Hb Orthopedic Review | Dr Hutaif General Orthopedics Re -...

Each of the possible answers may occur following triple arthrodesis. In numerous studies, ankle arthritis is the complication most likely to occur regardless of the underlying disease process.

The indication for surgery is intractable deformity, which is refractory to all forms of bracing. By refractory, one implies that skin breakdown or imminent infection is present. If surgery were performed, then it would consist of a tibiotalocalcaneal arthrodesis. There are no indications for this surgery in this patient. Once the neuropathic process has reached a stable point, a deformity is not likely to progress.

In the scenario of an elderly patient with questionable fixation into the femoral head and a non-healed femoral neck fracture, proper treatment is arthroplasty. In a physiologically younger patient, reduction and fixation of the fractures (femoral neck and subtrochanteric, if present) with methods such as a valgus producing osteotomy at the level of the subtrochanteric fracture are
recommended.
Figure A shows cannulated screw fixation of a right femoral neck fracture.
The referenced study by Oakey et al evaluated strength of proximal femurs after cannulated hip screw placement and found that placement of an inverted triangle had a higher ultimate load to failure than placement in a standard triangle format (two screws distal).

In younger active patients, tendon transfer is considered a preferable treatment option. The patient has failed a course of nonoperative management. Subacromial decompression may offer pain relief but may not be advisable in a patient with rotator cuff deficient shoulder. A total shoulder arthroplasty requires functionality of the supraspinatus and infraspinatus. A reverse total shoulder is an option to alleviate pain and perhaps improve forward flexion height and strength; however, reverse arthroplasty would not improve external rotation in this patient, and there is concern for longevity of the implant in younger _patient populations._

A two part stable intertrochanteric femur fracture can be treated with a sliding hip screw, with good biomechanical and clinical results.
The referenced article by Bolhofner et al reviews a series of 69 patients with a sliding hip screw and two hole side plate and notes that they did not have any failure of the side plate construct.
The referenced article by McLoughlin et al is a biomechanical evaluation of 2 versus 4 hole plates and found that peak load in the failure test was not found to be statistically different between the two-hole and four-hole designs. In cyclic testing, the two-hole configuration exhibited statistically smaller fragment migration in both shear and distraction than the four-hole design.

Ankle arthritis is rarely idiopathic. In the United States, the most common source of ankle arthritis is following trauma, usually of a major nature. Repetitive ankle injury, particularly when associated with recurrent instability and a varus or cavus foot, will likely lead to the development of ankle arthritis. Patients should be counseled that recurrent instability of the ankle, particularly when osteophytes are already present, frequently leads to arthritis.

General principles can be used as bunion surgery guidelines even though there is extensive debate on the topic. A distal metatarsal osteotomy is most appropriate for patients with mild deformity and no transfer metatarsalgia. A proximal osteotomy potentially can correct more severe
deformities. A lapidus procedure, or tarsometatarsal fusion, provides the highest potential to correct deformity plus the advantage of stabilizing the first tarsometatarsal joint and limiting or eliminating transfer metatarsalgia. A first MTP fusion is most appropriate for patients with severe first MTP arthrosis.
RECOMMENDED READINGS
1. [Easley ME, Trnka HJ. Current concepts review: hallux valgus part II: operative treatment. Foot Ankle Int. 2007 Jun;28(6):748-58. Review. PubMed PMID: 17592710.](http://www.ncbi.nlm.nih.gov/pubmed/17592710)[View Abstract at PubMed](http://www.ncbi.nlm.nih.gov/pubmed/17592710)
2. [Coughlin MJ, Shurnas PS. Hallux rigidus. Grading and long-term results of operative treatment. J Bone Joint Surg Am. 2003 Nov;85-A(11):2072-88. PubMed PMID: 14630834. ](http://www.ncbi.nlm.nih.gov/pubmed/14630834)[View Abstract at PubMed](http://www.ncbi.nlm.nih.gov/pubmed/14630834)

The patient has the classic symptoms, examination findings, and radiographs for a painful accessory navicular. Initial treatment should always be nonsurgical, specifically cast immobilization. Surgery should be reserved for those patients who fail nonsurgical management. Corticosteroids should not be injected into a posterior tibial tendon or insertion point because they can weaken the tendon and possibly cause tendon rupture. Triple arthrodesis and biopsy have no role in the management of a painful accessory navicular.
REFERENCE: Bordelon RL: Flatfoot in children and young adults, in Coughlin MJ, Mann RA (eds): Surgery of the Foot and Ankle, ed 6. St Louis, MO, Mosby, 1993, pp 717-756.

