100 High-Yield Orthopedic MCQs: Shoulder & Elbow | Mock Exam 251

Coxa saltans (snapping hip syndrome) can occur in two forms: external/lateral or interior/medial/anterior. This patient has the external/lateral form. The external/lateral form involves the iliotibial band, tensor fascia, or gluteus medius, which snaps over the greater trochanter. The external form usually can be treated with physical therapy alone; however, several recent studies report satisfactory results with surgical treatment. Faraj and associates reported good results from surgical Z-plasty in a series of 10 patients. White and associates reported good results in a series of 16 patients with 17 hips who underwent surgical release of an external snapping hip. The interior/medial/anterior form can involve the iliopsoas tendon, acetabular labrum, subluxation of the hip, and loose bodies. White RA, Hughes MS, Burd T, et al: A new operative approach in the correction of external coxa saltans: The snapping hip. Am J Sports Med 2004;32:1504-1508. Faraj AA, Moulton A, Sirivastava VM: Snapping iliotibial band: Report of ten cases and review of the literature. Acta Orthop Belg 2001;67:19-23.

Spondylolysis may develop as a stress fracture resulting from repetitive hyperextension during athletic activities. In young people, the pars interarticularis is thin, the neural arch has not yet reached maximum strength, and the intravertebral disk is less resistant to shear. While clinical symptoms may lead to the suspicion of spondylolysis, radiographic confirmation may be difficult in early cases. Plain radiographs may be negative initially, and the plain MRI scan may not offer good visualization of the pars. A bone scan with SPECT is very sensitive initially. CT scans with regular axial and reverse-gantry angled cuts may help determine the type of fracture and the course of treatment. Congeni J, McCulloch J, Swanson K: Lumbar spondylolysis: A study of natural progression in athletes. Am J Sports Med 1997;25:248-253.

The radiographs show a significant loss of the proximal anterior tibial cortex, consistent with an extensively damaged or deficient extensor mechanism. Such a deficit precludes insertion of another knee arthroplasty. Arthrodesis is the treatment of choice for this patient and is indicated for loss of the extensor mechanism and knee instability. A recent report on arthrodesis following removal of an infected prosthesis showed a union rate of 91% using a short intramedullary nail. Insertion of an antibiotic-impregnated PMMA spacer is not indicated because the rationale for using a spacer is to maintain a space for reinsertion of another prosthesis. Reconstruction of the extensor mechanism would not address the loss of the joint. Amputation is the final treatment option if the arthrodesis fails. Rand JA: Alternatives to reimplantation for salvage of the total knee arthroplasty complicated by infection. J Bone Joint Surg Am 1993;75:282-289. Lai KA, Shen WJ, Yang CY: Arthrodesis with a short Huckstep nail as a salvage procedure for failed total knee arthroplasty. J Bone Joint Surg Am 1998;80:380-388.

The possibility of an open joint injury should be considered in any patient who has a small periarticular laceration. Failure to promptly diagnose and treat such injuries may lead to septic arthritis. The diagnosis of an open joint is easily made when there is visible communication of the joint through the traumatic wound, or when intra-articular air is present on a radiograph. In the absence of these findings, the diagnosis of an open joint may be established by the saline load test, in which a volume of saline is injected into the joint under sterile conditions. If fluid extravasates through the traumatic wound, the diagnosis of an open joint is established. Voit and associates used a saline load test in 50 patients with periarticular lacerations suggestive of joint penetration. When they compared the clinical prediction of whether or not the laceration had penetrated the joint and the test results, the authors reported a false-positive clinical result in 39% of patients and a false-negative clinical result in 43%. The authors concluded that the saline load test was valuable in evaluating periarticular lacerations. Voit GA, Irvine G, Beals RK: Saline load test for penetration of periarticular lacerations. J Bone Joint Surg Br 1996;78:732-733.

The histology shows small round blue cells that are uniform in appearance; these findings are consistent with Ewing's sarcoma. The MRI scan shows infiltration of the marrow and a large surrounding soft-tissue mass. Based on these findings, the management of choice is systemic chemotherapy. Local control of the primary lesion is addressed by either surgical resection or radiation therapy or a combination of the two after the patient receives systemic chemotherapy. The clinical, radiographic, and histologic presentation of Ewing's sarcoma often can be confused with osteomyelitis. The histology shows an absence of inflammatory cells. Grier HE: The Ewing family of tumors: Ewing's sarcoma and primitive neuroectodermal tumors. Pediatr Clin North Am 1997;44:991-1004.

Tuberculosis of the spine is seen in 50% to 60% of skeletal disease and is most commonly found in the lower thoracic or upper lumbar spine. Typically two or more adjacent bodies are involved as seen in this MRI scan. The disk space is narrowed but still relatively preserved as opposed to pyogenic infections (black arrow). Epidural extensions often spread from vertebrae to vertebrae (white arrow); however, the posterior elements are not frequently involved (arrowhead). Tumors rarely spread to adjacent vertebrae. The anterior and posterior spread of the infectious process rules out trauma. Boachie-Adjei O, Squillante RG: Tuberculosis of the spine. Orthop Clin North Am 1996;27:95-103.

The extensor digiti mini quinti is most typically a tendon with two slips. The abductor pollicis longus has multiple slips that insert in order of frequency on the base of the first metacarpal, trapezium, and thenar muscles. The extensor pollicis longus, extensor carpi radialis brevis, and extensor indicis proprius consistantly have only one slip. von Schroeder HP, Botte MJ: Anatomy of the extensor tendons of the fingers: Variations and multiplicity. J Hand Surg Am 1995;20:27-34.

Internal impingement in the thrower's shoulder occurs in the abducted, externally rotated position as described by Walch and associates. The injury is thought to occur from repetitive contact between the posterosuperior portion of the labrum and glenoid against the articular side of the rotator cuff and greater tuberosity. Paley KJ, Jobe FW, Pink MM, et al: Arthroscopic findings in the overhand throwing athlete: Evidence for posterior internal impingement of the rotator cuff. Arthroscopy 2000;16:35-40. Jazrawi LM, McCluskey GM III, Andrews JR: Superior labral anterior and posterior lesions and internal impingement in the overhead athlete. Instr Course Lect 2003;52:43-63.

Multidirectional instability of the shoulder is defined as symptomatic instability in two or more directions (anterior, posterior) but must include a component of inferior instability. Initial treatment should always include physical therapy and instruction in a home exercise program that emphasizes periscapular and rotator cuff strengthening to improve the dynamic stability of the glenohumeral joint. Immobilization has not been shown to be effective. Open capsular shift and arthroscopic capsular plication remain the surgical options when appropriate nonsurgical management fails (typically a minimum of 6 months of dedicated therapy and home program). Thermal capsulorrhaphy remains controversial but is not recommended by many clinicians because of reported complications including recurrent instability, axillary nerve injury, chondrolysis, and capsular injury. Neer CS II, Foster CR: Inferior capsular shift for involuntary inferior and multidirectional instability of the shoulder: A preliminary report. J Bone Joint Surg Am 1980;62:897-908. D'Alessandro DF, Bradley JP, Fleischli JE, et al: Prospective evaluation of thermal capsulorrhaphy for shoulder instability: Indications and results, two- to five-year follow-up. Am J Sports Med 2004;32:21-33. Levine WN, Clark AM Jr, D'Alessandro DF, et al: Chondrolysis following arthroscopic thermal capsulorrhaphy to treat shoulder instability: A report of two cases. J Bone Joint Surg Am 2005;87:616-621.

