100 Orthopedic MCQs: Basic Science, Oncology, Trauma, Spine & Pediatrics | Comprehensive ABOS Review

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Several studies have shown that design of the femoral component, especially the trochlear groove portion, largely influences patellar tracking and patellofemoral contact stresses. A deep, curved anatomic femoral trochlear groove has been shown to have the lowest contact stresses. Petersilge WJ, Oishi CS, Kaufman KR, Irby SE, Colwell CW Jr: The effect of trochlear design on patellofemoral shear and compressive forces in total knee arthroplasty. Clin Orthop 1994;309:124-130. Theiss SM, Kitziger KJ, Lotke PS, Lotke PA: Component design affecting patellofemoral complications after total knee arthroplasty. Clin Orthop 1996;326:183-187.

Sudden death during total hip arthroplasty has been reported. In a report from the Mayo Clinic, intraoperative death occurred during cemented total hip arthroplasty in 23 patients. Fat and marrow embolization during preparation of the femur or cementing of the femoral component was believed to be responsible for the cardiopulmonary collapse that occurred during arthroplasty. Although fat and marrow emboli were found in the pulmonary capillaries of most of the patients on autopsy, this histologic section shows two particles of cement in the pulmonary capillaries. Parvizi J, Holiday AD, Ereth MH, et al: The Frank Stinchfield Award. Sudden death during primary hip arthroplasty. Clin Orthop 1999;369:39-48.

Some patients have minimal symptoms associated with hallux rigidus despite significant radiographic evidence of osteoarthritis. This patient's symptoms are primarily related to shoe pressure from the exostosis and can be managed with extra-depth shoe wear. Smith RW, Katchis SD, Ayson LC: Outcomes in hallux rigidus patients treated nonoperatively: A long-term follow-up study. Foot Ankle Int 2000;21:906-913.

Anterior superior iliac spine avulsion fractures are caused by sudden, forceful contractions of the sartorius and tensor fascia lata. These injuries occur in young athletes through the growth plate with the hip extended and the knee flexed, such as while sprinting or swinging a baseball bat. The athlete will often report a pop or snap at the time of injury. Displaced fractures usually can be seen on radiographs. CT or MRI can be obtained to confirm the diagnosis. In most patients, nonsurgical management consisting of rest and protected weight bearing yields satisfactory outcomes. Surgery is usually reserved for fractures with displacement of more than 3 cm and painful nonunions. Garrick JG (ed): Orthopaedic Knowledge Update: Sports Medicine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 139-153.

The suprascapular nerve passes through the suprascapular notch and the spinoglenoid notch before innervating the infraspinatus muscle. At both locations, the suprascapular nerve is prone to nerve compression, which often results from a ganglion cyst. The other anatomic locations are not associated with suprascapular nerve impingement. Romeo AA, Rotenberg DD, Bach BR: Suprascapular neuropathy. J Am Acad Orthop Surg 1999;7:358-367.

The lesion lies in zone II of the ulnar tunnel. In that zone the deep motor branch of the ulnar nerve is susceptible to compression. Distal to the hook of the hamate, the motor branch of the ulnar nerve dives deep to innervate the interossei as it begins to move from an ulnar to radial direction. Because of its course, it has little or no give in response to a mass effect from the floor of Guyon's canal. Ganglions are the most common cause of ulnar nerve entrapment in the wrist. Lesions in zone I can affect both sensory and motor aspects of the ulnar nerve as well as the motor innervation of the hypothenar muscles. Lesions at the elbow or mid-to-proximal forearm are associated with dorsal hand numbness and tingling. Kuschner SH, Gelberman RH, Jennings C: Ulnar nerve compression at the wrist. J Hand Surg Am 1988;13:577-580.

The radiograph shows a type V acromioclavicular joint injury. Type V injuries involve disruption of the acromioclavicular and coracoclavicular ligaments. Type I injuries involve a sprain of the acromioclavicular joint ligaments. Type II injuries involve disruption of the acromioclavicular joint ligaments; the coracoclavicular ligaments are partially injured. Sternoclavicular ligaments stabilize the medial clavicle and the sternum; they are not damaged with acromioclavicular joint dislocations. Fukuda K, Craig EV, An KN, et al: Biomechanical study of the ligamentous system of the acromioclavicular joint. J Bone Joint Surg Am 1986;68:434-439.

MRI is the preferred imaging study to evaluate the local tumor extension for soft-tissue lesions, but CT can be used if MRI is contraindicated (eg, patients with pacemakers). CT of the chest is always recommended in patients with high-grade sarcomas because 80% of metastases occur in the lungs. CT of the abdomen and pelvis is indicated in patients with lower extremity liposarcoma because some patients also have synchronous retroperitoneal liposarcoma. Lymph node metastasis occurs in up to 5% of patients with soft-tissue sarcoma. If the nodes are clinically enlarged, biopsy is indicated. Routine sentinel node biopsy currently is not recommended. Bone scan is not used in the staging of soft-tissue sarcoma as it has not been shown to be cost-effective. Demetri GD, Pollock R, Baker L, Balcerzak S, Casper E, Conrad C, et al: NCCN sarcoma practice guidelines: National Comprehensive Cancer Network. Oncology (Huntingt) 1998;12:183-218.

The radiograph reveals bilateral severe acetabular protrusio. The bone scan and history confirm involvement of multiple joints, including the knees and the hindfoot. Although the first four choices can all cause the acetabular protrusio, the associated multiple joint involvement suggests the diagnosis of rheumatoid arthritis. Arthrokatadysis, or primary protrusio acetabuli, is often associated with osteomalacia but not other joint disease. Developmental dysplasia is a common cause of bilateral hip pathology but does not have acetabular protrusio. Resnick D: Diagnosis of Bone and Joint Disorders, ed 3. Philadelphia, PA, WB Saunders, 1995, pp 956-957. Wheeless' Textbook of Orthopaedics: Acetabular Protrusio. www.wheelessonline.com/ortho/acetabular_protrusio

The size of the rotator cuff tear in both anteroposterior and mediolateral dimensions has been found to correlate best with outcome. Older patient age and rupture of the long head of the biceps tend to be associated with larger tears and, therefore, may be associated indirectly with a poorer outcome. Iannotti JP: Full-thickness rotator cuff tears: Factors affecting surgical outcome. J Am Acad Orthop Surg 1994;2:87-95.

A pure bending force produces a transverse fracture pattern. Spiral fractures are mainly rotational, oblique are uneven bending, segmental are four-point bending, and comminuted are either a high-speed torsion or crush mechanism. Tencer AF, Johnson KD: Biomechanics in Orthopaedic Trauma: Bone Fracture and Fixation. Philadelphia, PA, JB Lippincott, 1994. Gonza ER: Biomechanical long bone injuries, in Gonza ER, Harrington IJ (eds): Biomechanics of Musculoskeletal Injury. Baltimore, MD, Williams & Wilkins, 1982, pp 1-30.

The patient sustained an injury to the long thoracic nerve, which supplies the serratus anterior. Branches of C5 and C6 enter the scalenus medius, unite in the muscle, and emerge as a single trunk and pass down the axilla. On the surface of the serratus anterior, the long thoracic nerve is joined by the branch from C7 and descends in front of the serratus anterior, providing segmental innervation to the serratus anterior.

The most significant impact on long-term survival is the presence or absence of identifiable metastatic disease on initial presentation. All of these factors have been shown to be predictive of long-term survival to varying degrees. Enneking WF, Spanier SS, Goodman MA: A system for the surgical staging of musculoskeletal sarcoma. Clin Orthop Relat Res 1980;153:106-120.

