3-4. Examination reveals cervical stiffness and discomfort at the extremes of movement. His neurologic examination is normal. Treatment should now consist of

Explanation

DISCUSSION: Axial pain can be difficult to manage. Pain management is not always successful, and surgical approaches may provide disappointing results unless there is discrete pathology. Whereas planning of a surgical approach should consider prior approaches and preexisting laryngeal dysfunction, no compelling case for surgical intervention can be made for this patient. Therefore, management should consist of patient education, exercise, and nonnarcotic medication.
REFERENCES: Ahn NU, Ahn UM, Andersson GB, et al: Operative treatment of the patient with neck pain. Phys Med Rehabil Clin N Am 2003;14:675-692.
Algers G, Pettersson K, Hildingsson C, et al: Surgery for chronic symptoms after whiplash injury: Follow-up of 20 cases. Acta Orthop Scand 1993;64:654-656.
Rao R: Neck pain, cervical radiculopathy, and cervical myelopathy: Pathophysiology, natural history, and clinical evaluation. Instr Course Lect 2003;52:479-488.

Question 42

A 17-year-old man sustained a 5-mm laceration on the lateral aspect of the hindfoot while working on a farm. Examination in the emergency department revealed no fractures. Twenty-four hours later, he returns to the emergency department with increasing foot pain. Thin brown drainage is seen emanating from the wound. He has a temperature of 102.0° F (38.9° C), a pulse rate of 120, and a blood pressure of 80/40 mm Hg. Examination of the foot reveals diffuse swelling, ecchymosis, tenderness, and crepitus with palpation. Current radiographs are shown in Figures 40a and 40b. Management should now consist of

Explanation

DISCUSSION: The mechanism and environment in which the injury occurred, the clinical picture, and the radiographic findings of gas in the tissues suggest an anaerobic Gram-positive bacterial infection. This can be a life- and limb-threatening infection. Treatment should consist of wide debridement of all devitalized tissue, and intravenous antibiotics should be started. Wounds should be left open to allow bacterial effluent and increase oxygen tension in the wound. Hyperbaric oxygen may be used as an adjuvant but is no substitute for debridement.
REFERENCES: Pellegrini VD, Reid JS, Evarts CM: Complications, in Rockwood CA, Green DP, Bucholz RW, et al (eds): Rockwood and Green’s Fractures in Adults, ed 4. Philadelphia, PA, Lippincott-Raven, 1996, vol 1, pp 458-463.
Ayers DC, Murray DC: Complications of the treatment of fractures and dislocations: General considerations, in Epps Jr CH (ed): Complications in Orthopedic Surgery, ed 4. Philadelphia, PA, JB Lippincott, 1994, pp 3-48.

Question 43

Figure 13 shows the MRI scan of a 29-year-old rock climber who reports increasing shoulder pain and weakness. Based on these findings, atrophy will most likely occur in which of the following muscles?

Explanation

DISCUSSION: The MRI scan shows a cyst at the spinoglenoid notch. These cysts are often associated with a labral injury, such as a superior labrum anterior and posterior (SLAP) lesion. The suprascapular nerve passes through the suprascapular notch and sends motor branches to the supraspinatus and sensory branches to the capsule. At the spinoglenoid notch, the infraspinatus branch of the suprascapular nerve is compressed by the cyst, leading to isolated infraspinatus atrophy. The teres minor and the deltoid are innervated by the axillary nerve.
REFERENCES: Fehrman DA, Orwin JF, Jennings RM: Suprascapular nerve entrapment by ganglion cysts: A report of six cases with arthroscopic findings and review of the literature. Arthroscopy 1995;11:727-734.
Ianotti JP, Ramsey ML: Arthroscopic decompression of a ganglion cyst causing suprascapular nerve compression. Arthroscopy 1996;12:739-745.
Tirman PF, Feller JF, Janzen DL, Peterfy CG, Bergman AG: Association of glenoid labral cysts and labral tears in glenohumeral instability: Radiologic findings and clinical significance. Radiology 1994;190:653-658.

Question 44

A Trendelenburg gait is most likely to be seen in association with

Explanation

DISCUSSION: A Trendelenburg gait results from weakness of the gluteus medius, which is innervated by the L5 nerve root. A paracentral disk herniation at L4-L5 most commonly results in an L5 radiculopathy and thus weakness of the gluteus medius. A paracentral herniation at L5-S1 most commonly affects the S1 nerve root. A paracentral herniation at L3-L4, a central herniation at L3-L4, and a far lateral herniation at L4-L5 all affect the L4 root.
REFERENCES: Fardon DF, Garfin SR, Abitbol J, et al (eds): Orthopedic Knowledge Update: Spine 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 323-332.
Andersson GB, Deyo RA: History and physical examination in patients with herniated lumbar discs. Spine 1996;21:10S-18S.

Question 45

An otherwise healthy 78-year-old woman has low back and buttock pain. Rectal examination reveals a large sacral mass. Figures 7a and 7b show a CT scan and a sagittal MRI scan of the lumbosacral spine. A biopsy specimen is shown in Figure 7c. What is the most likely diagnosis?

Explanation

DISCUSSION: A chordoma is a malignant neoplasm originating from remnants of the notochord. It is usually localized to the midline with 50% at the sacrococcygeal area, 35% at the skull base, and 15% at the mobile portion of the spine. Large vacuolated cells (physaliferous cells) are a characteristic of the tumor.
REFERENCES: Mindell ER: Chordoma. J Bone Joint Surg Am 1981;63:501-505.
Samson IR, Springfield DS, Suit HD, Mankin HJ: Operative treatment of sacrococcygeal chordoma: A review of twenty-one cases. J Bone Joint Surg Am 1993;75:1476-1484.

Question 46

A patient has a large T11-T12 disk herniation that is causing substantial compression of the spinal cord. The patient reports walking imbalance over the past few weeks. Examination of the patient's reflexes is likely to show Review Topic

Explanation

The patient has a large thoracic disk herniation that is causing spinal cord compression. The history of gait imbalance suggests that the patient has thoracic level myelopathy. Assuming that the patient does not have lumbar stenosis, compression of the spinal cord at the T11-T12 level will cause upper motor neuron findings distal to it. Hyperreflexia of the upper extremities would suggest that the patient has cervical spinal cord compression. In this patient, the upper extremity reflexes should be normal. Most likely, the patient will exhibit hyperreflexia in the lower extremities, which is an upper motor tract sign.

Question 47

Two major pharmacologic classes of bisphosphonates exist: nitrogen-containing and non-nitrogen-containing compounds. The nitrogen-containing compounds work by which of the following actions?

Explanation

Bisphosphonates represent the most clinically important class of antiresorptive agents available to treat diseases characterized by osteoclast-mediated bone resorption. Two classes of bisphosphonates exist: nitrogen-containing and non-nitrogen-containing compounds. The non-nitrogen-containing bisphosphonates work by metabolizing into cytotoxic ATP analogs. The nitrogen-containing bisphosphonates work via the mevalonate pathway by inhibiting GTPase formation, leading to loss of GTP prenylation and eventual induction of osteoclast apoptosis.

Question 48

The function of which of the following structures is to resist internal tibial rotation with the knee in full extension? Review Topic

Explanation

The primary function of the posterior oblique ligament is to resist internal tibial rotation with the knee in full extension.
The posterior oblique ligament is a structure within the posteromedial corner of the knee, with attachments proximally to the adductor tubercle of the femur and distally to the tibia/posterior knee capsule. The posterior oblique ligament and posteromedial capsule play a significant role in the prevention of additional posterior tibial translation in the knee in the setting of posterior cruciate ligament injury. They also act to resist internal tibial rotation with the knee in full extension.
Griffith et al. reports that the posterior oblique ligament provides significant resistance to valgus and internal rotation forces with knee extension. They used a cadaver model and demonstrated that the superficial MCL resists valgus and external rotation forces more than the posterior oblique ligament, while the posterior oblique ligament is more involved in resisting internal rotation.
Tibor et al. reviews the anatomy of the posteromedial corner of the knee. They report that failing to recognize injury to these structures may cause failure of cruciate ligament reconstruction surgery, and that reconstruction or repair of the posteromedial corner may be indicated in the face of multiple ligament injuries.
Illustration A shows the posteromedial corner of the knee, including the posterior oblique ligament.
Incorrect answers:
1-4: These structures are not primary restraints to internal tibial rotation in full extension.

Question 49

In infantile idiopathic scoliosis, which of the following factors suggests progression? Review Topic

Explanation

Infantile idiopathic scoliosis occurs more commonly in boys, with a 3 to 1 male to female ratio. Neural axis abnormalities, hip dysplasia, and congenital heart disease are all associated with the condition; spontaneous correction frequently occurs. Curve progression can be predicted by the rib vertebral angle difference or the phase of the rib head. Rib overlap of the apical vertebral body or a rib vertebral angle difference of greater than 20 degrees indicates that the curve is likely to progress. Gender, family history, and age at presentation have not been found to be risk factors for progression.

Question 50

A 13-year-old boy has knee pain after sustaining a mild twisting injury while playing basketball 4 weeks ago. Radiographs and MRI scans are shown in Figures 24a through 24d, and biopsy specimens are shown in Figures 24e and 24f. Treatment should consist of

Explanation

DISCUSSION: The imaging studies and histology are consistent with high-grade osteosarcoma. The standard treatment for osteosarcoma is neoadjuvant chemotherapy combined with wide surgical resection that can be performed with amputation or limb salvage depending on characteristics unique to each tumor and each patient. In most patients, limb salvage surgery can be performed with reconstruction using allografts and/or megaprostheses. Osteosarcoma is poorly responsive to radiation therapy. Chemotherapy alone, in the absence of appropriate surgery, has not proven effective.
REFERENCES: Simon MA, Springfield DS: Surgery for Bone and Soft-Tissue Tumors. Philadelphia, PA, Lippincott-Raven, 1998, pp 265-274.
Gibbs CP, Weber K, Scarborough MT: Malignant bone tumors. Instr Course Lect 2002;51:413-428.

Question 51

Following its exit from the sciatic notch, the sciatic nerve passes between what two muscles?

Explanation

DISCUSSION: Though anatomic variations exist, both divisions of the sciatic nerve most commonly pass between the piriformis and superior gemellus. This anatomic consideration is relevant during the posterior approach to the hip, where careful retraction of the rotators avoids sciatic nerve injury.
REFERENCES: Hoppenfeld S, deBoer P: Surgical Exposures in Orthopaedics: The Anatomic Approach. Philadelphia, PA, JB Lippincott, 1984, pp 335-348.
Anderson JE (ed): Grant’s Atlas of Anatomy, ed 7. Baltimore, MD, Williams & Williams,

1978, Figure 4-34.
FOR ALL MCQS CLICK THE LINK ORTHO MCQ BANK

Question 52

When performing a posterior cruciate ligament reconstruction with a tibial inlay-type approach, what is the approximate anatomic distance of the popliteal artery from the screws used for fixation of the bone block?

Explanation

DISCUSSION: Miller and associates reported the results of a cadaveric study of the vascular risk of a posterior approach for posterior cruciate ligament reconstruction using the tibial inlay technique. The average distance from the screw to the popliteal artery was 21.1 mm
(range, 18.1 mm to 31.7 mm). Other approaches, such as the transtibial tunnel technique which involves drilling an anterior-posterior tunnel, have also been studied in cadavers. Matava and associates noted that increasing flexion reduces but does not completely eliminate the risk of arterial injury during arthroscopic posterior cruciate ligament reconstruction. However, this study did not use the small, medial utility incision recommended by Fanelli and associates, which creates an interval for the surgeon’s finger between the medial gastrocnemius and the posteromedial capsule so that any migration of the guidepin can be palpated and changed prior to any injury to the posterior neurovascular bundle.
REFERENCES: Matava MJ, Sethi NS, Totty WG: Proximity of the posterior cruciate ligament insertion to the popliteal artery as a function of the knee flexion angle: Implications for posterior cruciate ligament reconstruction. Arthroscopy 2000;16:796-804.
Miller MD, Kline AJ, Gonzales J, et al: Vascular risk associated with posterior approach for posterior cruciate ligament reconstruction using the tibial inlay technique. J Knee Surg 2002;15:137-140.
Johnson DH, Fanelli GC, Miller MD: PCL 2002: Indications, double-bundle versus inlay technique and revision surgery. Arthroscopy 2002;18:40-52.

Question 53

Which of the following ligaments provides the major static restraint to lateral patellar displacement?

Explanation

The medial patellofemoral ligament is found to arise from the adductor tubercle and pass deep to the VMO and inserts on the proximal aspect of the medial patella and on the undersurface of the distal aspect of the quadriceps mechanism. The ligament varies in size in each patient but is the major soft tissue restraint to lateral displacement of the patella. Conlin and Garth, et al. found that the medial patellofemoral ligament contributed 53% of the total force against lateral displacement of the patella.
The medial patellotibial band was found to be functionally unimportant and the medial patellomeniscal ligament was found to contribute 22% to the lateral displacement force.

Question 54

A 27-year-old right hand dominant construction worker falls off a scaffold onto his outstretched arm. Figure A exhibits the radiograph taken at a local emergency room. Following treatment, he is placed in a sling and follows up at your office two weeks later. He complains of a feeling that his arm is going to 'pop out'. Which specific physical examination finding is likely to be present? Review Topic

Explanation

The patient suffered a posterior shoulder dislocation, likely injuring the posterior capsule and/or labrum. Out of all the answer choices, Kim's test assesses posterior structures. Thus, Kim's test is the physical examination finding most likely to be present.
Posterior dislocations occur less frequently than anterior dislocations, and are often missed. Following closed reduction, persistent instability can occur, usually associated with posterior capsular or labral pathology. Posteriorly directed provocative maneuvers, such as the Kim test can be positive.
Robinson et al. performed an epidemiologic analysis on 120 posterior dislocations. Recurrent instability occurred at a rate of 17.7%. Risk factors for recurrent instability included age less than 40-years-old, dislocation during seizure, and a large reverse Hill-sachs (>1.5 cm3).
Kim et al. describe the Kim lesion, a separation between the posteroinferior labrum and the articular cartilage without complete detachment of the labrum, which cause persistent posterior instability.
Figure A depicts a posterior dislocation on xray. Illustration A depicts the Kim test, which is performed by having the patient seated, arm at 90° abduction, followed by flexing the shoulder to 45° forward flexion while simultaneously applying axial load on the elbow and posterior-inferior force on the upper humerus. The test is positive when there is pain. Video 1 depicts the proper way to perform a Kim Test.
Incorrect answers:

Question 55

Reconstruction of the injured structure is performed. After surgery, the patient initially notes limitation in motion, and later develops recurrent instability of the knee. Which factor most likely contributed to the development of instability?

Explanation

DISCUSSION
The anteromedial bundle originates on the anterior and proximal aspect of the lateral femoral condyle and inserts on the anteromedial aspect of the anterior cruciate ligament (ACL) footprint on the proximal tibia. The posterolateral bundle originates posterior and distal to 63 the anteromedial bundle and inserts on the posterolateral aspect of the tibial footprint. The fibers are parallel when the knee is in an extended position. As the knee moves into flexion,
the fibers of the anteromedial bundle rotate externally with respect to the posterolateral bundle. The anteromedial bundle is tensioned in both flexion and extension. The posteromedial bundle is tensioned in extension, but relaxes as the knee moves into flexion.
The lateral meniscus is more commonly injured with an acute injury to the ACL. The medial meniscus is injured more commonly when the ACL is chronically unstable.
The ACL is an intra-articular and intrasynovial structure. It is innervated by posterior articular branches from the tibial nerve. Innervation of the ACL involves several types of mechanoreceptors (Ruffini, Pacini, Golgi tendon, and free-nerve endings) that may contribute to proprioceptive function of the knee and modulation of quadriceps function.
Injury to the ACL is predominantly associated with instability to anterior translation of the tibia in extension. The ACL plays a secondary role to limit internal rotation of the tibia, and a loss of ACL stability is confirmed by the reduction of the tibia from a position of anterior translation and internal rotation (pivot shift). The radiographs demonstrate anterior placement of the femoral tunnel. The convex shape of the lateral femoral condyle can make it more difficult to visualize the anatomic femoral origin of the ACL. Failure to identify the
anatomic footprint can result in anterior placement of the femoral tunnel. Anterior ACL graft placement can result in its impingement against the posterior cruciate ligament and early limitation of knee flexion. Over time, impingement on the graft may result in stretching of the graft and recurrent knee instability symptoms.
RECOMMENDED READINGS
Duthon VB, Barea C, Abrassart S, Fasel JH, Fritschy D, Ménétrey J. Anatomy of the anterior cruciate ligament. Knee Surg Sports Traumatol Arthrosc. 2006 Mar;14(3):204-13. Epub 2005 Oct 19. Review. PubMed PMID: 16235056. View Abstract at PubMed
Zantop T, Petersen W, Sekiya JK, Musahl V, Fu FH. Anterior cruciate ligament anatomy and function relating to anatomical reconstruction. Knee Surg Sports Traumatol Arthrosc. 2006 Oct;14(10):982-92. Epub 2006 Aug 5. Review. PubMed PMID: 16897068. View Abstract at PubMed

Question 56

A 66-year-old male undergoes the procedure shown in figures A and B. After 4 years, he develops progressive pain and limitations in his daily function that is refractory to conservative measures. He is indicated for conversion to a total knee replacement with almost complete relief of his symptoms postoperatively. What preoperative factor likely led to the subsequent failure?

Explanation

unicompartmental arthroplasty. The absence of an ACL is a contraindication for mobile-bearing UKA.

OrthoCash 2020
Which of the following is the most common cause of early revision surgery (<20 weeks) following a hip resurfacing arthroplasty?
Periprosthetic fracture
Rupture of abductors
Dislocation
Heterotopic ossification
Post-operative stiffness
Periprosthetic fracture, specifically femoral neck fracture, is the most common cause of early revision less than 20 weeks following surgery.
The rate of femoral neck fractures following hip resurfacing varies, but most literature reports a rate of 1%. A majority of these fractures happen in the early post-operative period and are the most frequent cause of revision surgery within several months following surgery. The cause is usually multifactorial, but placing the femoral implant in varus, osteonecrosis, and notching have been proven risk factors for fracture.
Little el al. report on 377 patients undergoing hip resurfacing. 13 required revision including 8 for fracture of the femoral neck and 3 for loosening of a component. Evidence of osteonecrosis was seen in two of these cases, leading the authors to believe it may contributed to fracture.
Illustration A shows a comparison of a typical total hip replacement and a hip resurfacing arthroplasty. Illustration B shows notching of the femoral neck, a known cause of femoral neck fracture following hip resurfacing. Illustration C shows a femoral neck fracture in a patient with a hip resurfacing.

OrthoCash 2020
A 55-year-old male undergoes a revision total knee arthroplasty of an implant that is only 3 years old. At the time of surgery, the tibial polyethylene liner shows catastrophic delamination and cracking. What is the most likely cause of this extensive, accelerated wear of the polyethylene liner?
Sterilization in ethylene oxide
Gamma irradiation of the polyethylene liner in the presence of air
Gamma irradiation of the polyethylene liner with vacuum packaging
Gamma irradiation of the polyethylene liner in nitrogen
Gamma irradiation of the polyethylene liner in argon Corrent answer: 2
Irradiation of polyethylene in air (i.e. oxygen present) has been shown to be a risk factor for catastrophic failure after total knee replacement.
Free radicals are generated when polyethylene is irradiated in the presence of air. Initially, these free radicals result in cross-linking. However, if the polyethylene is exposed to these free radicals for an extended period of time, delamination, cracking, and catastrophic failure may ensue. The industry has completely abandoned this method of sterilization as a result. Currently, the standard of care is irradiation of polyethylene in an inert gas (e.g. argon, nitrogen or vacuum packaging). The amount of oxidative products when polyethylene is sterilized in the absence of oxygen is much less and does not lead to catastrophic failure.
Sterilization without irradiation is another option (ethylene oxide). When this occurs, there is no cross-linking and thus the increased wear properties are lost. However, since there is no oxidization, you do not have the risk of catastrophic failure as seen in those liners irradiated in the presence of oxygen.
The cited reference by McNulty et al. from Orthopedics discusses the influence of sterilization methods on wear performance. They found that gamma irradiation and storage of the polyethylene components in an essentially oxygen-free environment imparted by gamma irradiation in a vacuum foil pouch (GVF) protects the components from oxidization.
Illustration A shows a polyethylene liner that has undergone catastrophic wear as a result of irradiation in the presence of oxygen.
Incorrect Answers:
catastrophic wear, although wear properties are less than gamma irradiation in the absence of air.

OrthoCash 2020
Which of the following interventions reduces osteolysis around distal portion of the femoral stem when performing a total hip arthroplasty?
Use of an extended offset femoral neck component
Use of a proximal circumferentially coated ingrowth stem
Use of a collared stem
Use of a long femoral stem
Ensuring that the stem fills the diaphysis of the femur Corrent answer: 2
Osteolysis of the femur is caused by activation of macrophages by microscopic polyethylene particles within the "effective joint space", defined as any area where joint fluid can come into contact with bone. This can occur above the acetabular cup, through screw holes, and down the femoral shaft around the prosthetic stem. Ideally, with a cementless stem, both the proximal and metaphyseal femur are well filled by the prosthesis. Collared stems are used to augment poor calcar bone quality or bone loss.
Sinha et al showed in a retrospective review of 101 hips with cementless circumferentially coated femoral stems no distal femur osteolysis occurred, but 82% showed “evidence of proximal femur stress shielding”, though only 38% showed proximal femoral osteolysis.
OrthoCash 2020
During a minimally invasive approach to total hip arthroplasty a femoral periprosthetic fracture occurs. Which of the following steps is crucial to properly treat this complication?
Transitioning to an extensile approach to adequately visualize and reduce the fracture
Limiting post-operative weight bearing
Switching to a cemented femoral stem to avoid the stresses created during press-fit fixation
Delaying the arthroplasty until the fracture has healed
Supplementing the fracture with autograft Corrent answer: 1
Proper treatment of an intraoperative femoral fracture during total hip arthroplasty involves adequate exposure, anatomic reduction, and bypassing the fracture site by 2 cortical diameters of the femur with a long stem. This may involve repositioning the patient on the table if the arthroplasty is performed in the supine position. Minimally invasive surgical techniques have been developed to insert the components through smaller exposures and less soft tissue dissection. The purported advantages include faster rehabilitation, less blood loss, shorter hospital stays, and better cosmesis. However, complications an arise if the surgeon sacrifices surgical exposure and visualization.
Fehring et al review 3 cases of total hip arthroplasty performed through minimally invasive techniques with catastrophic outcomes. Intra-operative fracture, chronic instability, and death were all identified.
OrthoCash 2020
A 70-year-old man underwent total hip arthroplasty 4 months ago and has experienced 3 dislocations. Radiographs reveal no failure of the hardware and an acetabular component that has an abduction
angle of 40 degrees and a version of 10 degrees retroverted. What is the most appropriate treatment for the recurrent dislocations?
hip abduction brace
revision of the acetabular liner to a constrained type
revision of the entire acetabular component
revision of the femoral head to a larger size
revision to an extended offset prosthesis Corrent answer: 3
Per Dorr et al: post-operative hip instability can be caused by several factors: soft tissue imbalance, component malposition, or position. Component malposition, as in this case, should be treated with revision of the offending component. In this case the acetabulum was placed in retroversion when it should have been 15-20 degrees anteverted. None of the other options addresses the cause of the instability. According to Morrey, the most signficant risk factors to instability are prior hip surgery, trochanteric nonunion, and posterior surgical approach. He wrote that the most reliable way to correct instability is to reorient a retroverted acetabular cup.
OrthoCash 2020
In patients with sickle cell disease and asymptomatic osteonecrosis of the femoral head identified with magnetic resonance imaging, what percentage will eventually go on to femoral head collapse?

Question 57

A 59-year-old man underwent interposition arthroplasty for osteoarthritis of the elbow 9 years ago. Over the past year the patient has had increasing pain and elbow instability. There is no clinical evidence of infection, and radiographs show no new bony process. What is the best option for this patient?

Explanation

DISCUSSION: In a series reported by Blaine and associates, 12 patients were converted from interposition to total elbow arthroplasty. This procedure was successful in 10 out of 12 patients.
REFERENCES: Blaine TA, Adams R, Morrey BF: Total elbow arthroplasty after interposition arthroplasty for elbow arthritis. J Bone Joint Surg Am 2005;87;286-292.
Cheng SL, Morrey FB: Treatment of the mobile, painful arthritic elbow by distraction interposition arthroplasty. J Bone Joint Surg Br 2000;82:233-238.

Question 58

A 52-year-old man who weighs 325 lb is wheelchair-bound from severe degenerative arthritis of the left hip. Twenty-four hours after cementless total hip arthroplasty, he develops shortness of breath and evaluation shows a saddle pulmonary embolus. The patient is started on enoxaparin sodium at 150 mg every 12 hours. Two days later, the patient’s hematocrit is 20% despite four units of transfused packed cells, and he now has developed a complete sciatic nerve palsy. What is the best course of action?