Avulsion fractures of the tibial spine are rare injuries that result from rapid deceleration or hyperextension of the knee in skeletally immature individuals. This injury is the equivalent of ruptures of the anterior cruciate ligament in adults. These fractures are classified as types 1 through 3. Type 1 is a minimally displaced fracture, type 2 fractures have an intact posterior hinge, and type 3 fractures have complete separation. The radiograph demonstrates a completely displaced, or type III, tibial spine avulsion. Surgical reduction is indicated in type 2 fractures that fail to reduce with knee extension and in all type 3 fractures. Reduction may be arthroscopic or open, with fixation of the bony fragment using a method that maintains physeal integrity and prevents later growth arrest. Preferred techniques would be with suture or an intra-epiphyseal screw Wiley JJ, Baxter MP: Tibial spine fractures in children. Clin Orthop 1990;255:54-60. Mulhall KJ, Dowdall J, Grannell M, et al: Tibial spine fractures: An analysis of outcome in surgically treated type III injuries. Injury 1999;30:289-292. Owens BD, Crane GK, Plante T, et al: Treatment of type III tibial intercondylar eminence fractures in skeletally immature athletes. Am J Orthop 2003;32:103-105.

35b 35c Ninety percent of injuries to the proximal radius in children are radial neck fractures, and 50% of these fractures are through the metaphyseal bone. The remaining 50% are Salter-Harris type I or II fractures. These radiographs show a fracture of the radial head and subluxation of the radius anteriorly. Most congenital radial head dislocations are posterior lateral. Nonsurgical treatment modalities are unlikely to be successful due to the wide displacement of the fracture fragments, as well as dislocation of the radial head. Leung AG, Peterson HA: Fractures of the proximal radial head and neck in children with emphasis on those that involve the articular cartilage. J Pediatr Orthop 2000;20:7-14. Hashemi-Nejad A, Goddard NJ: Radial head fractures. Br J Hosp Med 1994;51:223-226.

The use of nasotracheal intubation is less desirable in patients with respiratory arrest because placement of the tube is most reliable when the patient is breathing. Nasotracheal intubation is advantageous in patients with suspected cervical spine trauma because it does not require hyperextension of the neck. A nasotracheal tube may be more comfortable than an orally placed tube because it is fixed at several points and moves less freely within the larynx, subglottic area, and trachea. The presence of a hemothorax or pneumothorax does not affect the choice of airway control but does require placement of a chest tube. Colice GL: Prolonged intubation versus tracheostomy in the adult. J Intern Care Med 1987;2:85.

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.

41b Transolecranon fracture-dislocations are most effectively managed with open reduction and internal fixation, followed by early aggressive range of motion. Concomitant injury to the collateral ligament is rare, and stability is achieved by anatomic reconstruction of the olecranon fracture with rigid fixation. The need for collateral ligament repair or a hinged external fixator is uncommon in this fracture pattern.

The findings are most consistent with a rupture of the anterior tibial tendon. The damaged area of tendon should be resected, followed by tendon reconstruction or tenodesis. The histology is not consistent with giant cell tumor of the tendon sheath, gout, or synovial sarcoma. Fibromatosis is characterized by a large number of spindle cells within the collagen background. Otte S, Klinger HM, Loreaz F, Haerer T: Operative treatment in case of closed rupture of the anterior tibial tendon. Arch Orthop Traum Surg 2002;122:188-190.

The spinal nerves primarily responsible for bladder function are the S2, S3, and S4 nerve roots. With significant compression of the cauda equina by either disk herniation, tumor, or degenerative stenosis, bladder dysfunction may result. Hoppenfeld S: Physical Examination of the Spine and Extremities. Norwalk, CT, Appleton-Century-Crofts, 1976, p 254.

Redislocation following acute dislocation occurs in approximately 3% of patients. This redislocation tends to occur in middle-aged and elderly patients. A higher incidence of redislocation occurs when there are accompanying fractures of the glenoid rim and the greater tuberosity. Robinson CM, Kelly M, Wakefield AE: Redislocation of the shoulder during the first six weeks after a primary anterior dislocation: Risk factors and results of treatment. J Bone Joint Surg Am 2002;84:1552-1559.

Popliteal snapping syndrome represents the most likely diagnosis. Barnes and Scott noted that the popliteus tendon can be a potential source of internal derangement after total knee arthroplasty. They noted that it can be subluxated anteriorly and posteriorly over a retained lateral femoral condyle osteophyte. Allardyce and associates described the condition as a popliteus condition, snapping as it rolls over a retained lateral femoral condylar osteophyte. Patellar clunk syndrome is a distinct syndrome associated with the patella and has been reported in posterior stabilized knees. In addition to crepitation with range of motion, the patella literally snaps or jumps as the knee is taken from flexion to extension. Beight JL, Yao B, Hozack WJ, et al: The patellar "clunk" syndrome after posterior stabilized total knee arthroplasty. Clin Orthop 1994;299:139-142. Barnes CL, Scott RD: Popliteus tendon dysfunction following total knee arthroplasty. J Arthroplasty 1995;10:543-545.

The CT scan is an important test to help determine the extent of involvement of the talocalcaneal facet in a talocalcaneal coalition. In a young patient with no arthritis and joint involvement of less than 50%, resection of the coalition and fat pad interposition has been shown to be successful. A calcaneal osteotomy does not address the coalition. Subtalar arthroereisis has been used for treatment of a flexible flatfoot; tarsal coalition patients have a rigid-type flatfoot deformity. Sullivan JA: The child's foot, in Morrissy RT, Weinstein SL (eds): Lovell and Winter's Pediatric Orthopaedics, ed 4. Philadelphia, PA, Lippincott-Raven, 1996, vol 2, pp 1077-1135.

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

A high index of suspicion is required to identify a possible navicular stress fracture, especially in runners. High pain tolerance in the competitive athlete and often minimal swelling contribute to frequent delays in diagnosis. Localized tenderness over the dorsal navicular (so-called "N spot") in a running athlete should alert the treating physician. In this patient, the radiographs are negative and the MRI scan shows marrow edema within the navicular. This could represent a stress reaction, stress fracture, or osteonecrosis. Appropriate management should include non-weight-bearing immobilization and obtaining a CT scan to determine if a fracture is present. Early surgical treatment may be considered but only if a fracture is identified. Lee A, Anderson R: Stress fractures of the tarsal navicular. Foot Ankle Clin 2004;9:85-104.

Severe valgus deformity is frequently accompanied by hypoplasia of the lateral femoral condyle. Posterior referencing instrumentation can substantially internally rotate the femoral component with respect to the transepicondylar axis and Whiteside's line. The femoral component malrotation must be corrected to properly address this problem. Berger RA, Della Valle CJ, Rubash HE: Patellofemoral problems in total knee arthroplasty, in Callaghan JJ, Rosenberg AG, Rubash HE, et al (eds): The Adult Knee. Philadelphia, PA, JB Lippincott, 2003, vol 2, pp 1245-1258.

Salvage of a total elbow arthroplasty is possible with early aggressive management of acute infection (symptoms for less than 30 days) with serial irrigation and debridement and antibiotic bead placement. This form of treatment is indicated when there are no radiographic or intraoperative signs of loosening. However, successful treatment is largely dependent on the organism. Staphylococcus epidermidis is associated with persistent infection because it is an encapsulating organism, and it is best treated with implant removal and IV antibiotics. Yamaguchi K, Adams RA, Morrey BF: Infection after total elbow arthroplasty. J Bone Joint Surg Am 1998;80:481-491.

41b The patient has a displaced four-part proximal humerus fracture. Given her age and the presence of osteopenia, a cemented hemiarthroplasty is the treatment of choice. The glenoid is uninjured so a total shoulder arthroplasty is not indicated. Percutaneous pinning in younger individuals with good bone quality may be indicated but not in an 82-year-old woman with osteopenia. Sling immobilization and immediate pendulum exercises will lead to a nonunion. Sling immobilization for 6 weeks followed by active range of motion will result in a nonunion or malunion with unacceptable functional results. Neer CS II: Displaced proximal humeral fractures: I. Classification and evaluation. J Bone Joint Surg Am 1970;52:1077-1089.

