100 Orthopedic MCQs: Trauma, Spine, Sports & Adult Recon | Comprehensive ABOS Board Review Mock Exam

The most predictable positive outcome from spinal surgery due to a cauda equina syndrome is early surgical intervention before any significant neurologic deficit develops. Meta-analysis studies demonstrate that surgical intervention more than 48 hours after the onset of cauda equina syndrome show an increased risk for poor outcomes. Ahn UM, Ahn NU, Buchowski JM, et al: Cauda equina syndrome secondary to lumbar disc herniation: A meta-analysis of surgical outcomes. Spine 2000;25:1515-1522.

Arthroscopic capsular release is an effective means of treating stiffness that is the result of capsular contractures, such as in the case of a tight Bankart repair. Open release allows lengthening of a surgically shortened subscapularis, such as after a tight Putti-Platt repair. Additional physical therapy is unlikely to be effective because 8 months of treatment has failed to result in improvement. Accepting this degree of asymptomatic limited motion is not advisable because of the functional limitations for the patient and the increased risk of postoperative degenerative arthritis. Warner JJ, Allen AA, Marks PH, Wong P: Arthroscopic release of postoperative capsular contracture of the shoulder. J Bone Joint Surg Am 1997;79:1151-1158.

The radiographs do not show significant arthrosis of the hallux metatarsophalangeal joint; therefore, arthrodesis is unnecessary. Orthotics will not correct the deformity. A distally based osteotomy will not achieve sufficient correction of the incongruity of deformity, and a Keller resection is not indicated in the younger population. The treatment of choice is a proximal metatarsal osteotomy with second toe correction.

The gradient-echo MRI scan highlights the ulnar and radial arteries, as indicated by the arrow. This technique suppresses the signal of the surrounding fat and causes the stationary surrounding tissues to become intermediate in signal intensity. The flowing blood is then easily identified with a bright signal because it does not absorb the radiofrequency pulse. Based on the findings, the diagnosis is an ulnar artery aneurysm, most likely caused by years of repetitive trauma as the result of catching baseballs. Neurolemmoma and giant cell tumor of the tendon sheath would be intermediately enhanced on this image sequence, and the continuity with the ulnar artery, demonstrated here, would not be expected. Lipomas are not enhanced using the gradient-echo technique. The chronic nature of the patient's symptoms is not indicative of a hematoma, and the hematoma would be dark on this imaging sequence since it is stationary tissue. Koman LA, Ruch DS, Patterson Smith B, et al: Vascular disorders, in Green DP, Hotchkiss RN, Pederson WC (eds): Green's Operative Hand Surgery, ed 4. New York, NY, Churchill Livingstone, 1999, vol 2, pp 2254-2302.

Excessive hindfoot valgus can lead to abutment between the calcaneus and fibula. This valgus force can lead to a stress fracture of the distal fibula. Surgery may be required if an insufficiency fracture recurs despite orthotic management. Of the choices listed, a subtalar arthrodesis is most likely to achieve rebalancing of the foot at the level of the deformity. Stephens HM, Walling AK, Solmen JD, Tankson CJ: Subtalar repositional arthrodesis for adult acquired flatfoot. Clin Orthop 1999;365:69-73

The patient has an acute fracture of the proximal pole. A 100% healing rate has been reported for open reduction and internal fixation of proximal pole fractures via a dorsal approach. This allows for direct viewing of the fracture line, facilitates reduction, and bone grafting can be done through the same incision if necessary. A vascularized or corticocancellous graft is reserved for nonunions. Proximal fractures are very slow to heal with a cast, if they heal at all. As a small fragment, percutaneous fixation is very difficult and has been reported for waist fractures. Rettig ME, Raskin KB: Retrograde compression screw fixation of acute proximal pole scaphoid fractures. J Hand Surg Am 1999;24:1206-1210.