Explanation

DISCUSSION: The purpose of this question is to draw attention to the early risks of therapeutic anticoagulation that will be instituted by an intensivist or pulmonologist to treat a life-threatening pulmonary embolus. The temporary vena cava filter is a recent innovation but will effectively reduce the risk of further pulmonary emboli. This requires reversal of anticoagulation for safe insertion of the filter and creates a safe situation for additional surgical solutions. Sciatic nerve compromise was caused by the expanding hematoma in this patient, which could be mitigated by exploration both to assess the nerve and to remove a large hematoma that presents its own longterm risks.
REFERENCES: Della Valle CJ, Steiger DJ, Di Cesare PE: Thromboembolism after hip and knee arthroplasty: Diagnosis and treatment. J Am Acad Orthop Surg 1998;6:327-336.
Weil Y, Mattan Y, Goldman V, et al: Sciatic nerve palsy due to hematoma after thrombolysis therapy for acute pulmonary embolism after total hip arthroplasty. J Arthroplasty 2006;21:456-459.
American Academy of Orthopaedic Surgeons Guideline on the Prevention of Symptomatic Pulmonary Embolism in Patients Undergoing Total Hip or Knee Arthroplasty, www.aaos.org/research/guidelines/ PEguide.asp

Question 59

A 67-year-old man with right shoulder osteoarthritis (OA) remains symptomatic despite a course of nonsurgical treatment. A CT scan of the shoulder shows eccentric posterior glenoid wear with 10° of retroversion. What is the appropriate management of this glenoid bone loss during surgery for an anatomic total shoulder arthroplasty?

Explanation

Total shoulder arthroplasty (TSA) is superior to hemiarthroplasty for primary OA. The most common complication of TSA is glenoid loosening and malposition, which are common causes of glenoid failure. Glenoid malposition decreases the glenohumeral contact area and subsequently increases contact pressures. Altering the stem version to accommodate glenoid retroversion does not appropriately address soft-tissue balancing. A retroversion of <12° to 15° can be corrected with eccentric reaming without excessively compromising glenoid bone stock and risking glenoid vault penetration by the glenoid component. Posterior
glenoid bone grafting may be considered for glenoid retroversion >15°.

Question 60

A 23-year-old male is an unrestrained driver in a motor vehicle accident and sustains an unstable pelvic ring fracture. During fluoroscopic-aided fixation, a lateral sacral view is required for proper placement of which of the following fixation methods?

Explanation

DISCUSSION: The lateral sacral view is used to place percutaneous iliosacral screws. Sacral alar morphology has been shown to be variable from patient to patient. Therefore, intraoperative fluoroscopy is recommended. During placement of the screws, the L5 nerve root is at risk.
Routt et al (1997) examined the sacral slope and sacral alar anatomy in cadavers and a series of patients. They determined that the pelvic outlet and lateral sacral plain films provide the best plain radiographic view of the sacral ala. They recommended routine usage of these views intraoperatively to guide screw placement.
Routt et al (2000) reported on the early complications of percutaneous placement of iliosacral screws for treatment of posterior pelvic ring disruptions. While technically challenging, this technique leads to less blood loss and lower rates of infection compared to traditional open techniques.
Barei et al described methods of anterior and posterior pelvic ring disruptions. They determined that successful placement depends on accurate closed reduction, excellent intraoperative fluoroscopic imaging, and detailed preoperative planning. Early treatment decreased hemorrhage, provides patient comfort, and allows early mobilization.

Question 61

A 12-year-old boy with an ankle fracture undergoes closed reduction under sedation in the emergency department. Figure 27 shows a lateral radiograph of the ankle after two attempts at closed reduction. Based on these findings, treatment should now consist of Review Topic

Explanation

The widening of the physis associated with incomplete reduction of this fracture suggests that periosteum is interposed at the fracture site. Clinical and animal study findings suggest that the interposed periosteum may lead to premature physeal closure. Repeated forceful attempts at reduction may subject the physis to further injury and should be avoided. Growth problems are common in children with Salter-Harris type I fractures of the lower extremities. Nonunions are rare in children with Salter-Harris type I fractures.

Question 62

A 32-year-old man sustained an L1 burst fracture with 90% canal compromise, intact posterior elements, and kyphosis of 25% at the L1 level. He has an incomplete neurologic injury. Definitive management should consist of

Explanation

DISCUSSION: With an incomplete injury, the best chance for recovery occurs when the canal is cleared and the neural structures are decompressed. Anterior decompression, vertebral body reconstruction, and anterior stabilization have been shown to be highly effective in the treatment of burst-type injuries. Laminectomy alone is contraindicated because it increases the instability. Short segment posterior fixation has a high rate of failure in this type of injury at this level.
REFERENCES: Kaneda K, Abumi K: Burst fractures with neurologic deficits of the thoracolumbar spine. J Bone Joint Surg Am 1997;79:69-83.
McGuire R Jr: The role of anterior surgery in the treatment of thoracolumbar fractures. Orthopedics 1997;20:959-962.

Question 63

A 66-year-old female presents to your clinic complaining of back pain, difficulty standing-up straight, weakness in her legs, and neurogenic claudication. On upright thoracolumbar radiographs, there is a 75 degree thoracolumbar curve with the apex at L2, and the C7 plumb line falls 12 cm anterior to the posterosuperior corner of S1. Aside from a decompression of the stenotic levels, which of the following choices will lead to the MOST reliable decrease in overall disability? Review Topic

Explanation

This patient has a spinal deformity in both the coronal and sagittal planes. Among the options given, correction of the sagittal vertical axis (SVA) to +3 cm is the most reliable predictor of clinical improvement.
Spinal malalignment in Adult Spinal Deformity (ASD) challenges balance mechanisms used for maintenance of an upright posture to achieve the basic human needs of preserving level visual gaze and retaining the head over the pelvis. Severe malalignment can result in greater muscular effort and energy expenditure to maintain the erect posture as well as use of compensatory mechanisms. As such, surgical correction of these deformities are aimed at achieving proper spinopelvic alignment.
Glassman et al. performed a multi-center retrospective study of 298 adults with spinal deformity. Regardless of operative (129 patients) or non-operative care (172 patients) a positive sagittal balance was the found to be the most reliable predictor of clinical symptoms in both patient groups.
Schwab et al. published a current concepts review on operative management for adult spinal deformities and identified three major goals of surgery: (1) Correct the SVA to
within 5 cm of neutral, (2) Ensure the pelvic tilt is less than 20 degrees, (3) Ensure the lumbar lordosis is within 9 degrees of the pelvic incidence.
Illustration A demonstrates how to measure the SVA. Illustration B depicts the realignment objectives in the saggital plane as described by Schwab et al.
Incorrect

Question 64

What is the most reproducible landmark for the accurate anatomic placement of the tibial tunnel for an anterior cruciate ligament (ACL) reconstruction?

Explanation

DISCUSSION: The anterior border of the PCL is the most accurate and reproducible landmark for appropriate placement of the tibial tunnel for an ACL reconstruction. The central sagittal insertion point of the ACL is consistently 10 to 11 mm anterior to the anterior border of the PCL ligament. The anterior border of the tibia is not well visualized and does not serve as a reference point. While the posterior border of the anterior horn of the lateral meniscus could be used as a reference point, it has twice the variability of the PCL reference point. The posterior border of the tibia is difficult to identify and has greater variability than the PCL relative to the AP dimension of the proximal tibial surface. The anterior horn of the medial meniscus is also more variable than the PCL.
REFERENCES: Hutchinson MR, Bae TS: Reproducibility of anatomic tibial landmarks for anterior cruciate ligament reconstructions. Am J Sports Med 2001;29:777-780.
McGuire DA, Hendricks SD, Sanders HM: The relationship between anterior cruciate ligament reconstruction tibial tunnel location and the anterior aspect of the posterior cruciate ligament insertion. Arthroscopy 1997;13:465-473.

Question 65

A further workup reveals elevations in serum cobalt and chromium levels and fluid collections surrounding the hip on MARS MR imaging. Revision THA is recommended. The most common complication following revision of a failed metal-on-metal hip arthroplasty is

Explanation

DISCUSSION
THA has proven durable and reliable for pain relief and improving function for patients with end-stage arthritis. Appropriate bearing selection is critical to minimize wear and hip complications. A metal-on-metal articulation is associated with excellent wear rates in vitro. With its capacity to offer a low wear rate with large femoral heads, it is an attractive bearing choice for THA. However, local soft-tissue reactions, pseudotumors, and potential systemic reactions including renal failure, cardiomyopathy, carcinogenesis, and potential teratogenesis with potential transfer of metal ions across the placental barrier make metal-on-metal bearings less desirable and relatively contraindicated for younger women of child-bearing age.
The workup of a painful metal-on-metal hip arthroplasty necessitates a systematic approach. Several algorithms have been proposed. Routine laboratory studies including sedimentation rate, CRP, and serum cobalt and chromium ion levels should be obtained for all patients with pain. Advanced imaging including MARS MRI should be performed to evaluate for the presence of fluid collections, pseudotumors, and abductor mechanism destruction. Infection can coexist with metal-on-metal reactions, so, when indicated (if the CRP level is elevated), a hip arthrocentesis should be obtained. However, in this setting, a manual cell count and differential should be obtained because an automated cell counter may provide falsely elevated cell counts.
The results of revision surgery for a failed metal-on-metal hip prosthesis can be variable. The amount of local tissue destruction and the integrity of the hip abductor mechanism can greatly influence outcomes. Instability is the most common complication following revision of failed metal-on-metal hip replacements.

Question 66

A 42-year-old woman sustains a closed posterior elbow dislocation. A closed reduction is performed, and the elbow appears stable under fluoroscopic examination. Initial treatment should consist of

Explanation

This is a simple (no associated fracture) elbow dislocation. Such dislocations can be treated with closed reduction followed by mobilization after 5 to 7 days to avoid stiffness, provided the elbow is stable through a full arc of motion at the time of reduction. If the elbow is unstable but has a short arc of stability, then using a hinged brace in the stable arc may be considered. (Note: It may be necessary to splint the elbow in pronation if the medial collateral ligament [MCL] is intact and the lateral collateral ligament [LCL] is disrupted, or in supination if the LCL is intact but the MCL disrupted.) Surgical reconstruction of the LCL and MCL may be required only if the elbow does not have a stable arc at the time of reduction. If unstable after reconstruction,
application of a hinged external fixator may be considered.

Question 67

Figures 8a through 8c show the lateral radiograph and T1- and T2-weighted MRI scans of a 14-year-old soccer player who reports aching thigh pain. The next most appropriate step in management should consist of

Explanation

DISCUSSION: Although the MRI findings could be misinterpreted as an aggressive soft-tissue process, the periosteal-based ossification on the radiograph in an athlete most likely suggests myositis ossificans. The radiograph should be repeated to see further maturation of the ossification with a typical “zoning” pattern. The zoning pattern is one of peripheral ossification. This is often best seen on a CT scan.
REFERENCES: King JB: Post-traumatic ectopic calcification in the muscles of athletes: A review. Br J Sports Med 1998;32:287-290.
Wang SY, Lomasney LM, Demos TC, Hopkinson WJ: Radiologic case study: Traumatic myositis ossificans. Orthopedics 1999;22:991-995, 1000.

Question 68

A diskectomy is performed in which the disk space is not aggressively debrided. When compared to techniques that involve aggressive debridement of the disk space, this results in

Explanation

DISCUSSION
This patient has disk herniation at the left L5-S1 level. This will generally affect the traversing S1 nerve. The S1 dermatome is on the lateral aspect and sole of the foot.
Surgical treatment generally involves a diskectomy with removal of the herniated fragment. This can be performed via a conventional open approach or minimally invasive endoscopic technique. Several recent meta-analyses have demonstrated equivalent outcomes with regard to leg pain and clinical outcomes. Although minimally invasive techniques have been associated with an increased rate of dural tear, the overall complication rate between the 2 techniques is not significantly different. Several studies have demonstrated a substantial learning curve associated with minimally invasive techniques, and the rate of complications decreases significantly with surgeon experience.
When performing a diskectomy, the herniated fragment alone can be removed (sequestrectomy) or some of the disk that remains in the disk space can be removed (complete diskectomy). Studies have shown no change in surgical time, blood loss, length of stay, or surgical complications when performing a sequestrectomy (compared to a more complete diskectomy). A sequestrectomy is associated with a higher rate of recurrent disk herniation at the surgical level.
RECOMMENDED READINGS
Kamper SJ, Ostelo RW, Rubinstein SM, Nellensteijn JM, Peul WC, Arts MP, van Tulder MW. Minimally invasive surgery for lumbar disc herniation: a systematic review and meta-analysis.
Eur Spine J. 2014 May;23(5):1021-43. doi: 10.1007/s00586-013-3161-2. Epub 2014 Jan 18.
PubMed PMID: 24442183. View Abstract at PubMed
Dasenbrock HH, Juraschek SP, Schultz LR, Witham TF, Sciubba DM, Wolinsky JP, Gokaslan ZL, Bydon A. The efficacy of minimally invasive discectomy compared with open discectomy: a meta-analysis of prospective randomized controlled trials. J Neurosurg Spine. 2012 May;16(5):452-62. doi: 10.3171/2012.1.SPINE11404. Epub 2012 Mar 9. PubMed PMID:

Question 69

A healthy 2-year-old boy falls from a swing and sustains a displaced midshaft femoral fracture with 1 cm of shortening. What is the most appropriate treatment?

Explanation

AL-Madena Copy
DISCUSSION: For children between the ages of 1 and 6 years, closed reduction and early spica casting is recommended. In some instances, associated injuries or body habitus may preclude cast treatment. Pavlik harness treatment of femoral fractures is for infants younger than 1 year of age. Rarely is there an indication for traction. Internal fixation is reserved in general for children older than age 6 years or with confounding factors.
REFERENCES: Abel MF (ed): Orthopaedic Knowledge Update: Pediatrics 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 271-280.
Flynn JM, Schwend RM: Management of pediatric femoral shaft fractures. J Am Acad Orthop Surg 2004;12:347-359.

Figure 29a Figure 29b

Question 70

Figures below show the radiographs obtained from a 79-year-old woman who has been experiencing increasing tibial pain 10 years after undergoing revision total knee arthroplasty. No evidence of infection is seen. What is the most appropriate treatment?

Explanation

DISCUSSION:
Stems are available for cemented and press-fit implantation. To be effective, press-fit stems should engage the diaphysis, as shown in Figures 3 and 4. They also assist in obtaining correct limb alignment. Short metaphyseal-engaging stems are associated with failure rates that range between 16% and 29%. Cemented stems may be shorter than press-fit stems, because they do not have to engage the diaphysis. Short, fully cemented stems offer the advantage of metaphyseal fixation. Hybrid stem fixation makes use of the metaphysis for cement fixation with metaphyseal cones or sleeves and diaphyseal-engaging press-fit stems.

Question 71

A 63-year-old woman who sustained a distal radial fracture 2 months ago now reports that she is unable to achieve active extension of the thumb at the interphalangeal joint. What type of trauma may lead to this clinical finding?

Explanation

DISCUSSION: Nondisplaced distal radial fractures have a higher rate of spontaneous rupture of the extensor pollicis longus tendon. The extensor mechanism is felt to impinge on the tendon following a nondisplaced fracture and causes either a mechanical attrition of the tendon or a local area of ischemia in the tendon.
REFERENCES: Helal B, Chen SC, Iwegbu G: Rupture of the extensor pollicis longus tendon in undisplaced Colles’ type of fracture. Hand 1982;14:41-47.
Hirasawa Y, Katsumi Y, Akiyoshi T, et al: Clinical and microangiographic studies on the rupture of the EPL tendon after distal radial fractures. J Hand Surg Br 1990;15:51-57.

Question 72

CLINICAL SITUATION Figures 1 and 2 are the radiographs of a 68-year-old woman who comes to the emergency department after stepping into a hole and twisting her ankle. She is complaining of isolated ankle pain and is unable to bear weight. After closed manipulative reduction and splint placement, she is scheduled for operative treatment. The stability of the syndesmosis should be evaluated after

Explanation

Discussion: The radiographs reveal a trimalleolar ankle fracture dislocation with an associated distal tibiofibular syndesmotic disruption. Medial and lateral malleolar stabilization are consistently agreed upon. The decision to stabilize the posterior malleolus is more controversial. Posterior malleolar stabilization accomplishes the following:
Restores incisura competence thereby reducing the incidence of syndesmotic malreduction by creating containment
Assists in stabilizing the syndesmosis via the posterior inferior tibiofibular ligament, potentially limiting the need for additional syndesmotic stabilization
Maximizes the surface area for ankle joint loading
Enhances posterior translational stability of the talus
The traditional indication for stabilization of the posterior malleolus is based on fragment size. However, fracture orientation varies and makes evaluation of the fragment size challenging with a lateral radiograph alone. The three primary types include the posterolateral oblique, medial extension, and shell. Because of the additive syndesmotic stability which is gained through the deep deltoid ligament and medial malleolar fixation, the anterior talofibular ligament and lateral malleolar fixation, and the posterior inferior tibiofibular ligament and posterior malleolar fixation, syndesmotic stability should only be assessed after all other points of instability that are planned for fixation are fixed.
Syndesmotic instability should be assessed with direct manipulation on both the anteroposterior and lateral views with special attention to the lateral view. Syndesmotic reduction should be assessed either through open visualization or by comparing closed reduction parameters (clear space, overlap, and fibular position on the lateral view) with the patient’s contralateral side (assuming no injury). This is more effective than using population norms secondary to the two types of syndesmotic morphologies which create different absolute values for these parameters.

Question 73

A 70-year-old woman reports anterior knee pain after undergoing an uncomplicated total knee arthroplasty 6 months ago. Examination reveals prepatellar tenderness, with no extensor lag. The radiographs shown in Figures 25a through 25c reveal a well-fixed patellar component. Management should consist of

Explanation

DISCUSSION: Patellar fractures that occur after a total knee arthroplasty are usually stress fractures. Integrity of the extensor mechanism precludes the need for surgical repair or internal fixation, while stability and fixation of the patellar component determine whether revision is indicated. A cylindrical cast and full weight bearing for 6 weeks is recommended for transverse fractures with an intact extensor mechanism and a stable component. A similar fracture, if vertical, may be treated with earlier motion.
REFERENCES: Rorabeck CH, Angliss RD, Lewis PL: Fractures of the femur, tibia, and patella after total knee arthroplasty: Decision making and principles of management, in Cannon WD Jr (ed): Instructional Course Lectures 47. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1998, pp 449-458.
Hozack WJ, Goll SR, Lotke PA, Rothman RH, Booth RE Jr: The treatment of patellar fractures after total knee arthroplasty. Clin Orthop 1988;236:123-127.
Rand JA: The patellofemoral joint in total knee arthroplasty. J Bone Joint Surg Am 1994;76:612-620.

Question 74

What is the neoplastic cell of origin for this tumor?

Explanation

DISCUSSION
Tenosynovial giant-cell tumors are widely known as pigmented villonodular synovitis (PVNS), although this term is misleading because this tumor type is a clonal neoplasm and does not involve an inflammatory process. It often is shown to have a t(1:2)(p13q37) karyotype resulting in CSF1-COL6A3 gene fusion. There are various amounts of mononuclear cells, osteoclastlike giant cells, foamy histiocytes, hemosiderophages, and chronic inflammatory cells. Local recurrences are common, but CSF1R inhibitors are being investigated in studies involving local control improvement and disease regression.
Targeted therapy trials to assist in control of the diffuse-type tenosynovial giant-cell tumor (formerly called PVNS) involve the use of monoclonal antibodies that inhibit CSF1R activation. CSF1R-expressing mononuclear phagocytes are affected by these monoclonal antibodies.
Infantile fibrosarcoma is associated with the t(12;15)(p13;q25) karyotype and ETV6-NTRK3 gene fusion product. Nodular fasciitis is associated with the t(17;22)(p13;q13.1) karyotype and MYH9-USP6 gene fusion product. Inflammatory myofibroblastic tumor is associated with translocations involving 2p23 resulting in multiple fusion products of ALK with TPM4 (19p13.1), TPM3 (1q21), CLTC (17q23), RANBP2 (2q13), ATIC (2q35), SEC31A (4q21), and CARS (11p15). No
nonpreferred response has a histologic appearance that includes hemosiderin, foamy histiocytes, and osteoclastlike giant cells.
A conformation-specific inhibitor of the juxtamembrane region of CSF1R is a synthetic molecule that is designed to access the autoinhibited state of the receptor through direct interactions with the juxtamembrane residues embedded in the adenosine 5’-triphosphate-binding pocket. It is designed to bind in the regulatory a-helix of the N-terminal lobe of the kinase domain in neoplastic cells of tenosynovial giant-cell tumor that have expression of the CSF1 gene. There is a structural plasticity of the domain of the CSF1R that allows the molecule to directly bind the autoinhibited state of CSF1R.
Another approach involves the development of the anti-CSF1R antibody, emactuzumab, which targets tumor-associated macrophages. A lower percentage of volume reduction has been reported with imatinib, a tyrosine kinase inhibitor. Alkylating agents have not been used in this benign neoplasm.
Tenosynovial giant-cell tumor is characterized by an overexpression of CSF1. CSF1R activation leads to recruitment of CSF1R-expressing cells of the mononuclear phagocyte lineage.
RECOMMENDED READINGS
Cassier PA, Gelderblom H, Stacchiotti S, Thomas D, Maki RG, Kroep JR, van der Graaf WT, Italiano A, Seddon B, Dômont J, Bompas E, Wagner AJ, Blay JY. Efficacy of imatinib mesylate for the treatment of locally advanced and/or metastatic tenosynovial giant cell tumor/pigmented villonodular synovitis. Cancer. 2012 Mar 15;118(6):1649-55. doi: 10.1002/cncr.26409. Epub 2011 Aug 5. PubMed PMID: 21823110. View Abstract at PubMed
Ladanyi M, Fletcher JA, Dal Cin P. Cytogenetic and molecular genetic pathology of soft tissue tumors. In: Goldblum JR, Folpe AL, Weis SW, eds. Enzinger & Weiss’s Soft Tissue Tumors. 6th ed. Philadelphia, PA: Elsevier Saunders; 2014:76-109.
Staals EL, Ferrari S, Donati DM, Palmerini E. Diffuse-type tenosynovial giant cell tumour: Current treatment concepts and future perspectives. Eur J Cancer. 2016 Aug;63:34-40. doi: 10.1016/j.ejca.2016.04.022. Epub 2016 Jun 5. Review. View Abstract at PubMed
Tap WD, Wainberg ZA, Anthony SP, Ibrahim PN, Zhang C, Healey JH, Chmielowski B, Staddon AP, Cohn AL, Shapiro GI, Keedy VL, Singh AS, Puzanov I, Kwak EL, Wagner AJ, Von Hoff DD, Weiss GJ, Ramanathan RK, Zhang J, Habets G, Zhang Y, Burton EA, Visor G, Sanftner L, Severson P, Nguyen H, Kim MJ, Marimuthu A, Tsang G, Shellooe R, Gee C, West BL, Hirth P, Nolop K, van de Rijn M, Hsu HH, Peterfy C, Lin PS, Tong-Starksen S, Bollag G. Structure-Guided Blockade of CSF1R Kinase in Tenosynovial Giant-Cell Tumor. N Engl J Med. 2015 Jul 30;373(5):428-37. doi:10.1056/NEJMoa1411366. PubMed PMID: 26222558. View Abstract at PubMed
Ries CH, Cannarile MA, Hoves S, Benz J, Wartha K, Runza V, Rey-Giraud F, Pradel LP, Feuerhake F, Klaman I, Jones T, Jucknischke U, Scheiblich S, Kaluza K, Gorr IH, Walz A, Abiraj K, Cassier PA, Sica A, Gomez-Roca C, de Visser KE, Italiano A, Le Tourneau C, Delord JP, Levitsky H, Blay JY, Rüttinger D. Targeting tumor-associated macrophages with anti-CSF-1R antibody reveals a strategy for cancer therapy. Cancer Cell. 2014 Jun 16;25(6):846-59. doi: 10.1016/j.ccr.2014.05.016. Epub 2014 Jun 2. PubMed PMID: 24898549.View Abstract at PubMed

Question 75

A 16-year-old female swimmer reports several episodes of atraumatic glenohumeral instability that occur with different arm positions. Examination reveals generalized ligamentous laxity and a positive sulcus sign, and her shoulder can be subluxated both anteriorly and posteriorly. Initial management should consist of

Explanation

DISCUSSION: The patient has multidirectional instability (MDI). It has been reported that a high percentage of patients with MDI respond to a properly structured exercise program that is continued for at least 3 to 6 months. If nonsurgical management fails to provide relief, stabilization with an inferior capsular shift procedure has been effective in a high percentage of patients. Unidirectional repairs, such as the Putti-Platt procedure, are unsuitable for correcting MDI. Thermal capsulorrhaphy has been reported to have a very high failure rate

(greater than 50%) for treating MDI.
REFERENCES: Burkhead WZ Jr, Rockwood CA Jr: Treatment of instability of the shoulder with an exercise program. J Bone Joint Surg Am 1992;74:890-896.
Neer CS II, Foster CR: Inferior capsular shift for involuntary inferior and multidirectional instability of the shoulder: A preliminary report. J Bone Joint Surg Am 1980;62:897-908.
Pollock RG, Owens JM, Flatow EL, et al: Operative results of the inferior capsular shift procedure for multidirectional instability of the shoulder. J Bone Joint Surg Am

2000;82:919-928.
Miniaci A, Birnie J: Thermal capsular shrinkage for treatment of multidirectional instability of the shoulder. J Bone Joint Surg Am 2003;85:2283-2287.