The patient has heterotopic ossification, a more common finding in patients who have sustained head injuries. Treatment will require removal of the heterotopic bone and anterior and posterior capsulectomies. The main concern about timing is the possible recurrence of heterotopic bone. While an extended wait was once thought necessary, this is no longer true. The timing is based on the time since injury and evidence of bone maturation on plain radiographs. A sharp marginal demarcation of the new bone and a trabecular pattern within it are usually present 3 to 6 months after onset, indicating that it is safe to proceed with surgical excision. It is not necessary to wait more than 6 months. Bone scan results are not good indicators because they may remain "hot" for long periods of time. The levels of alkaline phosphatase and serum calcium-phosphorus product do not need to be measured.

Although all of the above are potential complications after arthroscopic capsular release for adhesive capsulitis, the most common problem is the failure to regain normal glenohumeral motion. An immediate physical therapy program is critical to prevent this complication. Ghalambor N, Warner JJP: Arthroscopic capsular release: Evolution of the technique and its applications. Tech Shoulder Elbow Surg 2000;1:52-60.

These lesions are extremely vascular and can cause uncontrolled intraoperative bleeding; therefore embolization is the appropriate first treatment. Because the radiograph and CT scan show a lytic lesion in the supra-acetabular region that affects the weight-bearing dome and medial wall, the next step in treatment would most likely be a total hip arthroplasty and acetabular reconstruction. Treatment with bisphosphonates and radiation therapy will not prevent an acetabular fracture. Cementoplasty is an emerging technique in which cement is injected percutaneously into a lesion, but no long-term results have been reported. Radiofrequency ablation of bone metastases is also an emerging technique that provides palliative pain control. Layalle I, Flandroy P, Trotteur G, Dondelinger RF: Arterial embolization of bone metastases: Is it worthwhile? J Belge Radiol 1998;81:223-225.

Bone bruises are often noted on MRI after anterior cruciate and medial collateral ligament injuries. The significance of these injuries awaits long-term follow-up studies. The areas of increased signal on T2-weighted images represent areas of acute hemorrhage and are secondary to microfractures of the adjacent medullary trabeculae. Wright RW, Phaneuf MA, Limbird TJ, et al: Clinical outcome of isolated subcortical trabecular fractures (bone bruise) detected on magnetic resonance imaging in knees. Am J Sports Med 2000;28:663-667.

The radiograph reveals a Crowe IV deformity in a patient with developmental dysplasia of the hip. If hip arthroplasty is performed, then some degree of limb lengthening is anticipated. Excessive limb lengthening can result in sciatic nerve palsy in these patients. The peroneal branch of the sciatic nerve is most often affected. Of the muscles listed, only the extensor hallucis longus is innervated by the peroneal branch of the sciatic nerve. Eggli S, Hankemayer S, Muller ME: Nerve palsy after leg lengthening in total replacement arthroplasty for developmental dysplasia of the hip. J Bone Joint Surg Br 1999;81:843-845.

The patient has an acute grade III posterior cruciate ligament injury. The majority of grade I and II injuries can be treated with protected weight bearing and quadriceps rehabilitation, and most patients can return to sports within 2 to 4 weeks. In contrast, grade III injuries require immobilization in full extension for 2 to 4 weeks to protect the posterior cruciate ligament and the other posterolateral structures presumed to be damaged. The mainstay of postinjury rehabilitation for all posterior cruciate ligament injuries is quadriceps strengthening exercises, which have been shown to counteract posterior tibial subluxation. Miller MD, Bergfeld JA, Fowler PJ, Harner CD, Noyes FR: The posterior cruciate ligament injured knee: Principles of evaluation and treatment. Instr Course Lect 1999;48:199-207.

The flexor sheaths are in continuity with the deep spaces of the hand. The flexor sheaths of the thumb and little finger communicate with the radial and ulnar bursae, respectively, and these two bursae commonly communicate. The central digits do not communicate as readily with deep spaces of the hand but if flexor tendon sheath infection of the index, long, and right fingers is neglected, the potential exists for rupture into the deep midpalmar spaces. Peimer CA (ed): Surgery of the Hand and Upper Extremity: Acute and Chronic Sepsis. New York, NY, Mcgraw Hill, 1996, pp 1735-1741.

The sural nerve lies lateral to the Achilles tendon at the level of the foot but follows an oblique course proximally to lie directly over the tendon as it heads to the popliteal fossa. It is at risk with any proximal dissection from a direct posterior approach and in particular with procedures done at the musculotendinous junction. The nerve crosses over the lateral border of the Achilles tendon at an average of 9.8 cm above its insertion. Webb J, Moorjani N, Radford M: Anatomy of the sural nerve and its relation to the Achilles tendon. Foot Ankle Int 2000;21:475-477.

Internal fixation of the clavicle, glenoid, or both has been recommended for fractures of the clavicle and glenoid neck (floating shoulders). Recently, the inherent instability of these dual fractures has been questioned in a biomechanical model without further disruption of the coracoclavicular or acromioclavicular ligamentous structures. Nonsurgical management of the majority of combined scapular/glenoid fractures in patients with less than 10 mm of displacement has resulted in excellent shoulder function and will most likely achieve an excellent result in this patient. Egol KA, Connor PM, Karunakar MA, Sims SH, Bosse MJ, Kellam JF: The floating shoulder: Clinical and functional results. J Bone Joint Surg Am 2001;83:1188-1194. Williams GR Jr, Naranja J, Klimkiewicz J, et al: The floating shoulder: A biomechanical basis for classification and management. J Bone Joint Surg Am 2001;83:1182-1187.

Scapular body fractures in children are rare and are often associated with other injuries of the chest and thorax. Management is generally nonsurgical, unless the injury is open, and usually consists of support with a sling and gentle range-of-motion exercises to minimize shoulder stiffness. Green N, Swiontkowski M: Skeletal Trauma in Children, ed 2. Philadelphia, PA, WB Saunders, 1998, vol 3, pp 319-341.

The patient has a pars interarticularis defect of L5 without apparent listhesis. The other diagnoses are not present. Papanicolaou N, Wilkinson RH, Emmans JB, Treves S, Micheli LJ: Bone scintigraphy and radiography in young athletes with low back pain. Am J Roentgenol 1985;145:1039-1044.

The patient has a pronounced deformity with pain and degenerative arthritis; therefore, triple arthrodesis is the treatment of choice. Gastrocnemius or Achilles tendon lengthening may be a necessary adjunct to the triple arthrodesis, but alone is inadequate to allow for correction. Because the ankle-foot orthosis has failed to provide relief, a UCBL is not likely to help. Osteotomy procedures are designed for lesser deformities and well-preserved joints. Nunley JA, Pfeffer GB, Sanders RW, et al (eds): Advanced Reconstruction: Foot and Ankle. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 115-120.

The patient has a symptomatic os trigonum caused by impingement that occurs with maximal plantar flexion of the ankle in the demi-pointe or full-pointe position. Patients frequently report posterolateral pain localized behind the lateral malleolus that may be misinterpreted as a disorder of the peroneal tendon. Pain with passive plantar flexion (the plantar flexion sign) indicates posterior impingement, not a problem with the peroneal tendon. The symptoms are not characteristic of a stress fracture, nor do the radiographs show a stress fracture or an osteochondritis dissecans lesion. The os trigonum is modest in its dimensions. The incidence or magnitude of symptoms does not correlate with the size of the fragment. Large fragments may be asymptomatic, while small lesions may create significant symptoms. Marotta JJ, Micheli LJ: Os trigonum impingement in dancers. Am J Sports Med 1992;20:533-536.

The radiographs show classic findings for Koehler's disease (osteochondrosis of the navicular). The patient's age and clinical history are typical for this self-limiting condition. Patients will improve with time, but the duration of symptoms is much shorter if the patient is placed in a cast. There is no role for surgery in this disease.