Adequate decompression of the cervical cord can be achieved in a variety of ways depending on the pathoanatomy of the compression, but kyphosis is a relative contraindication to laminectomy alone. For laminectomy to be effective, the lordosis must be maintained so the cord can displace posteriorly away from the anterior structures. In addition, removing the posterior tension band increases the probability that the kyphosis will progress, therefore increasing the force against the front of the cord as it tents across the kyphosis. Albert TJ, Vaccaro A: Postlaminectomy kyphosis. Spine 1998;23:2738-2745. Truumees E, Herkowitz HN: Cervical spondylotic myelopathy and radiculopthy. Instr Course Lect 2000;49:339-360.

Revision of a failed patellar component can be difficult because of bone loss and damage to the extensor mechanism. Several authors have advised against reinsertion of a patellar component if the residual patellar thickness is 10 mm or less. Leaving an unresurfaced bony remnant in place at the time of revision or reimplantation surgery has been shown to be a reasonable option; however, the results are of a lower quality when compared with revision surgery where the patellar component can be retained or revised. The other treatment options have not been shown to be effective approaches to this problem. Rand JA: The patellofemoral joint in total knee arthroplasty. J Bone Joint Surg Am 1994;76:612-620. Pagnano MW, Scuderi GR, Insall JN: Patellar component resection in revision and reimplantation total knee arthroplasty. Clin Orthop 1998;356:134-138.

The patient has a Monteggia fracture-dislocation (proximal ulnar fracture and radial head dislocation). The posterior interosseous nerve branch of the radial nerve is the most likely to be injured and could result in weakness of thumb extension and finger metacarpal extension. Considerably less likely are injuries to the more proximal radial nerve branches supplying the extensor carpi radialis longus and brevis, resulting in weak wrist extension; the ulnar nerve supplying the digital intrinsics, resulting in weak finger abduction; the anterior interosseous branch of the median nerve, resulting in weakness of the flexor pollicis longus; and the distal median nerve, resulting in weakness of thumb opposition. Bado JL: The Monteggia lesion. Clin Orthop 1967;50:71-86.

The patient's clinical signs (fever and flank, hip, and abdominal pain) suggest a primary iliopsoas abscess. With an increased patient population who abuse drugs and/or who are HIV-positive, iliopsoas abscess may be more prevalent because of systemic bacterial seeding and may be potentially unrecognized. Diagnostic imaging studies provide a better understanding of the anatomic magnitude of the infection, give concrete confirmation of the diagnosis, and may suggest an underlying cause. Neither standard abdominal radiographs nor ultrasound studies are sensitive enough to be diagnostic of this disease process. CT has been established as the standard study for identifying the underlying cause of this abscess. The hip infection has most likely developed as a result of hematogenous spread from an infected skin lesion from the patient's IV drug use. Santaella RO, Fishman EK, Lipsett PA: Primary vs secondary iliopsoas abscess: Presentation, microbiology, and treatment. Arch Surg 1995;130:1309-1313.

Although cervical instability is a contraindication to posterior decompression alone, segmental instability in the myelopathic cervical spine can be addressed with concomitant posterior fusion with instrumentation. Cervical lordosis represents the ideal scenario for posterior decompressive procedures for myelopathy (laminectomy and laminoplasty) because compression from anterior osteophytes, if present, is relieved as the spinal cord migrates posteriorly. The anteroposterior diameter of the spinal canal does not have an impact on the selection of surgical approach. Posterior unroofing-type procedures in kyphotic cervical spines, however, are ineffective because anterior impingement on the spinal cord will remain; therefore, kyphosis of more than 10 degrees is considered a contraindication for posterior decompression. Emery SE: Cervical spondylotic myelopathy: Diagnosis and treatment. J Am Acad Orthop Surg 2001;9:376-388.

In a report of more than 70 hips treated by surgical dislocation, iatrogenic osteonecrosis failed to develop in any of the hips.

The "sunburst" radiographic appearance suggests an osteosarcoma, and the histologic findings confirm the diagnosis with malignant cells surrounded by pink osteoid. MRI scans are not particularly helpful in the diagnosis of osteosarcoma but are mandatory for surgical planning. Osteosarcomas are high-grade sarcomas that are best treated with chemotherapy and wide resection. Even though the peroneal nerve is involved, limb salvage is indicated. Survival after limb salvage is equivalent to amputation, with better function. Goorin AM, Abelson HT, Frei E: Osteosarcoma: Fifteen years later. N Engl J Med 1985;313:1637. Link MP, Goorin AM, Miser AW, et al: The effect of adjuvant chemotherapy on relapse-free survival in patients with osteosarcoma of the extremity. N Engl J Med 1986;314:1600.

Gene expression at the posttranslational level refers to proteins, as opposed to DNA or RNA. The only assay above that targets protein expression directly is the Western blot. Standard PCR is amplification of targeted DNA segments, regardless of whether or not they are actively expressed. Real-time PCR, Northern blot, and microarray expression profile analysis all quantify RNA as a means to determine posttranscriptional gene expression. Brinker MR: Cellular and molecular biology, immunology, and genetics in orthopaedics, in Miller MD (ed): Review of Orthopaedics, ed 3. Philadelphia, PA, WB Saunders, 2001, pp 81-94.

Malrotation of the foot is frequently overlooked in this clinical setting. This can be judged by evaluating and comparing the transmalleolar axes of the affected and unaffected legs. The rotation occurs through the physis and frequently is not recognized until the patient has been walking for a few months. The other conditions are not expected to occur in the clinical setting described. Phan VC, Wroten E, Yngve DA: Foot progression angle after distal tibial physeal fractures. J Pediatr Orthop 2002;22:31-35.

The posttraumatic lumbar kyphotic deformity will not remodel and is likely to worsen with time because the central line of gravity lies anterior to the deformity and the ligamentous disruption will not heal. The worsening deformity also puts the patient at some risk for future neurologic damage. Ebraheim NA, Savolain ER, Southworth SR, et al: Pediatric lumbar seat belt injuries. Orthopedics 1991;14:1010-1013.

The clinical photograph shows an acute capsulolabral avulsion from the anterior glenoid, also referred to as a Perthes-Bankart lesion. In patients who sustain an acute dislocation that requires a manual reduction, this pathologic lesion is observed with high frequency. In several research studies, it has been visualized in 80% to 95% of patients at arthroscopy. Taylor DC, Arciero RA: Pathologic changes associated with shoulder dislocations: Arthroscopic and physical examination findings in first-time, traumatic anterior dislocations. Am J Sports Med 1997;25:306-311.

The meniscal cartilage, like articular cartilage, possesses viscoelastic properties. The extracellular matrix is a biphasic structure composed of a solid phase (collagen, proteoglycan) that acts as a fiber-reinforced porous-permeable composite, and a fluid phase that may be forced through the solid matrix by a hydraulic pressure gradient. Although these properties are shared with articular cartilage, the meniscus is more elastic and less permeable than articular cartilage. Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 3-23.

When patients are compared at 5 years follow-up, there are no statistically significant differences between the two groups with respect to kyphosis, the degree of retropulsed bone resorption, pain and function levels, or the ability to return to work. Nonsurgical management of stable neurologically intact burst fractures has a very low incidence of complications. Wood K, Butterman G, Mehbod A, et al: Operative compared with nonoperative treatment of a thoracolumbar burst fracture without neurological deficit: A prospective, randomized study. J Bone Joint Surg Am 2003;85:773-781.