Question 76

Figure 18 shows the radiograph of a patient with a total hip arthroplasty dislocation. During revision, increasing the diameter of the femoral head while maintaining the ratio of head-to-neck diameter constant has the effect of

Explanation

DISCUSSION: Although there is strong clinical and laboratory evidence that suggests smaller head size is linked with lower rates of polyethylene wear, moving to the use of 22-mm heads from larger sizes would tend to increase the dislocation rate. The key premise to this argument is that the absolute size of the femoral neck remains unchanged. While neck diameters were appropriate for the early monoblock femoral components, the use of modular femoral stems allows the surgeon to place 22-mm heads onto the same neck and trunion as used by larger heads. This has the effect of lessening the head-to-neck diameter ratio, which then accentuates the rate of impingement and dislocation. Reducing the neck diameter in proportion to the head diameter would eliminate the range-of-motion penalty accompanying head size reduction.
Scifert and associates used a three-dimensional finite element model to study various combinations of femoral head size and neck ratios. They found that increasing the diameter of the femoral head while maintaining a constant head-to-neck diameter had the effect of significantly increasing the resisting moment necessary to induce a dislocation. The higher the head-to-neck ratio, the greater the range of motion until impingement and the greater the range of motion to dislocation.
REFERENCE: Scifert CF, Brown TD, Pedersen DR, Callaghan JJ: A finite element analysis of factors influencing total hip dislocation. Clin Orthop 1998;355:152-162.

Question 77

The images reveal T2-weighted MRI sequences with edema isolated to the infraspinatus. In the absence of a tear in the infraspinatus tendon, the edema is most likely due to compression of the suprascapular nerve in the spinoglenoid notch. As this pathology persists, progressive muscle atrophy and fatty infiltration can result. Compression of the suprascapular nerve in the suprascapular notch would have resulted in edema and weakness in both the supra- and infraspinatus muscles. Compression is commonly caused by cysts from the joint secondary to labral tears. A rotator cuff tear of the infraspinatus is not identified on these images, and there is no history of trauma provided. There is no evidence of an anteroinferior labral tear, nor would this be expected to result in external rotation weakness or MRI abnormality of the infraspinatus. Quadrilateral space syndrome results in compression of the axillary nerve, which supplies the teres minor. Correcr answer : C

Explanation

Figure 1 is the radiograph of a 12-year-old baseball player who has posterolateral elbow pain with throwing. The area of interest is designated by the black arrow. His range of motion and strength are full. No previous treatment has been provided. What is the most appropriate initial treatment?

Elbow arthroscopy with debridement

Immobilization and rest for 6 weeks

Corticosteroid injection

Open osteochondral autograft transfer

Osteochondritis dissecans of the capitellum is a painful condition that affects immature athletes who undergo repetitive compression of the radiocapitellar joint. Management is based primarily on the integrity of the articular cartilage surface and the stability of the lesion. Nonsurgical treatment is typically selected for patients

with early-grade, stable lesions, and it involves activity modification with cessation of sports participation. The duration of activity modification is dictated by symptoms, with 3 to 6 weeks of rest followed by return to sport in 3 to 6 months commonly used as a guideline. Strengthening and stretching exercises are commonly incorporated after the pain has subsided. Surgical intervention or corticosteroid injection would not be first-line treatment.

Figures 1 and 2 are the radiographs of a 69-year-old man with a history of treated prostate cancer and hemodialysis-dependent end- stage renal disease who presents to the emergency department with progressively worsening right shoulder pain and stiffness. Laboratory tests reveal a white blood cell count of 17,000, erythrocyte sedimentation rate, 75, and CRP, 10.1. He has a draining sinus located along the anterior shoulder. What is the best next step?

Question 78

In displaced calcaneal fractures, what fragment is the only one that remains in its anatomic position?

Explanation

DISCUSSION: The sustentaculum tali remains in its anatomic position because of its supporting ligamentous structures. This provides the key to the reconstruction of the calcaneus. The posterior facet is reduced to the sustentaculum tali and then fixed to it for stability. All of the other components of the calcaneus are then reduced to this complex.
REFERENCES: Sanders R: Displaced intra-articular fractures of the calcaneus. J Bone Joint Surg Am 2000;82:225-250.
Eastwood DM, Gregg PJ, Atkins RM: Intra-articular fractures of the calcaneum: Part I. Pathological anatomy and classification. J Bone Joint Surg Br 1993;75:183-188.
Eastwood DM, Langkamer VG, Atkins RM: Intra-articular fractures of the calcaneum: Part II. Open reduction and internal fixation by the extended lateral transcalcaneal approach. J Bone Joint Surg Br 1993;75:189-195.

Question 79

A 56-year-old woman undergoes an arthroscopic rotator cuff repair for a two-tendon retracted tear (supraspinatus and infraspinatus), requiring the use of four suture anchors placed in a double row technique. At her 1 month follow-up visit, what is the appropriate recommendation for her continued rehabilitation program? Review Topic

Explanation

Regardless of the technique of rotator cuff repair, the biology of tendon healing remains the same. Therefore, the repaired muscle tendon(s) must be protected from stress for a minimum of 6 weeks and more likely 8 weeks in a large two-tendon tear such as this patient had repaired. Therefore, at the 1 month follow-up visit, the patient should continue strict passive motion exercises and should perform no strengthening activities. Deltoid strengthening cannot be isolated from rotator cuff strengthening; therefore, deltoid strengthening is inappropriate as well. Because the infraspinatus is the primary shoulder external rotator, it should not be strengthened for 6 to 8 weeks. Supraspinatus strengthening at this time frame would likely ensure its disruption and result in failure of the surgery. Any resistance training at 1 month from surgery would likely result in tendon failure at the tendon-bone interface. The obligatory need to protect the muscles during healing will predictably result in atrophy but it is easier to strengthen healed muscles than it is to strengthen muscle/tendon units that have failed to heal.

Question 80

A 40-year-old male who sustained an open pilon fracture 2 weeks ago is scheduled for a below-the-knee amputation (BKA). What laboratory value is the best predictor for wound healing?

Explanation

DISCUSSION: Albumin is the best measure of nutrition that is vital for wound healing. Total protein is a valuable measure as well, however it is not as sensitive as albumin levels. Calcium levels and ESR/C-reactive protein levels play no role.

Question 81

A 52-year-old man has had right shoulder pain in the deltoid region that increases at night for the past 2 months. He denies any history of trauma. Examination reveals mild tenderness over the greater tuberosity, and the Neer and Hawkins impingement signs are positive. AP and outlet lateral radiographs are shown in Figures 24a and 24b. Initial management should consist of

Explanation

DISCUSSION: The patient has the findings of classic subacromial impingement. Initial management should consist of stretching exercises directed at the posterior capsule and a program of rotator cuff and deltoid strengthening exercises performed below the horizontal in a “safe” plane. The judicious use of subacromial cortisone injections (one or two) may be helpful. Anterior acromioplasty is reserved for patients who have failed to respond to nonsurgical management.
REFERENCES: Morrison DS, Frogameni AD, Woodworth P: Non-operative treatment of subacromial impingement syndrome. J Bone Joint Surg Am 1997;79:732-737.
Neer CS: Impingement lesions. Clin Orthop 1983;173:70-77.
Blair B, Rokito AS, Cuomo F, et al: Efficacy of injections of corticosteroids for subacromial impingement syndrome. J Bone Joint Surg Am 1996;78:1685-1689.

Question 82

A 45-year-old man has severe pain in both feet after his boots become wet while hunting. Examination 3 hours after the onset of symptoms reveals that his feet are cold to touch and the skin appears blanched. Management should consist of

Explanation

DISCUSSION: The patient has frostbite involving both feet. Rapid rewarming in a protected environment is the initial treatment. A footbath with water at 104.0 degrees F to 107.6 degrees F (40 degrees C to 42 degrees C) is ideal. This facilitates a uniform rewarming of the involved tissue. The other choices are less than ideal. Appliances such as heating pads provide uneven heating and may actually burn the skin.
REFERENCES: Pinzur MS: Frostbite: Prevention and treatment. Biomechanics 1997;4:14-21.
Fritz RL, Perrin DH: Cold exposure injuries: Prevention and treatment. Clin Sports Med 1989;8:111-128.

Question 83

-What is the recommended treatment for this injury?

Explanation

DISCUSSION FOR QUESTIONS 85 THROUGH 87
The hypertrophic zone of the growth plate has been implicated as the weak link in the physis in acute injuries. Epiphysiolysis of the proximal humerus in throwing athletes occurs as the result of tension and shear on the physis. More than 90% of affected patients who are treated with rest for an average of 3 months become asymptomatic. Prevention is the best option. Set limitations of the number of pitches and types of pitches depending on the age of the player. Also recommend use of proper pitching mechanics.

Question 84

In performing an opening wedge high tibial osteotomy at the tibial tubercle, the osteotome extends 5 mm posteriorly and centrally out of the bone as shown in Figures 17a and 17b. What is the first structure it enters?

Explanation

DISCUSSION: The major risk of performing a high tibial osteotomy is neurovascular injury. The new version of the high tibial osteotomy makes a transverse osteotomy at the level of the tibial tubercle. The osteotome is protected by the oblique belly of the popliteus muscle. The popliteal artery and vein and tibial nerve all lie posterior to the muscle. The soleus muscle originates below this level.
REFERENCES: Clement CD: Anatomy: A Regional Atlas of Human Anatomy, ed 3.

Baltimore, MD, Munich, Germany, Urban and Schwarzberg, 1987, Figure 422.
Netter FH: Atlas of Human Anatomy. Summit, NJ, Ciba-Geigy, 1989, plate 480.

Question 85

Figure 10 shows the AP radiograph of an ambulatory 76-year-old patient. What is the most appropriate surgical treatment option for this patient?

Explanation

DISCUSSION: The patient has a periprosthetic fracture around a loose cemented femoral component. The proximal bone stock is poor; therefore, this fracture may be categorized as Vancouver 3-B. Hip arthrodesis and resection arthroplasty provide suboptimal results, particularly for ambulatory patients. Although impaction allografting may be an option to restore the bone stock in a younger patient, the latter procedure will be very difficult to perform when the proximal bone is poor in quality and fractured. Cementing another component into this wide femur is not an option. The best option for revision of the femoral component in this elderly patient is proximal femoral replacement arthroplasty.
REFERENCES: Malkani AL, Settecerri JJ, Sim FH, et al: Long-term results of proximal femoral replacement for non-neoplastic disorders. J Bone Joint Surg Br 1995;77:351-356.
Parvizi J, Sim FH: Proximal femoral replacements with megaprostheses. Clin Orthop 2004;420:169-175.

Question 86

Figure 1 is the radiograph of a 31-year-old man who had left shoulder pain after a fall during a snowboarding jump. Residual displacement of 5 mm after closed reduction is most likely to result in

Explanation

Humerus fractures account for 11% of all fractures among snowboarders and are the second-most-common upper-extremity fracture after radius fractures (48%). Surgical fixation is recommended for fractures with residual displacement >5 mm, or >3 mm in active patients involved in frequent overhead activity. Malunion can result in a mechanical block to shoulder abduction or external rotation and altered rotator cuff mechanics, causing weakness. A rich arterial network provides a favorable healing environment for greater tuberosity fractures. Consequently, nonunion and osteonecrosis are uncommon.

Question 87

A patient reports persistent anterior shoulder pain following a forceful external rotation injury to the shoulder. An MRI scan is shown in Figure 4. The patient remains symptomatic despite 3 months of nonsurgical management. Treatment should now consist of Review Topic

Explanation

The MRI scan reveals a subscapularis tear with a biceps that is out of the groove. Treatment in this patient is most predictable if the subscapularis is repaired. The biceps should either be tenodesed or tenotomized since it is unstable. Recentering of the biceps has been found to be unpredictable. Treatment of these lesions has been shown to have better results if the biceps is either released or tenodesed. This prevents recurrent biceps symptoms that can be source of surgical failure.

Question 88

Based on the findings seen at C5-6 in Figure 30, the most likely deficit for this patient will be weakness of the

Explanation

DISCUSSION: A herniated cervical disk at C5-6 causes a C6 radiculopathy. There are eight cervical nerve roots and seven cervical vertebrae, and C8 exits between the C7 and T1 vertebrae. The C6 nerve root typically innervates the biceps and wrist extensor. The deltoid is predominantly innervated by C5. The wrist flexor and triceps are predominantly innervated by C7. Grip strength is predominantly a function of C8.
REFERENCE: Hoppenfeld S: Evaluation of nerve root lesions involving the upper extremity, in Orthopaedic Neurology. Philadelphia, PA, JB Lippincott, 1977, pp 7-23.

Question 89

What is the most appropriate surgical treatment for a stage III symptomatic scapholunate advanced collapsed (SLAC) wrist?

Explanation

DISCUSSION: SLAC is the end result of chronic scapholunate instability. The arthritis follows a predictable pattern. Stage I disease involves cartilage loss between the waist of the scaphoid and the radial styloid. In stage II, the arthritis progresses to include the proximal pole of the scaphoid and the scaphoid fossa of the radius. Finally, stage III goes on to include arthritis of the capitolunate joint. The only treatment option that addresses all of the sites of arthritis is the scaphoid excision and four corner fusion.
REFERENCES: Ashmead DT IV, Watson HK, Damon C, et al: Scapholunate advanced collapse wrist salvage. J Hand Surg Am 1994;19:741-750.
Sauerbier M, Trankle M, Linsner G, et al: Midcarpal arthrodesis with complete scaphoid excision and interposition bone graft in the treatment of advanced carpal collapse (SNAC/SLAC wrist): Operative technique and outcome assessment. J Hand Surg Br 2000;25:341-345.

Question 90

Figure 46 shows the radiograph of a 65-year-old man who reports restricted range of motion and pain with sitting 18 months after undergoing right side revision total hip arthroplasty. What is the most appropriate management? L Intensive physiotherapy

Explanation

DISCUSSION: The presence of Brooker grade 1 or 2 heterotopic ossification (HO) does not influence the outcome of total hip arthroplasty, whereas restricted range of motion and pain may occur in patients with more severe grade 3 or 4 HO. Treatment may be nonsurgical or surgical. Nonsurgical management includes intensive physiotherapy during the maturation phase of the disease in an attempt to limit the final stiffness. There appears to be no data regarding the effectiveness of this treatment. There is no role for NSAIDs or radiotherapy as a treatment for preexisting HO. Surgical treatment involves excision of the heterotopic bone and can be expected to improve the functional outcome. Bisphosphonates have been used in the past, but their use has been discontinued as they only postpone ossification until treatment is stopped.
REFERENCES: Board TN, Karva A, Board RE, et al: The prophylaxis and treatment of heterotopic ossification following lower limb arthroplasty. J Bone Joint Surg Br 2007;89:434-440.
Harkess JW, Crockarell JR: Arthroplasty of the hip, in Canale ST, Beaty JH (eds): Campbell’s Operative
Orthopaedics, ed 11. Philadelphia, PA, Mosby Elsevier, 2008, vol 1, pp 314-483.

Question 91

A 36-year-old man has a 2-day history of acute lower back pain with severe radicular symptoms in the left lower extremity. The patient has a positive straight leg test at 40 degrees on the left side and mild decreased sensation on the dorsum of the left foot. What is the most appropriate management at this time? Review Topic

Explanation

In the absence of any severe progressive neurologic deficits or other red flags, the most appropriate management for an acute lumbar disk herniation is nonsurgical care. Conservative treatments such as limited bed rest, anti-inflammatory medications, and judicious use of pain medications are appropriate in this clinical situation. Up to 90% of patients will experience a resolution of symptoms without the need for surgical intervention within a 3-month window. In the acute setting, with no neurologic deficits, immediate MRI of the lumbar spine is neither beneficial nor warranted. Likewise, without signs of an acute deficit, emergent surgical intervention and caudal epidural steroid injections are not needed.

Question 92

A 36-year-old professional baseball player reports the acute onset of severe right groin pain while attempting to avoid being hit by a baseball while at bat. Examination reveals tenderness, soft-tissue swelling, and ecchymosis in the right groin extending over the medial thigh. MRI scans are shown in Figures 8a and 8b. Management should consist of

Explanation

DISCUSSION: The MRI scans reveal a severe avulsion injury of the adductor muscle from the pubic ramus with muscle edema and hemorrhage. Injury to the adductor muscle group, a “pulled groin,” is caused by forceful external rotation of an abducted leg. Pain is immediate and severe in the groin region. Tenderness is at the site of injury along the subcutaneous border of the pubic ramus. Treatment is dictated by the severity of the symptoms but generally consists of rest, ice, and protected weight bearing, followed by a rehabilitation program that begins with gentle stretching and progresses to resistance exercise with a gradual return to sports. Immobilization should be avoided because this promotes muscle tightness and scarring. No data exist to suggest that open repair yields a better outcome than nonsurgical management. Tenotomy has been performed in high-level athletes with chronic groin pain following injury.
REFERENCES: Gilmore J: Groin pain in the soccer athlete: Fact, fiction, and treatment. Clin Sports Med 1998;17:787-793.
Irshad K, Feldman LS, Lavoie C, et al: Operative management of “hockey groin syndrome”:
12 years of experience in National Hockey League players. Surgery 2001;130:759-766.

Question 93

Which of the following is true regarding changes in the vascularity of the adult intervertebral disc with age? Review Topic

Explanation

As a person ages through adulthood, neovascularization of the intervertebral disc originates from the outer annulus.
The intervertebral disc is composed of an outer structure called the annulus fibrosis and an inner structure called the nucleus pulposus. The annulus fibrosis is composed
of type 1 collagen, water, and proteoglycans. The inner nucleus pulposus is composed of type 2 collagen, water, and proteoglycans. Intervertebral discs are avascular with capillaries terminating at the end plates. The nucleus pulposus receives nutrition primarily through diffusion through blood vessels within the endplate.
Roberts et al. review the histology and pathology of the intervertebral disc. They note that at birth, the cartilagenous end plates have large vascular channels through them as well as vascular channels through the annulus. Soon after birth, these vascular channels close with none remaining at the end of the first decade of life. However, with age, more blood vessels grow into the disc from the outer annulus fibrosis in response to degenerative changes.
Illustration A is a diagram of the vascular supply in an adult intervertebral disc. Incorrect Answers:

Question 94

Contraindications to cervical laminectomy as a treatment for cervical spondylotic myelopathy include which of the following findings?

Explanation

DISCUSSION: Cervical laminectomy is an accepted treatment for multilevel cervical spondylotic myelopathy. When the compression is posterior, laminectomy addresses it directly; when the compression is anterior, it is addressed indirectly (the spinal cord floats posteriorly away from the anterior compression). Preexisting kyphosis is a contraindication to laminectomy because the cord is unable to float posteriorly away from the anterior compression, and the risk for increasing kyphosis is significant. Kyphosis after laminectomy is more likely to develop in younger patients who have fewer degenerative changes to stabilize the spine.
REFERENCES: Malone DG, Benzyl EC: Laminotomy and laminectomy for spinal stenosis causing radiculopathy or myelopathy, in Clark CR (ed.): The Cervical Spine, ed 3. Philadelphia, PA, Lippincott Raven, 1998, pp 817-825.
Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 673-680.

Question 95

Chemotherapy is routinely included in the treatment of which of the following soft-tissue sarcomas?

Explanation

DISCUSSION: Most soft-tissue sarcomas are treated with a combination of radiation therapy and wide resection. Rhabdomyosarcomas are an exception, where chemotherapy is included in all treatment plans. Chemotherapy for other soft-tissue sarcomas is controversial.
REFERENCES: Enzinger FM, Weiss SW: Rhabdomyosarcoma, in Soft Tissue Tumors, ed 3. St Louis, MO, CV Mosby, 1995, p 539.
Hays DM: Rhabdomyosarcoma. Clin Orthop 1993;289:36-49.

Question 96

A 17-year-old high school football player is seen for follow-up after sustaining an injury 3 days ago. He reports that he tackled a player, felt numbness throughout his body, and could not move for approximately 15 seconds. A spinal cord injury protocol was initiated on the field. Evaluation in the emergency department revealed a normal neurologic examination and full painless neck motion. He states that he has no history of a similar injury. An MRI scan of the cervical spine is normal. During counseling, the patient and his family should be informed that he has sustained

Explanation

DISCUSSION: The long-term effect of transient quadriplegia is unknown. Based on a history of one brief episode of transient quadriplegia and normal examination and MRI findings, the risk of permanent spinal cord injury with a return to play is low. There is a risk of recurrent episodes of transient quadriplegia after the initial episode.
REFERENCES: Morganti C, Sweeney CA, Albanese SA, et al: Return to play after cervical spine injury. Spine 2001;26:1131-1136.
Odor JM, Watkins RG, Dillin WH, et al: Incidence of cervical spinal stenosis in professional and rookie football players. Am J Sports Med 1990;18:507-509.
Torg JS, Naranja RJ Jr, Palov H, et al: The relationship of developmental narrowing of the cervical spinal canal to reversible and irreversible injury of the cervical spinal cord in football players. J Bone Joint Surg Am 1996;78:1308-1314.
Vaccaro AR, Watkins B, Albert TJ, et al: Cervical spine injuries in athletes: Current return-to-play criteria. Orthopedics 2001;24:699-703.

Question 97

An 18-year-old football player lands on a flexed knee and ankle after being tackled. Examination reveals increased external rotation and posterior translation and varus at 30° of flexion, which decreases as the knee is flexed to 90°. What is the most likely diagnosis?

Explanation

DISCUSSION: The flexed knee and ankle mechanism of injury can result in a PCL and/or posterolateral corner injury. The examination reveals an isolated injury to the posterolateral corner (arcuate, popliteus, posterolateral capsule). This results in increased posterior translation and external rotation, as well as varus that is most notable at 30° of flexion and decreases as the knee is further flexed to 90°. Combined PCL and posterolateral corner injuries are characterized by increasing instability as the knee is flexed to 90° from 30°, while isolated PCL tears show the greatest degree of instability at 90° of flexion. A rupture of the quadriceps tendon would not affect anterior or posterior stability, whereas an isolated rupture of the lateral collateral ligament, which is a rare injury, is characterized by varus instability at 30° of knee flexion without posterior translation.
REFERENCES: Harner CD, Hoher J: Evaluation and treatment of posterior cruciate ligament injuries. Am J Sports Med 1998;26:471-482.
Veltri DM, Warren RF: Isolated and combined posterior cruciate ligament injuries. J Am Acad Orthop Surg 1993;1:67-75.

Question 98

An axial T 1 -weighted MRI scan of the pelvis is shown in Figure 13. The arrow is pointing to what muscle?

Explanation

DISCUSSION: The obturator internus muscle originates from the internal pelvic wall and passes laterally through the lesser sciatic foramen, banking around the ischium below the sacrospinous ligament before inserting on the medial aspect of the greater trochanter.
REFERENCES: Higuchi T: Normal anatomy and magnetic resonance appearance of the pelvis, in Takahashi HE, Morita T, Hotta T, Ogose A (eds): Operative Treatment of Pelvic Tumors. Tokyo, Japan, Springer-Verlag, 2003, pp 4-21.
Berquist TH: Pelvis, hips and thigh, in Berquist TH (ed): MRI of the Musculoskeletal System,

ed 4. Philadelphia, PA, Lippincott Williams and Wilkins, 2001, pp 210-238.

Question 99

A 19-year-old girl has had pain and swelling in the right ankle for the past 4 months. She denies any history of trauma. Examination reveals a small soft-tissue mass over the anterior aspect of the ankle and slight pain with range of motion of the ankle joint. The examination is otherwise unremarkable. A radiograph and MRI scan are shown in Figures 45a and 45b, and biopsy specimens are shown in Figures 45c and 45d. What is the most likely diagnosis?