Injury to the latissimus dorsi tendon recently has been reported as a cause of pain in the thrower’s shoulder. The etiology of this injury is felt to be eccentric overload during the follow-through of the throwing motion. Recommended management for this unusual injury consists of a short period of rest, followed by physical therapy to restore shoulder motion and strength. Throwing is allowed when the athlete demonstrates full, pain-free motion and good strength and balance of the rotator cuff and scapular rotator muscles. Currently there are no defined indications for surgical repair.
REFERENCES: Schickendantz MS, Ho CP, Keppler L, et al: MR imaging of the thrower’s shoulder: Internal impingement, latissimus dorsi/subscapularis strains and related injuries.
Magn Reson Imaging Clin N Am 1999;7:39-49.
Livesey JP, Brownson P, Wallace WA: Traumatic latissimus dorsi: Tendon rupture. J Shoulder Elbow Surg 2002;11:642-644.

DISCUSSION: When polyethylene undergoes oxidation, the material undergoes a decrease in strength and
ductility, and an increase in the elastic modulus. This makes the material more brittle, and leaves it vulnerable to delamination, fracture, and pitting.
REFERENCE: Barrack RL, Booth RE Jr, Lonner JH, et al (eds): Orthopaedic Knowledge Update: Hip and Knee
Reconstruction 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 163-176.

The radiograph reveals severe intestinal dilatation, which has occurred as the result of acute colonic pseudo-obstruction and is associated with excessive narcotic administration following total joint arthroplasty. Anesthetic type, antibiotic administration, and warfarin have not been associated with this obstruction. Electrolyte imbalances such as hypokalemia have been associated with postsurgical acute colonic pseudo-obstruction.

Flexion contractures are the most common complication of elbow dislocations. About 15% of patients lose more than 30 degrees of flexion. The risk of contracture is proportional to the duration of immobilization. Elbows should be moved within the first few days after reduction. The splinting is for comfort and protection only while the pain subsides.
REFERENCES: Mehlhoff TL, Noble PC, Bennett JB, Tullos HS: Simple dislocation of the elbow in the adult: Results after closed treatment. J Bone Joint Surg Am 1988;70:244-249.
Linscheid RL, O’Driscoll SW: Elbow dislocations, in Morrey BF (ed): The Elbow and Its Disorders, ed 2. Philadelphia, PA, WB Saunders, 1993, pp 441-452.
O’Driscoll SW, Jupiter JB, King GJ, Hotchkiss RN, Morrey BF: The unstable elbow. Instr Course Lect 2001;50:89-102.
Ross G, McDevitt ER, Chronister R, Ove PN: Treatment of simple elbow dislocation using an immediate motion protocol. Am J Sports Med 1999;27:308-311.

Lacerated radial nerves are associated with open humeral fractures. All open humeral fractures with radial nerve palsy should be managed with radial nerve exploration and skeletal stabilization. Closed humeral fractures with associated radial nerve palsy usually have an intact nerve with neurapraxia. Most of these patients recover without surgical treatment. If the patient has multiple injuries, skeletal stabilization may be indicated to improve mobilization. For an isolated closed humeral fracture with a radial nerve palsy, the treatment of choice is splinting for 1 to 2 weeks, followed by a humeral fracture brace.
REFERENCES: Ring D, Chin K, Jupiter JB: Radial nerve palsy associated with high-energy humeral shaft fractures. J Hand Surg Am 2004;29:144-147.
Foster RJ, Swiontkowski MF, Bach AW, et al: Radial nerve palsy caused by open humeral shaft fractures. J Hand Surg Am 1993;18:121-124.

A number of factors affect nerve conduction velocity; for example, increased body temperature increases nerve conduction velocity. Nerve conduction velocity is slowed by advancing age, compression, decreased blood flow, and fibrosis (from large imprecise sutures used for nerve repair). There is no _association between hand dominance and nerve conduction velocity._

The Willis reference states “the single most important symptom of impending compartment syndrome is pain out of proportion to the injury." This symptom requires a conscious patient. Most children requiring a reduction for a displaced upper or lower extremity fracture will become comfortable soon after the reduction has been completed. Children requiring frequent analgesia or complaining loudly about pain should be examined very carefully for possible compartment syndrome.” The key wording in this question is “earliest indicator”. Pulselessness, paralysis, pallor, and parasthesias are all late indicators.
The Willis article also lists the most reliable signs of a developing compartment syndrome as severe pain with passive stretching of the involved compartment, pain with palpation of the involved compartment, sensory disturbances