Tarsal coalitions commonly present in the preadolescent age group as a rigid, planovalgus foot. Small coalitions of the calcaneonavicular joint or the middle facet of the talocalcaneal joint can be excised with interposition of fat or muscle tissue. Isolated calcaneocuboid joint coalitions are very rare. This patient has an associated large talocalcaneal coalition; therefore, resection is contraindicated. Surgery is warranted after failure of nonsurgical management, and because of the involvement of two joints, the only viable option for the severely symptomatic foot is triple arthrodesis. Vincent KA: Tarsal coalition and painful flatfoot. J Am Acad Orthop Surg 1998;6:274-281.

Because the patient has sustained a major high-energy injury to the pelvic ring, it can be assumed that there is serious bleeding or hemodynamic instability related to a pelvic vascular injury. The goal of intervention at this time is to assist in the resuscitative effort and to stop the bleeding. All attempts at providing fluid and blood are important, but without cessation of the bleeding continued loss occurs and significant problems can ensue such as coagulopathy and multiple organ failure. Noninvasive methods of stabilizating the pelvic ring should be used to stop the bleeding. These methods include wrapping a sheet around the pelvis or using commercially available belts, vacuum beanbags, or pneumatic shock garments. This will provide time to prepare for arteriography and/or external fixation. The next step is debatable but in view of negative findings for intra-abdominal blood, arteriography performed with the pelvis reduced using noninvasive methods would be ideal. Bassam D, Cephas GA, Ferguson KA, Beard LN, Young JS: A protocol for the initial management for unstable pelvic fractures. Am Surg 1998;64:862-867. Levine AM (ed): Orthopaedic Knowledge Update: Trauma. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1996, pp 217-226.

A Latarjet procedure is similar to a Bristow procedure, but with the Latarjet procedure a larger portion of the coracoid is transferred to the scapular neck at the anteroinferior glenoid. As in a Bristow procedure, if the fragment is pulled or twisted during the dissection or during fixation, the musculocutaneous nerve can be injured. With loss of biceps function, elbow flexion and forearm supination will be weaker. Ho E, Cofield RH, Balm MR, Hattrup SJ, Rowland CM: Neurologic complications of surgery for anterior shoulder instability. J Shoulder Elbow Surg 1999;8:266-270. Boardman ND 3rd, Cofield RH: Neurologic complications of shoulder surgery. Clin Orthop 1999;368:44-53.

Cancellous bone strength and stiffness are determined primarily by the apparent density (the amount of bone per unit volume). Strength varies approximately as the square of the density, and stiffness as the cube of the density; therefore, these are very strong relationships. Cancellous bone strength also depends on the mineral content, the rate of loading (it is viscoelastic), the anatomic level, and the trabecular number (an histomorphometry term), but all to a markedly lesser extent than density. Carter DR, Hayes WC: The compressive behavior of bone as a two-phase porous structure. J Bone Joint Surg Am 1977;59:954-962.

41b 41c In a young person with solitary osteochondroma, the best surgical indication is symptoms that limit activity. A growth deformity is unlikely to occur at this age. Malignant degeneration is exceptionally rare and noted most commonly in adults. Growth is expected until skeletal maturity. Mirra JM: Bone Tumors: Clinical, Radiologic, and Pathologic Correlations. Philadelphia, PA, Lea and Febiger, 1989, pp 1626-1659.

The clinical photograph shows a classic boutonniere deformity. It is likely that the patient sustained a volar dislocation of the proximal interphalangeal joint, with a concomitant rupture of the central slip insertion of the extensor tendon. Peimer CA, Sullivan DJ, Wild DR: Palmar dislocation of the proximal interphalangeal joint. J Hand Surg Am 1984;9:39-48.

The classic MRI appearance of a soft-tissue sarcoma is a well-defined heterogeneous mass deep to the fascia. MRI has greatly enhanced our ability to identify and characterize soft-tissue masses. In many patients, MRI is diagnostic and may obviate the need for biopsy. In other patients, it may indicate with high probability that the mass is malignant and consideration for referral can be made. A common misconception is that sarcomas are infiltrative; therefore, physicians mistakenly exclude the diagnosis of a sarcoma based on a well-defined mass seen on MRI. However, sarcomas grow centrifugally with balloon-like expansion compressing surrounding normal tissue; as such, they appear well defined. Many benign soft-tissue masses such as lipomas are similarly well defined. However, MRI is especially useful in identifying fat. Lipomas appear to be homogeneous masses with fat signal characteristics on all sequences. Ill-defined soft-tissue masses include infection, trauma, and desmoid tumors. Heterogeneity is not unique to malignant tumors but is a characteristic of soft-tissue sarcomas. Bancroft LW, Peterson JJ, Kransdorf MJ, Nomikos GC, Murphey MD: Soft tissue tumors of the lower extremities. Radiol Clin North Am 2002;40:991-1011. Berquist TH, Ehman RL, King BF, et al: Value of MR imaging in differentiating benign from malignant soft-tissue masses: Study of 95 lesions. Am J Roentgenol 1990;155:1251-1255.

The patient has a dynamic varus deformity secondary to spasticity of the tibialis anterior during stance phase with inverter/everter imbalance. The patient still has active motion of the tibialis anterior; therefore, an out-of-phase posterior tibial tendon transfer should not be performed. The same is true of the Bridle procedure. Transfer of the posterior tibialis in this patient may also result in subsequent planovalgus deformity. Lengthening of the Achilles tendon through a percutaneous tenotomy will restore dorsiflexion and decrease clonus from the stretch response. If adequate dorsiflexion is not obtained intraoperatively, then posterior tibialis tendon lengthening may be considered. A split tibialis anterior tendon transfer to the lateral cuneiform, or, transfer of the entire tendon to the cuneiform should correct the varus component and compensate for the weakened peroneals. Yamamoto H, Okumura S, Morita S, et al: Surgical correction of foot deformities after stroke. Clin Orthop Relat Res 1992;282:213-218. Piazza SJ, Adamson RL, Moran MF, et al: Effects on tensioning errors in split transfers of tibialis anterior and posterior tendons. J Bone Joint Surg Am 2003;85:858-865.

It is important that the radii of a metal-on-metal head to cup articulation be such that there is polar contact. As the radii become closer to equal, conditions favor higher frictional torque and equatorial seizing. The "bedding in" of metal-on-metal surfaces and their stiffness are both components of the properties considered in the design of polar contact surfaces.

Bilateral flattening of the femoral heads suggests multiple epiphyseal dysplasia; therefore, a skeletal survey is indicated to look for involvement of other epiphyses. Unilateral flattening of the femoral head would suggest Legg-Perthes disease. Sponseller PD: Skeletal dysplasias, in Morrissy RT, Weinstein SL (eds): Lovell and Winter's Pediatric Orthopaedics, ed 5. Philadelphia, PA, Lippincott Williams & Wilkins, 2001, pp 269-270.

The patient has several indications that he is not ready for definitive fixation of the femoral shaft fracture at this point. He is cold with a core temperature of 93 degrees F, and hypothermia of less than 95 degrees F (35 degrees C) has been shown to be associated with an increased mortality rate in trauma patients. The patient has also not been resuscitated based on his increasing lactate levels and although controversial, it has been shown that temporary external fixation leads to a lower incidence of multiple organ failure and acute respiratory distress syndrome. Shafi S, Elliot AC, Gentilello L: Is hypothermia simply a marker of shock and injury severity or an independent risk factor for mortality in trauma patients? Analysis of a large national trauma registry. J Trauma 2005;59:1081-1085. Pape HC, Hildebrand F, Pertschy S, et al: Changes in the management of femoral shaft fractures in polytrauma patients: From early total care to damage control orthopedic surgery. J Trauma 2002;53:452-461.