Explanation

DISCUSSION: Giant cell tumors typically occur in a juxta-articular location involving the epiphysis and metaphysis of long bones, usually eccentric in the bone. The radiographs show a destructive process within the distal tibia and an associated soft-tissue mass. The histology shows multinucleated giant cells in a bland matrix with a few scattered mitoses. Osteosarcoma can have a similar destructive appearance but a very different histologic pattern with osteoid production. Ewing’s sarcoma also can have a diffuse destructive process in the bone. The histologic pattern of Ewing’s sarcoma is diffuse round blue cells. Aneurysmal bone cysts typically are seen as a fluid-filled lesion on imaging studies and have only a scant amount of giant cells histologically. Metastatic adenocarcinoma does not demonstrate the pattern shown in the patient’s histology specimen.
REFERENCES: Wold LA, et al: Atlas of Orthopaedic Pathology. Philadelphia, PA, WB Saunders, 1990, pp 198-199.
Simon M, et al: Surgery for Bone and Soft Tissue Tumors. Philadelphia, PA, Lippincott Raven, 1998, pp 200-202.

Question 100

The radiographs shown in Figures 71a through 71c, and the CT scan shown in Figure 71d reveal an acetabular fracture that should be classified as

Explanation

The fracture shown represents a both column fracture described by Letournel and Judet. The fracture is a combination of a posterior column fracture and an anterior column fracture. T-type, transverse and hemitransverse all have a transverse element to them. The fracture shown involves more than just the anterior column.
Note the classic “Spur Sign” seen in these radiographs. This is pathognomonic of a both-column fracture of the acetabulum.
The other defining feature of the both column fx (as evident by these films) is that there is no intact acetabulum connected to the bone fragment which is connected to the ipsilateral SI joint.

Full Question & Answer Text (for Search Engines)

Question 1:

A 12-year-old child with spina bifida paraplegia requires brace management for ankle stability. Which of the following principles applies to brace management in this individual?

Options:

A shorter lever arm is more effective in limiting pressure.
Limbs with mild contractures do better with bracing than flaccid limbs through increased force concentration.
Three-point pressure effect works best to prevent the joint from buckling.
Four-point pressure effect works best to prevent the joint from buckling.
Smaller base support provides increased stability.

Correct Answer: Three-point pressure effect works best to prevent the joint from buckling.

Explanation:

Question 2:

Options:

antiviral therapy.
IV broad-spectrum antibiotics.
partial claviculectomy and fibulectomy.
symptomatic relief with anti-inflammatory drugs.
bone marrow aspiration and biopsy.

Correct Answer: symptomatic relief with anti-inflammatory drugs.

Explanation:

Question 3:

Which of the following findings best describes the acetabular fracture shown in Figure 38?

Options:

Posterior column with articular impaction and a free fragment
Anterior column with articular impaction
Posterior wall with an intra-articular fragment
Posterior wall with articular impaction and a free intra-articular fragment
Posterior wall with articular impaction

Correct Answer: Posterior wall with articular impaction and a free intra-articular fragment

Explanation:

DISCUSSION: The CT scan shows a posterior wall fracture with impaction of the articular surface and a free fragment within the joint. Proper treatment of this injury requires not only reduction and fixation of the posterior wall fragment but also removal of the free fragment and elevation of the depressed articular segment.
REFERENCES: Letournel E, Judet R: Fractures of the Acetabulum, ed 2. Berlin, Germany, Springer Verlag, 1993.
Matta J: Surgical treatment of acetabular fractures, in Browner BD, Jupiter JB, Levine AM, et al (eds): Skeletal Trauma, ed 3. Philadelphia, PA, WB Saunders, 2003, vol 1, pp 1109-1149.

Question 4:

Porous hydroxyapatite is placed into a bone defect. Incorporation of this bone graft substitute is expected to follow which of the following patterns?

Options:

Neovascularization and appositional new bone growth
Creeping substitution
Inflammatory response with sequestration
Dissolution of the graft material and osteoblastic bone formation
Bridging bone formation without incorporation of the graft

Correct Answer: Neovascularization and appositional new bone growth

Explanation:

Question 5:

- A patient who had previously undergone a salvage pelvic (Chiari) osteotomy now requires a total hip arthroplasty. The most frequent complication of this procedure is

Options:

fracture of the acetabulum
protrusion of the acetabulum
inadequate inferior coverage
inadequate superior coverage
inadequate anterior and posterior coverage

Correct Answer: inadequate anterior and posterior coverage

Explanation:

Question 6:

Figure 1 is the ultrasound of a 23-year-old patient who has had a volar radial 1.5-cm tender and painful wrist mass for 6 months. The additional workup prior to surgery should consist of

Options:

serum and urine protein electrophoresis.
a chest CT scan.
MRI with intravenous contrast.
age-appropriate presurgical laboratory studies.

Correct Answer: age-appropriate presurgical laboratory studies.

Explanation:

Question 7:

Options:

Electrode placement
Stimulation failure
Anesthetic effect
Cord ischemia from retraction
Cerebral ischemia from retraction

Correct Answer: Cerebral ischemia from retraction

Explanation:

DISCUSSION: The change noted is focal and confined to the cortex, sparing the opposite side, both lower extremities, and the subcortical waveforms, making all the choices unlikely with the exception of carotid compression with focal cortical ischemia. This may be associated with poor collateral flow from the opposite hemisphere due to an incomplete circle of Willis.
REFERENCES: Drummond JC, Englander RN, Gallo CJ: Cerebral ischemia as an apparent complication of anterior cervical discectomy in a patient with an incomplete circle of Willis. Anesth Analg 2006;102:896-899.
Yeh YC, Sun WZ, Lin CP, et al: Prolonged retraction on the normal common carotid artery induced lethal stroke after cervical spine surgery. Spine 2004;29:E431-E434.

Question 8:

Options:

Injury to the lumbar sympathetic chain
Injury to the parasympathetic nerve
Immune response to the allograft bone
Occlusion of the left iliac vein
Prolonged retraction of the left iliac artery

Correct Answer: Injury to the lumbar sympathetic chain

Explanation:

Question 9:

Which of the following findings is likely to be pathologic in a thin, well-conditioned endurance athlete?

Options:

Left ventricular hypertrophy by voltage on electrocardiography (ECG)
Primary AV block on ECG
II/IV systolic murmur increased with standing and Valsalva maneuver
Nonspecific STT wave changes in the lateral leads on ECG
Resting sinus bradycardia at 40 beats per minute

Correct Answer: II/IV systolic murmur increased with standing and Valsalva maneuver

Explanation:

Question 10:

Options:

Contact area and contact pressure both decrease.
Contact area and contact pressure both increase.
Contact area and contact pressure both remain the same.
Contact area increases and contact pressure decreases.
Contact area decreases and contact pressure increases.

Correct Answer: Contact area increases and contact pressure decreases.

Explanation:

Question 11:

Options:

be able to run and walk without pain.
refrain from vigorous activity for 6 months.
achieve full hip and knee range of motion.
achieve symmetric lower extremity strength.
have radiographic evidence of a circumferential external bridging callus.

Correct Answer: have radiographic evidence of a circumferential external bridging callus.

Explanation:

DISCUSSION: While it is recommended that a patient gain full range of motion, pain-free function, and symmetric strength prior to returning to vigorous activities, it is absolutely essential that radiographs of the fracture site reveal a circumferential external bridging callus to prevent refracture. This is particularly important for comminuted femoral fractures with various sized fragments. It is also recommended that a return to rodeo riding be postponed for at
least 1 year.
REFERENCES: Brumback RJ, Ellison TS: Intermedullary nailing of femoral stress fractures. J Bone Joint Surg Am 1992;74:106-112.
Bucholz RW, Jones A: Fractures of the shaft of the femur. J Bone Joint Surg Am
1991;73:1561-1566.
Butler MS, Brumback RJ: Interlocking nailing for ipsilateral fractures of the femur, femoral shaft, and distal part of the femur. J Bone Joint Surg Am 1991;73:1492-1502.

Question 12:

While lifting weights, a patient feels a pop in his arm. He has the deformity shown in Figure 30. If left untreated, the patient will have the greatest deficiency in

Options:

shoulder flexion.
elbow flexion.
forearm pronation.
forearm supination.
wrist flexion.

Correct Answer: forearm supination.

Explanation:

Question 13:

Options:

Calcaneal stress fracture
Hindfoot coalition
Insertional Achilles tendonitis
Plantar fasciitis

Correct Answer: Plantar fasciitis

Explanation:

Question 14:

A 72-year-old woman who fell on her right shoulder while using a treadmill is now unable to elevate her right arm. An MRI scan is shown in Figure 7. What is the most likely diagnosis?

Options:

Axillary nerve injury
Anterior dislocation
Extension of a chronic large rotator cuff tear
Suprascapular nerve entrapment from a ganglion cyst
Greater tuberosity avulsion

Correct Answer: Extension of a chronic large rotator cuff tear

Explanation:

Question 15:

Which of the following treatments of polyethylene results in the highest amount of oxidative degradation?

Options:

Ethylene oxide sterilization
Gamma irradiation in air
Gamma irradiation in an inert environment
Gamma irradiation followed by cross-linking
Gas plasma sterilization

Correct Answer: Gamma irradiation in air

Explanation:

Question 16:

Options:

Arterial injury
Sciatic nerve palsy
Infection
Acetabular component loosening

Correct Answer: Acetabular component loosening

Explanation:

Question 17:

Options:

Antiresorptive bisphosphonate medication
A repeat dual-energy x-ray absorptiometry scan (DEXA) and treatment if the T-score is less than -2.5
A repeat DEXA scan and treatment if the T-score is greater than -1.5
No treatment since the BMD is not in osteoporotic range
(PTH) taraparatide hormone followed by surgery

Correct Answer: Antiresorptive bisphosphonate medication

Explanation:

DISCUSSION: A DEXA scan is most appropriately used to establish a baseline score. Even if the bone mineral density is not within the osteoporotic range (T-score less than -2.5), a prior fragility fracture is a strong risk factor for a second fracture as a result of factors other than bone density, such as worsening vision or balance, confusion, or other predispositions to falls. The guidelines of the National Osteoporosis Foundation indicate that, following a fragility hip fracture, active anti-osteoporotic medication should be initiated, whether or not a DEXA scan is performed. A recent study showed that antiresorptive therapy following a hip fracture reduces not only the risk of a second fracture but also overall mortality.
REFERENCE: Gardner MJ, Brophy RH, Demetrakopoulos D, et al: Interventions to improve osteoporosis treatment following hip fracture: A prospective, randomized trial. J Bone Joint Surg Am 2005;87:3-7.

Question 18:

Options:

aggressive management should be considered to improve the outcome of this group of multiply injured patients.”
Tran et al compared polytrauma patients with foot injuries to 14 polytrauma patients without foot injury at a minimum of 12 months from injury. The AAOS lower limb and foot and ankle outcomes data collection questionnaire showed significantly lower scores in the foot injury group. The Constant score is used for evaluation of shoulder conditions.
Prader-Willi syndrome and Angelman syndrome are examples of a genetic phenomenon by which certain genes are expressed in a parent-of-origin-specific manner. What is the name of this genetic phenomenon?
matched polytrauma patient without a foot injury?

Correct Answer: aggressive management should be considered to improve the outcome of this group of multiply injured patients.”

Explanation:

This patient with hemophilia A is presenting with an intramuscular hematoma surrounding the iliacus muscle which is likely to cause femoral nerve compression. Paresthesias would be expected in the L4 nerve distribution.
Excessive bleeding into joints and muscles is a common manifestation of hemophilia. The iliacus muscle is a frequent site of hemorrhage in patients with severe or moderate hemophilia. Intramuscular hematoma of the iliacus muscle is likely to occur following play or sporting events that include forceful contraction of the hip flexor muscles. As the hematoma expands, it may
compress the adjacent femoral nerve, potentially resulting in complete femoral nerve palsy. Femoral nerve compression typically includes paresthesias in the distribution of the terminal saphenous nerve branch.
Gilbert et al. review the complex relationship between recurrent bleeding, synovitis, and the development of arthritis in the patient with hemophilia. They discuss both conservative and surgical treatment modalities in these patients and recommend arthroscopic synovectomy for the knee and ankle joints. They conclude that the greatest risk to these procedures is a decreased range of motion.
Kuo et al. reports on a fourteen-year-old healthy boy with an 11-day history of pain and weakness in the right lower limb following a fall. They report pain in the right lower extremity, numbness of the anterior aspect of the right thigh and medial border of the right leg and foot, inability to ambulate and
weakened quadriceps muscle strength. MRI revealed an iliacus hematoma with a complete femoral nerve palsy. He underwent CT-guided percutaneous drainage for decompression with complete resolution of the palsy.
Illustration A is a diagram of dermatomal distribution. Illustration B shows the lumbar plexus demonstrating the intimate relationship of the femoral nerve to the iliacus muscle.
Incorrect Answers:
A 45-year-old male trauma patient presents with multiple extremity injuries including the foot injury shown in Figure A. The foot fracture is treated surgically, and heals without any initial complications. At a minimum of 12 months, this patient will be expected to have which of the following scores compared to a
Patients with pauciarticular juvenile rheumatoid arthritis (JRA), specifically the subgroup with elevated antinuclear antibody (ANA) titers, are associated with the highest incidence (~75%) of anterior uveitis. As a result, referral for an ophthalmology consultation is recommended.
Pauciarticular JRA is the most common subgroup of JRA and typically presents between the ages of 2 to 4 years with mild swelling of one to four joints. The diagnosis is typically one of exclusion as laboratory studies, including erythrocyte sedimentation rate and rheumatoid factor, are usually within normal limits. In JRA, iridocyclitis, a type of anterior uveitis typically occurs following the onset of synovitis but may precede the joint symptoms. This iridocyclitis is frequently indolent but requires immediate ophthalmologic consultation for a slit-lamp examination because if left untreated, anterior uveitis may progress to loss of vision.
Foeldavri et al. review JRA anterior uveitis. They report an overall incidence of
10%, but this is dependent on the JRA subtype. They noted that a large proportion of children with JRA develop uveitis in the first year of disease and
90% after 4 years. They state that early age of JRA onset, oligoarticular subtype, and ANA reactivity are the main risk factors for the development of uveitis. They conclude that JRA-associated uveitis is important to recognize and treat early to prevent any visual damage.
Hawkins et al. review bilateral chronic anterior uveitis in JRA. They report that female gender, oligoarthritis, and presence of antinuclear antibodies are risk factors.
They report on treatment options, including the use of biologics. They conclude that stepwise immunomodulatory therapy is indicated, with new biologic drugs being used in cases of refractory uveitis.
Incorrect Answers:
Anterior 4: Pompe disease is a glycogen storage disease which may lead to ptosis (drooping of the upper eyelid), not anterior uveitis
A 9-year-old male with hemophilia A presents with severe groin pain, parasthesias over the medial aspect of the distal tibia, and difficulty ambulating several hours after a soccer game. He is believed to have an intramuscular hematoma surrounding the iliacus muscle. Which nerve is MOST likely to be compressed?
Which of the following conditions places the patient at highest risk for anterior uveitis and necessitates referral to an ophthalmologist?
Salmonella is a classic cause of osteomyelitis in patients with sickle cell disease.
Sickle cell disease is a genetic disorder of hemoglobin synthesis. The disease occurs in two phenotypes: sickle cell anemia (most severe) and sickle cell trait (most common). The two most common causes of osteomyelitis in children with sickle cell disease are
Staphylococcus aureus and Salmonella. Although S. aureus is the most common cause of osteomyelitis in the general population, the literature varies on which is the most common in patients with sickle cell disease. The increased risk in these patients may be associated with gastrointestinal microinfarcts, poor circulation of blood in bone, and splenic infarcts that predispose patients to infection by encapsulated bacteria (i.e., Salmonella).
Piehl et al. analyzed records of seven hundred seventeen patients with sickle cell disease treated over a thirteen-year period. They identified and retrospectively reviewed sixteen cases of osteomyelitis in fifteen patients. The authors found Salmonella to be the causative organism in thirteen cases with Proteus mirabilis, Escherichia coli, and Staphylococcus aureus all affecting one patient each. The authors report the annual incidence of osteomyelitis in their series as 0.36%.
Givner et al. reviewed sixty-eight cases of osteomyelitis in children with sickle cell disease and positive cultures over a ten year period. Of the sixty-eight, 50 (75%) yielded Salmonella and Staphylococci was isolated 7 (10%). In
addition, the authors report non-speciated gram-positive cocci were isolated in
11 (16%), non-speciated gram-negative rods in 5 (7%), and non-specified bacteria in 2 (3%). The authors conclude Salmonella is the most common pathogen causing osteomyelitis in patients with major sickle hemoglobinopathies.
Epps et al. reviewed fifteen patients with sickle cell disease and osteomyelitis. Staphylococcus aureus was isolated in eight cases (53%), Salmonella in six (40%), and Proteus mirabilis in one (7%). The authors conclude S. aureus, not Salmonella, may be the most common cause of osteomyelitis associated in patients with sickle-cell disease.
Figure A demonstrates an osteolytic lesion of the distal tibia and Figure F demonstrates sickle-shaped erythrocytes.
Incorrect Answers
Low toughness is a disadvantage of ceramic bearings in total hip arthroplasty.
Ceramic is a non-metal that demonstrates excellent wear characteristics when used with polyethylene in total hip arthroplasty. Although it has a high Young's modulus, it has a low fracture toughness. Subsequently, ceramic is poorly resistant to crack formation. In contrast, UHMWPE has a high fracture toughness because of the presence of very long hydrocarbon chains.
Santavirta et al. review alternative bearing materials to improve wear in total hip arthroplasty. Alumina ceramics are noted to be biostable and bioinert. The best wear properties are noted with ceramic-on-ceramic bearings. For current ceramic constructs, fracture risk is less than 1 per 1000.
Lang et al. review the use of ceramics in total hip replacement. The authors note that ceramic has high compressive strength and high wettability. Low fracture toughness and linear elastic behavior increase the risk of breakage of ceramic components under stress. Processing improvements, enhanced head- neck interfaces and liner modifications have lead to a decrease in the rate of ceramic fracture.
Illustration A shows a compromised ceramic head as a manifestation of the low fracture toughness of the material.
Incorrect Answers:
An 8-year-old African American female presents with lower extremity pain and subjective fever. On exam there is tenderness about the distal tibia. Further workup reveals elevated inflammatory markers and a lytic lesion (Figure A). An aspirate is obtained and cultures grow Salmonella. Additional investigation is most likely to reveal which of the following findings (Figure B-F)?
An ideal fluid film lubrication regime minimizes friction. A larger head size results in a greater development of full-film lubrication due to the increased relative sliding velocity of the larger bearing surfaces. Increased surface roughness inhibits the formation of the film lubrication. The most important factor influencing the predicted lubrication film thickness
has been found to be the radial clearance between the ball and the socket.
Jin et al report that slight clearance, not complete congruence, is optimal for formation of the optimal fluid film lubrication. They note that full fluid film lubrication may be achieved in these hard/hard bearings provided that the surface finish of the bearing surface and the radial clearance are chosen correctly and maintained.
Dumbleton reviewed the literature of metal-on-metal THA and concluded that the current literature does not show any clinical benefit of metal-on-metal compared to metal on poly. Metal-on-metal has been shown to have higher metal ion level in blood, and measurement of these levels is recommended to help identify those at risk of adverse effects from metal on metal prostheses.
Low toughness is a disadvantage of which of the following bearing surfaces used in total hip arthroplasty?
This attending did not fully disclose that the resident would be performing the cementing portions of the case unsupervised. This represents an ethically unsound scenario as the patient was misled regarding involvement of the resident in their surgery.
The informed consent process is grounded in the ethical principle of autonomy. Informed consent represents a shared decision making process where a
patient understands all the risks and benefits of a surgery fully and makes an informed decision. However, the patient's choice of surgeon is felt to be critical
to the informed consent process and any variation from that surgeon performing the surgery should be discussed explicitly. A surgeon who performs surgery or part of surgery on the patient without prior consent may be held liable for battery.
Kocher presents three cases demonstrating the spectrum of "ghost surgery". They state the substitution of an authorized surgeon with an unauthorized surgeon or allowing surgical trainees to operate without appropriate guidance constitutes "ghost surgery".
Deviation from what is explicitly discussed has been justified in an emergency scenario or if the treatment is aimed at an overall condition.
Bhattacharyya et al reviewed malpractice claims for factors that positively correlated with successful defense. They found that those who performed informed consent in the office had lower risk of malpractice payment. They conclude surgeons can decrease their risk of malpractice claims by performing informed consent in the office and documenting the discussion.
Incorrect Answers:
Which of the following features of metal-on-metal total hip arthroplasty does not allow for improved fluid film lubrication between the components?
The patient sustained a fragility fracture with lab work consistent with primary hyperparathyroidism.
Hyperparathyroidism is commonly caused by increased activity of the parathyroid glands resulting in high levels of PTH. Increased circulating levels of PTH leads to calcium being "sucked" out of bone and into the serum. This
alteration in calcium hemostasis leads to low-density bone and a predisposition to fragility type fractures. When present, lab values are much different from standard age-related osteoporosis. Furthermore, referral to medical and surgical endocrinology specialists for directed treatments may improve overall bone quality and prevent further fragility fractures.
Fraser summarizes primary and secondary hyperparathyroidism. He describes the normal physiologic response to low calcium of an increase in PTH. Increased PTH has three downstream effects of increased tubular resorption of calcium by the kidneys, increased osteoclast activity to harvest calcium from bone, and increased active vitamin D levels leading to increased bowel absorption of calcium.
Singhal et al. reviewed hyperparathyroidism and what the orthopedic surgeon should know. They state when a patient presents with a pathologic fracture and elevated serum calcium levels, an appropriate lab workup for hyperparathyroidism should be done. They stated when surgery is needed for hyperparathyroidism and fracture, surgery can safely be performed simultaneously as demonstrated by 3 case examples.
Figure A exhibits a left femoral neck fracture, which is a fragility fracture associated with poor bone density. Illustration A is a figure from Fraser's article exhibiting the
feedback loop from the hypothalamus, pituitary, adrenal/glandular axis.
Incorrect answers:
Prior to undergoing a total knee arthroplasty at an academic medical center a patient is told during informed consent by the attending surgeon that resident involvement in the case will be limited to retracting. During the case the attending is present up to trialing of the selected components. The surgeon leaves prior to cementing to start trialing components in another case while the chief resident remains alone in the room for the completion of the case. Which of the following is true regarding the ethics of this practice?
Patients in factorial randomized control trials (RCT) are assigned to groups that receive a specific combination of interventions and non-interventions.
In factorial RCTs, patients are randomized to groups receiving treatment A and B, treatment A or control, treatment B or control, or no treatment. This study design is useful because two interventions can be assessed with the same
study population and any interaction between the treatments can be determined (for example, does treatment A work differentially when combined with treatment B). Other randomized control trial designs include parallel, cluster, and crossover. Parallel studies are performed by having two or more groups that exclusively have one intervention without group overlap.
Crossover studies have each group receive each intervention in a random sequence. Cluster design studies have pre-existing groups of participants
(such as schools, or cities) that are randomly selected to receive or not receive an intervention.
Karlsson and the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine published an exhaustive guide to research for evidence-based medicine in a step-wise fashion. They cover levels of evidence, design for randomized control trials and the CONSORT checklist. They also describe proper study design of cohort, case- control, case series, systematic review, meta-analysis studies. The second half of the guide discusses appropriate outcome measures, statistical analyses, and data interpretation, reporting complications, and concludes with steps to writing a scientific article.
Incorrect Answers:
A 66-year-old woman falls from standing and sustains the injury shown in Figure A. Her most recent T score was -1.9, 3 months prior to presentation. Preoperative lab work reveals elevated serum calcium, elevated alkaline phosphatase, decreased serum phosphorus, and elevated parathyroid hormone (PTH). Which of the following correctly describes the underlying etiology of her osteopenia?
The most recent update of the CDC guidelines for the prevention of SSI issues a category IA strong recommendation stating that "in clean and clean- contaminated procedures, do not administer additional antimicrobial prophylaxis doses after the surgical incision is closed in the operating room, even in the presence of a drain."
The previous 2002 CDC guidelines for the prevention of SSI focused on three performance parameters: (1) initiation of parenteral antibiotics within 1 hour of the surgical incision, (2) selection of an appropriate antibiotic, and (3) discontinuation of antibiotics within 24 hours. The most recent updated 2017
CDC guidelines for the prevention of SSI has several notable changes with an emphasis that additional doses of antibiotics after initial prophylaxis are no longer recommended.
Berrios-Torres et al. review the 2017 updates to the CDC guidelines for prophylaxis against SSI. Strong recommendations include that in clean and clean-contaminated cases, additional antimicrobial prophylaxis should not be administered after the surgical incision is closed in the operating room, even in the presence of a drain. Furthermore, the authors discuss that there is no evidence that re-dosing intraoperative antibiotics or continuation of antibiotics until surgical drains have been removed provides any additional protection against surgical site infection.
O'Hara et al. highlights the key updates in the most recent CDC guidelines for prevention of SSI. The authors present specific suggestions for translating these recommendations into evidence-based policies and practices. They conclude that the implementation of new and existing guidelines in SSI prevention requires thoughtful and careful collaboration with several inter- professional and interdisciplinary teams.
Incorrect Answers:
Which of the following study designs describes a randomized controlled trial in which two interventions are applied separately or in combination to study groups?
The patient has an allergy to cephalosporins and a history of an MRSA infection. Of the choices listed, vancomycin is the best preoperative antibiotic for this patient.
The choice of preoperative antibiotics is of great interest given the large
medical and economic cost of periprosthetic infections. Standard preoperative prophylaxis in patients undergoing total joint arthroplasty consists of cefazolin or cefuroxime. In patients with beta-lactam allergies, the treatment options include clindamycin or vancomycin. Vancomycin is often the antibiotic of choice given it's higher efficacy with regard to MRSA prevention. In those patients who are considered at risk for MRSA infection and a beta-lactam allergy, vancomycin can be supplemented with an aminoglycoside (gentamicin) or aztreonam.
Bratzler et al. review antimicrobial prophylaxis for surgery and state for orthopedic joint replacement procedures cefazolin or cefuroxime is the recommended antibiotic. For patients with a confirmed beta-lactam allergy, they recommend vancomycin or clindamycin. They also state antibiotics should be stopped within 24hrs after surgery.
Dellinger et al. review antibiotics for surgical prophylaxis. They state the standard antibiotics for orthopedic procedures are cefazolin or cefuroxime. They state if there is also a concern for MRSA infection vancomycin can be added in addition to the above antibiotics.
Incorrect Answers:
Which of the following is STRONGLY recommended by the most recent (2017) Centers for Disease Control and Prevention (CDC) Guidelines with regard to antimicrobial prophylaxis for the prevention of surgical site infection (SSI)?
Clindamycin is a bacterial protein synthesis inhibitor by inhibiting ribosomal translocation at the 50S subunit.
Clindamycin is primarily bacteriostatic but may be bactericidal at higher concentrations.
Side effects of clindamycin may include a hypersensitivity reaction and pseudomembranous colitis. Resistance to clindamycin is conferred by a plasmid that alters the 50s ribosome binding site for clindamycin. The D- zone test is used to determine whether an organism has inducible resistance
to clindamycin.
Marcotte and Trzeciak published a review on community-acquired methicillin- resistant Staphylococcus aureus (CA-MRSA). They reported that CA-MRSA
does not have predictable susceptibility to clindamycin. They conclude that clindamycin also presents a risk for the development of Clostridium difficile colitis and inducible clindamycin resistance for which a D-zone test should be performed when culture results reveal erythromycin resistance.
Steward et al. performed a lab study to determine the efficacy of testing for induced clindamycin resistance in erythromycin-resistant Staphylococcus aureus. They reported that resistance to erythromycin and clindamycin can occur through methylation of their ribosomal target site (50s), which is mediated by erm genes. They conclude that disk diffusion is the preferred method for testing S. aureus isolates for inducible clindamycin resistance.
Incorrect Answers:
A 68-year-old man is scheduled to undergo total hip arthroplasty. He states he had an anaphylactic reaction after taking cefazolin for an MRSA hand infection 10 years ago. Which of the following best describes the preoperative antibiotic that should be administered for this patient?
Advanced glycation end-products (AGEs) cause excessive cross-linking of collagen in aging articular cartilage. As a result, the stiffness is increased.
AGEs are produced by spontaneous nonenzymatic glycation of proteins when sugars (glucose, fructose, ribose) react with lysine or arginine residues. The most abundant matrix protein in cartilage is Type II collagen. AGEs cause changes to the aging cartilage matrix and the aging chondrocyte. The increased cross-linking of Type II collagen results in an increase in cartilage stiffness (i.e. increase in the modulus of elasticity) and an increase in brittleness (i.e. less strain needed to go from the yield point to the fracture point on the stress-strain curve). As a result of the change in the aging cartilage’s biomechanical properties, it's susceptible to fatigue failure. Additionally, AGEs decrease the anabolic response of chondrocytes from autocrine signaling via TGF-beta, IGF-1, BMP-7, and OP-1. These two initial mechanisms contribute to aging cartilage to eventually lead to the development of osteoarthritis.
Li et al. reviewed age-related changes in cartilage and seek to define the different
mechanisms between aging cartilage and osteoarthritis. They state that with AGEs, there is excessive collagen cross-linking increases cartilage stiffness, while shortening/degradation of aggrecan leads to loss of sugar side chains and water-binding ability. Additionally, increased levels of AGEs are associated with a decline in anabolic activity. They state that these changes to cartilage make it more vulnerable to damage and therefore the onset of osteoarthritis. This is contrast to the initial steps in the mechanism of osteoarthritis which is characterized by cell proliferation, formation of chondrocyte clusters, increased synthesis of irregular cartilage matrix, and eventually a pro-catabolic and pro-inflammatory state that results in an imbalance in cartilage homeostasis and cartilage matrix breakdown.
Anderson et al. reviewed the relationship between osteoarthritis and aging.
They state that knee cartilage thins with aging, especially on the femoral and patellar sides, suggesting a gradual loss of cartilage matrix. AGEs formation leads to modification of type II collagen by cross-linking of collagen molecules, increasing stiffness and brittleness and increasing susceptibility to fatigue failure. Furthermore, describe the senescent phenotype of the chondrocyte
and its similarities with osteoarthritic chondrocyte phenotype.
Incorrect Answers:
Which of the following antibiotics works by binding to the 50S ribosomal subunit?
The patient has clinical signs and symptoms of gout. Figure D would correspond to this diagnosis as it shows negatively birefringent needle-shaped monosodium urate crystals.
Gout is an idiopathic disorder of nucleic acid metabolism that leads to hyperuricemia and deposition of monosodium urate crystals, most commonly in the joints of the lower limb (knee, ankle, and classically the 1st metatarsophalangeal joint). Diagnosis can be confirmed with joint arthrocentesis revealing negatively birefringent needle-shaped crystals. Treatment of acute gout flares is generally comprised of NSAIDs and colchicine, and chronic gout is treated with allopurinol to prevent the build-up
of uric acid.
Shmerling et al. prospectively analyzed the synovial fluid test results of 100 consecutive patients undergoing diagnostic arthrocentesis. They noted that synovial fluid white blood cell count (WBC) and the percentage of polymorphonuclear cells performed well as discriminators between inflammatory and noninflammatory diseases. Given the diagnostic value of synovial WBCs, the authors concluded that ordering of chemistry studies of synovial fluid should be discouraged because they are likely to provide misleading or redundant information.
Chiodo et al. review the use of intra-articular aspiration and injections for both diagnosis and treatment of disorders of the lower extremity such as infectious arthritis, gout, pigmented villonodular synovitis (PVNS), rheumatoid arthritis, and hemophilia. The authors discuss the importance of knowledge of regional anatomy, procedural indications, and appropriate techniques for successful aspiration/injection. The authors review safe and effective aspiration and injection techniques for the lower extremity, including the hip, knee, foot, and ankle.
Figure A reveals hemosiderin stained multinucleated giant cells consistent with PVNS. Figure B is a gram stain revealing gram-positive cocci in clusters consistent with Staphylococcus aureus. Figure C reveals rhomboid-shaped, positively birefrigerant crystal consistent with calcium pyrophosphate/pseudogout. Figure D reveals negatively birefringent needle- shaped crystals of monosodium urate/gout. Figure E reveals a collection of histiocytes and inflammatory cells around prominent intimal hyperplasia.
Incorrect Answers
An increase in advanced glycation end-products (AGEs) is characteristic of which of the following clinical conditions and results in which pathologic process?
Regardless of the number of level I studies included in a systematic review, having one study with <80% follow-up decreases the level of evidence for this review from level I to level II.
After classifying the type of study (e.g. therapeutic study, prognostic study, diagnostic study, economic analysis, or decision analysis) the “level of evidence” is then determined. The level of evidence (on a scale of I through V) for medical research is determined. It is important to consider the characteristics of a study’s design. This would include the percent follow-up, utilization of a control group, presence of blinding, heterogeneity of results, and process of randomization. Specific to meta-analyses and systematic reviews, it is important to know that the lowest quality study used in the review determines the level of evidence. In evidence-based medicine, higher levels of evidence have a larger impact on clinical recommendations.
Bhandari et al. analyzed the interobserver agreement among reviewers in categorizing the type of study, level of evidence, and subclassification for different clinical studies. The authors had 6 different surgeons with different levels of training in epidemiology analyzed 51 separate papers published in JBJS. The results demonstrated that the interobserver absolute agreement for the type of study and the level evidence was 82% and 67%, respectively. The epidemiology-trained reviewers had nearly perfect agreement in categorizing the type of study, level of evidence, and subclassification.
Wright et al. published an editorial introducing the different types of study designs and defined the different levels of evidence. Illustration A is a figure from this editorial.
Incorrect Answers:
A 55-year-old male, alcoholic, presents to the ER with acute right knee swelling and pain x 3 days. He admits to prior episodes of this pain that resolve after a few days. Serum labs reveal an ESR of 40 mm/hr and CRP of 5 mg/dl. He undergoes right knee aspiration and based on the results, he is discharged home on colchicine with the presumed diagnosis of gout. Which of the following images of the aspiration results are consistent with this diagnosis?
conclude that the patient populations and outcomes measure are homogenous and you do not have any concerns with randomization. You notice one of
the studies included had 70% follow-up, yet the remaining studies had
>80% follow-up. Knowing this, you appropriately assign what level of evidence to the systematic review?
The correct sequence of events should be the surgeon reads the surgical information on the consent to the patient, then the surgeon marks the surgical site with the patient’s assistance, then allows the anesthesia team to perform their procedure, and then performs a final Time-Out with the surgical team immediately prior to the surgical incision.
Orthopedic surgical patients are at risk of surgical errors due the number of procedures that can be performed on the bilateral extremities. The responsibility to identify the correct surgical procedure at the correct location has expanded beyond only the surgeon. The entire surgical team is
responsible for confirming the patient, surgical site, and surgical procedure. All members on the surgical team should be valued and emboldened to “speak up’ and actively participate. To help improve communication and reduce complications, surgical safety checklists have become common. In a statement
published by the AAOS is 2015, they support the use of standardized surgical systems, including the use checklists, as it is critically important to keep patients safe. In 1998, the AAOS introduced the “Sign Your Site” safety program to reduce wrong-site surgeries through improved site identification. Permanent ink should be used to mark the site(s) with the patient's assistance prior to surgery, and the site(s) should be confirmed by the surgical team during the Time-Out immediately before the start of the surgical procedure.
Singer et al. performed a study to evaluate the association between surgical teamwork and surgery safety checklist performance. Their results emphasized the importance of surgeon buy-in and clinical leadership to initiating and maintaining surgical safety checklists. In addition to surgeon buy-in and clinical leadership, factors that help maintain high-quality and consistent surgical teamwork were communication, coordination, respect, and assertiveness.
Incorrect Answers:
You are reviewing a systematic review on the 90-day complication rate and outcome for same day total joint arthroplasty for publication. After you analyze the methodology of the 6 randomized controlled trials included in the review, you
preoperative paperwork outside the room. The patient is taken to surgery and receives an interscalene block on the left shoulder after sedation. At the final Time- Out, the surgeon realizes a discrepancy with the laterality when the consent is read aloud. The surgeon aborts the case and wakes the patient. What is the correct sequence of events that should have happened to prevent this error? A: The surgeon begins
the surgery B: The surgical team performs a Time-Out C: The surgeon marks the surgical site D: The surgeon reads the surgical information on the consent to the patient E: The anesthesia team administers a local extremity block
Enchondral ossification occurs with relative stability constructs, which is represented by the bridge plate in figure C.
Fracture healing is a complex process that occurs in several key steps. The type of healing that occurs is dependent on the stability and strain of the fracture environment. In constructs with very little strain, also referred to as absolute stability, there is primary bone healing through Haversian remodeling. This produces very little callus and does not rely on a cartilage precursor. Relative stability constructs with higher strains produce a cartilage precursor, which subsequently ossifies in later stages of healing, also referred to as enchondral ossification.
Perren reviewed the biological mechanisms of fracture healing. The author discussed the importance of skeletal stiffness for limb function in addition to the healing process that utilizes soft tissue compensatory mechanisms to aid
in fracture healing. The author concluded that the goal of fracture healing is to obtain a functional limb to allow for daily mobility and activity.
Gerstenfeld et al. investigated the effect of non-selective and COX-2 selective NSAIDs effects on bone healing in a rat model. They reported a significantly higher nonunion rate in valdecoxib treated rats compared to the ketorolac group. They also noted that withdrawal of either drug at six days resulted in prostaglandin E2 levels returning to normal levels after 14 days. The authors concluded that COX-2 specific NSAIDs inhibited bone healing greater than nonspecific NSAIDs with the magnitude of the effect dependent on the duration of treatment, but the effects on prostaglandin E2 levels appear reversible with discontinuation of the drug.
Figure A is the AP radiograph of the left distal tibia with three lag screws through a spiral fracture. Figure B is the lateral radiograph of the right elbow with an olecranon plate.
Figure C is the AP radiograph of the right distal femur with a lateral bridge plate. Figure D is an AP radiograph of the left ankle with a lag screw and neutralization plate on the distal fibula. Figure E is the lateral radiograph of the forearm with a compression plate on the radius.
Incorrect Answers:
A 31-year-old man is scheduled to undergo a right shoulder arthroscopic labral repair. The surgeon is running behind and hurries to the preoperative holding area. The surgeon greets the patient and verbally confirms the operative site with the patient. The surgeon leaves the patient’s room and completes the appropriate
The yield point is the transition point between elastic and plastic deformation. The yield strength is defined as the amount of stress necessary to produce a specific amount of permanent deformation.
Stress is the amount of force applied to a material and strain is the deformation resulting
from that stress. This is graphically depicted as a stress- strain curve, where the X-axis represents strain and the Y-axis represents stress. The elastic modulus of a material is the linear region of the graph (rise over run/stress on strain). Remember, an elastic material is one that resists a change in shape (less strain or deformation under increasing stress). Non- linear regions include the toe region for some materials (tendons/ligaments) and the plastic zone, which occurs after the yield point.
Mantripragada et al. provide a review of recent advances in designing orthopaedic implants. Of note, they discuss modifications to metallic implants to reduce unwanted effects, such as nickel-free stainless steel. They also go over newer alloys with desirable mechanical and biological properties, such as tantalum, niobium, zirconium, and magnesium.
Kennedy et al. provide a classic in-vitro tension study of the human knee ligaments. They used an Instron Tension Analyzer to test the ultimate failure of the medial collateral, lateral collateral, anterior cruciate, and posterior cruciate ligaments at different loading rates. They found that the posterior cruciate ligament was the strongest (the other ligaments were all of
comparable strength) and that microscopic failure occurred before macroscopic failure. Illustration A represents a stress-strain curve.
Incorrect Answers:
is a phenomenon especially associated with a ductile material; the diameter of the material is diminished prior to fracture.
material can absorb before fracture and is the area under the stress-strain curve. Answer 5: The toe region is seen in materials such as ligaments and tendons and represents the straightening of the crimped ligament fibers.
Which of the following fixation constructs would achieve fracture healing through enchondral ossification?
The preosteoclast (precursor to the osteoclast) is the only cell of myeloid origin. The remainder of the cells involved in bone formation, remodeling, and metabolism are of mesenchymal origin.
Osteoclast signaling, function, and biology have grown increasingly well understood over the past few decades. Osteoclast activity is regulated by
osteoblasts, thereby coupling bone formation and resorption. Osteoclast differentiation from myeloid precursor cells is stimulated by key molecules including RANK, PU-1, and CSF-1. An understanding of these molecular pathways is essential to developing effective directed anti-resorptive therapies.
Zaidi et al. present a comprehensive review of proliferation, differentiation, and hormonal regulation of cells of the bone. The authors specifically discuss the unique origin of the osteoclast from the myeloid lineage and conversely the mesenchymal origin of the osteoblast. Furthermore, they highlight the
most recent understanding of the molecular mechanisms involved in osteoclast formation
and signaling, including M-CSF and RANKL.
Caterson et al. discusses mesenchymal differentiation in the context of musculoskeletal regeneration. The authors review the growth factors and bioactive signaling molecules involved in directed differentiation itno the various mesodermal lineages including bone, cartilage, muscle, tendon, marrow, and adipose. They emphasize the importance of understanding these pathways to regenerative medicine.
Illustration A is a diagram illustrating the difference between mesenchymal and myeloid lineages.
Incorrect answers:
The point on a stress-strain curve that separates the plastic and elastic regions is defined as which of the following:
Due to the risk of inducible clindamycin resistance in erythromycin-resistant MRSA, a D-test should be performed.
Isolates of MRSA that are resistant to erythromycin have been shown to become resistant to clindamycin through a process called inducible resistance, which is conferred by a plasmid that alters the 50S ribosome binding site for both clindamycin and erythromycin. Thus, when culture results reveal erythromycin-resistant MRSA, a D-zone test should be performed to check for inducible clindamycin resistance. The D-zone test is performed by
placing an erythromycin disk in proximity to a clindamycin disk on an agar plate inoculated with methicillin-resistant S aureus (MRSA). A zone of inhibition in the shape of the letter "D" is seen with an inducible strain and is considered a positive test. If the D- zone test is positive, then clindamycin should not be used because the strain of MRSA can become resistant to the treatment.
Marcotte et al. published a review on community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). They reported that clindamycin has activity against Streptococcus species, but it is not as predictable against CA- MRSA. Clindamycin also presents a risk for the development of Clostridium difficile colitis and inducible clindamycin resistance. for which a D-zone test should be performed when culture results reveal erythromycin resistance.
Steward et al. performed a study to determine the efficacy of testing for induced clindamycin resistance in erythromycin-resistant Staphylococcus aureus. They reported that resistance to erythromycin and clindamycin can occur through methylation of their ribosomal target site (25), which is typically mediated by erm genes. They found that disk diffusion is the preferred method for testing S. aureus isolates for inducible clindamycin resistance.
Illustration A is an image of a positive D-zone test, which indicates inducible clindamycin resistance.
Incorrect Answers:
Which of the following cells involved in bone metabolism derives from a myeloid origin?
Enoxaparin primarily exerts its effects by inhibiting Factor Xa, which is labeled C in Figure A.
Enoxaparin is a low molecular weight heparin (LMWH) that primarily exerts its effects by inhibiting Factor Xa. It achieves this by binding to antithrombin to form a complex that irreversibly inactivates clotting factor Xa. Enoxaparin has the advantage of not requiring laboratory monitoring and can be reversed with protamine sulfate. However, it is important to note that protamine sulfate is less effective in reversing enoxaparin compared to unfractionated heparin (UFH).
Hyers published a review on the past, present, and future management of venous thromboembolism. He found that, for the most part, LMWH and other newer anticoagulants have been shown to be superior to UFH in terms of the venographic endpoint. He also reports that several meta-analyses have demonstrated that LMWH offers superior benefit to UFH for VTE prevention in hip and knee surgery patients.
Tørholm et al. performed a study to determine outcomes of thromboprophylaxis using LMWH compared to placebo in elective hip surgery. They found that 9 (16%) patients in the treatment group and 19 (35%) in the placebo group developed deep venous thrombosis. The risk of thrombosis in the placebo group was increased with prolonged surgery and occurred more frequently during the first 4 postoperative days. They concluded that LMWH offers safe and easily administered thromboprophylaxis in total hip replacement.
Figure A is an image of the coagulation cascade. Illustration A is an image of the
coagulation cascade with the sites of action of the various anticoagulants labeled.
Incorrect Answers:
A 42-year-old IV drug user presents to the emergency department with a large abscess on his forearm. A bedside I&D is performed and he is started on broad-spectrum IV antibiotics. Initial results from his cultures demonstrate methicillin-resistant Staphlycoccus aureus (MRSA) that is also resistant to erythromycin. The team would like to transition him to oral clindamycin. Prior to transitioning him to clindamycin, which additional laboratory test should be performed?
Teriparatide promotes bone formation in patients at high risk of fractures due to severe osteoporosis that is refractory to multiple treatments, including bisphosphonates and cement augmentation. Teriparatide is a human recombinant N-terminal parathyroid hormone.
Teriparatide administered in daily injections results in bony formation, whereas continuous infusion results in bony resorption. In rat models, teriparatide caused an increase in the incidence of osteosarcoma, and thus should only be prescribed for patients for whom the potential benefits outweigh the potential risk. It can be administered in isolation or as an adjunct treatment during bisphosphonate therapy. However, in patients on long-term bisphosphonate therapy, discontinuation of bisphosphonates are advised to reduce potential complications of atypical femur fractures and jaw osteonecrosis.
Watts et al. published a review article on postmenopausal osteoporosis. They reported that bisphosphonates can accumulate in bone, thus after a period of treatment, lower- risk patients should be offered a drug holiday. Denosumab, on the other hand, is not sustained when treatment is discontinued, so no drug holiday is warranted. They concluded that, although there are safety
concerns regarding atypical femoral fracture and osteonecrosis of the jaw with long term use, the benefit of hip fracture risk reduction far outweighs the risk of these relatively uncommon side effects.
Song et al. performed a meta-analysis to investigate the effect of teriparatide monotherapy and the additive effect of teriparatide on antiresorptive agents in postmenopausal women with osteoporosis. They reported that teriparatide monotherapy significantly improved bone mineral density (BMD) in the lumbar spine, total hip, and femoral neck compared with placebo; the additive effect
of teriparatide over hormone replacement therapy (HRT) and denosumab agents was evident in all 3 skeletal sites; however, teriparatide plus alendronate did not demonstrate additive effect in total hip and femoral neck. They concluded that, for patients with osteoporosis who were at high risk for fracture, BMD increased more in patients receiving teriparatide than in those receiving alendronate.
Saag et al. compared the use of teriparatide or alendronate in the management of glucocorticoid-induced osteoporosis. They reported that BMD had increased more in the teriparatide group than in the alendronate group in the lumbar spine and total hip at 6 and 12 months, respectively. They also reported significantly fewer new vertebral fractures in the teriparatide group compared to the alendronate group. They concluded that in severely osteoporotic patients at high risk for fracture, BMD increased more in patients receiving teriparatide than in those receiving alendronate.
Figure A depicts multiple vertebral insufficiency fractures in the setting of a prior cement augmentation procedure.
Incorrect Answers:
Where in the coagulation cascade shown in Figure A does enoxaparin primarily exert its effects?
This patient is presenting with signs of a septic nonunion after open reduction and internal fixation (ORIF) of a radial shaft fracture. Of the choices listed, C- reactive protein (CRP) is the best predictor of infection in the setting of nonunion.
Nonunions after fracture fixation may occur from infection. The most sensitive and readily-available laboratory marker to detect infection is the CRP. CRP is an acute phase reactant that significantly rises within 6 hours after tissue damage or onset of clinical infection. CRP then peaks 2-3 days later and returns to normal levels 5-21 days after the inciting event if it is treated (e.g. antibiotics for cellulitis). In septic nonunions, the chance of fracture healing is low if the infection is not properly treated, and chronic infection can lead to substantially elevated CRP values.
Wang et al. evaluated the effectiveness of laboratory tests in the diagnosis of
infected nonunion. They reported that the sensitivity and specificity of CRP for detection of infected nonunions are both higher than those of IL-6. They concluded that the diagnostic utility of CRP was superior to IL-6, which is contrary to similar studies comparing these markers in prosthetic joint infection patients.
Stucken et al. performed a study to investigate the utility of a standardized protocol to rule out infection in high-risk patients and to evaluate the efficacy of each component of the protocol. They reported that the ESR and the CRP levels were both independently accurate predictors of infection. They
concluded that their protocol can help surgeons to risk-stratify patients prior to the surgical treatment of a nonunion, allowing them to counsel patients more appropriately.
Figure A depicts a nonunion of a radial shaft fracture after ORIF. Incorrect Answers:
An 85-year-old woman presents with severe back pain and the CT shown in Figure A. Her history is notable for prior vertebral compression fractures for which she underwent a cement augmentation procedure. She has been on bisphosphonates for the last 5 years, without improvement of her osteoporosis. She has no history of malignancy. What is the mechanism of action of the medication that should be prescribed for her refractory osteoporosis?
A receiver operating characteristic (ROC) curve is used to determine responsiveness.
Responsiveness is a measure of the diagnostic ability of different tests. It can be determined by calculating the C-statistic, which represents the area under a
Receiver Operating Characteristic (ROC) curve. On a ROC curve, the false positive rate (1 - specificity) is plotted on the x-axis, while the true positive rate (sensitivity) is plotted on the y-axis. The higher the area under the curve, the more responsive the outcome measure. A value of 0.5 indicates a random chance and a therefore useless test, while values above 0.75 usually are considered to be adequately responsive.
Kocher et al. published a review on clinical epidemiology and biostatistics for orthopaedic surgeons. They reported that the relationship between the sensitivity and specificity of a diagnostic test can be portrayed with use of a receiver operating characteristic (ROC) curve. A ROC graph shows the relationship between the true- positive rate (sensitivity) on the y-axis and the false-positive rate (1 − specificity) on the x-axis plotted at each possible cutoff. Overall diagnostic performance can be evaluated on the basis of the area under the ROC curve.
Hanley et al. published a review on the meaning and use of the area under a receiver operating characteristic (ROC) curve. They reported that it represents the probability that a randomly chosen diseased subject is (correctly) rated or ranked with greater suspicion than a randomly chosen non-diseased subject.
Illustration A is an example of a ROC curve. Illustration B is an example of a funnel plot. Illustration C is an example of a Kaplan-Meier curve. Illustration D is a table outlining the interpretation of the Cronbach alpha coefficient. Illustration E is an example of a forest plot.
Incorrect Answers:
A 32-year-old man underwent open reduction and internal fixation for an open radial shaft fracture 6 months ago. He is now experiencing fevers and chills at night and pain and swelling over the surgical site. A current radiograph is depicted in Figure A. What is the most accurate laboratory test for assessing his most likely diagnosis?
The Patient-Reported Outcomes Measurement Information System (PROMIS) has been shown to have reduced floor and ceiling effects compared to other assessment tools.
The PROMIS system was developed to produce a highly reliable, precise, and versatile assessment of outcomes. When administered in a computerized adaptive mode, each question that is answered is followed with a customized follow-up question based on the previous response, which allows for reduced testing items and time. Further, the results of the assessment are reported in T-scores with 50 being the population norm and with a standard deviation of

Question 19:

Options:

Arthroscopic Bankart procedure
Physical therapy
SAWA shoulder brace
Latarjet procedure

Correct Answer: Physical therapy

Explanation:

Question 20:

What is the most common presentation of a benign bone tumor in childhood?