The A2 and A4 pulleys are considered the most important parts of the pulley system. If these two structures are preserved, 80% of finger flexion can be maintained. If the pulley system is not left intact or is not reconstructed, “bow-stringing” of the flexor tendons occurs with loss of full flexion. The A2 pulley is over the proximal phalanx and the A4 pulley is over the middle phalanx.
REFERENCES: Doyle JR: Anatomy of the finger flexor tendon sheath and pulley system.
J Hand Surg Am 1988;13:473-484.
Strickland JW: Flexor tendon injuries: I. Foundations of treatment. J Am Acad Orthop Surg 1995;3:44-54.

Figures A and B show a plateau fracture with a lateral split and depression of the articular surface. In treating tibial plateau fractures, calcium phosphate has been shown to have the least amount of articular subsidence on follow-up examinations due to its high compressive strength.
The study by Lobenhoffer et al noted improved radiographic outcomes and earlier weightbearing with usage of calcium phosphate cement. Welch and Zhang reproduced tibial plateau fractures in goats and compared cancellous autograft to calcium phosphate cement augmentation. At 24 hours, four of five specimens treated with autograft had subsidence of the fragment. Only two specimens from limbs treated with cement showed minimal subsidence; the remaining were congruent.
Yetkinler’s study compared cement to no cement treatment in a model of depressed plateau fractures. Calcium phosphate cement of high compressive
strength provided equivalent or better stability than conventional open reduction
and internal fixation with either auto/allograft bone which had both a lower compressive strength and reduced mechanical stability.

One of the most important examples of corrosion is the breakdown of ultra-high density polyethylene. Wear particles result in osteolysis and bone loss. When UHMWPE is sterilized in air, free radicals are generated and lead to oxidative degradation of the UHMWPE.
The other responses refer to:
Ram extrusion: Manufacturing method for UHMWPE C ompression molding: Manufacturing method for UHMWPE Direct molding: Manufacturing method for UHMWPE Sterilization with ethylene oxide: Alternative
C orrect Answer: Sterilization in an ambient environment

DISCUSSION: Direct measurement and finite element modeling results show that
approximately 20% of the vertical load is borne by the posterior structures of the lumbar
spine in the upright position.

Scientific References

: Adams MA, Hutton WC: The effect of posture on the role of the apophyseal joints in resisting intervertebral compressive forces. J Bone Joint Surg Br 1980;62:358-362.
Goel VK, Kong W, Han JS, Weinstein JN, Gilbertson LG: A combined finite element and optimization investigation of lumbar spine mechanics with and without muscles. Spine 1993;18:1531-1541.

- Use of an interbody strut at L5-S1

The diagnostic criteria for chronic exertional compartment syndrome is pressure >15 mm Hg at rest, or
>30 mm Hg at 1 minute post exercise, or >20 mm Hg at 5 minutes post-exercise. The anterior and lateral compartments are the only ones that meet strict diagnostic criteria for chronic exertional compartment syndrome. The superficial posterior compartment, although close to meeting criteria, is not responsible _for the patient's symptoms and falls below current thresholds for diagnosis._

Normal syndesmotic relationships include a tibiofibular clear space smaller than 6 mm on both AP and mortise views. In a 1989 cadaveric study by Harper and Keller, a tibiofibular clear space exceeding 6 mm on both the AP and mortise views was the most reliable predictor of early syndesmotic widening. Tibiofibular overlap is measured 1 cm proximal to the plafond. Normal values exceed 6 mm or 42% of the width of the fibula on the AP view, or 1 mm on the mortise view. Proximal fibula fracture can occur in isolation without syndesmotic injury, frequently after direct trauma. The medial clear space is the distance between the lateral border of the medial malleolus and the medial border of the talus and is measured at the level of the talar dome. In the mortise view with the ankle in neutral dorsiflexion, the medial clear space should be equal to or smaller than the superior clear space between the talar dome and the tibial plafond. ?A normal medial clear space may be present with syndesmotic injury and consequently lacks sensitivity and specificity.
RECOMMENDED READINGS
[Zalavras C, Thordarson D. Ankle syndesmotic injury. J Am Acad Orthop Surg. 2007 Jun;15(6):330-9. Review. PubMed PMID: 17548882. ](http://www.ncbi.nlm.nih.gov/pubmed/17548882)[View Abstract at PubMed](http://www.ncbi.nlm.nih.gov/pubmed/17548882)
[Wuest TK. Injuries to the Distal Lower Extremity Syndesmosis. J Am Acad Orthop Surg. 1997 May;5(3):172-181. PubMed PMID: 10797219. ](http://www.ncbi.nlm.nih.gov/pubmed/10797219)[View Abstract at PubMed](http://www.ncbi.nlm.nih.gov/pubmed/10797219)
[Harper MC, Keller TS. A radiographic evaluation of the tibiofibular syndesmosis. Foot Ankle. 1989 Dec;10(3):156-60. PubMed PMID: 2613128. ](http://www.ncbi.nlm.nih.gov/pubmed/2613128)[View Abstract at PubMed](http://www.ncbi.nlm.nih.gov/pubmed/2613128)
CLINICAL SITUATION FOR QUESTIONS 37 THROUGH 40
A 41-year-old man sustained a twisting injury while running up stairs 4 weeks ago. He was treated in an ankle brace and has been bearing weight since the injury occurred. He has no history of ankle problems, but he now has ankle pain, swelling, and instability. The pain is aggravated by stairs, and the instability is worse on unlevel ground. Radiographs do not show a fracture.