The traditional treatment of a reduced type II fracture is a halo vest. A 20-year-old man will tolerate a halo vest better than the elderly or women. Anterior screw fixation has gained increasing support; however, it too has risks and requires a significant learning curve. More recently, C1 lateral mass screws have become more popular. The long-term results and benefits have not yet been determined. Spivak JM, Connolly PF (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, p 193. Kiovikko MP, Kiuru MJ, Koskinen SK, et al: Factors associated with nonunion in conservatively-treated type-II fractures of the odontoid process. J Bone Joint Surg Br 2004;86:1146-1151. Herkowitz HN, Garfin SR, Eismont FJ: Rothman-Simone The Spine, ed 5. Philadelphia, PA, Saunders Elsevier, 2006, p 1091.

The lunotriquetral interosseous ligament stabilizes the lunotriquetral joint. The scapholunate interosseous ligament stabilizes the scapholunate joint. The ulnolunate ligament originates from the base of the ulnar styloid and inserts in the lunate. The ulnotriquetral ligament originates from the base of the ulnar styloid and inserts on the triquetrum. The ulnolunate and the ulnotriquetral ligaments are important stabilizers to the ulnar side of the wrist. The short radiolunate ligament originates on the volar ulnar margin of the distal radius and inserts in the ulnar margin of the lunate. Berger RA: Ligament anatomy, in Cooney WP, Linscheid RL, Dobyns JH (eds): The Wrist, Diagnosis and Operative Management. St Louis, MO, Mosby, 1998, pp 73-105.

The posterior band of the inferior glenohumeral ligament is the most important restraint to posterior subluxation of the glenohumeral ligament with the shoulder in 90 degrees of flexion and internal rotation. With the shoulder in external rotation, the subscapularis is an important stabilizer to posterior subluxation. When the shoulder is in neutral rotation, the coracohumeral ligament is the primary stabilizer. The middle glenohumeral ligament functions primarily to resist anterior translation of the shoulder in the midrange of abduction. The supraspinatus muscle and tendon have relatively little contribution to anterior and posterior translation of the glenohumeral joint. Blasier RB, Soslowsky LJ, Malicky DM, Palmer ML: Posterior glenohumeral subluxation: Active and passive stabilization in a biomechanical model. J Bone Joint Surg Am 1997;79:433-440.

29b 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.

Once degenerative changes have occurred, soft-tissue procedures are not indicated. Triple arthrodesis is the treatment of choice for adult-acquired flatfoot. Isolated fusion of the subtalar or talonavicular joint will not be sufficient to correct the problem. Lutter LD, Mizel MS, Pfeffer GB (eds): Orthopaedic Knowledge Update: Foot and Ankle. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1994, pp 269-282.

The union rate for minimally displaced midthird scaphoid fractures is quite high with cast immobilization while allowing a return to sports. Inadequate immobilization results in a much higher nonunion rate. Early fixation and rehabilitation have been proposed for sports or positions that are not amenable to cast immobilization. While immobilization of a nondisplaced fracture results in an acceptably high union rate, there is no advantage to fixation in conjunction with immobilization in the course of healing. With adequate immobilization and protection, play restrictions until healing has occurred are unnecessary. Rettig AC, Kollias SC: Internal fixation of acute stable scaphoid fractures in the athlete. Am J Sports Med 1996;24:182-186. Rettig AC, Weidenbener EJ, Gloyeske R: Alternative management in midthird scaphoid fractures in the athlete. Am J Sports Med 1994;22:711-714.

The prevalence of postoperative ileus associated with total joint arthroplasty has been reported to be as high as 3%. Metabolic abnormalities such as hypokalemia are believed to contribute to the onset of ileus and Ogilvie's syndrome (acute pseudo-obstruction of the colon). Prolonged bed rest also has been associated with the development of ileus and Ogilvie's syndrome. Untreated Ogilvie's syndrome can result in cecal perforation. Ileus usually is not accompanied by mechanical obstruction. Antibiotic administration and the type of anesthesia used have not been correlated with development of ileus. Administration of warfarin has been associated with elevated prothrombin time/partial thromboplastin time and international normalized ratio levels when ileus is managed with a nasogastric tube and suction. Metabolic imbalances must be corrected to reverse the ileus process. Iorio R, Healy WL, Appleby D: The association of excessive warfarin anticoagulation and postoperative ileus after total joint replacement surgery. J Arthroplasty 2000;15:220-223.

The patient has symptomatic postoperative heterotopic ossification after total hip arthroplasty. Postoperative prophylactic treatments include nonsteroidal anti-inflammatory drugs (usually indomethacin) or low-dose irradiation. The heterotopic ossification shown here is quite mature; therefore, nonsurgical management will not be successful. Surgical excision of grade III or IV heterotopic ossification should be followed with postoperative irradiation to minimize the chances of recurrence. Ayers DC, Evarts CM, Parkinson JR: The prevention of heterotopic ossification in high-risk patients by low-dose radiation therapy after total hip arthroplasty. J Bone Joint Surg Am 1986;68:1423-1430.

45b 45c The elongated anterior process of the calcaneus reaching distally toward the navicular is an abnormal finding. Instead of viewing the rounded, blunt distal anterior process of the calcaneus, a bridge extends to the navicular, albeit incomplete. These findings are consistent with a fibrous coalition. CT can reveal a stress fracture of the calcaneus, arthritis of the subtalar joint with subchondral cysts, or an os peroneal bone disruption in the peroneus longus, but those entities are not shown here. The plantar fascia is intact. Richardson EG: Sesamoids and accessory bones of the foot, in Coughlin MJ, Mann RA (eds): Surgery of the Foot and Ankle, ed 7. St Louis, MO, Mosby, 1999, pp 702-732.

The radioscaphocapitate ligament is the most radial of the extrinsic volar ligaments of the wrist. It has a mean attachment to the radius 4 mm from the tip of the radial styloid. Nakamura T, Cooney WP III, Lui WH, et al: Radial styloidectomy: A biomechanical study on the stability of the wrist joint. J Hand Surg Am 2001;26:85-93.

The athlete has symptoms referable to the axillary, musculocutaneous, and suprascapular nerves resulting from an injury to the upper trunk of the brachial plexus. This portion of the plexus is formed by contributions of the fourth through sixth cervical nerve roots. This area is often contused or stretched following a tackling maneuver that results in either depression of the shoulder from contact at Erb's point or traction of the upper plexus from forced stretching of the neck to the contralateral side. Schenck CD: Anatomy of the innervation of the upper extremity, in Torg JS (ed): Athletic Injuries to the Head, Neck, and Face, ed 2. St Louis, MO, Mosby-Year Book, 1991.

The patient has an AP I pelvic ring disruption with minimal symphyseal widening. The best treatment is nonsurgical management and weight bearing as tolerated. This will help close the anterior pelvic ring during the healing process. Pelvic binders are excellent for acute treatment of widely displaced pelvic fractures but are not recommended for long-term use. Open reduction and internal fixation is not indicated for this injury and furthermore, the posterior ring is not injured. Matta JM: Indications for anterior fixation of pelvic fractures. Clin Orthop Relat Res 1996;329:88-96. Templeman DC, Schmidt AH, Sems SA, et al: Diastasis of the symphysis pubis: Open reduction internal fixation, in Wiss D (ed): Masters Techniques in Orthopaedic Surgery-Fractures, ed 2. Philadelphia, PA, Lippincott Williams and Wilkins, 2006, pp 639-648.

A common side effect of interscalene nerve block for shoulder surgery is the blockade of the ipsilateral phrenic nerve. This, in turn, results in paresis of the diaphragm and up to a 30% reduction in pulmonary function volumes. Therefore, interscalene nerve block generally is not recommended for patients whose respiratory function is compromised. Other relative and absolute contraindications for interscalene nerve blocks include allergy to local anesthetics, infection at the injection site, uncontrolled seizure disorder, coagulation abnormality, and preexisting neurologic injury. Chelly JE: Indications for upper extremity blocks, in Chelly JE (ed): Peripheral Nerve Blocks, ed 2. Philadelphia, PA, Lippincott Williams & Wilkins, 2004, pp 19-27.