Elbow dislocations in children are rare injuries and usually result from a fall on an outstretched arm. The incidence of these injuries increases as patients age and concurrently the incidence of supracondylar humerus fractures decreases. In adolescent patients, simple elbow dislocations are treated with splint immobilization and the initiation of physical therapy once comfortable. The practitioner must be aware of structures that may get caught in the joint on reduction. These include the median nerve as well as the medial epicondyle. In this patient, the radiographs reveal a medial epicondyle fracture. Postreduction radiographs show the joint to be incongruous secondary to intra-articular displacement. At this point, the most appropriate treatment is to perform an open reduction and repair of the medial epicondyle fragment. Rasool MN: Dislocations of the elbow in children. J Bone Joint Surg Br 2004;86:1050-1058.

Hook of the hamate fractures typically occur as a result of direct force from swinging a bat, golf club, or racket. Pain is localized to the hypothenar eminence. The injury is best seen on a carpal tunnel view. CT will confirm the diagnosis. Chronic cases can be associated with neuropathy of the ulnar nerve. Excision of the hook through the fracture site usually yields satisfactory results, allowing the athlete to return to competition. Parker RD, Berkowitz MS, Brahms MA, et al: Hook of the hamate fractures in athletes. Am J Sports Med 1986;14:517-523.

The child has an injury involving both the growth plate and the articular surface of the ankle. Because of the significant displacement, open reduction and internal fixation is indicated to realign the physis and joint surface. The best method of fixation to avoid growth arrest is one that does not cross the physis. This is usually achieved by a transverse epiphyseal screw parallel to the physis. If the metaphyseal fragment was large enough, a transverse metaphyseal screw could be used instead. The incidence of growth arrest following physeal ankle injuries is as high as 50%, and long-term follow-up is indicated. Cass JR, Peterson HA: Salter-Harris Type-IV injuries of the distal tibial epiphyseal growth plate, with emphasis on those involving the medial malleolus. J Bone Joint Surg Am 1983;65:1059-1070.

The short-form 36 is an excellent tool for measuring the patient's perception of treatment outcome because it is a patient-generated, validated assessment of physical, social, and role function, emotional and mental health, energy/fatigue, pain, health perception, and health change. The Nurick criteria is an evaluation of physical function with gradations of ambulation and daily function. The Japanese Orthopaedic Association score gives points for function in activities of daily living but does not assess perception of general health. The neck disability index assesses the impact of neck pain on daily life, and the Odom criteria are the surgeon's evaluations of degree of radicular pain and deficit. Albert TJ, Mesa JJ, Eng K, McIntosh TC, Balderston RA: Health outcome assessment before and after lumbar laminectomy for radiculopathy. Spine 1996;21:960-963. Swiontkowski MF, Buckwalter JA, Keller RB, Haralson R: The outcomes movement in orthopaedic surgery: Where we are and where we should go. J Bone Joint Surgery Am 1999;81:732-740.

The cervical spine may be involved in a child with polyarticular or systemic JRA; fusion or instability can occur. Radiographic assessment of the cervical spine should include lateral flexion-extension views. The potential exists for spinal cord injury during intubation or positioning in the presence of an unstable cervical spine. Limitations of the TMJ and micrognathia may affect ease of intubation and administration of anesthesia via a mask. If the TMJ and jaw are involved, some patients may have dental findings such as dental caries and even abscesses which can affect surgery. Some children, particularly those with systemic arthritis, may be taking corticosteroids long-term and may need stress dosing with complex surgeries. Although it is important to routinely check for uveitis and iritis in children with JRA, this usually is not needed preoperatively. Uveitis and iritis are less likely in a child with systemic JRA. Cassity JT, Petty RE (eds): Textbook of Pediatric Rheumatology, ed 5. Philadelphia, PA, WB Saunders, 2005. Ilowite N: Current treatment of juvenile rheumatoid arthritis. Pediatrics 2002;109:109-115. Ruddy S, Harris ED, Sledge CB (eds): Kelley's Textbook of Rheumatology, ed 6. Philadelphia, PA, WB Saunders, 2001.

When managing a complex intra-articular fracture, it is imperative that there is adequate visualization of the joint; this usually means an extensile approach. At the elbow, this is usually through a transolecranon osteotomy. The recent addition of a muscle-sparing approach as described by Bryan and Morrey has gained popularity, but it is difficult to maintain soft-tissue viability and it may put the ulnar nerve at risk. A triceps-splitting approach, which can be used for simple single articular splits into the joint where extra-articular reduction is available, is possible and good results have been reported. To date, there is minimal data on these alternative approaches for comminuted intra-articular distal humeral fractures. McKee MD, Mehne DK, Jupiter JP: Fractures of the distal humerus: Part II, in Browner BD, Jupiter JP, Levine AM, Trafton P (eds): Skeletal Trauma, ed 2. Philadelphia, PA, WB Saunders, 1998, pp 1483-1522 McKee MD, Wilson TL, Winston L, Schemitsch EH, Richards RR: Functional outcome following surgical treatment of intra-articular distal humeral fractures through a posterior approach. J Bone Joint Surg Am 2000;82:1701-1707. Patterson SD, Bain GI, Mehta JA: Surgical approaches to the elbow. Clin Orthop 2000;370:19-33.

Failure of the scalene block, necessitating general anesthesia or the immediate administration of narcotic medications, is the most common complication, occurring in 3% to 18% of patients. Cardiac arrest or cardiovascular collapse has been reported in anecdotal occurrences. Seizure that is the result of intravascular injection of local anesthetic is a rare complication, with an incidence reported of 0% to 6%. Neurologic complications, including laryngeal and phrenic nerve injuries, are rare although parathesias lasting up to 2 weeks have been reported in up to 3% of patients. Weber SC, Jain R: Scalene regional anesthesia for shoulder surgery in a community setting: An assessment of risk. J Bone Joint Surg Am 2002;84:775-779.

The radiograph shows the typical findings of achondroplasia. The defect is in fibroblast growth factor receptor 3. The pedicles narrow distally in the lumbar spine. The pelvis is low and broad with narrow sciatic notches and ping-pong paddle-shaped iliac wings. This is often called a champagne glass pelvis. Type I collagen abnormalities are typically found in osteogenesis imperfecta, and type II collagen defects are found in spondyloepiphyseal dysplasia and Kneist syndrome. COMP is defective in multiple epiphyseal dysplasia. Sulfate transport defects are seen in diastrophic dysplasia. Johnson TR, Steinbach LS: Essentials of Musculoskeletal Imaging. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 809-812.

Severely displaced acromioclavicular injuries disrupt the deltotrapezial fascia and muscular origin in addition to the ligaments (acromioclavicular and coracoclavicular or trapezoid and conoid). When the deltoid is still attached to the clavicle, an isometric shoulder shrug will tend to reduce the displacement. When the deltoid is detached but the trapezius is attached, this manuever will increase the deformity and surgery may be indicated.

Radiographic abnormalities such as coxa magna, coxa breva secondary to growth arrest, and coxa plana and acetabular deformities are associated with healed Legg-Calve-Perthes disease. Femoral heads that were flat yet congruent with the acetabulum are at risk for disabling arthritis in the sixth decade of life in 50% of these untreated patients. As the normal ball-and-socket joint deforms to a flattened cylinder, the hip loses abduction and rotation capability, while retaining flexion and extension potential. If the femoral head is flat and is not concentric with the acetabulum, early severe arthritis occurs. Hinge abduction and anterior impingement are known sequelae of a flat, incongruent femoral head.

All of the variables have been proposed as possible causes for the increased incidence of ACL tears in women versus men. The general differences in the level of neuromuscular training however, specifically conditioning and muscle strength, have been shown to play the greatest role. Harmon KJ, Ireland ML: Gender differences in noncontact anterior cruciate ligament injuries. Clin Sports Med 2000;19:287-302. Arendt EA: Knee injury patterns among men and women in collegiate basketball and soccer. Am J Sports Med 1995;23:694-701.