DISCUSSION: Secondary amenorrhea is defined as the absence of menstrual bleeding for 6 months or the absence of three to six consecutive menstrual cycles after normal menses has begun. The prevalence of amenorrhea among female athletes is estimated at 10% to 20% in women who exercise vigorously and as high as 40% to 66% in elite runners and professional ballet dancers.
REFERENCES: Garrick JG (ed): Orthopaedic Knowledge Update: Sports Medicine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 345-346.
Feingold D, Hame SL: Female athlete triad and stress fractures. Orthop Clin North Am 2006;37:575-583.

DISCUSSION: Physiologic bowing is common and benign. Bowing is typically symmetric, involves both the femur and tibia, and is usually most prominent in toddlers. It usually resolves by 2 years of age but there is great variability. By age 36 months, almost all children will correct spontaneously. In children with physiologic bowing, the screening examination is typically normal and a family history is absent; therefore, radiographs are not necessary. If the deformity has not resolved by age 2 years, an AP radiograph of the lower limbs should be obtained. This provides documentation of the severity of the bowing, permits measurement of the metaphyseal-diaphyseal angle and/or Langenskiold grade, and allows evaluation for conditions such as rickets or bony dysplasia. No treatment is indicated for physiologic bowing.

REFERENCES: Abel MF (ed): Orthopaedic Knowledge Update: Pediatrics 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, p 7.
Salenius P, Vankka E: The development of the tibiofemoral angle in children. J Bone Joint Surg Am
J V _:_

During an anterior approach to the L4-L5 disk space for anterior lumbar interbody fusion, meticulous exposure is paramount to allow for safe preparation of the disk space and subsequent arthrodesis. Although all of these structures can come into play during the exposure, the aorta lies anterior to the L4 vertebral body and bifurcates at this level. The vena cava bifurcates just distal to this. The ureters lie to both sides of the anterior spine. The right common iliac artery and the left common iliac vein originate after the bifurcation of the great vessels and lie caudal to the L4 vertebra.
RECOMMENDED READINGS
Hoppenfeld S, deBoer P: Surgical Exposures in Orthopaedics: The Anatomic Approach. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2003:226-235.
Agur AMR, Lee MJ, eds. Grant's Atlas of Anatomy. 10th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 1999:89.

DISCUSSION: The standard of care is a legal concept that is elusive and amorphous, although the term is used widely by physicians to mean different things. Different state courts across the United States have also applied different meanings to the term “standard of care.” Most commonly, the standard of care is that which a reasonable physician would have done under similar circumstances. Expert testimony from other physicians is often required to educate a jury in a medical malpractice trial about the applicable standard of care. As a general rule, treatment that exhibits knowledge, skill, diligence, and care on the part of the physician is likely to fall within the standard of care, regardless of variations in the definition of this term.
REFERENCES: Lewis MH, Gohagan JK, Merenstein DJ: The locality rule and the physician’s dilemma: Local medical practices vs the national standard of care. JAMA 2007;297:2633-2637.
AAOS Expert Witness Program, www3.aaos.org/member/expwit/expertwitaess.cfm