It is critical to withhold active range of motion of the shoulder within the first 6 weeks after arthroplasty for acute fracture to prevent tuberosity avulsion. When radiographic and clinical findings show that the tuberosities are healed, active motion may be instituted, usually at 6 to 8 weeks. Immediate passive range-of-motion exercises, including external rotation with a stick, pendulum, and passive elevation, should begin within the limits of the repair on the day of surgery to prevent stiffness. Hartstock LA, Estes WJ, Murray CA, et al: Shoulder hemiarthroplasty for proximal humerus fractures. Orthop Clin North Am 1998;29:467-475.

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.

When a lateral condylectomy alone is performed for all bunionette deformities, a high recurrence rate is expected. Lateral condylectomy should be used alone when the primary deformity is an enlarged lateral condyle of the fifth metatarsal head. In cases with significant divergence of the fifth metatarsal shaft in relationship to the fourth metatarsal shaft or with lateral bowing of the distal fifth metatarsal shaft, the lateral fifth metatarsal prominence will not be effectively reduced and recurrent symptoms and deformity are expected. Transfer metatarsalgia and/or dislocation of the metatarsophalangeal joint can infrequently occur with excessive metatarsal head excision. Arthrosis of the metatarsophalangeal joint has not been frequently reported. Coughlin MJ, Mann RA: Keratotic disorders of the plantar skin, in Coughlin MJ, Mann RA (eds): Surgery of the Foot and Ankle, ed 6. St Louis, MO, Mosby-Year Book, 1993, pp 413-465. Kelikian H: Deformities of the lesser toe, in Kelikian H (ed): Hallux Valgus, Allied Deformities of the Forefoot and Metatarsalgia. Philadelphia, PA, WB Saunders, 1965, pp 327-330.

The patient has an oligotrophic nonunion of the distal femoral fracture. Although the proximal fracture appears incompletely united, it was stable at exchange nailing. The treatment of choice is exchange reamed nailing to at least 2 mm above the nail in place. Bone grafting is debatable. Recent studies have shown a 70% to 75% success rate with exchange nailing only, so in nonhypertrophic nonunions, bone grafting can be considered. Nonsurgical management consisting of observation or external stimulation runs the risk of implant failure. Plate fixation is acceptable but is considered a second choice because of the need to consider stabilization of the proximal fracture until union is achieved. Also, plate fixation definitely requires bone grafting. Webb LX, Winquist RA, Hansen ST: Intramedullary nailing and reaming for delayed union or nonunion of the femoral shaft: A report of 105 consecutive cases. Clin Orthop 1986;212:133-141. Weresh MJ, Hakanson R, Stover MD, et al: Failure of exchange reamed intramedullary nailing for ununited femoral shaft fractures. J Orthop Trauma 2000;14:335-338.

13b 13c 13d 13e The patient has an isthmic spondylolysis. The plain radiographs are normal, but the MRI scans show increased marrow edema and signal at the L5 pars interarticularis. Findings of bilateral hamstring tightness and increased pain with extension over flexion suggests spondylolysis. The MRI scans do not show any signs of the other conditions. Wiltse LL, Rothman SL: Spondylolisthesis: Classification, diagnosis and natural history. Sem Spine Surg 1993;5:264-280.

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.

Only three thromboembolic treatment protocols have reached Grade 1A status for the American College of Chest Physicians Guidelines for thromboembolic prophylaxis after total hip arthroplasty and total knee arthroplasty. Grade 1A evidence shows a clear benefit/risk improvement with supportive data from randomized clinical trials, which are strongly applicable in most clinical circumstances. Warfarin is recommended but at an INR level of 2 to 3. Low-molecular-weight heparin and fondaparinox are also acceptable treatment options. Aspirin, adjusted dose unfractionated heparin, and elastic compressive stockings are not recommended as stand-alone options. Colwell C: Evidence based guidelines for prevention of venous thromboembolism: Symposia. Proceedings of the 2005 AAOS Annual Meeting. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2005, pp 15-18.

Shock can be defined as inadequate tissue perfusion. Resuscitation or the resolution of shock is defined as when oxygen debt has been repaid, tissue acidosis is eliminated, and aerobic metabolism has been restored in all tissue beds. The end points for resuscitation are not clearly defined, but occult shock can still be present in the setting of normal vital signs and normal urine output due to selective perfusion of organ systems. Tisherman SA, Barie P, Bokhari F, et al: Clinical practice guideline: End point of resuscitation. J Trauma 2004;57:898-912. Moore FA, McKinley BA, Moore EE, et al: Inflammation and the Host Response to Injury, a large-scale collaborative project: Patient-oriented research core--standard operating procedures for clinical care. III. Guidelines for shock resuscitation. J Trauma 2006;61:82-89.

The most reliable test for a relatively isolated posterolateral complex (PLC) injury is the asymmetric tibial external rotation or "dial test." It can be performed with the patient prone or supine. When greater than 10 degrees of external rotation at 30 degrees of flexion is present when compared with the opposite knee, it indicates significant damage to the posterolateral structures. Asymmetric external rotation, which is also present at 90 degrees of flexion, indicates injury to the posterior cruciate ligament (PCL) as well. Varus laxity may indicate significant damage to both the PLC and PCL. Approximately 35% of the normal population may have a reverse pivot shift when examined under anesthesia; therefore, it is considered a less specific test. The external rotation/recurvatum and posterolateral drawer tests are adjunctive in assessing isolated posterolateral laxity but are not thought to be as reliable. Veltri DM, Warren RF: Isolated and combined posterior cruciate injuries. J Am Acad Orthop Surg 1993;1:67-75.

The history and examination findings suggest an acute fracture of the hook of the hamate. The radiographic study considered most helpful in identifying this type of fracture is the carpal tunnel view. PA and lateral views of the wrist will not adequately visualize the hook of the hamate. Bruerton's view is intended for the assessment of the metacarpophalangeal joints. Pathology would not be suspected in the scaphoid, metacarpals, or the phalanges, so the scaphoid view and the PA, lateral, and oblique views of the hand would not be helpful. Green DP, Hotchkiss RN, Pederson WC (eds): Operative Hand Surgery, ed 4. New York, NY, Churchill Livingstone, 1999, p 855.

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.

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.

The magnitudes of out-of-plane loads on a total hip replacement during activities of daily living can be substantial. Bergmann and associates studied these forces about two instrumented hip prostheses. They noted that the torsional moment about the hip during stair climbing is twice as high as during slow walking and that similar moments are generated during slow jogging. Higher loads were noted when the patients stumbled without falling. They also noted that the torsional moments observed in vivo were close to or even exceeded the experimentally determined limits of the torsional strength of implant fixations. Hurwitz DE, Andriacchi TP: Biomechanics of the hip, in Callaghan JJ, Rosenberg AG, Rubash HE (eds): The Adult Hip. Philadelphia, PA, Lippincott Raven, 1998, pp 75-85.

26b 26c The mechanism of injury, physical examination, and radiographs indicate a "high" ankle sprain with disruption of the distal tibiofibular ligaments and interosseous membrane. These injuries typically involve pronation and external rotation forces. In addition, recovery is significantly delayed, often requiring 6 to 8 weeks to heal. Radiographs obtained months after recovery often show calcification within the distal syndesmosis, which is not typically symptomatic. This patient has gross instability, resulting in a high incidence of chronic diastasis and subluxation leading to impaired function. Treatment should consist of reduction and stabilization with a transsyndesmotic screw because this injury demonstrates a widened syndesmosis. Boytim MJ, Fisher DA, Neumann L: Syndesmotic ankle sprains. Am J Sports Med 1991;19:294-298.