Fluoroquinolones have been associated with increased rates of tendinitis, with special predilection for the Achilles tendon. Tenocytes in the Achilles tendon have exhibited degenerative changes when viewed microscopically after fluoroquinolone administration. Recent clinical studies have shown an increased relative risk of Achilles tendon rupture of 3.7. The other listed drugs have no known increase in tendon rupture rates nor tendinitis. van der Linden PD, van de Lei J, Nab HW, et al: Achilles tendinitis associated with fluoroquinolones. Br J Clin Pharmacol 1999;48:433-437. Bernard-Beaubois K, Hecquet C, Hayem G, et al: In vitro study of cytotoxicity of quinolones on rabbit tenocytes. Cell Biol Toxicol 1998;14:283-292.

Emboli are created during TKA. Usually there is an increased incidence with the use of intramedullary rods that disrupt the marrow contents. These are not fat emboli per se. They are material composed of fat cells and marrow that act like pulmonary emboli to obstruct small arterioles in the lung. They are different from free fat emboli that are seen in fractures and that lead to chemical injury to the lung rather than obstructive injury. Markel DC, Femino JE, Farkas P, et al: Analysis of lower extremity embolic material after total knee arthroplasty in a canine model. J Arthroplasty 1999;14:227-232. Pell AC, Christie J, Keating JF, et al: The detection of fat embolism by transoesophageal echocardiography during reamed intramedullary nailing: A study of 24 patients with femoral and tibial fractures. J Bone Joint Surg Br 1993;75:921-925.

Indications for surgery in spinal infections include progressive destruction despite antibiotic treatment, an abscess requiring drainage, neurologic deficit, need for diagnosis, and/or instability. This patient has a progressive neurologic deficit. Debridement performed at the site of the abscess should effect canal decompression. Once the debridement is complete back to viable bone, the defect can be reconstructed with a strut graft. Additional posterior stabilization is used as deemed necessary by the degree of anterior destruction. CT-guided needle aspiration, while occasionally useful in the earliest phases of an infection, produces frequent false-negative results and would provide little useful information in the management of this patient. Emery SE, Chan DP, Woodward HR: Treatment of hematogenous pyogenic vertebral osteomyelitis with anterior debridement and primary bone grafting. Spine 1989;14:284-291. Lifeso RM: Pyogenic spinal sepsis in adults. Spine 1990;15:1265-1271.

New onset pain and stiffness in the young arthritic shoulder is a difficult problem to treat. Initial management should be aimed at reducing pain and improving motion in all planes. This patient's activities and age preclude a shoulder arthroplasty at this time. If nonsurgical management fails to provide relief, then arthroscopic debridement and capsular release may be beneficial. Norris TR (ed): Orthopaedic Knowledge Update: Shoulder and Elbow 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 257-266.

Nondisplaced transverse fractures of the phalanges are stable. Immobilization in the intrinsic plus position will prevent MCP joint stiffness. Displaced oblique fractures are more at risk for instability. Stern PJ: Fractures of the metacarpals and phalanges, in Green DP, Hotchkiss RN, Pederson WC, et al (eds): Green's Operative Hand Surgery, ed 5. Philadelphia, PA, Elsevier, 2005, p 281.

The great medullary artery originates as a direct or indirect branch of the left posterior intercostal artery, usually between T8 and T12. It becomes intradural and crosses over one to three disk spaces before turning to the midline where it anastomoses with the anterior spinal artery. Injury to this artery can result in devastating ischemia of the lower spinal cord. Lu J, Ebraheim NA, Biyani A, Brown JA, Yeasting RA: Vulnerability of great medullary artery. Spine 1996;21:1852-1855.

With a full-thickness articular cartilage injury, a healing response is initiated with hematoma, stem cell migration, and vascular ingrowth. This response produces type I collagen and resultant fibrous cartilage rather than desired hyaline cartilage as produced by chondrocytes. This repair cartilage has diminished resiliency, stiffness, poor wear characteristics, and the predilection for arthritis. Type I collagen is also found in the annulus of intervertebral disks, tendon, bone, meniscus, and skin. Type II is found in articular cartilage and nucleus pulposus of intervertebral disks. Type III is found in skin and blood vessels, type IV is found in basement membranes, and type X is found in the calcified layer of cartilage. Arendt EA (ed): Orthopaedic Knowledge Update: Sports Medicine 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 19-28.

Based on the available literature, the probability of development of glenoid dysplasia in the setting of a significant limitation of external rotation is close to 70%. Humeral dysplasia is also likely and can be managed surgically. Efforts are being made to identify procedures that will prevent glenoid dysplasia and help maintain function. Pearl ML, Edgerton BW: Glenoid deformity secondary to brachial plexus birth palsy. J Bone Joint Surg Am 1998;80:659-667. Waters PM, Smith GR, Jaramillo D: Glenohumeral deformity secondary to brachial plexus birth palsy. J Bone Joint Surg Am 1998;80:668-677.

Pain with passive motion of the toes is a recognized early sign of increased compartment pressures. At a minimum, a baseline evaluation of the leg compartment pressures should be obtained. While it is normal for the patient to have pain related to the associated muscle contusions, any significant concerns should be addressed immediately in light of the severe consequences likely when a compartment syndrome occurs. Mubarak SJ, Owen CA, Hargens AR, et al: Acute compartment syndromes: Diagnosis and treatment with the aid of the wick catheter. J Bone Joint Surg Am 1978;60:1091-1095.

According to a study by the Scoliosis Research Society, the use of anterior decompression is most predictable for improving neurologic status. This is particularly true of bowel and bladder functional loss. Laminectomy is contraindicated because it further destabilizes the spine. Posterior instrumentation and indirect reduction through distraction and ligamentotaxis only incompletely decompress the compromised canal and are successful only if performed within 48 hours of injury. While some improvement may occur with closed management, the amount of recovery is less than that achieved with surgical decompression. A posterior approach and instrumentation may be added to the anterior decompression based on the characteristics of associated injuries to the posterior element. Gertzbein SD: Scoliosis Research Society multicenter spine fracture study. Spine 1992;17:528-540. Garfin SR, Vaccaro AR (eds): Orthopaedic Knowledge Update: Spine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1997, pp 197-215.

Informed consent is generally considered to be a process of mutual decision making between the physician and patient. The physician is required to provide to the patient all material information that is needed for the patient to make an informed decision. The courts have held that a patient's choice of surgeon is as important to the consent as the procedure itself. Assistance by a surgical trainee with adequate supervision is permissible when there has been adequate disclosure. Adequate supervision may be defined as active participation by the attending during the essential parts of the procedure. Allowing a substitute surgeon to operate on a patient without the patient's knowledge "ghost surgery" may result in charges of battery against the substitute surgeon and malpractice against the surgeon to whom the patient gave consent. Kocher MS: Ghost surgery: The ethical and legal implications of who does the operation. J Bone Joint Surg Am 2002;84:148-150.

Injuries to the ulnar collateral ligament of the MCP joint of the thumb commonly occur in recreational skiers. Historically, this injury has been referred to as "gamekeeper's thumb." The ligament consists of the proper collateral ligament and the more volar accessory collateral ligament. In extension, the accessory ligament is taut, and in flexion, the proper ligament is taut. For a complete tear of the ligament complex to occur, there must be laxity in full extension. Incomplete tears respond well to thumb spica splinting or casting for 2 to 3 weeks and gradual resumption of range of motion. Prolonged immobilization of incomplete injuries leads to higher rates of MCP joint stiffness. Stener B: Displacement of the ruptured ulnar collateral ligament of the metacarpo-phalangeal joint of the thumb: A clinical and anatomical study. J Bone Joint Surg Br 1971;44:869.

The recurrence rate of anterior dislocation of the shoulder after the first episode in athletes younger than age 20 years is thought to be as high as 90%, making surgery after the initial episode a consideration. The rate drops from 50% to 75% in the 20- to 25-year age group and down to 15% in patients older than age 40 years. An excellent prospective study of 257 patients in Sweden showed that there was no difference in those who did or did not complete 3 weeks of immobilization. The study also showed variability among different age groups in the importance of athletic participation; athletes in the 12- to 22-year age group had a higher recurrence rate, whereas the more sedentary patients in the 23- to 29-year age group had a higher rate. Hovelius L: The natural history of primary anterior dislocation of the shoulder in the young. J Orthop Sci 1999;4:307-317.