DISCUSSION: Oxidation of polyethylene has been associated with increased rates of polyethylene wear. Oxidation occurs after polyethylene has been irradiated in the presence of oxygen. Gamma irradiation has been commonly employed to sterilize the polyethylene prior to sterile packaging. Over the last decade, several methods of reducing oxidation of polyethylene have been used. These include irradiation in an inert gas (such as argon or nitrogen), irradiation in vacuum packaging, and avoiding irradiation altogether and sterilizing the polyethylene with ethylene oxide, gas plasma, or vaporized hydrogen peroxide. Crosslinking polyethylene has been done with gamma irradiation and electron beam irradiation. Heating/ melting the material after irradiation allows the free radical chains within the polyethylene to cross-link together rather than oxidize.
REFERENCE: Barrack RL, Booth RE Jr, Lonner JH, et al (eds): Orthopaedic Knowledge Update: Hip and Knee Reconstruction 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 333-344.

The quadrigia effect can occur due to over-advancement of the FDP tendon during repair (usually greater than 1 cm), development of FDP tendon adhesions, and (as in this case) "over the top" repair of the FDP tendon to the extensor tendon after amputation at the distal phalanx level. All of these conditions result in a functionally shortened FDP tendon of the injured digit. Because the FDP tendons of the long, ring, and small digits share a common muscle belly, excursion of the combined tendons is equal to the shortest tendon. Therefore, the uninjured digits will not have full excursion of their respective FDP tendons and will not be able to close into a full fisting position. Treatment of this condition is most commonly release
of the injured FDP tendon. A lumbrical plus deformity can occur in amputations distal to the flexor digitorum superficialis insertion through the middle phalanx. The FDP tendon retracts and increases tension on the lumbrical muscle, which leads to paradoxical interphalangeal (IP) joint extension with attempted flexion. Intrinsic tightness and interphalangeal joint contractures can be caused by hand trauma _but would not lead to the clinical condition this patient has._

Masses exceeding 5 cm in size and any deep mass should be evaluated with MRI prior to biopsy or excision to ensure the most viable tissue is sampled and to minimize morbidity and complications from an improperly placed biopsy site. Examinations are unreliable when attempting to determine if a mass is a simple lipoma, and any large or deep mass should be considered a sarcoma until proven otherwise. PET/CT is a staging examination to evaluate for metastatic or multifocal disease. These are expensive tests that should not be ordered prior to MR imaging of the primary lesion. For patients that are unable to obtain an MRI, CT of the mass is the preferred imaging modality.
RECOMMENDED READINGS
11. [Gilbert NF, Cannon CP, Lin PP, Lewis VO. Soft-tissue sarcoma. J Am Acad Orthop Surg. 2009 Jan;17(1):40-7. Review. PubMed PMID: 19136426.](http://www.ncbi.nlm.nih.gov/pubmed/19136426)[View Abstract at PubMed](http://www.ncbi.nlm.nih.gov/pubmed/19136426)
12. [Damron TA, Beauchamp CP, Rougraff BT, Ward WG Sr. Soft-tissue lumps and bumps. Instr Course Lect. 2004;53:625-37. Review. PubMed PMID: 15116652.](http://www.ncbi.nlm.nih.gov/pubmed/15116652)[View Abstract at PubMed](http://www.ncbi.nlm.nih.gov/pubmed/15116652)
13. Simon MA. Diagnostic Strategies. In: Simon MA, Springfield D, eds. _Surgery for Bone and Soft Tissue Tumors_. Philadelphia, PA: Lippincott-Raven; 1998:21-30.
CLINICAL SITUATION FOR QUESTIONS 9 THROUGH 11
Figures 9a through 9d are the anteroposterior and lateral radiographs, CT scan, and technetium bone scan of a 12-year-old boy who has experienced 7 months of pain in his lower leg. The pain limits his ability to participate in sports and he is having difficulty sleeping. He is afebrile, and laboratory study findings including an erythrocyte sedimentation rate, C-reactive protein, and complete blood count are within normal limits.

During flexion and extension of the normal knee, the AL bundle of the PCL is taut in flexion, and the PM bundle is taut when the knee is near extension. The AL bundle is approximately two times larger at its midsubstance, stiffer, and has a higher ultimate load than the PM bundle. In vitro testing has demonstrated that by tensioning the AL bundle at 90 degrees of flexion and the PM bundle at 0 degrees of flexion, essentially normal knee kinematics are restored. Tensioning the AL bundle at 45 degrees of flexion and the PM bundle at 0 degrees of flexion would result in increased laxity with flexion at 90+ degrees. Tensioning the AL bundle at 90 degrees of flexion and the PM bundle at 45 degrees of flexion would result in increased laxity near extension.
REFERENCES: Harner CD, Janaushek MA, Kanamori A, Yagi M, Vogrin T, Woo SL: Biomechanical analysis of a double-bundle posterior cruciate ligament reconstruction. Am J Sports Med 2000;28:144-151.
Mannor DA, Shearn JT, Grood ES, Noyes FR, Levy MS: Two-bundle posterior cruciate ligament reconstruction: An in vitro analysis of graft placement and tension. Am J Sports Med 2000;28:833-845.