Astion and associates analyzed 23 acetabular components, out of a total of 173 implanted, that had failed because of either migration or severe osteolysis. The radiographic appearance of osteolysis was positively associated with the duration that the implant had been in situ. The prevalence of osteolysis was also significantly greater in acetabular components with an outer diameter of 55 mm or less (a polyethylene thickness of 8.5 mm or less). Thirteen of the 23 components were revised at a mean of 70 months after the index operation. Examination of the retrieved acetabular components revealed extensive polyethylene damage on the articular and back surfaces of the liners. Cracks in the polyethylene rim of the liner and deformation of the antirotation notch in the polyethylene rim were common findings. The density of the polyethylene was greater than expected, and more particles than anticipated had not fused with the surrounding polyethylene. Factors related to both the design and the material contributed to the failure of these porous-coated anatomic acetabular components.

Using mechanical failure of fixation as the end point, Udomkiat and associates demonstrated a 12-year survivorship of 99.1% for titanium press-fit acetabular components without supplementary screw fixation. This study suggests that it is unlikely that the use of supplementary screws would lead to improved results. In addition, polyethylene wear debris tends to migrate through screw holes and along the course of screws. Screw holes also decrease the available surface for bone ingrowth. Screws that back up may be a source of backside polyethylene wear. This suggests that screw holes and the use of screws should be avoided when they are unnecessary for cup fixation.

Proximal humeral fractures in children are classified as metaphyseal or Salter-Harris type I or II fractures, and most of these fractures are treated with closed methods. Eighty percent of the growth of the humerus comes from the proximal physis; therefore, tremendous remodeling potential is present. Indications for open reduction include open fractures or severely displaced fractures in adolescents with minimal growth remaining. Acceptable limits of reduction in adolescent proximal humeral fractures include bayonet apposition and angulation of less than 35 degrees. Common blocks to reduction in adolescents include the biceps tendon and periosteum. For this fracture, use of a shoulder sling without reduction will lead to healing and an excellent result as the proximal humerus remodels. Kohler R, Trillaud JM: Fracture and fracture separation of the proximal humerus in children: Report of 136 cases. J Pediatr Orthop 1983;3:326-332. Beaty JH: Fractures of the proximal humerus and shaft in children. Instr Course Lect 1992;41:369-372. Dobbs MB, Luhmann SL, Gordon JE, et al: Severely displaced proximal humeral epiphyseal fractures. J Pediatr Orthop 2003;23:208-215. Beringer DC, Weiner DS, Noble JS, et al: Severely displaced proximal humeral epiphyseal fractures: A follow-up study. J Pediatr Orthop 1998;18:31-37.

The patient has sacral agenesis. Clinical signs include the classic dimpling over the buttocks and the characteristic lower extremity deformities. Imperforate anus is often associated with this disorder. Although motor function correlates with the level of vertebral defect, sensation is usually intact. This is important therapeutically, because patients are not as prone to pressure sores as are those with myelodysplasia. Kyphosis may develop in many patients with lumbosacral agenesis, but lordosis is unusual. Latex allergy and progressive neural deterioration may occur in patients with either myelodysplasia or sacral agenesis but is more common in the former.

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.

An os trigonum is usually asymptomatic, but this accessory bone has been associated with persistent posterior ankle pain, which has been described as os trigonum syndrome. This usually affects athletes and ballerinas. Forced plantar flexion leads to impingement of the os trigonum against the posterior tibial plafond, and flexor hallucis tendinitis may develop. It may be difficult to differentiate a fractured trigonal process from the os trigonum. MRI may reveal bone marrow edema that may aid in the diagnosis of os trigonum syndrome. Steroid injections may lead to tendon rupture. The results of excision of a symptomatic os trigonum through a posteromedial or lateral approach are favorable, with a rapid return to full function. The main complication of this procedure is sural nerve injury with a lateral approach. Hedrick MR, McBryde AM: Posterior ankle impingement. Foot Ankle Int 1994;15:2-8.

The incidence of recurrent disk herniation after a successful diskectomy is approximately 5% to 10%. Indications for surgical diskectomy for a recurrence are the same as for a primary diskectomy. Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 685-698.

The correct decision on return to sports participation after episodes of transient quadraparesis is controversial. Cantu and Mueller feel strongly that the loss of cerebrospinal fluid space about the spinal cord signifies an unacceptable risk for future spinal cord injury if the athlete returns to sports. However, Watkins and Torg and Lasgow have reported no evidence of increased spinal cord injury in athletes with narrow spinal canals, even in football. These authors suggest judgment be used in advising return to contact or high-energy sports and that the physician's responsibility is to give accurate and relevant information, allowing the athlete to make his or her own choice regarding return to sports participation. Cantu R, Mueller FO: Catastrophic spine injuries in football (1977-1989). J Spinal Disord 1990;3:227-231. Watkins RG: Neck injuries in football players. Clin Sports Med 1986;5:215-246. Torg JS, Lasgow SG: Criteria for return to contact activities following cervical spine injury. Clin Sports Med 1991;1:12-26.

The median nerve courses superficial to the ulnar artery, deep to the fibrous arch of the superficialis muscle, and deep to the superficial head of the pronator teres muscle. The median nerve lies within the interval between the flexor digitorum superficialis muscle and the flexor digitorium muscle as it progresses toward the wrist. Hoppenfeld S, deBoer P: Surgical Exposures in Orthopaedics, ed 2. Philadelphia, PA, Lippincott-Raven, 1994, pp 118-131.

32b 32c The incidence of osteonecrosis following displaced talar neck fractures is most related to the extent of initial fracture displacement. With increasing fracture displacement, the tenuous vascular supply to the talar body is more at risk for damage, thereby increasing the risk of osteonecrosis. Although displaced talar neck fractures have historically been considered a surgical emergency, recent studies have shown that the timing of surgical intervention bears no impact on the development of osteonecrosis. While nicotine use has an influence on fracture healing, it has never been shown to be a factor in osteonecrosis, nor has posterior-to-anterior screw fixation or the quality of fracture reduction. Lindvall E, Haidukewych G, Dipasquale T, et al: Open reduction and stable fixation of isolated, displaced talar neck and body fractures. J Bone Joint Surg Am 2004;86:2229-2234.

The most common bone tumor in the hand is an enchondroma. Forty-two percent of these lesions occur in the small tubular bones. They frequently present with a fracture in these locations. Fractures are usually treated nonsurgically. Indications for surgery include patients with symptomatic lesions or those who are considered high risk for recurrent fracture. The histologic appearance of an enchondroma in the hand is more cellular than enchondromas found in the long bones. Menendez LR (ed): Orthopaedic Knowledge Update: Musculoskeletal Tumors. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, p 103.

Teres minor originates from the middle third of the dorsal surface of the lateral border of the scapula. It is supplied by the axillary nerve (C5). Williams PL, Warwick R, Dyson M, Bannister LH: Myology, in Gray's Anatomy, ed 37. Edinburgh, Scotland, Churchill Livingstone, 1989, pp 611-615.

Dynamic midfoot supination that is the result of peroneal weakness is a common residual problem after cast correction or surgical reconstruction of a congenital idiopathic clubfoot. Dynamic supination is unlikely to resolve spontaneously. Most parents do not want to use brace support forever. Transfer of the posterior tibialis to the dorsum of the foot has shown poor results in clubfeet. Preferred treatments include: 1) transfer of the entire anterior tibialis tendon to the lateral cuneiform, or 2) split transfer of the anterior tibialis tendon to the cuboid or to the peroneus brevis tendon. Kuo KN, Hennigan SP, Hastings ME: Anterior tibial tendon transfer in residual dynamic clubfoot deformity. J Pediatr Orthop 2001;21:35-41. Garceau GJ: Anterior tibial tendon transfer for recurrent clubfoot. Clin Orthop 1972;84:61-65.