Delayed wound healing and wound dehiscence is the most common complication of surgical management of calcaneal fractures through an extensile lateral approach, occurring in up to 25% of patients. Most wounds ultimately heal with local treatment; the deep infection rate is approximately 1% to 4% in closed fractures. Posttraumatic arthritis may develop despite open reduction and internal fixation, but the percentages remain low. Peroneal tendinitis may occur from adhesions within the tendon sheath or from prominent hardware but is relatively uncommon. Nonunion of a calcaneal fracture is rare. Sanders RW, Clare MP: Fractures of the calcaneus, in Coughlin MJ, Mann RA, Saltzman CL (eds): Surgery of the Foot and Ankle, ed 8. Philadelphia, PA, Mosby-Elsevier, 2007, vol 2, pp 2017-2073.

The MRI scans reveal a meso os acromiale with edema at the site in a skeletally mature patient. Sher JS: Anatomy, biomechanics, and pathophysiology of rotator cuff disease, in Iannotti JP, Williams GR (eds): Disorders of the Shoulder: Diagnosis and Management. Philadelphia, PA, Lippincott Williams & Wilkins, 1999, p 23.

Ecchymosis on the medial side of the ankle is distributed in the posterior tibialis tendon sheath location, posterior to the medial malleolus, and extending inferiorly to the tendon's attachment on the navicular. MRI is the imaging study of choice to determine the extent of tendon damage. MRI will also help assess the deltoid ligament. Bone scans and CT are helpful in identifying osteochondral fractures and occult fractures; however, these studies are not indicated for this patient. Peroneal tendons are located lateral on the ankle. Arthroscopy of the ankle joint would not be helpful in assessing the posterior tibial tendons. Lutter LD, Mizel MS, Pfeffer GB (eds): Orthopaedic Knowledge Update: Foot and Ankle. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1994, pp 307-317.

The radiographs show massive subsidence of the lateral side of the tibia with severe tibial bone loss and a fractured proximal fibula. Reconstruction should consist of a large metal or bony lateral tibial augmentation, and a stem long enough to bypass the defect is required. The femoral and tibial components are articulating without any remaining polyethylene medially; therefore, the femoral component is damaged and needs revision. The insertions of the lateral ligaments are absent, thereby rendering the lateral side of the knee predictably unstable. Also, the large valgus deformity compromises the medial collateral ligament. The posterior cruciate ligament is also likely to be deficient with this much tibial bone destruction. The patient requires a posterior stabilized femoral component at the minimum, and possibly a constrained femoral component. Retention of the femoral component, even though it may be well-fixed, jeopardizes the outcome. Lotke PA, Garino JP: Revision Total Knee Arthroplasty. New York, NY, Lippincott-Raven, 1999, pp 137-250. Insall JN, Windsor RE, Scott WN, et al: (eds): Surgery of the Knee, ed 2. New York, NY, Churchill Livingstone, 1993, pp 935-957.

Symptoms of activity-related low back pain, physical findings of pain with extension, lateral bending, and resuming an upright position, and relative hamstring tightness are consistent with spondylolysis. While the initial diagnostic work-up should include plain radiographs of the lumbosacral spine, the findings may be negative because it can take weeks or months for the characteristic changes to become apparent. SPECT has been a useful adjunct in the diagnosis of spondylolysis when plain radiographs are negative. Since the patient's pain is activity related and she is otherwise healthy, evaluation for infection is not indicated. Because the neurologic examination is normal, electromyography, nerve conduction velocity studies, and MRI are not indicated. CT can be used in those instances in which SPECT and bone scans are negative. Ciullo JV, Jackson DW: Pars interarticularis stress reaction, spondylolysis, and spondylolisthesis in gymnasts. Clin Sports Med 1985;4:95-110. Collier BD, Johnson RP, Carrera GF, et al: Painful spondylolysis or spondylolisthesis studied by radiography and single photon emission computed tomography. Radiology 1985;154:207-211. Jackson DW, Wiltse LL, Cirincione RT: Spondylolysis in the female gymnast. Clin Orthop 1976;117:68-73.

Advocates of resurfacing hip arthroplasty cite preservation of the proximal femoral bone stock as the main advantage of this procedure over total hip arthroplasty. Fracture of the retained femoral neck has been reported following resurfacing arthroplasty. The exact etiology of the latter is unknown. Technical errors, such as notching of the femoral neck or possibly disruption of the blood supply to the femoral head during extensive soft-tissue exposure, may result in femoral neck fracture. Gabriel JL, Trousdale RT: Stem fracture after hemiresurfacing for femoral head osteonecrosis. J Arthroplasty 2003;18:96-99.

IV broad-spectrum antibiotics should be administered for 7 days. This regimen, when compared to fragment removal or other antibiotic regimens, has been shown to reduce the incidence of spinal infections and reduce the need for metallic fragment removal with perforation of a viscus. Roffi RP, Waters RL, Adkins RH: Gunshot wounds to the spine associated with a perforated viscus. Spine 1989;14:808-811.

After an osteoporotic vertebral compression fracture, the risk of subsequent fractures at adjacent levels increases. This is felt to be the result of a shifting of the sagittal alignment more anteriorly, putting more stress on the osteopenic vertebral bodies and their anterior cortices. Pain generally resolves with rest, but this may take weeks or months. It has been demonstrated experimentally that osteoporotic vertebral bodies are actually less stiff and weaker after a compression fracture; therefore, deformity predisposes to further deformity. The extensor musculature often fatigues over time and usually does not hypertrophy. Frontal plane deformity is a rare development. Heaney RP: The natural history of vertebral osteoporosis: Is low bone mass an epiphenomenon? Bone 1992;13:S23-S26.

Transcription factors regulate the activation or repression of cartilage-specific genes. Sox-9, considered a major regulator of chondrogenesis, regulates several cartilage-specific genes during endochondral ossification, including collagen types II, IV, and XI and aggrecan. Li J, Sandell LJ: Transcriptional regulation of cartilage-specific genes, in Rosier RN, Evans C (eds): Molecular Biology in Orthoapedics, Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 21-24.

The radiographs reveal osteoarthritis and proximal humeral head migration. Integrity of the rotator cuff must be questioned based on these radiographic changes. The status of the rotator cuff is the most influential factor affecting postoperative function in shoulder hemiarthroplasty. The coracoacromial ligament provides a barrier to humeral head proximal migration in the face of a rotator cuff tear. The radiographs do not indicate significant humeral head or glenoid erosion. Acromioclavicular arthritis is often asymptomatic. Iannotti JP, Norris TR: Influence of preoperative factors on outcome of shoulder arthroplasty for glenohumeral osteoarthritis. J Bone Joint Surg Am 2003;85:251-258.

The superficial portion of the MCL contributes 57% and 78% of medial stability at 5 degrees and 25 degrees of knee flexion, respectively. The deep MCL and posteromedial capsule act as secondary restraints at full knee extension. The anterior cruciate ligament and PCL also provide secondary resistance to valgus loads.

Burks and Schaffer described an approach to the tibial insertion of the posterior cruciate ligament that uses the interval between the semimembranosus and the medial gastrocnemius. The medial gastrocnemius muscle is retracted laterally and protects the neurovascular bundle. This approach is used to repair an avulsion of the posterior cruciate ligament tibial attachment or for performing a posterior cruciate ligament tibial inlay reconstruction. Berg EE: Posterior cruciate ligament tibial inlay reconstruction. Arthroscopy 1995;8:95-99.