Rheumatoid arthritis (RA) is a complex multisystem disorder. It has been suggested that patients with RA have an impaired capacity to control infection with Epstein-Barr virus. Epstein-Barr virus has oncogenic potential and is implicated in the development of some lymphomas. Recent publications provide evidence for an altered Epstein-Barr virus-host balance in patients with RA who have a relatively high Epstein-Barr virus load. Large epidemiologic studies confirm that lymphoma is more likely to develop in patients with RA than in the general population. The overall risk of development of lymphoma has not risen with the increased use of methotrexate or biologic agents. Histologic analysis reveals that most lymphomas in patients with RA are diffuse large B cell lymphomas, a form of non-Hodgkin lymphoma. Epstein-Barr virus is detected in a proportion of these. Patients with RA do not have prevalence for infection with any of the other mentioned viruses. Callan MF: Epstein-Barr virus, arthritis, and the development of lymphoma in arthritis patients. Curr Opin Rheumatol 2004;16:399-405.

Rejecting this proposal is the only appropriate course of action. Accepting it would, in essence, be receiving a huge gift from industry in the form of a sailboat. Physicians frequently assert that they are not influenced by gifts and relationships with industry representatives, but evidence is to the contrary. Such an arrangement constitutes a tremendous incentive to use the manufacturer's products. The fact that the boat partnership seems completely outside of the orthopaedic business relationship does not excuse it. Conflicts of interest should always be resolved and in the best interest of patient care, and in this case the best course clearly is to avoid the conflict of interest totally. An equal interest in the boat does not eliminate the conflict of interest. AAOS Standard of Professionalism -Orthopaedist -Industry Conflict of Interest (Adopted 4/18/07), Mandatory Standard numbers 6-8. www3.aaos.org/member/profcomp/SOPConflictsIndustry.pdf Opinions on Ethics and Professionalism: The Orthopaedic Surgeon's Relationship with Industry (Document 1204), in Guide to the Ethical Practice of Orthopaedic Surgery, ed 7. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2007, pp 36-40. www.aaos.org/about/papers/ethics/1204eth.asp AdvaMed Code of Ethics on Interactions with Health Care Professionals, Advanced Medical Technology Association, Washington, DC. www.AdvaMed.org

Neurologic injury after shoulder replacement is relatively uncommon, occurring in 4% of shoulders in one large series. The importance of identifying and protecting the musculocutaneous and axillary nerves cannot be overemphasized; it is especially critical during revision arthroplasty when the normal anatomic relationships have been distorted. The long deltopectoral approach leaving the deltoid attached to the clavicle was found to be significant in the development of postoperative neurologic complications. A correlation was found between surgical time and postoperative neurologic complications, with long surgical times being associated with more neurologic complications. The presumed mechanism of injury is traction on the plexus that occurs during the surgery. A neurologic injury after total shoulder arthroplasty usually does not interfere with the long-term outcome of the arthroplasty itself; it is best managed by protective measures with passive range of motion of the involved extremity. Wirth MA, Rockwood CA Jr: Complications of shoulder arthroplasty. Clin Orthop 1994;307:47-69.

In children, the main route of infection in skeletal TB is through hematogenous spread from a primary source. The mycobacterium is deposited in the end arterials in the vertebral body adjacent to the anterior aspect of the vertebral end plate. Thus, the anterior portion of the vertebral body is most commonly involved. The lower thoracic region is the most common segment; next in decreasing order of frequency are the lumbar, upper thoracic, cervical, and sacral regions. Teo HE, Peh WC: Skeletal tuberculosis in children. Pediatric Radiol 2004;34:853-860.

The radial head is an important secondary stabilizer of the elbow, helping to resist valgus forces. There has been a movement toward open reduction and internal fixation of the radial head when technically feasible, especially in a relatively high-demand athlete or laborer. The examination and radiograph suggest that displacement of the fragment is great enough to create a mechanical block. Extended splinting would only serve to encourage arthrofibrosis. Early range of motion is appropriate if there is minimal displacement of the radial head fragement, it is stable, and there is no mechanical block to motion. Fragments larger than one third of the joint surface should be excised only if it is not possible to reduce and repair the fragment. Primary excision of the radial head should be avoided if possible. Complications after excision of the radial head include muscle weakness, wrist pain, valgus elbow instability, heterotopic ossification, and arthritis. Hotchkiss RN: Displaced fractures of the radial head: Internal fixation or excision? J Am Acad Orthop Surg 1997;5:1-10.