Loss of external rotation can lead to degenerative joint disease following an anterior stabilization procedure. A tight anterior capsule will prevent internal impingement. Risk of thoracic outlet syndrome should not be increased. Subscapularis detachment is a risk following open anterior repair; however, a gain in external rotation would be noted. In time, this patient's shoulder may show increased posterior glenohumeral wear but should not have symptoms of recurrent subluxation unless multidirectional instability is present. Hawkins RJ, Angelo RL: Glenohumeral osteoarthrosis: A late complication of the Putti-Platt repair. J Bone Joint Surg Am 1990;72:1193-1197.

Acetaminophen inhibits prostaglandin E2 production via IL-1 B, without affecting cyclooxygenase-2 enzymatic activity. The therapeutic concentrations of acetaminophen induce an inhibition of IL-1 B-dependent NF-kappa B nuclear translocation. The selectivity of this effect suggests the existence of an acetaminophen-specific activity at the transcriptional level that may be one of the mechanisms through which the drug exerts its pharmacologic effects. Acetaminophen does not affect any of the other enzymes named above.

Migration of total hip femoral components has been measured by RSA, a technique that affords accuracy of 2 degrees and 0.5 mm. Several published studies on total hip arthroplasty femoral components have established the importance of this technique. Both cemented and cementless components migrate, with the rate of migration suggesting the adequacy of fixation of a component. Migration of 1 mm to 2 mm (occurring in either the varus-coronal plane and retroversion-transverse plane, or both) has been associated with a higher risk of loosening of the component.

The most common finding at exploration of an inappropriately placed pedicle screw is displacement of the nerve. Pedicle breach is common, ranging from 2% to 20%, but most are asymptomatic. All of the choices are possible, but in a large series conducted by Lonstein and associates, the authors reported that displacement of the root, most often medial, was the most common finding. Laceration, contusion, or transfixion usually was not seen. Spinal fluid leakage occurs less frequently and is not expected in the minimal broach illustrated. Esses SI, Sachs BL, Dreyzin V: Complications associated with the technique of pedicle screw fixation: A selected survey of ABS members. Spine 1993;18:2231-2238. Laine T, Lund T, Ylikoski M, et al: Accuracy of pedicle screw insertion with and without computer assistance: A randomised controlled clinical study in 100 consecutive patients. Eur Spine J 2000;9:235-240.

The elbow dislocates by a three-dimensional movement of supination and valgus during flexion. Additional trauma during reduction is minimized by recreating the deformity and reducing the elbow in supination. The actual maneuver includes full supination (actually hypersupination) of the elbow in a valgus position. This is followed by pushing the olecranon distally in line with the long axis of the ulna while swinging the elbow into varus, and then relaxing the supination torque. Postreduction stability is enhanced in pronation, except when the soft-tissue disruption is extensive. O'Driscoll SW: Elbow dislocations, in Morrey BF (ed): The Elbow and Its Disorders, ed 2. Philadelphia, PA, WB Saunders, 1993, p 414.

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been shown to increase the risk of pseudarthrosis. In a controlled rabbit study, nonunions were reported with the use of toradol and indomethacin. NSAIDs are commonly used medications with the potential to diminish osteogenesis. Studies clearly have demonstrated inhibition of spinal fusion following the postoperative administration of several NSAIDs, including ibuprofen. Cigarette smoking is another potent inhibitor of spinal fusion. Glassman SD, Rose SM, Dimar JR, et al: The effect of postoperative nonsteroidal anti-inflammatory drug administration on spinal fusion. Spine 1998;23:834-838.

The treatment of choice for pelvic chondrosarcoma is wide resection via an internal hemipelvectomy. Chondrosarcoma requires surgical resection for control and does not respond to traditional chemotherapy or external beam radiation. Hip arthroplasty with acetabular reconstruction and curettage and cementation of the lesion are intralesional procedures that result in a higher incidence of local recurrence of tumor. Pring M, Weber KL, Unni K, Sim FH: Chondrosarcoma of the pelvis: A review of sixty-four cases. J Bone Joint Surg Am 2001;83:1630-1642.

1b 1c 1d 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 patient has a subperiosteal abscess. Because aspiration revealed 10 mL of purulent fluid, the treatment of choice is surgical incision and drainage of the abscess, followed by immobilization to reduce the risk of pathologic fracture. With an adequate response to IV antibiotics and a susceptible bacteria, the patient may then be switched to oral antibiotics.

Arthrodesis of the talonavicular joint eliminates almost all hindfoot motion. Arthrodesis of the subtalar joint eliminates 74% of talonavicular motion and 44% of calcaneocuboid motion. Arthrodesis of the calcaneocuboid joint eliminates 33% of talonavicular motion and 8% of subtalar motion. Arthrodesis of the naviculocuneiform or cuboid-fifth metatarsal joint has limited effect on hindfoot motion. Astion DJ, Deland JT, Otis JC, et al: Motion of the hindfoot after simulated arthrodesis. J Bone Joint Surg Am 1997;79:241-246.

The most common location for soft-tissue tumors to metastasize is the lungs. Depending on the grade of the sarcoma, metastases develop in as many as 50% of patients with soft-tissue sarcomas. Tumor grade is considered the most significant prognostic factor in predicting risk of metastases, with high-grade lesions at greatest risk. Staging CT of the chest should be performed once the diagnosis of a soft-tissue sarcoma is suspected or confirmed. Regular surveillance of patients treated for soft-tissue sarcomas includes follow-up CT scans at regular intervals. Intra-abdominal metastases are uncommon but may occur, particularly in patients with myxoid liposarcoma. Regional metastases are relatively uncommon and occur in approximately 5% of all patients with soft-tissue sarcoma. The incidence of regional nodal metastases is higher for synovial sarcoma and epithelioid sarcomas than other soft-tissue sarcomas. Sim FH, Frassica FJ, Frassica DA: Soft-tissue tumors: Diagnosis, evaluation, and management. J Am Acad Orthop Surg 1994;2:202-211.

Plexiform neurofibromas are lesions found in patients with NF1. Clinical reports show the prevalence of plexiform neurofibroma to be 20% to 30% but increases to 40% when imaging studies are routinely obtained. The lesions are characterized by diffuse hypertrophy of the involved nerves but with preservation of the nerves' fascicular organization. The lesions may involve the dermis or may arise in the deeper structures. Palpation of a dermal lesion provokes an image of a "bag of worms." Plexiform neurofibromas may cause disfigurement and hyperpigmentation of the overlying skin. The lesions also can cause diffuse hypertrophy of the soft tissue and bone, with resultant changes ranging from a relatively minor limb-length discrepancy to gigantism of the entire extremity. Dural ectasia is frequently found in patients with NF1. Therefore, MRI should be obtained prior to planning spinal procedures in these patients; however, dural ectasia is not the cause of limb overgrowth. Lisch nodules are benign hamartomas of the iris. The lesions are uncommon during early childhood but are found in all adults with NF1. Juvenile xanthogranuloma has a low occurrence rate in patients with NF1; its presence is associated with juvenile chronic myeloid leukemia. Malignant peripheral nerve sheath tumors, formally called neurofibrosarcoma, result from malignant degeneration of a plexiform neurofibroma. This condition occurs in up to 4% of patients with NF1. Localized pain, an enlarging mass, or progressive neurologic symptoms suggest a malignant peripheral nerve sheath tumor in a patient with NF1. However, progressive neurologic symptoms also may occur with benign growth of a plexiform neurofibroma. Alman BA, Goldberg MJ: Syndromes of orthopaedic importance, in Morrissy RT, Weinstein SL (eds): Lovell and Winter's Pediatric Orthopaedics, ed 5. Philadelphia, PA, Lippincott Williams and Wilkins, 2001, pp 287-338.