While many low-demand patients with injuries to the ulnar collateral ligament can be treated nonsurgically, Jobe and associates described two situations in which ulnar collateral ligament reconstruction is indicated: (1) an acute complete rupture in a competitive athlete who uses the upper extremities extensively and who wishes to remain active; and (2) chronic pain or instability that does not improve after at least 3 months of nonsurgical management. Rarely is direct surgical repair of the ligament possible or able to withstand the valgus stresses applied to the elbow. Most authors recommend surgical reconstruction of the ulnar collateral ligament using a palmaris longus, plantaris, or fourth toe extensor tendon from the fourth autograft. Andrews JR, Jelsma RD, Joyce ME, et al: Open surgical procedures for injuries to the elbow in throwers. Oper Tech Sports Med 1994;4:109-133. Jobe FW, Kvitne RS: Elbow instability in the athlete. Instr Course Lect 1991;40:17-23.

The histology shows eosinophils with a background of larger cells (Langerhans' cells). This is consistent with eosinophilic granuloma. Localized sites are best treated with curettage, steroid injection, or observation. Chemotherapy is used only if there is systemic involvement. Mirra JM: Eosinophilic granuloma, in Bone Tumors: Clinical, Radiologic, and Pathologic Correlations. London, England, Lea and Febiger, 1989, pp 1023-1060. Sessa S, Sommelet D, Lascombes P, Prevot J: Treatment of Langerhans-cell histiocytosis in children: Experience at the Children's Hospital of Nancy. J Bone Joint Surg Am 1994;76:1513-1525.

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.

The reported failure rate is in the range of 15%, which may be the result of incorrect diagnosis, improper web space selection, or formation of a stump neuroma. Therefore, the procedure should be approached with caution, measures should be taken to ensure that the diagnosis is accurate, and nonsurgical options should be exhausted. Mizel MS, Miller RA, Scioli MW (eds): Orthopaedic Knowledge Update: Foot and Ankle 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1998, pp 101-111. Beskin JL: Nerve entrapment syndromes of the foot and ankle. J Am Acad Orthop Surg 1997;5:261-269.

The patient's findings are consistent with an intermediate form of spinal muscular atrophy. Children with this condition appear normal at birth but are not able to walk. The disorder affects anterior horn cells. Fasciculations may be present, but deep tendon reflexes are typically absent. The development of scoliosis is almost universal with this type of spinal muscular atrophy. More than 90% of patients with spinal muscular atrophy have deletions in the telomeric survival motor neuron gene. Peripheral myelin protein 22 is abnormal in Charcot-Marie-Tooth type IA. Connexin 32 is abnormal in the X-linked type of Charcot-Marie-Tooth disease. Neurofibromin is affected in neurofibromatosis type 1. Friedreich's ataxia is secondary to a disorder of frataxin. Buckwalter JA, Einhorn TA, Simon SR (eds): Orthopaedic Basic Science, ed 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2000, pp 111-131.

The radiograph shows a benign-appearing cortically based lesion eroding the underlying cortex, producing a saucer-shaped defect typical of a periosteal chondroma. The histology shows benign-appearing neoplastic cartilage. Although enchondroma would have the same histologic appearance, radiographs generally show a lesion with a central medullary epicenter. The benign-appearing histology does not support chondrosarcoma. Chondromyxoid fibroma will generally show histologic elements of its fibrous and myxoid components. Chondroblastoma typically demonstrates histologic findings of polyhedral cells separated by a chondroid matrix with pericellular, lattice-like "chicken wire" calcification. Schajowicz F: Tumors and Tumorlike Lesions of Bone: Pathology, Radiology, and Treatment, ed 2. Berlin, Springer-Verlag, 1994, pp 147-151.

In the midforearm, the ulnar nerve travels deep to the flexor carpi ulnaris muscle and ulnar to the ulnar artery as it lies on the flexor digitorum profundus muscle. In this region, the ulnar nerve and artery lie side-by-side, whereas more proximal in the forearm, the ulnar artery originates from the brachial artery in the antecubital fossa, and the ulnar nerve lies within the cubital tunnel. Hoppenfeld S, deBoer P: Surgical Exposures in Orthopaedics, ed 2. Philadelphia, PA, Lippincott-Raven, 1994, pp 118-131.

A variety of methodologies have been used to decrease the need for homologous blood transfusions following THA. Some of the effective strategies include preoperative donation of autologous units, intraoperative salvage and recycling, preoperative injection of erythropoietin, and regional anesthesia. Cementless fixation and use of wound drains have been shown to increase the blood loss with THA. Huo MH, Paly WL, Keggi KJ: Effect of preoperative autologous blood donation and intraoperative and postoperative blood recovery on homologous blood transfusion requirement in cementless total hip replacement operation. J Am Coll Surg 1995;180:561-567. Bierbaum BE, Callaghan JJ, Galante JO, Rubash HE, Tooms RE, Welch RB: An analysis of blood management in patients having a total hip or knee arthroplasty. J Bone Joint Surg Am 1999;81:2-10.

The iliacus muscle is a frequent site of hemorrhage in patients with severe or moderate hemophilia. In patients with moderate hemophilia, hemorrhage into the iliacus muscle often follows play or sporting events that include forceful contraction of the hip flexor muscles. An expanding iliacus hematoma compresses the adjacent femoral nerve, with one study reporting 60% complete femoral nerve palsy in hemophiliacs with an iliacus or iliopsoas hemorrhage. Femoral nerve compression typically includes paresthesias in the distribution of the terminal saphenous nerve branch. Hip joint hemarthrosis may occur, but this condition is not as frequent in hemophiliacs as muscle hemorrhage into the iliacus muscle. More importantly, a hip joint hemarthrosis is not associated with significant compression of the femoral nerve. Avulsion fractures of the anterior superior iliac spine typically occur during adolescence and are not associated with saphenous nerve paresthesias. Slipped capital femoral epiphysis does not have an increased association with hemophilia and usually occurs during the adolescent years. Greene WB: Diseases related to the hematopoietic system, in Morrissy RT, Weinstein SL (eds): Lovell and Winter's Pediatric Orthopaedics, ed 5. Philadelphia, PA, Lippincott Williams and Wilkins, 2001, pp 379-426.

Histologic studies have shown that increased bone turnover is the rule in OI. Pamidronate (and all bisphosphonates) reduce osteoclast-mediated bone resorption. Osteoblastic new bone formation on the periosteal surface of long bones is minimally impaired. With inhibition of osteoclastic bone resorption on the endosteal surface, the cortex of the bone can begin to thicken as it does with normal growth in individuals unaffected by OI. Mineralization and collagen matrix organization are not directly affected by pamidronate. Zeitlin L, Fassier F, Glorieux FH: Modern approach to children with osteogenesis imperfecta. J Pediatr Orthop B 2003;12:77-87. Falk MJ, Heeger S, Lynch KA, et al: Intravenous bisphosphonate therapy in children with osteogenesis imperfecta. Pediatrics 2003;111:573-578.

The patient has had a clear and sudden onset of a profound neurologic deficit. The radiographic studies suggest a lesion in the conus medullaris that appears to be intradural and intramedullary. MRI, with and without contrast, will best evaluate this mass further. The addition of gadolinium allows further evaluation of vascularity and the extent of the lesion. Eichler ME, Dacey RG: Intramedullary spinal cord tumors, in Bridwell KH, Dewald RL (eds): The Textbook of Spine Surgery, ed 2. Philadelphia, PA, Lippincott-Raven, 1997, vol 2, pp 2089-2116.

The radiographs and MRI scans both show an avulsion of the anterior cruciate ligament, which has been described by Meyers and McKeever in three different fracture patterns. Type I fractures are nondisplaced or have minimal displacement of the anterior margin. Type II fractures have superior displacement of their anterior aspect with an intact posterior hinge. Type III fractures are completely displaced. Although the injury is visible on the radiographs, it is more subtle in adults than children. Thus, MRI is helpful in clarifying this injury in adults. Open or arthroscopic reduction and internal fixation is recommended for type II and type III fractures that do not respond to closed reduction. Meyers MH, McKeever FM: Fracture of the intercondylar eminence of the tibia. J Bone Joint Surg Am 1970;52:1677-1684. Wiss DA, Watson JT: Fractures of the tibial plateau, in Rockwood CA, Green DP, Bucholz RW, et al (eds): Rockwood and Green's Fractures in Adults. Philadelphia, PA, Lippincott-Raven, 1996, pp 1920-1953.