Options:

Pain
Deformity
Pathologic fracture
Presence of a mass
Incidental finding

Correct Answer: Incidental finding

Explanation:

Question 21:

5 mm of change in the atlanto-dens interval (ADI) between flexion and extension views

Options:

Posterior atlanto-dens interval (PADI) <14 mm
Progressive myelopathy
ADI > 10 mm with no change on flexion/extension views

Correct Answer: Posterior atlanto-dens interval (PADI) <14 mm

Explanation:

Question 22:

What are the four most common soft-tissue sarcomas to spread via the lymph node system?

Options:

Rhabdomyosarcoma, malignant fibrous histiocytoma, epithelioid sarcoma, clear cell sarcoma
Malignant fibrous histiocytoma, synovial sarcoma, clear cell sarcoma, epithelioid sarcoma
Liposarcoma, rhabdomyosarcoma, synovial sarcoma, clear cell sarcoma
Rhabdomyosarcoma, clear cell sarcoma, epithelioid sarcoma, synovial sarcoma
Liposarcoma, clear cell sarcoma, rhabdomyosarcoma, epithelioid sarcoma

Correct Answer: Rhabdomyosarcoma, clear cell sarcoma, epithelioid sarcoma, synovial sarcoma

Explanation:

DISCUSSION: Soft-tissue sarcomas most frequently metastasize to the lung, but certain histologic types have a predilection for the lymph node system as well. Rhabdomyosarcoma, clear cell sarcoma, epithelioid sarcoma, and synovial sarcoma are four of the most common types to spread in this fashion. Careful evaluation and/or sentinel lymph node biopsy plays a role in disease staging and prognosis.
REFERENCES: Riad S, Griffin AM, Liberman B, et al: Lymph node metastasis in soft-tissue sarcoma in an extremity. Clin Orthop Relat Res 2004;426:129-134.
Blazer DG III, Sabel MS, Sondak VK: Is there a role for sentinel lymph node biopsy in the management of sarcoma? Surg Oncol 2003;12:201-206.

Question 23:

Which of the following types of intra-articular pathology is associated with lateral meniscal cysts? Review Topic

Options:

Discoid meniscus
Posterolateral corner injury
Vertical meniscal tears
Middle third lateral meniscal tears
Popliteus tendon tears

Correct Answer: Middle third lateral meniscal tears

Explanation:

Question 24:

A 35-year-old active woman with rheumatoid arthritis experiences right shoulder pain following an extended course of corticosteroids (Figures 96a and 96b).

Options:

Humeral head resurfacing/shoulder hemiarthroplasty
Anatomic total shoulder arthroplasty (TSA)
Reverse total shoulder arthroplasty (rTSA)
Rotator cuff repair
Open reduction and internal fixation (ORIF)

Correct Answer: Humeral head resurfacing/shoulder hemiarthroplasty

Explanation:

DISCUSSION
The indication for anatomic TSA is end-stage glenohumeral arthritis with an intact rotator cuff. For the 62-year-old man, his radiographs reveal osteoarthritis, and his MR image shows an intact rotator cuff. Although humeral head replacement has historically been employed for this disorder, pain relief is not as reliable as with TSA, and the revision rate is higher. rTSA is generally reserved for patients with a nonfunctional rotator cuff.
For this 58-year-old patient with a full-thickness rotator cuff tear, preserved motion, and weakness in forward elevation, a rotator cuff repair is the most appropriate treatment. In the absence of degenerative changes, shoulder hemiarthroplasty or anatomic TSA is not indicated. Although indications for rTSA continue to evolve, well-compensated range of motion and a medium-sized rotator cuff tear in a younger patient are not among them.
rTSA is an emerging treatment for comminuted proximal humerus fractures in elderly patients. Although hemiarthroplasty has been a traditional treatment, current evidence suggests rTSA more reliably restores range of motion, and this 78-year-old patient's CT scan shows a small and comminuted greater tuberosity fragment that is unlikely to heal. ORIF is another option, but the CT scan also shows a small humeral head fragment that suggests osteopenia, making fixation more tenuous and likely less reliable.
A common problem associated with hemiarthroplasty for glenohumeral osteoarthritis is symptomatic glenoid degeneration that necessitates revision. This 55-year-old patient’s images reveal this is the case, although his infection workup is negative. His examination findings suggest an intact subscapularis repair. With a functioning rotator cuff and symptomatic glenoid arthritis, a conversion to anatomic TSA is indicated. In the absence of a functioning rotator cuff in an older patient, an rTSA is a better option.
This 72-year-old patient has classic symptoms and radiographs of cuff tear arthropathy. For patients with massive rotator cuff tear and glenohumeral arthritis, neither anatomic TSA nor rotator cuff repair is indicated. Hemiarthroplasty has historically been indicated for cuff tear arthropathy, but rTSA outcomes for this disorder have been superior and are now the preferred option.
Comminuted proximal humerus fractures in young, active patients are treated primarily with ORIF. The absence of glenohumeral arthritis removes anatomic TSA as a possibility, and concerns about implant longevity in younger, active patients such as this 40-year-old laborer contraindicate rTSA. Hemiarthroplasty is still employed in 3- and 4-part fractures but is generally reserved for subacute presentations or dislocations in which the humeral head is dysvascular and unlikely to survive. In this acute setting, a fixation procedure is preferred.
The 71-year-old patient who has had 2 failed rotator cuff repairs has an MR image that reveals another recurrent tear that is retracted to the glenoid. Her examination findings reveal classic signs
of a decompensated rotator cuff tear with pseudoparalysis and weakness in forward elevation. Although infection is a concern in the setting of multiply failed rotator cuff repair, the workup is negative in this scenario. Because this patient has a dysfunctional rotator cuff and has failed previous attempts at repair, a conversion to rTSA is the better option. In the absence of degenerative changes, hemiarthroplasty and anatomic TSA are not indicated.
The indications for hemiarthroplasty continue to narrow, but it is still a consideration for young patients with unipolar shoulder degeneration. In this 35-year-old patient, her MR image shows avascular necrosis in the humeral head, and her arthroscopy suggests arthritic change only on the humeral side with an uncompromised glenoid. To best treat young and active patients, a hemiarthroplasty that articulates with healthy glenoid cartilage can provide good pain relief and functional outcomes. Anatomic TSA is also reasonable but not an optimal option considering the normal glenoid condition. rTSA is not a consideration when a young patient’s MR images reveal an intact rotator cuff.
RECOMMENDED READINGS
Torchia ME, Cofield RH, Settergren CR. Total shoulder arthroplasty with the Neer prosthesis: longterm results. J Shoulder Elbow Surg. 1997 Nov-Dec;6(6):495-505. PubMed PMID: 9437598.
View
Abstract at PubMed
Chalmers PN, Slikker W 3rd, Mall NA, Gupta AK, Rahman Z, Enriquez D, Nicholson GP. Reverse total shoulder arthroplasty for acute proximal humeral fracture: comparison to open reduction-internal fixation and hemiarthroplasty. J Shoulder Elbow Surg. 2014 Feb;23(2):197-204. doi: 10.1016/j.jse.2013.07.044. Epub 2013 Sep 27. PubMed PMID: 24076000.
View Abstract at PubMed
Groh GI, Wirth MA. Results of revision from hemiarthroplasty to total shoulder arthroplasty utilizing modular component systems. J Shoulder Elbow Surg. 2011 Jul;20(5):778-82. doi: 10.1016/j.jse.2010.09.014. Epub 2011 Jan 13. PubMed PMID: 21232989.
View Abstract at PubMed
Orfaly RM, Rockwood CA Jr, Esenyel CZ, Wirth MA. Shoulder arthroplasty in cases with avascular necrosis of the humeral head. J Shoulder Elbow Surg. 2007 May-Jun;16(3 Suppl):S27-32. Epub 2006 Nov 16. PubMed PMID: 17113317.
View Abstract at PubMed
Sershon RA, Van Thiel GS, Lin EC, McGill KC, Cole BJ, Verma NN, Romeo AA, Nicholson GP. Clinical outcomes of reverse total shoulder arthroplasty in patients aged younger than 60 years. J Shoulder Elbow Surg. 2014 Mar;23(3):395-400. doi: 10.1016/j.jse.2013.07.047. Epub 2013 Oct 12. PubMed PMID: 24129052.
View Abstract at PubMed

Question 25:

Which of the following best describes the use of epidural morphine and steroid paste after laminectomy?

Options:

Associated with an 11% rate of postoperative surgical site complications
Associated with a less than 1% rate of surgical site infections
Associated with a decreased rate of postoperative urinary retention
Considered the standard for outpatient microdiskectomy
Should only be used in the absence of radiculopathy

Correct Answer: Associated with an 11% rate of postoperative surgical site complications

Explanation:

DISCUSSION: Kramer and associates conducted a retrospective review during an “epidemic” period to identify the risk factors associated with a sudden increase in the rate of surgical site infections. They found in a multivariate analysis that the use of morphine nerve paste resulted in a 7.6-fold increase in postoperative surgical wound debridement, and an 11% rate of surgical site complications.
REFERENCES: Kramer MH, Mangram AJ, Pearson ML, et al: Surgical-site complications associated with a morphine nerve paste used for postoperative pain control after laminectomy. Infect Control Hosp Epidemiol 1999;20:183-186.
Lowell TD, Errico TJ, Eskenazi MS: Use of steroids after discectomy may predispose to infection. Spine 2000;25:516-519.

Question 26:

Intrinsic muscles of the foot act on the toes by

Options:

abducting the metatarsophalangeal joints and flexing the interphalangeal joints.
extending the metatarsophalangeal and interphalangeal joints.
extending the metatarsophalangeal joints and flexing the interphalangeal joints.
flexing the metatarsophalangeal and interphalangeal joints.
flexing the metatarsophalangeal joints and extending the interphalangeal joints.

Correct Answer: flexing the metatarsophalangeal joints and extending the interphalangeal joints.

Explanation:

DISCUSSION: Intrinsic muscles of the foot function to flex the metatarsophalangeal joints and extend the interphalangeal joints.
REFERENCES: Myerson MS, Shereff MJ: The pathologic anatomy of claw and hammertoes.
J Bone Joint Surg Am 1989;71:45-49.
Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 71-80.

Question 27:

Options:

Renal osteodystrophy
Diastrophic dysplasia
Metaphyseal dysplasia
Osteogenesis imperfecta
Fibrous dysplasia

Correct Answer: Metaphyseal dysplasia

Explanation:

DISCUSSION: The widening, bowing, and cupping of the physes indicate some form of metabolic bone disease; therefore, the most likely diagnosis is renal osteodystrophy. The age of onset makes X-linked hypophosphatemic rickets less likely. The ground glass lesions and widening of the medullary canal characteristic of fibrous dysplasia are not present. There are no fractures creating the deformities indicating osteogenesis imperfecta.
There is an asymmetry of the deformities that makes diastrophic dysplasia less likely.
REFERENCES: Goldberg MJ, Yassir W, Sadeghi-Nejad A: Clinical analysis of short stature. J Pediatr Orthop 2002;22:690-696.
Parmar VS, Stanitski DF, Stanitski CL: Interpretation of radiographs in a pediatric limb deformity practice: Do
radiologists contribute? J Pediatr Orthop 1999;19:732-734. Question 4
Patients with slipped capital femoral epiphysis are more likely to experience a delay in definitive diagnosis if they initially present to a physician reporting which of the following problems?
L Limp
Hip pain
Knee pain
Proximal thigh pain
Buttock pain
DISCUSSION: A delay in diagnosis of slipped capital femoral epiphysis (SCFE) can lead to significant worsening of the deformity or even progression from a stable to an unstable SCFE. Those patients that report knee pain as their primary complaint are most likely to experience significant delay. Other variables associated with this delay include Medicaid insurance and stable SCFE.
REFERENCES: Kocher MS, Bishop JA, Weed B, et al: Delay in diagnosis of slipped capital femoral epiphysis.
AL-Madena Copy
10 • American Academy of Orthopaedic Surgeons
Pediatrics 2004;113:e322-e325.
Rahme D, Comley A, Foster B, et al: Consequences of diagnostic delays in slipped capital femoral epiphysis. J Pediatr Orthop B 2006;15:93-97.

Question 28:

During a posterior approach to the right Achilles tendon, the surgeon encounters a nerve running with the small saphenous vein as shown in Figure 22. This nerve innervates what part of the foot?

Options:

Posterior heel
Plantar-lateral foot
Plantar-medial foot
Dorso-lateral foot
Dorso-medial foot

Correct Answer: Dorso-lateral foot

Explanation:

DISCUSSION: The sural nerve runs with the small saphenous vein on the posterior leg just lateral to the Achilles tendon. It is formed by contributions from both the tibial and common peroneal nerves and provides sensation on the dorso-lateral aspect of the foot.
REFERENCES: Aktan Ikiz ZA, Ucerler H, Bilge O: The anatomic features of the sural nerve with an emphasis on its clinical importance. Foot Ankle Int 2005;26:560-567.
Lawrence SJ, Botte MJ: The sural nerve in the foot and ankle: An anatomic study with clinical and surgical implications. Foot Ankle Int 1994;15:490-494.

Question 29:

A 72-year-old woman falls onto her left hip after tripping over a curb during her daily 3-mile walk. An injury radiograph is shown in Figure A. What is the best long term solution?

Options:

Cannulated screws
Valgus intertrochanteric osteotomy
Unipolar hemiarthroplasty
Bipolar hemiarthroplasty
Total hip arthroplasty

Correct Answer: Unipolar hemiarthroplasty

Explanation:

Question 30:

Figure 32 shows the radiograph of a laborer who jammed his thumb in a fall. Examination reveals pain at the base of the thumb and proximal thenar eminence region. Management should consist of

Options:

open reduction and internal fixation.
closed reduction, percutaneous pin fixation, and casting.
dynamic thumb traction.
external fixation.
functional bracing followed by occupational therapy.

Correct Answer: closed reduction, percutaneous pin fixation, and casting.

Explanation:

Question 31:

Options:

Observation, repeat radiographs, and reexamination in 6 weeks
A 14-day course of indomethacin
A 4-week course of indomethacin
Plan for a return to the operating room at 10 weeks for excision of the heterotopic bone
Arrange urgently for 800 centigrey of radiation to the soft tissues and areas of heterotopic bone around the hip, with shielding of the implants

Correct Answer: Observation, repeat radiographs, and reexamination in 6 weeks

Explanation:

DISCUSSION: The development of heterotopic bone occurs early after hip arthroplasty. The process begins within days after surgery; therefore, prophylactic treatment must be in the early postoperative period (preoperative radiation given within 24 hours of surgery, or postoperative radiation given within 72 hours of surgery, or nonsteroidal antiinflammatory drugs (NSAIDs) given postoperatively for 7 to 21 days - longer duration has not been shown to be of any additional benefit). At 6 weeks, prophylactic treatment with NS
AID
s or radiation is no longer effective. Surgery at 10 weeks would be premature because the patient is currently asymptomatic with regards to the heterotopic bone, and surgery prior to full maturation of the bone may increase the risk for more abundant recurrence of bone.
REFERENCES: Balboni TA, Gobezie R, Mamon HJ: Heterotopic ossification: Pathophysiology, clinical features, and the role of radiotherapy for prophylaxis. Int J Radiat Oncol Biol Phys 2006;65:1289-1299. Fransen M, Neal B: Non-steroidal anti-inflammatory drugs for preventing heterotopic bone formation after hip arthroplasty. Cochrane Database Syst Rev 2004;3:CD001160.
Neal BC, Rodgers A, Clark T, et al: A systematic survey of 13 randomized trials of non-steroidal antiinflammatory
drugs for the prevention of heterotopic bone formation after major hip surgery. Acta Orthop Scand 2000;71:122-128.

Question 32:

In the most common condition causing a winged scapula, which of the following nerves is affected?

Options:

Long thoracic nerve
Spinal accessory nerve
Suprascapular nerve
Dorsal scapular nerve
Thoracodorsal nerve

Correct Answer: Long thoracic nerve

Explanation:

DISCUSSION: A winged scapula is most often associated with Parsonage-Turner syndrome, a condition thought to be due to an inflammatory or immune-mediated mechanism. Certain muscles are predisposed, particularly the serratus anterior muscle innervated by the long thoracic nerve. Other less common nerve lesions (eg, the spinal accessory and dorsal scapular nerves) may also cause winged scapulae.
REFERENCES: Kline DG, Hudson AR: Nerve Injuries: Operative Results for Major Nerve Injuries, Entrapments and Tumors. Philadelphia, PA, WB Saunders, 1995.
van Alfen N, van Engelen BG: The clinical spectrum of neuralgic amyotrophy in 246 cases. Brain 2006;129:438-450.

Question 33:

Spontaneous rupture of the extensor pollicis longus tendon is most frequently associated with which of the following scenarios?

Options:

Nondisplaced distal radius fracture
Nondisplaced Rolando fracture
Second metacarpal base fracture
Boxer's fracture
Nondisplaced radial styloid fracture

Correct Answer: Nondisplaced distal radius fracture

Explanation:

Question 34:

Options:

Gentle physical therapy and lifestyle modification to reduce demands on the symptomatic muscles
Vigorous physical therapy to rehabilitate the weak muscle groups
Muscle biopsy
MRI of the lumbosacral spine
Electromyography and nerve conduction velocity studies

Correct Answer: Gentle physical therapy and lifestyle modification to reduce demands on the symptomatic muscles

Explanation:

Question 35:

The arrow in the axial T 1 -weighted MRI scan shown in Figure 18 is pointing to which of the following structures?

Options:

Ulnar artery
Ulnar nerve in Guyon’s canal
Deep branch of the ulnar nerve only
Median nerve
Radial artery

Correct Answer: Ulnar nerve in Guyon’s canal

Explanation:

Question 36:

Options:

resection of the coalition bar.
subtalar fusion.
medial sliding calcaneal osteotomy.
Dwyer osteotomy.

Correct Answer: subtalar fusion.

Explanation:

DISCUSSION
When contemplating the causes of subtalar joint degeneration in young patients, an unstable tarsal coalition should be considered in the absence of antecedent trauma. Initial treatment with casting is appropriate because this intervention can relieve symptoms for many patients. There are 2 surgical options for a symptomatic tarsal coalition: bar resection or completion fusion. Risk factors for a poor outcome after bar resection are adult age and a bar that encompasses more than 50% of the middle facet of the subtalar joint. Because this patient has both risk factors, the appropriate procedure is a subtalar fusion.
RECOMMENDED READINGS
Comfort TK, Johnson LO. Resection for symptomatic talocalcaneal coalition. J PediatrOrthop. 1998 May-Jun;18(3):283-8. PubMed PMID: 9600549.
View Abstract at PubMed
Thorpe SW, Wukich DK. Tarsal coalitions in the adult population: does treatment differ from the adolescent? Foot Ankle Clin. 2012 Jun;17(2):195-204. doi: 10.1016/j.fcl.2012.03.004. Epub 2012 Apr 6. Review. PubMed PMID: 22541520.
View Abstract at PubMed

Question 37:

Options:

Open reduction under general anesthesia
Closed reduction under general anesthesia with fluoroscopy
Closed reduction under general anesthesia without fluoroscopy
Conscious sedation in the emergency department and closed reduction with fluoroscopy
Conscious sedation in the emergency department and closed reduction without fluoroscopy

Correct Answer: Closed reduction under general anesthesia with fluoroscopy

Explanation:

Question 38:

The MRI findings shown in Figure 51 would most likely create which of the following signs and symptoms?

Options:

Weakness of the left extensor hallucis longus and a sensory deficit in the first dorsal web space
Diminished right Achilles tendon reflex and weakness of the gastrocnemius-soleus complex
Pain radiating into the anteromedial aspect of the left knee, diminished patellar tendon reflex, and difficulty climbing stairs
Numbness in the right first dorsal web space and a slap foot gait
Urinary retention and right quadriceps weakness with diminished patellar tendon reflex

Correct Answer: Pain radiating into the anteromedial aspect of the left knee, diminished patellar tendon reflex, and difficulty climbing stairs

Explanation:

Question 39:

What are the two terminal branches of the lateral cord of the brachial plexus?

Options:

Musculocutaneous and median
Musculocutaneous and axillary
Median and axillary
Ulnar and median
Ulnar and medial pectoral

Correct Answer: Musculocutaneous and median

Explanation:

DISCUSSION: The lateral cord divides into the musculocutaneous and median nerves. The posterior cord terminates into the axillary and radial nerves. The medial cord divides into the ulnar and median nerves.
REFERENCES: Hollinshead WH: Anatomy for Surgeons, ed 3. Philadelphia, PA, Harper and Row, 1982, pp 228-236.
Shin AY, Spinner RJ, Steinmann SP, et al: Adult traumatic brachial plexus injuries. J Am Acad Orthop Surg 2005;13:382-396.

Question 40:

In X-linked hypophosphatemic rickets, the gene defect may be found in which of the following?

Options:

GNAS1
CLCN7
TGF-BR2
PHEX
COLIA1

Correct Answer: PHEX

Explanation:

Question 41:

Options:

posterior fusion at C3-C7.
anterior fusion at C3-7 with plate fixation through the same scar.
anterior fusion at C3-7 with plate fixation through a right-sided incision.
an epidural steroid injection.
patient education, exercise, and nonnarcotic medication.

Correct Answer: patient education, exercise, and nonnarcotic medication.

Explanation:

Question 42:

Options:

intravenous antibiotics.
hyperbaric oxygen therapy and intravenous antibiotics.
surgical debridement, primary wound closure, and intravenous antibiotics.
surgical debridement, closure of the wound over drains, and intravenous antibiotics.
surgical debridement, leaving the wound open, and intravenous antibiotics.

Correct Answer: surgical debridement, leaving the wound open, and intravenous antibiotics.

Explanation:

Question 43:

Options:

Infraspinatus and supraspinatus
Infraspinatus
Supraspinatus
Teres minor
Deltoid

Correct Answer: Infraspinatus

Explanation:

Question 44:

A Trendelenburg gait is most likely to be seen in association with

Options:

a central disk herniation at L3-L4.
an ipsilateral paracentral disk herniation at L3-L4.
an ipsilateral paracentral disk herniation at L4-L5.
an ipsilateral paracentral disk herniation at L5-S1.
an ipsilateral far lateral disk herniation at L4-L5.

Correct Answer: an ipsilateral paracentral disk herniation at L4-L5.

Explanation:

Question 45:

Options:

Chondrosarcoma
Chordoma
Metastatic renal cell carcinoma
Metastatic breast cancer
Infection

Correct Answer: Chordoma

Explanation:

Question 46:

Options:

normal reflexes in the upper extremities and hyperreflexia in the lower extremities.
hyperreflexia in the upper extremities and normal reflexes in the lower extremities.
hyperreflexia in the upper extremities and hyporeflexia in the lower extremities.
hyperreflexia in the upper and lower extremities.
hyporeflexia in the upper and lower extremities.