26
For patients with known bleeding disorders, a pneumatic compression device alone is recommended over pharmacoprophylaxis to minimize risk for excessive bleeding and wound complications. Factor VIII deficiency (hemophilia) and active liver disease are the 2 conditions for which support is strongest to withhold anticoagulation. Protein C deficiency and protein S deficiency are associated with increased risk for thrombosis, as is the factor V Leiden mutation.

Previously healthy, poly-trauma patients, presenting with platelet counts of
<70,000 will fall into the pathophysiological category of 'in extremis'. This will
support the role of damage control orthopaedics in the decision making process of this patients fracture management.
Damage control orthopaedics (DCO) is a staged approach for the management of polytrauma patients. It is most ideal for trauma patients that are clinically unstable or in extremis. In these patients, immediate surgery is thought to cause a “second hit” phenomenon, which may lead to ARDS, multi-organ failure, or even death. A patient is classified as 'unstable' or 'in extremis', if he or she meets the criteria in at least three of the four pathophysiological parameters; blood pressure <90mmHg, platelets count <70,000, temperature
<32°C and major soft tissue injuries.
Pape et al. (2005) described four classes of patients, based on their clinical status: stable, borderline, unstable, and in extremes. The term “borderline” was coined to describe a patient who is categorized as stable before surgery, but is at significant risk of unexpected deterioration and organ dysfunction postoperatively.
Pape et al. (2009) outlined that stable patient can undergo early definitive fracture fixation as necessary. In contrast, unstable patient should be resuscitated and adequately stabilized with temporary fixation before receiving definitive orthopaedic care.
Illustration A shows a table outlining the classification system used by Pape to classify patients into their clinical status of stable, borderline, unstable, and in extremes.
Incorrect Answers:
Answer 1: Lactate level = 1.9 mmol/L (normal range <2.5 mmol/L) would classify this patient into a stable category.
Answer 2: Fibrinogen = 1.1 g/dL (normal range >1 g/dL) would classify this patient into a stable category.
Answer 4: Urine output = 50 cc/hr (normal range >150 cc/hr)would classify this patient into a borderline category.
Answer 5: Base deficit = 2 mmol/L (normal range -2 to +2 mmol/L) would classify this patient into a stable category.

This patient has ischiofemoral impingement, in which there is abnormal contact between the lesser trochanter and the lateral border of the ischium. Patients typically present with posteriorly based hip pain and do not respond to intra-articular diagnostic injections. Examination can demonstrate pain with long strides, pain with palpation over the area, as well as reproduction of symptoms with the patient in the contralateral decubitus position and taking the affected hip into passive extension (ischiofemoral impingement test). MRI demonstrates a narrowed ischiofemoral space, as well as increased signal within the quadratus femoris muscle. The diagnosis can be confirmed with a diagnostic injection into this area. Treatment is typically nonsurgical, with surgical intervention consisting of resection of the lesser _trochanter reserved for refractory cases._

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DISCUSSION: The radiographs and MRI scan show a displaced tibial eminence fracture. Meyer and McKeever classified these injuries, with type 1 being a nondisplaced tibial eminence fracture; type 2 being a displaced tibial eminence fracture with a posterior hinge, and type 3 being a displaced tibial eminence fracture. Tibial eminence fractures in children are equivalent to anterior cruciate ligament tears in adults. Treatment should be anatomic reduction, which often requires an arthroscopic or open procedure, followed by fixation.
REFERENCES: Green NE, Swiontkowski MF: Skeletal Trauma in Children, ed 3. Philadelphia, PA, WB Saunders, 2003, pp xvi, 452-455, 638.
Zionts LE: Fractures around the knee in children. J Am Acad Orthop Surg 2002;10:345-355.