The patient has a scaphoid fracture with cystic resorption of the distal aspect of the midthird of the scaphoid. This fracture is unlikely to heal without intervention. Percutaneous pinning, closed manipulation, and bone grafting will not restore alignment. Treatment requires restoration of scaphoid length, bone grafting, and internal fixation to obtain healing with normal alignment. Cooney WP, Linscheid RL, Dobyns JH, Wood MB: Scaphoid nonunion: Role of anterior interpositional bone grafts. J Hand Surg Am 1988;13:635-650. Fernandez DL: A technique for anterior wedge-shaped grafts for scaphoid nonunions with carpal instability. J Hand Surg Am 1984;9:733-737. Stark HH, Rickard TA, Zemel NP, Ashworth CR: Treatment of ununited fractures of the scaphoid by illiac bone grafts and Kirschner-wire fixation. J Bone Joint Surg Am 1988;70:982-991.

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.

The primary carcinoma most likely to metastasize distal to the elbow and knees is lung carcinoma. Renal cell carcinoma can also metastasize to distal sites. Most metastatic bone disease occurs in the vertebral bodies, pelvis, and proximal long bones. Simon MA, Bartucci EJ: The search for the primary tumor in patients with skeletal metastases of unknown origin. Cancer 1986;58:1088-1095.

Ganglion cysts are the most common mass or mass-like lesions seen in the hand and wrist. They arise in a variety of locations, including synovial joints or tendon sheaths. The most common location is the dorsal/radial wrist arising from the dorsal scapholunate interosseous ligament.

The radiographs show classic hinge abduction. The diagnostic feature is the failure of the lateral epiphysis to slide under the acetabular edge with abduction, and the abduction view shows medial dye pooling because of distraction of the hip joint. Persistent hinge abduction has been shown to prevent femoral head remodeling by the acetabulum. Radiographic changes are characteristic of severe involvement with Legg-Calve-Perthes disease.The Catterall classification cannot be well applied without a lateral radiograph, but this degree of involvement would likely be considered a grade III or IV. Because the lateral pillar is involved, this condition would be classified as type C using the Herring lateral pillar classification scheme.

The radiograph shows that the two-level anterior cervical diskectomy and fusion has healed. In addition, the patient has good range of motion and the neurologic examination is normal. Based on these findings, the patient can return to play immediately. Patients with one- or two-level anterior cervical diskectomies and fusions that have healed fully can return to play. Any loss of motion, persistent neurologic deficit, or significant adjacent segment degeneration may preclude a player from returning. Thomas B, McCullen GM, Yuan HA: Cervical spine injuries in football players. J Am Acad Orthop Surg 1999;7:338-347.

The images reveal a region of increased signal within the rectus femoris muscle with mild, ill-defined surrounding edema. The presence of high intensity signal on the T1-weighted image favors acute blood, in this case associated with a rectus femoris muscle tear or fatty tissue. However, because of fat suppression, a fatty lesion or lipoma would be dark on STIR, rather than bright as in this image. Most foreign bodies are low intensity signal and if small, are difficult to evaluate with MRI. The lack of adjacent subcutaneous soft-tissue edema or surrounding fluid makes pyomyositis an unlikely diagnosis.

The radiograph reveals destruction of the femoral head with loss of the articular cartilage. These findings are consistent with an infected hip, and aspiration will confirm the diagnosis. Although the patient could have advanced osteonecrosis, typically the cartilage interval is maintained and such destruction is rarely associated with osteonecrosis.

In examining a traditional Muslim woman, a male physician should have another woman present, and the patient's husband, if possible. Only the affected limb or area needing examination should be exposed.

The findings are consistent with a neurapraxia of the anterior interosseous branch of the median nerve. This is the most common nerve palsy seen with supracondylar humerus fractures, followed closely by radial nerve palsy. Nearly all cases of neurapraxia following supracondylar humerus fractures resolve spontaneously, and therefore, further diagnostic studies and surgery are not indicated. Cramer KE, Green NE, Devito DP: Incidence of anterior interosseous nerve palsy in supracondylar humerus fractures in children. J Pediatr Orthop 1993;13:502-505.