Correct Answer: normal reflexes in the upper extremities and hyperreflexia in the lower extremities.

Explanation:

Question 47:

Two major pharmacologic classes of bisphosphonates exist: nitrogen-containing and non-nitrogen-containing compounds. The nitrogen-containing compounds work by which of the following actions?

Options:

COX inhibition
ATPase formation
GTPase inhibition
DNA gyrase inhibition
RNA polymerase inhibition

Correct Answer: GTPase inhibition

Explanation:

Question 48:

The function of which of the following structures is to resist internal tibial rotation with the knee in full extension? Review Topic

Options:

Anterior cruciate ligament
Iliotibial band
Popliteus tendon
Popliteofibular ligament
Posterior oblique ligament

Correct Answer: Posterior oblique ligament

Explanation:

Question 49:

In infantile idiopathic scoliosis, which of the following factors suggests progression? Review Topic

Options:

Age at presentation
Rib overlap of the apical vertebra
Rib vertebral angle difference of greater then 10 degrees
Male gender
Family history

Correct Answer: Rib overlap of the apical vertebra

Explanation:

Question 50:

Options:

neoadjuvant chemotherapy followed by surgical resection and reconstruction.
chemotherapy followed by radiation therapy.
IV antibiotics for 4 weeks, followed by oral antibiotics for 4 weeks.
surgical resection and reconstruction followed by chemotherapy.
radiation therapy alone.

Correct Answer: neoadjuvant chemotherapy followed by surgical resection and reconstruction.

Explanation:

DISCUSSION: The imaging studies and histology are consistent with high-grade osteosarcoma. The standard treatment for osteosarcoma is neoadjuvant chemotherapy combined with wide surgical resection that can be performed with amputation or limb salvage depending on characteristics unique to each tumor and each patient. In most patients, limb salvage surgery can be performed with reconstruction using allografts and/or megaprostheses. Osteosarcoma is poorly responsive to radiation therapy. Chemotherapy alone, in the absence of appropriate surgery, has not proven effective.
REFERENCES: Simon MA, Springfield DS: Surgery for Bone and Soft-Tissue Tumors. Philadelphia, PA, Lippincott-Raven, 1998, pp 265-274.
Gibbs CP, Weber K, Scarborough MT: Malignant bone tumors. Instr Course Lect 2002;51:413-428.

Question 51:

Following its exit from the sciatic notch, the sciatic nerve passes between what two muscles?

Options:

Piriformis and superior gemellus
Superior gemellus and obturator internus
Inferior gemellus and quadratus femoris
Gluteus medius and minimus
Quadratus femoris and gluteus maximus

Correct Answer: Piriformis and superior gemellus

Explanation:

DISCUSSION: Though anatomic variations exist, both divisions of the sciatic nerve most commonly pass between the piriformis and superior gemellus. This anatomic consideration is relevant during the posterior approach to the hip, where careful retraction of the rotators avoids sciatic nerve injury.
REFERENCES: Hoppenfeld S, deBoer P: Surgical Exposures in Orthopaedics: The Anatomic Approach. Philadelphia, PA, JB Lippincott, 1984, pp 335-348.
Anderson JE (ed): Grant’s Atlas of Anatomy, ed 7. Baltimore, MD, Williams & Williams,
1978, Figure 4-34.
FOR ALL MCQS CLICK THE LINK ORTHO
MCQ BANK

Question 52:

Options:

5 mm
10 mm
15 mm
20 mm
25 mm

Correct Answer: 20 mm

Explanation:

Question 53:

Which of the following ligaments provides the major static restraint to lateral patellar displacement?

Options:

Medial patellotibial
Medial patellofemoral
Medial patellomeniscal
Lateral patellofemoral
Lateral patellotibial

Correct Answer: Medial patellofemoral

Explanation:

Question 54:

Options:

Hornblower's Test
Jobe's Test
Apprehension Sign with shoulder abducted and externally rotated
Speed's Test
Kim's Test

Correct Answer: Hornblower's Test

Explanation:

Question 55:

Options:

Inadequate graft strength
Failure to restore graft length
Malposition of the femoral tunnel
Malposition of the tibial tunnel

Correct Answer: Malposition of the femoral tunnel

Explanation:

DISCUSSION
The anteromedial bundle originates on the anterior and proximal aspect of the lateral femoral condyle and inserts on the anteromedial aspect of the anterior cruciate ligament (ACL) footprint on the proximal tibia. The posterolateral bundle originates posterior and distal to
63
the anteromedial bundle and inserts on the posterolateral aspect of the tibial footprint. The fibers are parallel when the knee is in an extended position. As the knee moves into flexion,
the fibers of the anteromedial bundle rotate externally with respect to the posterolateral bundle. The anteromedial bundle is tensioned in both flexion and extension. The posteromedial bundle is tensioned in extension, but relaxes as the knee moves into flexion.
The lateral meniscus is more commonly injured with an acute injury to the ACL. The medial meniscus is injured more commonly when the ACL is chronically unstable.
The ACL is an intra-articular and intrasynovial structure. It is innervated by posterior articular branches from the tibial nerve. Innervation of the ACL involves several types of mechanoreceptors (Ruffini, Pacini, Golgi tendon, and free-nerve endings) that may contribute to proprioceptive function of the knee and modulation of quadriceps function.
Injury to the ACL is predominantly associated with instability to anterior translation of the tibia in extension. The ACL plays a secondary role to limit internal rotation of the tibia, and a loss of ACL stability is confirmed by the reduction of the tibia from a position of anterior translation and internal rotation (pivot shift). The radiographs demonstrate anterior placement of the femoral tunnel. The convex shape of the lateral femoral condyle can make it more difficult to visualize the anatomic femoral origin of the ACL. Failure to identify the
anatomic footprint can result in anterior placement of the femoral tunnel. Anterior ACL graft placement can result in its impingement against the posterior cruciate ligament and early limitation of knee flexion. Over time, impingement on the graft may result in stretching of the graft and recurrent knee instability symptoms.
RECOMMENDED READINGS
Duthon VB, Barea C, Abrassart S, Fasel JH, Fritschy D, Ménétrey J. Anatomy of the anterior cruciate ligament. Knee Surg Sports Traumatol Arthrosc. 2006 Mar;14(3):204-13. Epub 2005 Oct 19. Review. PubMed PMID: 16235056.
View
Abstract at PubMed
Zantop T, Petersen W, Sekiya JK, Musahl V, Fu FH. Anterior cruciate ligament anatomy and function relating to anatomical reconstruction. Knee Surg Sports Traumatol Arthrosc. 2006 Oct;14(10):982-92. Epub 2006 Aug 5. Review. PubMed PMID: 16897068.
View Abstract at PubMed

Question 56:

Options:

ACL reconstruction 20 years ago
Spontaneous osteonecrosis of the knee involving the medial compartment
A history of inflammatory arthritis
Body weight of 80kg
degree varus deformity Corrent answer: 3 Inflammatory arthritides are considered contraindications for a partial knee replacement due to the likely progression of arthritis in the native compartments. Unicompartmental arthroplasty (UKA) is generally considered an excellent procedure provided that appropriate surgical indications are used for patient selection. Classic indications for UKA include unicompartmental disease in patients older than 60 with relatively low activity demands. Additionally, the patients should weigh less than 82 kg, have minimal pain at rest, have motion >90 degrees, varus deformity <10 degrees, and flexion contractures <10 degrees. While most of these classic indications are still used today, recent studies are showing excellent results in younger, heavier, and more active patients. Inflammatory arthropathy is a contra-indication to unicompartmental knee replacement due to the high risk of continued arthritis progression in the other compartments. These patients should undergo total knee replacement instead. Heyse et al. retrospectively reviewed the results of unicompartmental arthroplasty for spontaneous osteonecrosis of the knee (SONK). 75.7% of patients were "very satisfied" with the procedure and 21.6% were "satisfied." At 15 years, 90.6% of unicompartmental arthroplasties had not been revised. Overall, the authors feel it is an excellent procedure for SONK. Price et al. reviewed 682 medial Oxford UKA knees for 20-year survival. They found the all-cause revision survival rate was 91%. 29 revision procedures occurred at a mean time of 3.3 years postoperatively. The most common cause of revision was lateral arthrosis (34%), followed closely by component loosening (31%). They concluded that Oxford medial UKA has good survival even into the second decade postoperatively. Figure A and B show AP and lateral images of a left knee status post medial unicompartmental knee arthroplasty. Specifically, this is the Oxford UKA system. Illustration A is a T2-weighted MRI demonstrating SONK. Incorrect Answers:

Correct Answer: degree varus deformity Corrent answer: 3 Inflammatory arthritides are considered contraindications for a partial knee replacement due to the likely progression of arthritis in the native compartments. Unicompartmental arthroplasty (UKA) is generally considered an excellent procedure provided that appropriate surgical indications are used for patient selection. Classic indications for UKA include unicompartmental disease in patients older than 60 with relatively low activity demands. Additionally, the patients should weigh less than 82 kg, have minimal pain at rest, have motion >90 degrees, varus deformity <10 degrees, and flexion contractures <10 degrees. While most of these classic indications are still used today, recent studies are showing excellent results in younger, heavier, and more active patients. Inflammatory arthropathy is a contra-indication to unicompartmental knee replacement due to the high risk of continued arthritis progression in the other compartments. These patients should undergo total knee replacement instead. Heyse et al. retrospectively reviewed the results of unicompartmental arthroplasty for spontaneous osteonecrosis of the knee (SONK). 75.7% of patients were "very satisfied" with the procedure and 21.6% were "satisfied." At 15 years, 90.6% of unicompartmental arthroplasties had not been revised. Overall, the authors feel it is an excellent procedure for SONK. Price et al. reviewed 682 medial Oxford UKA knees for 20-year survival. They found the all-cause revision survival rate was 91%. 29 revision procedures occurred at a mean time of 3.3 years postoperatively. The most common cause of revision was lateral arthrosis (34%), followed closely by component loosening (31%). They concluded that Oxford medial UKA has good survival even into the second decade postoperatively. Figure A and B show AP and lateral images of a left knee status post medial unicompartmental knee arthroplasty. Specifically, this is the Oxford UKA system. Illustration A is a T2-weighted MRI demonstrating SONK. Incorrect Answers:

Explanation:

unicompartmental arthroplasty. The absence of an ACL is a contraindication for mobile-bearing UKA.
OrthoCash 2020
Which of the following is the most common cause of early revision surgery (<20 weeks) following a hip resurfacing arthroplasty?
Periprosthetic fracture
Rupture of abductors
Dislocation
Heterotopic ossification
Post-operative stiffness
Periprosthetic fracture, specifically femoral neck fracture, is the most common cause of early revision less than 20 weeks following surgery.
The rate of femoral neck fractures following hip resurfacing varies, but most literature reports a rate of 1%. A majority of these fractures happen in the early post-operative period and are the most frequent cause of revision surgery within several months following surgery. The cause is usually multifactorial, but placing the femoral implant in varus, osteonecrosis, and notching have been proven risk factors for fracture.
Little el al. report on 377 patients undergoing hip resurfacing. 13 required revision including 8 for fracture of the femoral neck and 3 for loosening of a component. Evidence of osteonecrosis was seen in two of these cases, leading the authors to believe it may contributed to fracture.
Illustration A shows a comparison of a typical total hip replacement and a hip resurfacing arthroplasty. Illustration B shows notching of the femoral neck, a known cause of femoral neck fracture following hip resurfacing. Illustration C shows a femoral neck fracture in a patient with a hip resurfacing.
OrthoCash 2020
A 55-year-old male undergoes a revision total knee arthroplasty of an implant that is only 3 years old. At the time of surgery, the tibial polyethylene liner shows catastrophic delamination and cracking. What is the most likely cause of this extensive, accelerated wear of the polyethylene liner?
Sterilization in ethylene oxide
Gamma irradiation of the polyethylene liner in the presence of air
Gamma irradiation of the polyethylene liner with vacuum packaging
Gamma irradiation of the polyethylene liner in nitrogen
Gamma irradiation of the polyethylene liner in argon
Corrent answer: 2
Irradiation of polyethylene in air (i.e. oxygen present) has been shown to be a risk factor for catastrophic failure after total knee replacement.
Free radicals are generated when polyethylene is irradiated in the presence of air. Initially, these free radicals result in cross-linking. However, if the polyethylene is exposed to these free radicals for an extended period of time, delamination, cracking, and catastrophic failure may ensue. The industry has completely abandoned this method of sterilization as a result. Currently, the standard of care is irradiation of polyethylene in an inert gas (e.g. argon, nitrogen or vacuum packaging). The amount of oxidative products when polyethylene is sterilized in the absence of oxygen is much less and does not lead to catastrophic failure.
Sterilization without irradiation is another option (ethylene oxide). When this occurs, there is no cross-linking and thus the increased wear properties are lost. However, since there is no oxidization, you do not have the risk of catastrophic failure as seen in those liners irradiated in the presence of oxygen.
The cited reference by McNulty et al. from Orthopedics discusses the influence of sterilization methods on wear performance. They found that gamma irradiation and storage of the polyethylene components in an essentially oxygen-free environment imparted by gamma irradiation in a vacuum foil pouch (GVF) protects the components from oxidization.
Illustration A shows a polyethylene liner that has undergone catastrophic wear as a result of irradiation in the presence of oxygen.
Incorrect Answers:
catastrophic wear, although wear properties are less than gamma irradiation in the absence of air.
OrthoCash 2020
Which of the following interventions reduces osteolysis around distal portion of the femoral stem when performing a total hip arthroplasty?
Use of an extended offset femoral neck component
Use of a proximal circumferentially coated ingrowth stem
Use of a collared stem
Use of a long femoral stem
Ensuring that the stem fills the diaphysis of the femur
Corrent answer: 2
Osteolysis of the femur is caused by activation of macrophages by microscopic polyethylene particles within the "effective joint space", defined as any area where joint fluid can come into contact with bone. This can occur above the acetabular cup, through screw holes, and down the femoral shaft around the prosthetic stem. Ideally, with a cementless stem, both the proximal and metaphyseal femur are well filled by the prosthesis. Collared stems are used to augment poor calcar bone quality or bone loss.
Sinha et al showed in a retrospective review of 101 hips with cementless circumferentially coated femoral stems no distal femur osteolysis occurred, but 82% showed “evidence of proximal femur stress shielding”, though only 38% showed proximal femoral osteolysis.
OrthoCash 2020
During a minimally invasive approach to total hip arthroplasty a femoral periprosthetic fracture occurs. Which of the following steps is crucial to properly treat this complication?
Transitioning to an extensile approach to adequately visualize and reduce the fracture
Limiting post-operative weight bearing
Switching to a cemented femoral stem to avoid the stresses created during press-fit fixation
Delaying the arthroplasty until the fracture has healed
Supplementing the fracture with autograft
Corrent answer: 1
Proper treatment of an intraoperative femoral fracture during total hip arthroplasty involves adequate exposure, anatomic reduction, and bypassing the fracture site by 2 cortical diameters of the femur with a long stem. This may involve repositioning the patient on the table if the arthroplasty is performed in the supine position. Minimally invasive surgical techniques have been developed to insert the components through smaller exposures and less soft tissue dissection. The purported advantages include faster rehabilitation, less blood loss, shorter hospital stays, and better cosmesis. However, complications an arise if the surgeon sacrifices surgical exposure and visualization.
Fehring et al review 3 cases of total hip arthroplasty performed through minimally invasive techniques with catastrophic outcomes. Intra-operative fracture, chronic instability, and death were all identified.
OrthoCash 2020
A 70-year-old man underwent total hip arthroplasty 4 months ago and has experienced 3 dislocations. Radiographs reveal no failure of the hardware and an acetabular component that has an abduction
angle of 40 degrees and a version of 10 degrees retroverted. What is the most appropriate treatment for the recurrent dislocations?
hip abduction brace
revision of the acetabular liner to a constrained type
revision of the entire acetabular component
revision of the femoral head to a larger size
revision to an extended offset prosthesis
Corrent answer: 3
Per Dorr et al: post-operative hip instability can be caused by several factors: soft tissue imbalance, component malposition, or position. Component malposition, as in this case, should be treated with revision of the offending component. In this case the acetabulum was placed in retroversion when it should have been 15-20 degrees anteverted. None of the other options addresses the cause of the instability. According to Morrey, the most signficant risk factors to instability are prior hip surgery, trochanteric nonunion, and posterior surgical approach. He wrote that the most reliable way to correct instability is to reorient a retroverted acetabular cup.
OrthoCash 2020
In patients with sickle cell disease and asymptomatic osteonecrosis of the femoral head identified with magnetic resonance imaging, what percentage will eventually go on to femoral head collapse?

Question 57:

Options:

Bracing
Physiotherapy
Cortisone injection
Conversion to total elbow arthroplasty
Revision interposition arthroplasty

Correct Answer: Conversion to total elbow arthroplasty

Explanation:

DISCUSSION: In a series reported by Blaine and associates, 12 patients were converted from interposition to total elbow arthroplasty. This procedure was successful in 10 out of 12 patients.
REFERENCES: Blaine TA, Adams R, Morrey BF: Total elbow arthroplasty after interposition arthroplasty for elbow arthritis. J Bone Joint Surg Am 2005;87;286-292.
Cheng SL, Morrey FB: Treatment of the mobile, painful arthritic elbow by distraction interposition arthroplasty. J Bone Joint Surg Br 2000;82:233-238.

Question 58:

Options:

Emergent exploration of the sciatic nerve
Transfusion to raise the hematocrit to 30% and sequential neurovascular examinations
Placement of a vena cava filter, halt anticoagulation, blood transfusion, and exploration of the sciatic nerve
Transfusion to raise the hematocrit to 30%, continued administration of enoxaparin, and sequential neurovascular examinations
Placement of a temporary vena cava filter and exploration of the sciatic nerve

Correct Answer: Placement of a vena cava filter, halt anticoagulation, blood transfusion, and exploration of the sciatic nerve

Explanation:

Question 59:

Options:

In situ glenoid component implantation
Hemiarthroplasty
Eccentric reaming of glenoid
Posterior glenoid bone graft

Correct Answer: Eccentric reaming of glenoid

Explanation:

Question 60:

Options:

Anterior column percutaneous screw placement
Posterior column percutaneous screw placement
Pubic symphysis plating
Supra-acetabular pin placement
Percutaneous iliosacral screw placement

Correct Answer: Anterior column percutaneous screw placement

Explanation:

Question 61:

Options:

at least two more attempts at closed reduction in the emergency department before the patient’s sedation wears off.
at least two attempts at closed reduction in the operating room under general anesthesia with muscle relaxation.
acceptance of the reduction because the alignment is satisfactory and growth problems are rare with Salter-Harris type I fractures.
open reduction, extraction of any interposed periosteum, and smooth wire fixation to prevent nonunion.
open reduction, extraction of any interposed periosteum, and smooth wire fixation to decrease the chance of premature physeal closure.

Correct Answer: open reduction, extraction of any interposed periosteum, and smooth wire fixation to decrease the chance of premature physeal closure.

Explanation:

Question 62:

Options:

bed rest for 8 weeks, followed by mobilization in a total contact thoracolumbosacral orthosis.
immediate laminectomy only.
anterior decompression, vertebral body reconstruction, and stabilization.
in situ posterior fusion.
short segment posterior fixation and fusion.

Correct Answer: anterior decompression, vertebral body reconstruction, and stabilization.

Explanation:

Question 63:

Options:

Ensuring the lumbar lordosis is within 15 degrees of the pelvic incidence
Decreasing the cobb angle to less than 25 degrees
Correcting the sagittal vertical axis to +3 cm from neutral
Increasing the pelvic tilt to greater than 20 degrees
Stopping the fusion at L5

Correct Answer: Ensuring the lumbar lordosis is within 15 degrees of the pelvic incidence

Explanation:

Question 64:

What is the most reproducible landmark for the accurate anatomic placement of the tibial tunnel for an anterior cruciate ligament (ACL) reconstruction?

Options:

Anterior border of the tibia
Anterior border of the posterior cruciate ligament (PCL)
Posterior border of the tibia
Posterior border of the anterior horn of the lateral meniscus
Posterior border of the anterior horn of the medial meniscus

Correct Answer: Anterior border of the posterior cruciate ligament (PCL)

Explanation:

Question 65:

Options:

infection.
instability.
loosening.
periprosthetic fracture.

Correct Answer: instability.

Explanation:

Question 66:

A 42-year-old woman sustains a closed posterior elbow dislocation. A closed reduction is performed, and the elbow appears stable under fluoroscopic examination. Initial treatment should consist of

Options:

early mobilization only.
surgical reconstruction of medial and lateral collateral ligaments.
active motion in a hinged brace from 30° to 120°.
application of hinged external fixator with early mobilization.

Correct Answer: early mobilization only.

Explanation:

Question 67:

Options:

CT of the chest.
a bone scan.
a repeat radiograph in 6 to 8 weeks.
repeat MRI in 6 to 8 weeks.
an open biopsy.

Correct Answer: a repeat radiograph in 6 to 8 weeks.

Explanation:

Question 68:

A diskectomy is performed in which the disk space is not aggressively debrided. When compared to techniques that involve aggressive debridement of the disk space, this results in

Options:

less intraoperative blood loss.
an increased rate of recurrent disk herniation.
a shorter length of hospital stay.
a higher rate of surgical complications.

Correct Answer: an increased rate of recurrent disk herniation.

Explanation:

DISCUSSION
This patient has disk herniation at the left L5-S1 level. This will generally affect the traversing S1 nerve. The S1 dermatome is on the lateral aspect and sole of the foot.
Surgical treatment generally involves a diskectomy with removal of the herniated fragment. This can be performed via a conventional open approach or minimally invasive endoscopic technique. Several recent meta-analyses have demonstrated equivalent outcomes with regard to leg pain and clinical outcomes. Although minimally invasive techniques have been associated with an increased rate of dural tear, the overall complication rate between the 2 techniques is not significantly different. Several studies have demonstrated a substantial learning curve associated with minimally invasive techniques, and the rate of complications decreases significantly with surgeon experience.
When performing a diskectomy, the herniated fragment alone can be removed (sequestrectomy) or some of the disk that remains in the disk space can be removed (complete diskectomy). Studies have shown no change in surgical time, blood loss, length of stay, or surgical complications when performing a sequestrectomy (compared to a more complete diskectomy). A sequestrectomy is associated with a higher rate of recurrent disk herniation at the surgical level.
RECOMMENDED READINGS
Kamper SJ, Ostelo RW, Rubinstein SM, Nellensteijn JM, Peul WC, Arts MP, van Tulder MW. Minimally invasive surgery for lumbar disc herniation: a systematic review and meta-analysis.
Eur Spine J. 2014 May;23(5):1021-43. doi: 10.1007/s00586-013-3161-2. Epub 2014 Jan 18.
PubMed PMID: 24442183.
View Abstract at PubMed
Dasenbrock HH, Juraschek SP, Schultz LR, Witham TF, Sciubba DM, Wolinsky JP, Gokaslan ZL, Bydon A. The efficacy of minimally invasive discectomy compared with open discectomy: a meta-analysis of prospective randomized controlled trials. J Neurosurg Spine. 2012 May;16(5):452-62. doi: 10.3171/2012.1.SPINE11404. Epub 2012 Mar 9. PubMed PMID:

Question 69:

A healthy 2-year-old boy falls from a swing and sustains a displaced midshaft femoral fracture with 1 cm of shortening. What is the most appropriate treatment?

Options:

Pavlik harness
Skeletal traction for 3 weeks followed by a spica cast
Skin traction for 3 weeks followed by a spica cast
Closed reduction and spica casting
Closed reduction and an intramedullary pin

Correct Answer: Closed reduction and spica casting

Explanation:

AL-Madena Copy
DISCUSSION: For children between the ages of 1 and 6 years, closed reduction and early spica casting is recommended. In some instances, associated injuries or body habitus may preclude cast treatment. Pavlik harness treatment of femoral fractures is for infants younger than 1 year of age. Rarely is there an indication for traction. Internal fixation is reserved in general for children older than age 6 years or with confounding factors.
REFERENCES: Abel MF (ed): Orthopaedic Knowledge Update: Pediatrics 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 271-280.
Flynn JM, Schwend RM: Management of pediatric femoral shaft fractures. J Am Acad Orthop Surg 2004;12:347-359.
Figure 29a Figure 29b

Question 70:

Options:

Retain the components, and implant a tibial strut allograft.
Revise the tibial component with a metaphyseal cone and metaphyseal uncemented stem.
Revise the tibial component with a metaphyseal cone and a press-fit diaphyseal-engaging stem.
Revise the tibial component with a long cemented diaphyseal-engaging stem.

Correct Answer: Revise the tibial component with a metaphyseal cone and a press-fit diaphyseal-engaging stem.