2010 Pediatric Orthopaedic Examination Answer Book • 79

Figure 96

Internal impingement is the direct contact of the undersurface of the posterior supraspinatus on the posterosuperior labrum in late cocking during the typical throwing motion. This can result in labrum tearing, undersurface rotator cuff tearing or both in their respective locations (as illustrated in Figure 2). Anterior glenohumeral instability (or microinstability) can happen in the setting of throwing for many years as the anterior capsule stretches in the throwing position. This is thought to be exacerbated by posterior capsule tightness that can occur from repetitive microtrauma and scarring during the latter stages of throwing. Posterior instability and subacromial impingement are not typical pathology in the thrower's shoulder and are not exemplified in the throwing motion or arthroscopic images.

Atrial fibrillation is responsible for approximately 80% of all upper extremity emboli. All other cardiac conditions listed can cause upper extremity emboli; however, atrial fibrillation is the most common cause. Patients with an upper extremity embolic event should undergo prompt evaluation, with a careful history and physical examination as well as focused laboratory tests for hypercoagulability. Arterial Doppler studies or angiography is/are warranted. Electrocardiogram and echocardiogram are also used to evaluate for potential cardiac abnormalities. Consultation with vascular, radiology, and cardiology personnel is often necessary when patients present with upper extremity emboli. Treatment usually involves anticoagulation, embolectomy if necessary, and treatment for any recognized cardiac _abnormality._

- Anatomic total shoulder arthroplasty (TSA)_

The CT scans show evidence of a lateral wall blowout and malunion without significant arthrosis of the subtalar joint. In a young patient, it is preferable to avoid a fusion and allow residual motion by performing an exostectomy that decompresses the lateral subtalar joint and peroneal tendons.
REFERENCES: Chandler JT, Bonar SK, Anderson RB, et al: Results of in situ subtalar arthrodesis for late sequelae of calcaneus fractures. Foot Ankle Int 1999;20:18-24.
Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2003, p 52.

There is an increased rate of injury to the piriformis tendon, medial femoral circumflex artery branches, gluteus minimus, and superior gluteal nerve branches are noted with the piriformis starting site. Increased injury to the gluteus medius is seen with a greater trochanteric starting point.
The referenced study by Dora et al noted increased injury to the piriformis tendon with a piriformis starting point (as compared to a more lateral insertion site).
The classic referenced article by Johnson et al notes that anterior placement of the starting point >6mm over the recommended start leads to increased hoop stresses and possible burst-type fractures.
The classic referenced study by Winquist et al reviewed their series of 520 femur fractures treated by antegrade nailing; they report a 99.1% union rate.

The radiographs demonstrate a 3-part proximal humerus fracture with an intra-articular split. The postoperative radiograph shows a humeral hemiarthroplasty with the humeral head resting just below the top of the greater tuberosity. This puts the shoulder at risk of impingement and loss of abduction and elevation. The remaining answer choices are all possible, but much less likely complications.
Zuckerman et al review 26 hemiarthroplasties performed for 3 and 4 part proximal humerus fractures. The procedure reliably produced pain free shoulders, but the function was much less predictable with up to 25% demonstrating some loss of daily function.
In an Instructional Course Lecture, Bigliani et al review techniques for humeral arthroplasty and soft tissue preservation. Of note, the humeral head should rest above the level of the greater tuberosity to prevent impingement. Closure
of the rotator interval is not necessary during this procedure and can over-tighten the anterior soft tissue restraints causing loss of external rotation.

For stage III adult-acquired flatfoot deformity characterized by dysfunction of the posterior tibial tendon, rigid valgus deformity of the hindfoot, and arthritic changes of the hindfoot joints,arthrodesis is the favored procedure. In an overweight patient with degenerative changes affecting the subtalar and Chopart joints, triple arthrodesis is the best treatment option. Subtalar arthrodesis only addresses the talocalcaneal joint and continues to render the patient symptomatic in the talonavicular and calcaneocuboid joints. Advanced stage III disease precludes reconstructive procedures involving calcaneal osteotomy and tendon transfer.

The patient has a hyperostotic condition of the cervical spine, most likely ankylosing spondylitis. Because of a rigid and osteoporotic spine, relatively minor falls can result in unstable spinal injuries with significant instability and a high risk for neurologic sequelae. The patient has an unstable injury at C6 with an incomplete spinal cord injury, necessitating urgent decompression and stabilization.Studies have shown that, in
patients with ankylosing spondylitis, stand-alone anterior stabilization results in a high failure rate. Halo-thoracic vests carry a high risk of septic and pulmonary issues, especially in the elderly. Uninstrumented fusion will provide insufficient stability in such patients.