The more severe the trauma, the higher the rate of subsequent clavicular nonunion. Neither duration nor type of immobilization has been clearly demonstrated to be a causative factor in the development of nonunion. Similarly, closed reduction has not been found to alter the healing course in midshaft clavicular fractures. Lazarus MD, Seon C: Fractures of the clavicle, in Bucholz RW, Heckman JD, Court-Brown C (eds): Fractures in Adults. Philadelphia, PA, Lippincott Williams and Wilkins, 2006, vol 2, pp 1241-1242.

An isolated avulsion of the lesser tuberosity occurs very rarely and usually is found in 12- and 13-year-old adolescents. The MRI scans reveal a tear of the humeral attachment of the inferior glenohumeral ligament, a so-called HAGL lesion. This injury to the inferior glenohumeral ligament occurs much less commonly than the classic Bankart lesion (anterior inferior labral tear). A tear of the subscapularis occurs with a similar mechanism of injury but generally occurs in older individuals. Bokor DJ, Conboy VB, Olson C: Anterior instability of the glenohumeral joint with humeral avulsion of the glenohumeral ligament: A review of 41 cases. J Bone Joint Surg Br 1999;81:93-96.

The most common complication following acetabular or pelvic ring injury is deep venous thrombosis (DVT). Without prophylaxis, rates of DVT are as high as 70% to 80%. With prophylaxis, the rates are around 10%. Infection rates in surgical repair of acetabular fractures are relatively low but a history of diabetes mellitus and a significant Morel-Lavalle lesion certainly increase the risk. However, even with these two complicating factors, the rates of infection are still lower than 10%. Sciatic nerve palsy rates from the injury alone approach 20% and iatrogenic injury is usually less than 2%. Degenerative changes to the hip following this injury approach 20% to 25%, even with an anatomic reduction. Geerts WH, Code KI, Jay RM, et al: A prospective study of venous thromboembolism after major trauma. N Engl J Med 1994;331:1601-1606.

Internal rotators of the shoulder include the subscapularis, pectoralis major, teres major, and latissimus dorsi muscles. The subscapularis has two portions, with the upper portion receiving its innervation from the upper subscapular nerve (C5) and the lower portion from the lower subscapular nerve (C5-6). The two tests commonly performed to isolate the internal rotation to the subscapularis muscle are the lift-off test and the belly press test. Electromyographic findings have shown the lift-off test to be more accurate for the lower portion of the subscapularis and the belly press test to be more sensitive for the upper portion. Hintermeister RA, Lange GW, Schultheis JM, Bey MJ, Hawkins RJ: Electromyographic activity and applied load during shoulder rehabilitation exercises using elastic resistance. Am J Sports Med 1998;26:210-220.

The use of bisphosphonates has been recently associated with the development of osteonecrosis of the jaw. Length of exposure seems to be the most important risk factor for this complication. The type of bisphosphonate may play a role and previous dental procedures may be a precipitating factor. Bisphosphonates are a class of therapeutic agents originally designed to treat loss of bone density (ie, alendronate). The primary mechanism of action of these drugs is inhibition of osteoclastic activity, and it has been shown that these drugs are useful in diseases with propensities toward osseous metastases. In particular, they are effective in diseases in which there is clear upregulation of osteoclastic or osteolytic activity, such as breast cancer and multiple myeloma, and have developed into a mainstay of treatment for individuals with these diseases. Although shown to reduce skeletal events, there has been no improvement in patient survival. Bamias A, Kastritis E, Bamia C, et al: Osteonecrosis of the jaw in cancer after treatment with bisphosphonates: Incidence and risk factors. J Clin Oncol 2005;23:8580-8587. Thakkar SG, Isada C, Smith J, et al: Jaw complications associated with bisphosphonate use in patients with plasma cell dyscrasias. Med Oncol 2006;23:51-56.

The radiograph reveals a subchondral lesion in the metacarpophalangeal joint that is lytic and expansile. The MRI scans show a mass that is moderate in intensity on the T2-weighted image and has some gadolinium uptake. There are no cystic components in this lesion. The subchondral location and expansile nature are highly suggestive of giant cell tumor of bone. A lesion with this appearance might also represent an aneurysmal bone cyst, given the amount of expansion present. Menendez LR (ed): Orthopaedic Knowledge Update: Musculoskeletal Tumors. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 113-118.

Several studies have shown that ultra-high molecular weight polyethylene liners used in total hip arthroplasties wear at a rate of 0.1 to 0.2 mm/yr. The orthopaedic surgeon performing total hip arthroplasties should be aware of the average wear rate so that potential problems can be identified when following patients postoperatively. Callaghan JJ, Albright JC, Goetz DD, Olejniczak JP, Johnston RC: Charnley total hip arthroplasty with cement: Minimum twenty-five year follow-up. J Bone Joint Surg Am 2000;82:487-497.

The prognosis of Legg-Perthes disease in children younger than age 6 years is good. There is no indication that surgical treatment will improve the outcome. Range-of-motion exercises to prevent contracture may be helpful. Herring JA, Kim HT, Browne R: Legg-Calve-Perthes disease: Prospective multicenter study of the effect of treatment on outcome. J Bone Joint Surg Am 2004;86:2121-2134.

Most closed simple dislocations are best managed with early range of motion. Posterior dislocation typically occurs through a posterolateral rotatory mechanism. When placed in pronation, the elbow has greater stability when the medial ligamentous structures are intact. In traumatic dislocations, MRI rarely provides additional information that will affect treatment. In elbows that remain unstable, primary repair is preferred over ligament reconstruction. Cast immobilization increases the risk of arthrofibrosis.

Based on the radiographic findings, the patient has melorheostosis, a rare, benign connective tissue disorder that is characterized by a cortical thickening of bone. It produces a "dripping candle wax" appearance with dense hyperostosis that flows along the cortex. Ectopic bone formation is a consideration but is associated with injuries or burns. Bone infarcts produce intraosseous sclerosis typically affecting the distal femur with the "smoke up chimney" appearance. Infection is always a consideration but typically does not have the linear osteitis seen in melorheostosis. Juxacortical chondroma is a benign cartilage growth that arises from the capsule and may involve the underlying cortical bone but rarely the medullary canal. Campbell CJ, Papademetriou T, Bonfiglio M: Melorheostosis: A report of the clinical, roentgenographic, and pathological findings in fourteen cases. J Bone Joint Surg Am 1968;50:1281-1304.

Rehabilitation of the quadriceps muscle following a partial tear of the PCL has been associated with a favorable outcome. The quadriceps acts an antagonist to the PCL because its contraction results in anterior tibial translation, which reduces the tensile stress on the injured ligament. Strengthening of the hamstring musculature increases posterior tibial translation and is contraindicated during the early rehabilitative phase following a PCL injury. Brace use has not been found to significantly alter the outcome following nonsurgical management of PCL tears. Parolie JM, Bergfeld JA: Long-term results of nonoperative treatment of isolated posterior cruciate ligament injuries in the athlete. Am J Sports Med 1986;14:35-38.