Explanation:

Question 71:

Options:

Nondisplaced fracture
Open fracture
Severely comminuted fracture
Dorsal perilunate dislocation
Repeated attempts at reduction

Correct Answer: Nondisplaced fracture

Explanation:

Question 72:

Options:

fixation of the lateral malleolus.
fixation of the medial malleolus.
fixation of the posterior malleolus.
all planned fixation is completed .

Correct Answer: all planned fixation is completed .

Explanation:

Discussion:
The radiographs reveal a trimalleolar ankle fracture dislocation with an associated distal tibiofibular syndesmotic disruption. Medial and lateral malleolar stabilization are consistently agreed upon. The decision to stabilize the posterior malleolus is more controversial. Posterior malleolar stabilization accomplishes the following:
Restores incisura competence thereby reducing the incidence of syndesmotic malreduction by creating containment
Assists in stabilizing the syndesmosis via the posterior inferior tibiofibular ligament, potentially limiting the need for additional syndesmotic stabilization
Maximizes the surface area for ankle joint loading
Enhances posterior translational stability of the talus
The traditional indication for stabilization of the posterior malleolus is based on fragment size. However, fracture orientation varies and makes evaluation of the fragment size challenging with a lateral radiograph alone. The three primary types include the posterolateral oblique, medial extension, and shell. Because of the additive syndesmotic stability which is gained through the deep deltoid ligament and medial malleolar fixation, the anterior talofibular ligament and lateral malleolar fixation, and the posterior inferior tibiofibular ligament and posterior malleolar fixation, syndesmotic stability should only be assessed after all other points of instability that are planned for fixation are fixed.
Syndesmotic instability should be assessed with direct manipulation on both the anteroposterior and lateral views with special attention to the lateral view. Syndesmotic reduction should be assessed either through open visualization or by comparing closed reduction parameters (clear space, overlap, and fibular position on the lateral view) with the patient’s contralateral side (assuming no injury). This is more effective than using population norms secondary to the two types of syndesmotic morphologies which create different absolute values for these parameters.

Question 73:

Options:

closed treatment with early motion.
a cylindrical cast and restricted weight bearing.
open reduction and internal fixation.
patellar revision.
patellectomy.

Correct Answer: closed treatment with early motion.

Explanation:

Question 74:

What is the neoplastic cell of origin for this tumor?

Options:

Lymphocyte
Monocyte
Macrophage
Mononuclear phagocyte

Correct Answer: Mononuclear phagocyte

Explanation:

DISCUSSION
Tenosynovial giant-cell tumors are widely known as pigmented villonodular synovitis (PVNS), although this term is misleading because this tumor type is a clonal neoplasm and does not involve an inflammatory process. It often is shown to have a t(1:2)(p13q37) karyotype resulting in CSF1-COL6A3 gene fusion. There are various amounts of mononuclear cells, osteoclastlike giant cells, foamy histiocytes, hemosiderophages, and chronic inflammatory cells. Local recurrences are common, but CSF1R inhibitors are being investigated in studies involving local control improvement and disease regression.
Targeted therapy trials to assist in control of the diffuse-type tenosynovial giant-cell tumor (formerly called PVNS) involve the use of monoclonal antibodies that inhibit CSF1R activation. CSF1R-expressing mononuclear phagocytes are affected by these monoclonal antibodies.
Infantile fibrosarcoma is associated with the t(12;15)(p13;q25) karyotype and ETV6-NTRK3 gene fusion product. Nodular fasciitis is associated with the t(17;22)(p13;q13.1) karyotype and MYH9-USP6 gene fusion product. Inflammatory myofibroblastic tumor is associated with translocations involving 2p23 resulting in multiple fusion products of ALK with TPM4 (19p13.1), TPM3 (1q21), CLTC (17q23), RANBP2 (2q13), ATIC (2q35), SEC31A (4q21), and CARS (11p15). No
nonpreferred response has a histologic appearance that includes hemosiderin, foamy histiocytes, and osteoclastlike giant cells.
A conformation-specific inhibitor of the juxtamembrane region of CSF1R is a synthetic molecule that is designed to access the autoinhibited state of the receptor through direct interactions with the juxtamembrane residues embedded in the adenosine 5’-triphosphate-binding pocket. It is designed to bind in the regulatory a-helix of the N-terminal lobe of the kinase domain in neoplastic cells of tenosynovial giant-cell tumor that have expression of the CSF1 gene. There is a structural plasticity of the domain of the CSF1R that allows the molecule to directly bind the autoinhibited state of CSF1R.
Another approach involves the development of the anti-CSF1R antibody, emactuzumab, which targets tumor-associated macrophages. A lower percentage of volume reduction has been reported with imatinib, a tyrosine kinase inhibitor. Alkylating agents have not been used in this benign neoplasm.
Tenosynovial giant-cell tumor is characterized by an overexpression of CSF1. CSF1R activation leads to recruitment of CSF1R-expressing cells of the mononuclear phagocyte lineage.
RECOMMENDED READINGS
Cassier PA, Gelderblom H, Stacchiotti S, Thomas D, Maki RG, Kroep JR, van der Graaf WT, Italiano A, Seddon B, Dômont J, Bompas E, Wagner AJ, Blay JY. Efficacy of imatinib mesylate for the treatment of locally advanced and/or metastatic tenosynovial giant cell tumor/pigmented villonodular synovitis. Cancer. 2012 Mar 15;118(6):1649-55. doi: 10.1002/cncr.26409. Epub 2011 Aug 5. PubMed PMID: 21823110.
View Abstract at PubMed
Ladanyi M, Fletcher JA, Dal Cin P. Cytogenetic and molecular genetic pathology of soft tissue tumors. In: Goldblum JR, Folpe AL, Weis SW, eds.
Enzinger & Weiss’s Soft Tissue Tumors
. 6th ed. Philadelphia, PA: Elsevier Saunders; 2014:76-109.
Staals EL, Ferrari S, Donati DM, Palmerini E. Diffuse-type tenosynovial giant cell tumour: Current treatment concepts and future perspectives. Eur J Cancer. 2016 Aug;63:34-40. doi: 10.1016/j.ejca.2016.04.022. Epub 2016 Jun 5. Review.
View Abstract at PubMed
Tap WD, Wainberg ZA, Anthony SP, Ibrahim PN, Zhang C, Healey JH, Chmielowski B, Staddon AP, Cohn AL, Shapiro GI, Keedy VL, Singh AS, Puzanov I, Kwak EL, Wagner AJ, Von Hoff DD, Weiss GJ, Ramanathan RK, Zhang J, Habets G, Zhang Y, Burton EA, Visor G, Sanftner L, Severson P, Nguyen H, Kim MJ, Marimuthu A, Tsang G, Shellooe R, Gee C, West BL, Hirth P, Nolop K, van de Rijn M, Hsu HH, Peterfy C, Lin PS, Tong-Starksen S, Bollag G. Structure-Guided Blockade of CSF1R Kinase in Tenosynovial Giant-Cell Tumor. N Engl J Med. 2015 Jul 30;373(5):428-37. doi:10.1056/NEJMoa1411366. PubMed PMID: 26222558.
View Abstract at PubMed
Ries CH, Cannarile MA, Hoves S, Benz J, Wartha K, Runza V, Rey-Giraud F, Pradel LP, Feuerhake F, Klaman I, Jones T, Jucknischke U, Scheiblich S, Kaluza K, Gorr IH, Walz A, Abiraj K, Cassier PA, Sica A, Gomez-Roca C, de Visser KE, Italiano A, Le Tourneau C, Delord JP, Levitsky H, Blay JY, Rüttinger D. Targeting tumor-associated macrophages with anti-CSF-1R antibody reveals a strategy for cancer therapy. Cancer Cell. 2014 Jun 16;25(6):846-59. doi: 10.1016/j.ccr.2014.05.016. Epub 2014 Jun 2. PubMed PMID: 24898549.
View Abstract at PubMed

Question 75:

Options:

a strengthening program for the rotator cuff and scapular muscles.
arthroscopic thermal capsulorrhaphy.
an inferior capsular shift.
a glenoid osteotomy.
a Putti-Platt repair.

Correct Answer: a strengthening program for the rotator cuff and scapular muscles.

Explanation:

DISCUSSION: The patient has multidirectional instability (MDI). It has been reported that a high percentage of patients with MDI respond to a properly structured exercise program that is continued for at least 3 to 6 months. If nonsurgical management fails to provide relief, stabilization with an inferior capsular shift procedure has been effective in a high percentage of patients. Unidirectional repairs, such as the Putti-Platt procedure, are unsuitable for correcting MDI. Thermal capsulorrhaphy has been reported to have a very high failure rate
(greater than 50%) for treating MDI.
REFERENCES: Burkhead WZ Jr, Rockwood CA Jr: Treatment of instability of the shoulder with an exercise program. J Bone Joint Surg Am 1992;74:890-896.
Neer CS II, Foster CR: Inferior capsular shift for involuntary inferior and multidirectional instability of the shoulder: A preliminary report. J Bone Joint Surg Am 1980;62:897-908.
Pollock RG, Owens JM, Flatow EL, et al: Operative results of the inferior capsular shift procedure for multidirectional instability of the shoulder. J Bone Joint Surg Am
2000;82:919-928.
Miniaci A, Birnie J: Thermal capsular shrinkage for treatment of multidirectional instability of the shoulder. J Bone Joint Surg Am 2003;85:2283-2287.

Question 76:

Options:

increasing the force to dislocation of the femoral head.
increasing the range of motion until impingement of the neck on the liner.
decreasing the resisting moment to dislocation of the femoral head.
decreasing the range of motion until dislocation of the femoral head.
decreasing the range of motion until impingement of the neck on the liner.

Correct Answer: increasing the range of motion until impingement of the neck on the liner.

Explanation:

Question 77:

Options:

A 41-year-old right-hand-dominant man has been treated nonsurgically for right elbow arthritis. His radiographs reveal end-stage ulnohumeral arthritis with complete loss of the joint space. He reports pain during the mid-arc of elbow flexion and extension. During the last 8 years, he has attempted activity modification, medication, physical therapy, and multiple cortisone injections. His symptoms have progressed, resulting in constant pain, loss of a functional range of motion, and an inability to perform many activities of daily living. Secondary to his age and activity demands, he undergoes a soft-tissue interposition arthroplasty of his elbow with an Achilles allograft. Which presurgical finding correlates with elevated risk for postsurgical complications?
Inflammatory elbow arthritis
A presurgical flexion-extension elbow arc of approximately 50°
Retained distal humerus hardware on presurgical radiographs
Evidence of presurgical elbow instability End-stage posttraumatic or inflammatory elbow arthritis in active, high-demand patients remains difficult to treat. Traditional total elbow arthroplasty is discouraged in this demographic secondary to concerns about implant longevity. Soft-tissue interposition arthroplasty does not necessitate the same activity and weight restrictions for patients after surgery and remains a reasonable salvage procedure. Larson and Morrey published their findings on 38 patients with a mean age of 39 years following soft-tissue interposition arthroplasty for posttraumatic and inflammatory end-stage elbow arthritis. These investigators reported a significant improvement in Mayo Elbow Performance Score in addition to improvement in the flexion-extension arc from 51° to 97° after surgery. They reported worse results and elevated incidence of complications for patients with presurgical elbow instability. Retained hardware from prior surgery was not deemed a contraindication.

Correct Answer: Inflammatory elbow arthritis

Explanation:

Figure 1 is the radiograph of a 12-year-old baseball player who has posterolateral elbow pain with throwing. The area of interest is designated by the black arrow. His range of motion and strength are full. No previous treatment has been provided. What is the most appropriate initial treatment?
Elbow arthroscopy with debridement
Immobilization and rest for 6 weeks
Corticosteroid injection
Open osteochondral autograft transfer
Osteochondritis dissecans of the capitellum is a painful condition that affects immature athletes who undergo repetitive compression of the radiocapitellar joint. Management is based primarily on the integrity of the articular cartilage surface and the stability of the lesion. Nonsurgical treatment is typically selected for patients
with early-grade, stable lesions, and it involves activity modification with cessation of sports participation. The duration of activity modification is dictated by symptoms, with 3 to 6 weeks of rest followed by return to sport in 3 to 6 months commonly used as a guideline. Strengthening and stretching exercises are commonly incorporated after the pain has subsided. Surgical intervention or corticosteroid injection would not be first-line treatment.
Figures 1 and 2 are the radiographs of a 69-year-old man with a history of treated prostate cancer and hemodialysis-dependent end- stage renal disease who presents to the emergency department with progressively worsening right shoulder pain and stiffness. Laboratory tests reveal a white blood cell count of 17,000, erythrocyte sedimentation rate, 75, and CRP, 10.1. He has a draining sinus located along the anterior shoulder. What is the best next step?

Question 78:

In displaced calcaneal fractures, what fragment is the only one that remains in its anatomic position?

Options:

Posterior tubercle
Posterior articular facet
Anterior process
Sustentaculum tali
Lateral wall

Correct Answer: Sustentaculum tali

Explanation:

Question 79:

Options:

Initiate isometric external rotation strengthening and continue passive range of motion.
Initiate eccentric supraspinatus strengthening and continue passive range of motion.
Initiate light resistance training to minimize atrophy and continue passive range of motion.
Continue passive range of motion and initiate concentric deltoid strengthening.
Continue passive range of motion with no active strengthening of the shoulder muscles.

Correct Answer: Continue passive range of motion with no active strengthening of the shoulder muscles.

Explanation:

Question 80:

A 40-year-old male who sustained an open pilon fracture 2 weeks ago is scheduled for a below-the-knee amputation (BKA). What laboratory value is the best predictor for wound healing?

Options:

serum albumin level
total protein level
calcium levels
C-reactive protein
ESR

Correct Answer: serum albumin level

Explanation:

Question 81:

Options:

a program of stretching exercises and rotator cuff strengthening exercises.
a series of six cortisone injections.
arthroscopic acromioplasty.
arthroscopic acromioplasty and laser capsulorrhaphy.
open acromioplasty.

Correct Answer: a program of stretching exercises and rotator cuff strengthening exercises.

Explanation:

Question 82:

Options:

slow rewarming in cool 77 degrees F (25 degrees C) water.
rapid rewarming in a footbath at 104.0 degrees F to 107.6 degrees F (40 degrees C to 42 degrees C).
rewarming in 98.6 degrees F (37 degrees C) water.
heated blankets at 100.4 degrees F (38 degrees C).
a heating pad at 104.0 degrees F (40 degrees C).

Correct Answer: rapid rewarming in a footbath at 104.0 degrees F to 107.6 degrees F (40 degrees C to 42 degrees C).

Explanation:

Question 83:

-What is the recommended treatment for this injury?

Options:

Bankart repair
Hanging arm cast
Rest and no pitching for 3 months
Resume a throwing program but avoid curveballs and sliders

Correct Answer: Rest and no pitching for 3 months

Explanation:

DISCUSSION FOR QUESTIONS 85 THROUGH 87
The hypertrophic zone of the growth plate has been implicated as the weak link in the physis in acute injuries. Epiphysiolysis of the proximal humerus in throwing athletes occurs as the result of tension and shear on the physis. More than 90% of affected patients who are treated with rest for an average of 3 months become asymptomatic. Prevention is the best option. Set limitations of the number of pitches and types of pitches depending on the age of the player. Also recommend use of proper pitching mechanics.

Question 84:

Options:

Popliteal artery
Popliteal vein
Tibial nerve
Popliteus muscle
Soleus muscle

Correct Answer: Popliteus muscle

Explanation:

DISCUSSION: The major risk of performing a high tibial osteotomy is neurovascular injury. The new version of the high tibial osteotomy makes a transverse osteotomy at the level of the tibial tubercle. The osteotome is protected by the oblique belly of the popliteus muscle. The popliteal artery and vein and tibial nerve all lie posterior to the muscle. The soleus muscle originates below this level.
REFERENCES: Clement CD: Anatomy: A Regional Atlas of Human Anatomy, ed 3.
Baltimore, MD, Munich, Germany, Urban and Schwarzberg, 1987, Figure 422.
Netter FH: Atlas of Human Anatomy. Summit, NJ, Ciba-Geigy, 1989, plate 480.

Question 85:

Figure 10 shows the AP radiograph of an ambulatory 76-year-old patient. What is the most appropriate surgical treatment option for this patient?

Options:

Revision arthroplasty using a cemented femoral component
Impaction allografting of the femoral component
Proximal femoral replacement arthroplasty
Resection arthroplasty
Hip arthrodesis

Correct Answer: Proximal femoral replacement arthroplasty

Explanation:

DISCUSSION: The patient has a periprosthetic fracture around a loose cemented femoral component. The proximal bone stock is poor; therefore, this fracture may be categorized as Vancouver 3-B. Hip arthrodesis and resection arthroplasty provide suboptimal results, particularly for ambulatory patients. Although impaction allografting may be an option to restore the bone stock in a younger patient, the latter procedure will be very difficult to perform when the proximal bone is poor in quality and fractured. Cementing another component into this wide femur is not an option. The best option for revision of the femoral component in this elderly patient is proximal femoral replacement arthroplasty.
REFERENCES: Malkani AL, Settecerri JJ, Sim FH, et al: Long-term results of proximal femoral replacement for non-neoplastic disorders. J Bone Joint Surg Br 1995;77:351-356.
Parvizi J, Sim FH: Proximal femoral replacements with megaprostheses. Clin Orthop 2004;420:169-175.

Question 86:

Figure 1 is the radiograph of a 31-year-old man who had left shoulder pain after a fall during a snowboarding jump. Residual displacement of 5 mm after closed reduction is most likely to result in

Options:

nonunion.
osteonecrosis.
altered rotator cuff mechanics.
normal shoulder function.

Correct Answer: altered rotator cuff mechanics.

Explanation:

Question 87:

Options:

repair of the superior labrum.
isolated supraspinatus repair.
biceps recentering.
subscapularis repair and biceps tenodesis.
subscapularis repair and recentering of the biceps tendon.

Correct Answer: subscapularis repair and biceps tenodesis.

Explanation:

Question 88:

Based on the findings seen at C5-6 in Figure 30, the most likely deficit for this patient will be weakness of the

Options:

deltoid.
wrist flexor.
wrist extensor.
triceps.
grip.

Correct Answer: wrist extensor.

Explanation:

Question 89:

What is the most appropriate surgical treatment for a stage III symptomatic scapholunate advanced collapsed (SLAC) wrist?

Options:

Radioscapholunate arthrodesis
Scaphotrapeziotrapezoid arthrodesis
Scaphocapitate arthrodesis
Proximal row carpectomy
Scaphoid excision and capitate-lunate-triquetrum-hamate arthrodesis

Correct Answer: Scaphoid excision and capitate-lunate-triquetrum-hamate arthrodesis

Explanation:

DISCUSSION: SLAC is the end result of chronic scapholunate instability. The arthritis follows a predictable pattern. Stage I disease involves cartilage loss between the waist of the scaphoid and the radial styloid. In stage II, the arthritis progresses to include the proximal pole of the scaphoid and the scaphoid fossa of the radius. Finally, stage III goes on to include arthritis of the capitolunate joint. The only treatment option that addresses all of the sites of arthritis is the scaphoid excision and four corner fusion.
REFERENCES: Ashmead DT IV, Watson HK, Damon C, et al: Scapholunate advanced collapse wrist salvage. J Hand Surg Am 1994;19:741-750.
Sauerbier M, Trankle M, Linsner G, et al: Midcarpal arthrodesis with complete scaphoid excision and interposition bone graft in the treatment of advanced carpal collapse (SNAC/SLAC wrist): Operative technique and outcome assessment. J Hand Surg Br 2000;25:341-345.

Question 90:

Options:

Alendronate
Indomethacin
Radiotherapy
Excision

Correct Answer: Alendronate

Explanation:

Question 91:

Options:

Urgent admission to the hospital for surgical intervention
Immediate MRI of the lumbar spine as an outpatient
Anti-inflammatory medications and activity modification
Caudal epidural steroid injection
Electromyography

Correct Answer: Anti-inflammatory medications and activity modification

Explanation:

Question 92:

Options:

open repair.
immobilization.
aspiration and steroid injection.
rest, ice, and rehabilitation.
tenotomy.

Correct Answer: rest, ice, and rehabilitation.

Explanation:

Question 93:

Which of the following is true regarding changes in the vascularity of the adult intervertebral disc with age? Review Topic

Options:

Neovascularization occurs from the nucleus pulposus
Neovascularization occurs from the outer annulus
Neovascularization occurs from the endplates
There is no change in vascularity
There is a decrease in vascularity

Correct Answer: Neovascularization occurs from the nucleus pulposus

Explanation:

Question 94:

Contraindications to cervical laminectomy as a treatment for cervical spondylotic myelopathy include which of the following findings?

Options:

Multilevel disease with spinal cord compression
Anterior spinal cord compression
Posterior spinal cord compression
Cervical kyphosis
Ossification of the posterior longitudinal ligament

Correct Answer: Cervical kyphosis

Explanation:

Question 95:

Chemotherapy is routinely included in the treatment of which of the following soft-tissue sarcomas?

Options:

Angiosarcoma
Malignant fibrous histiocytoma
Liposarcoma
Rhabdomyosarcoma
Clear cell sarcoma

Correct Answer: Rhabdomyosarcoma

Explanation:

Question 96:

Options:

a spinal cord injury and he cannot participate in contact sports.
no obvious injury and can return to all sports without risk of recurrence.
no obvious injury, but he is at a high risk for breaking his neck in athletic competition.
transient quadriplegia only, but this places him at greater risk for future spinal cord injury and he should refrain from all contact sports.
transient quadriplegia and that there is no evidence of increased risk of permanent spinal cord injury should he return to contact sports.

Correct Answer: transient quadriplegia and that there is no evidence of increased risk of permanent spinal cord injury should he return to contact sports.

Explanation:

DISCUSSION: The long-term effect of transient quadriplegia is unknown. Based on a history of one brief episode of transient quadriplegia and normal examination and MRI findings, the risk of permanent spinal cord injury with a return to play is low. There is a risk of recurrent episodes of transient quadriplegia after the initial episode.
REFERENCES: Morganti C, Sweeney CA, Albanese SA, et al: Return to play after cervical spine injury. Spine 2001;26:1131-1136.
Odor JM, Watkins RG, Dillin WH, et al: Incidence of cervical spinal stenosis in professional and rookie football players. Am J Sports Med 1990;18:507-509.
Torg JS, Naranja RJ Jr, Palov H, et al: The relationship of developmental narrowing of the cervical spinal canal to reversible and irreversible injury of the cervical spinal cord in football players. J Bone Joint Surg Am 1996;78:1308-1314.
Vaccaro
AR
, Watkins B, Albert TJ, et al: Cervical spine injuries in athletes: Current return-to-play criteria. Orthopedics 2001;24:699-703.

Question 97:

Options:

Torn posterolateral corner
Torn posterior cruciate ligament (PCL) and posterolateral corner
Torn PCL
Rupture of the quadriceps tendon
Rupture of the lateral collateral ligament

Correct Answer: Torn posterolateral corner

Explanation:

Question 98:

An axial T 1 -weighted MRI scan of the pelvis is shown in Figure 13. The arrow is pointing to what muscle?

Options:

Adductor magnus
Pectineus
Obturator externus
Obturator internus
Levator ani

Correct Answer: Obturator internus

Explanation:

DISCUSSION: The obturator internus muscle originates from the internal pelvic wall and passes laterally through the lesser sciatic foramen, banking around the ischium below the sacrospinous ligament before inserting on the medial aspect of the greater trochanter.
REFERENCES: Higuchi T: Normal anatomy and magnetic resonance appearance of the pelvis, in Takahashi HE, Morita T, Hotta T, Ogose A (eds): Operative Treatment of Pelvic Tumors. Tokyo, Japan, Springer-Verlag, 2003, pp 4-21.
Berquist TH: Pelvis, hips and thigh, in Berquist TH (ed): MRI of the Musculoskeletal System,
ed 4. Philadelphia, PA, Lippincott Williams and Wilkins, 2001, pp 210-238.

Question 99:

Options:

Osteogenic sarcoma
Ewing’s sarcoma
Giant cell tumor of bone
Aneurysmal bone cyst
Metastatic adenocarcinoma

Correct Answer: Giant cell tumor of bone

Explanation:

Question 100:

- The radiographs shown in Figures 71a through 71c, and the CT scan shown in Figure 71d reveal an acetabular fracture that should be classified as

Options:

t-type
both column
transverse
anterior column
anterior column posterior hemitransverse

Correct Answer: both column

Orthopedic Surgery MCQs: Arthroplasty, Fracture & Hip Exam Prep | Part 18

Orthopedic Surgery Board Review MCQs: Arthroplasty, Fracture, Ankle & Hip | Part 79

Key Takeaway

About This Board Review Set

How to Use the Interactive Quiz

Topics Covered in Part 79

Sample Questions from This Set

Why Active MCQ Practice Works

Chapter Index