Because of the safety concerns, immunogenicity issues, and production complications associated with viral vectors, nonviral delivery systems were developed by complexing of genes (DNA) to various chemical formulations. Nonviral delivery systems stabilize DNA and increase its uptake and include plasmids, peptides, cationiCliposomes, DNA-ligand complexes (recognize
specifiCcell-surface receptors, leading to receptor-mediated uptake), and gene gun (particles of gold coated with DNA, forced into the cells with high velocity bombardment). However, nonviral vector efficiency is lower than viral vectors

DISCUSSION: Staphylococcus epidermidis is the most common organism found in an infected total hip arthroplasty greater than 3 months from the origional surgery. Staphylococcus aureus is more common in acute postoperative infections, and E. coli is associated with infections of the urinary tract. Streptococcus species are less common.

REFERENCE: Barrack RL, Booth RE Jr, Lonner JH, et al (eds): Orthopaedic Knowledge Update: Hip and Knee Reconstruction 3. Rosemont, IL American Academy of Orthopedic Surgeons, 2006, pp 475-503.

Figure 82

The MR image shows a far lateral disk herniation impinging on the exiting nerve root lateral to the exiting foramen. This is reached most directly with a far lateral (Wiltse) approach. This is a posterior paramedian approach that uses the interval between the paraspinal muscles (multifidus and longissimus) and arrives onto the facet joints. The intertransverse membrane can then be released, exposing the far lateral disk herniation. A posterior midline approach will allow easy access to the spinal canal, which is medial to the disk herniation, and will not allow for easy disk removal without the need for a facetectomy, which would destabilize the level. An anterior approach would not allow for access to the far lateral disk herniation, nor would a traditional retroperitoneal or newer transpsoas approach.
RECOMMENDED READINGS
[Wiltse LL, Spencer CW. New uses and refinements of the paraspinal approach to the lumbar spine. Spine (Phila Pa 1976). 1988 Jun;13(6):696-706. PubMed PMID: 3175760. ](http://www.ncbi.nlm.nih.gov/pubmed/3175760)[View](http://www.ncbi.nlm.nih.gov/pubmed/3175760)[ ](http://www.ncbi.nlm.nih.gov/pubmed/3175760)[Abstract at PubMed](http://www.ncbi.nlm.nih.gov/pubmed/3175760)
[Epstein NE. Evaluation of varied surgical approaches used in the management of 170 far-lateral lumbar disc herniations: indications and results. J Neurosurg. 1995 Oct;83(4):648-56. PubMed PMID: 7674015. ](http://www.ncbi.nlm.nih.gov/pubmed/7674015)[View Abstract at PubMed](http://www.ncbi.nlm.nih.gov/pubmed/7674015)

A semiconstrained prosthesis can provide excellent results in carefully selected patients. Because the radiographs show extensive joint destruction with loss of the capitellum and trochlea, a capitellocondylar total elbow (unconstrained) prosthesis is contraindicated. Elbow fusion is poorly accepted, and the radiographs show too much articular destruction for a radial head excision, synovectomy, or interposition arthroplasty to be effective.
REFERENCES: Ewald FC, Simmons ED Jr, Sullivan JA, et al: Capitellocondylar total elbow replacement in rheumatoid arthritis: Long-term results. J Bone Joint Surg Am 1993;75:498-507.
Morrey BF, Adams RA: Capitellocondylar total elbow replacement in rheumatoid arthritis. J Bone Joint Surg Am 1992;74:479-490.

An amputation through the wrist, palm, or forearm is an indication for attempted replantation. The caliber of the vessels and other structures provides a favorable environment for reconstruction.

DISCUSSION: The mechanism by which bisphosphonates act is by inhibiting osteoclasts. One mechanism of bisphosphonates is to cause osteoclast apoptosis. Another mechanism of bisphosphonates is to disrupt the cytoskeleton of osteoclasts, resulting in loss of the ruffled border. The uncoupling of bone resorption and bone formation with decreased bone resorption results in increased bone mineralization. This translates into fewer fractures in patients with osteogenesis imperfecta and improved quality of life.

REFERENCES: Bumei G, Vlad C, Georgescu I, et al: Osteogenesis imperfecta: Diagnosis and treatment. J Am Acad Orthop Surg 2008;16:356-366.
Lin JT, Lane JM: Bisphosphonates. J Am Acad Orthop Surg 2003; 11:1-4.
Seikaly MG, Kopanati S, Salhab N, et al: Impact of alendronate on quality of life in children with osteogenesis imperfecta. J Pediatr Orthop 2005;25:786-791.

Figure 40