With subscapularis tendon ruptures that have biceps tendon pathology, treatment with tenodesis or tenotomy has improved clinical results. Subluxation or dislocation of the biceps tendon is common with subscapularis rupture. Dislocation of the biceps can occur either beneath the tendon, within the tendon, or extra-articularly. In all cases, the restraints to medial translations of the biceps have been disrupted. Attempts at recentering the biceps have not been successful, and clinical results appear to be improved when tenodesis or tenotomy is employed in the treatment of the unstable biceps associated with subscapularis tears. Edwards TB, Walch G, Sirvenaux F, et al: Repair of tears of the subscapularis: Surgical technique. J Bone Joint Surg Am 2006;88:1-10. Deutsch A, Altchek DW, Veltri DM, et al: Traumatic tears of the subscapularis tendon: Clinical diagnosis, magnetic resonance imaging findings, and operative treatment. Am J Sports Med 1997;25:13-22.

The problem with this reconstruction is the medial protrusion of the base plate. The use of a base plate with an offset stem can prevent the protrusion and thus the impingement and pain. Allograft bone or smoothing the outline with cement would be just as prominent and likely to cause pain. An ingrowth surface may improve soft-tissue attachment but would still leave the implant protruding medially and likely to cause pain. A nonstemmed tibial base plate would lead to less medial protrusion but at the expense of a smaller area for load carriage on the proximal tibia.

The femoral component should be implanted with enough external rotation to facilitate patellar tracking. Proper tracking requires a normal Q angle and is affected by axial and rotational alignment of the femur and tibia. An excessive Q angle can result from internal rotation of either component, medialization of the tibial tray, or lateralization of the patellar component. Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 559-582.

Multiple attempts at closed reduction, delayed surgery for proximal humeral fractures, and associated closed head injury all have been associated with a higher incidence of heterotopic ossification. Rockwood CA Jr, Matsen FA III (eds): The Shoulder. Philadelphia, PA, WB Saunders, 1998, vol 1, p 291.

The hypoglossal nerve exits from the ansa cervicalis at approximately the C2-3 level and can be injured during retraction up to the C2 level. The superior laryngeal nerve lies at about C4-5. The facial nerve is much higher. The vagus nerve runs with the internal jugular and carotid much more laterally. The phrenic nerve exits posteriorly. Chang U, Lee MC, Kim DH: Anterior approach to the midcervical spine, in Kim DH, Henn JS, Vaccaro AR, et al (eds): Surgical Anatomy and Techniques to the Spine. Philadelphia, PA, Saunders Elsevier, 2006, pp 45-54.

The imaging studies show a chondrosarcoma; therefore, surgical treatment is indicated. There is no role for intralesional treatment of an exophytic lesion, particularly in the pelvis. Even obtaining a biopsy specimen risks intrapelvic contamination, although many surgeons would still perform a biopsy prior to a resection to confirm the diagnosis. Chondrosarcoma is considered resistant to both radiation therapy and chemotherapy; therefore, radiation therapy generally is not used except for unresectable lesions. Chemotherapy would be used only for metastatic disease or in patients with high-grade chondrosarcoma. The grade would not be known until after resection, and in this patient, the histology slide showed a grade I neoplasm. Chemotherapy would not be used preoperatively because a cartilage tumor is unlikely to shrink, and in this patient, the lesion is resectable. Springfield DS, Gebhardt MS, Mcguire MH: Chondrosarcoma: A review. J Bone Joint Surg Am 1996;78:141-149.

During Patrick's test, also known as the FABER test, the flexed, abducted, and externally rotated hip is positioned to isolate sacroiliac pathology. Back pain with this test is not considered diagnostic. With Kernig's sign, the spinal cord is placed on stretch, eliciting root or meningeal irritation by forcibly flexing the patient's head and neck with his or her hands clasped behind the head. For Lasegue's sign, the patient performs a straight leg raise with the immobile hip already held in flexion. The femoral stretch test can be performed in the prone position or side lying, but the hip is held in extension while the knee is flexed, testing for femoral neuritis. Watkins RG: History, physical examination, and diagnostic tests for back and lower extremity problems, in Watkins RG (ed): The Spine in Sports. St Louis, MO, Mosby, 1996, Chapter 7.

The literature supports similar clinical outcomes after surgical and nonsurgical methods. The chief difference lies in the complications between the groups. Surgical patients experience more wound problems but a significantly lower rerupture rate. Although suturing the tendon allows earlier mobility, the tendon healing time is unchanged. Nonsurgical methods are less expensive to provide. Maffulli N: Rupture of the Achilles tendon. J Bone Joint Surg Am 1999;81:1019-1036. Cetti R, Christensen SE, Ejsted R, Jensen NM, Jorgensen U: Operative versus nonoperative treatment of Achilles tendon rupture: A prospective randomized study and review of the literature. Am J Sports Med 1993;21:791-799.

The hallmark of neurogenic shock is hypotension without tachycardia. It is associated most commonly with high cervical spinal cord injuries and results from loss of function of the sympathetic nervous system. Because the peripheral vasculature is dilated due to loss of its sympathetic tone, continued rapid administration of fluid corrects the hypotension and can quickly lead to fluid overload and congestive heart failure. Therefore, neurogenic shock is best treated by the use of pressors. Cardioversion or administration of antibiotics or systemic steroids is not appropriate treatment for this patient's hypotension. Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 179-187.

Anteromedial displacement of the tibial tubercle unloads the distal and lateral facets of the patella and shifts the forces to the proximal and medial facets. Therefore, if findings indicate arthrosis predominately in the medial and proximal areas of the patella, this is considered a relative contraindication because it may accentuate arthritic symptoms. Fulkerson JP: Anteromedialization of the tibial tuberosity for patellofemoral malalignment. Clin Orthop 1983;177:176-181. Bellemans J, Cauwenberghs F, Witvrouw E, et al: Anteromedial tibial tubercle transfer in patients with chronic anterior knee pain and a subluxation-type patellar malalignment. Am J Sports Med 1997;25:375-381.

The thoracolumbosacral orthosis with thigh extension best immobilizes the lumbosacral junction. Fidler and Plasmans have demonstrated increased motion at the lumbosacral junction with the standard chairback-type brace. Connolly PJ, Grob D: Bracing of patients after fusion for degenerative problems of the lumbar spine: Yes or no? Spine 1998;23:1426-1428.

Wide variations in the anatomy of the anterosuperior portion of the labrum and the middle glenohumeral ligament have been reported and are more common than previously thought. The labrum attached to the glenoid rim and a flat/broad middle glenohumeral ligament is the most common "normal" variation. A cord-like middle glenohumeral ligament is often associated with the presence of a sublabral hole. An anterosuperior labrum confluent with a cord-like middle glenohumeral ligament and no labral attachment to bone is the configuration of the Buford complex. The prevalence of each variation from one recent study is as follows: #1: 86.6%; #2: 3.3%; #3: 8.6%; and #4: 1.5%. Rao AG, Kim TK, Chronopoulos E, et al: Anatomical variants in the anterosuperior aspect of the glenoid labrum. J Bone Joint Surg Am 2003;85:653-659. Ilahi OA, Labbe MR, Cosculluela P: Variants of the anterosuperior glenoid labrum and associated pathology. Arthroscopy 2002;18:882-886.

Knee pain and swelling in the first week after ACL reconstruction is usually related to a postoperative hemarthrosis. A large hemarthrosis creates capsular distension, which inhibits active quadriceps contraction by a neurologic reflex, the H. reflex. Kennedy and associates reported that an experimentally induced knee effusion at 60 mL was found to result in profound inhibition of reflexly evoked quadriceps contraction. Removal of the hemarthrosis by aspiration will improve strength and often instantaneously restore the ability to contract the quadriceps muscle. A large effusion will also limit knee flexion. EMG and NCVS are not necessary unless there is a high index of suspicion of a femoral neuropathy. Diagnostic ultrasonography is not necessary in this patient but can be useful in the assessment of patellar tendon integrity. MRI is not indicated and would most likely be limited by artifact and postoperative changes. Continuous passive motion is not indicated and would most likely worsen the patient's symptoms. Kennedy JC, Alexander IJ, Hayes KC: Nerve supply of the human knee and its functional importance. Am J Sports Med 1982;10:329-335.