While all of the above may contribute to the etiology of a tibial plateau fracture following unicompartmental knee arthroplasty, the recent literature has clearly noted that pin placement for fixation of tibial resection guides is the most critical factor associated with a tibial plateau fracture following unicompartmental knee arthroplasty. Vince and Cyran suggest that fractures associated with unicompartmental knee arthroplasty might be avoidable by limiting the number and paying attention to the location of the pin holes that are created to secure the tibial resection guides. Brumby and associates suggest avoiding multiple guide pin holes in the proximal tibia for unicompartmental knee arthroplasty. They currently recommend the use of one centrally placed pin and an ankle clamp to stabilize the resection guide. Yang and associates note that a medial tibial plateau fracture in association with minimally invasive unicompartmental knee arthroplasty can be eliminated by avoiding fixation pins close to the medial tibial cortex. Brumby SA, Carrington R, Zayontz S, et al: Tibial plateau stress fracture: A complication of unicompartmental knee arthroplasty using 4 guide pinholes. J Arthroplasty 2003;18:809-812. Yang KY, Yeo SJ, Lo NN: Stress fracture of the medial tibial plateau after minimally invasive unicompartmental knee arthroplasty: A report of 2 cases. J Arthroplasty 2003;18:801-803.

Neer and associates focused on mechanical and nutritional factors as the etiology of rotator cuff arthropathy. McCarty and associates, in describing a similar syndrome known as Milwaukee shoulder, focused on an inflammatory cause in proposing the pathogenic role of hydroxyapatite, a basic calcium phosphate. Neer CS II, Craig EV, Fukuda H: Cuff-tear arthropathy. J Bone Joint Surg Am 1983;65:1232-1244.

The radiographs reveal a large femoral metaphyseal lytic lesion with well-defined borders. Joint space narrowing medially is consistent with polyethylene wear. The most likely diagnosis is particle-mediated osteolysis. Metastatic tumors and primary sarcomas adjacent to an arthroplasty are extremely rare. In addition, malignant tumors and infection would more likely reveal a destructive lesion with poorly defined borders and increased uptake on a bone scan. Stress shielding with massive bone loss has not been described in knee arthroplasty literature, although this entity has been observed in fully porous-coated femoral implants in total hip arthroplasty. Robinson EJ, Mulliken BD, Bourne RB, et al: Catastrophic osteolysis in total knee replacement: A report of 17 cases. Clin Orthop Relat Res 1995;321:98-105. Archibeck MJ, Jacobs JJ, Roebuck KA, et al: The basic science of periprosthetic osteolysis. Instr Course Lect 2001;50:185-195.

In a multivariate analysis, the strongest factor for the development of compartment syndrome is fracture of the proximal third of the forearm. However, compartment syndrome can still occur without a fracture. Therefore, these patients should be followed with a high level of suspicion for the development of compartment syndrome. Moed BR, Fakhouri AJ: Compartment syndrome after low-velocity gunshot wounds to the forearm. J Orthop Trauma 1991;5:134-137.

During transaxillary resection of the first rib, the long thoracic nerve is at risk as it passes either through or posterior to the middle scalene muscle. Injury to this nerve may occur as the result of overly aggressive retraction of the middle scalene during the procedure. Leffert RD: Thoracic outlet syndrome. J Am Acad Orthop Surg 1994;2:317-325.

The diagnosis of neurofibromatosis may be based on the presence of at least six cafe-au-lait spots larger than 5 mm in diameter and the osseous lesion shown in Figure 18c. Neurofibromatosis occurs in 50% of patients who have an anterolateral bowing deformity of the tibia, and this bowing may be the first clinical manifestation of this disorder. The patient has anterolateral bowing of the tibia and fibula that warrants concern for a possible fracture and pseudarthrosis; therefore, the limb should be protected in a total contact orthosis to prevent fracture. In contradistinction to posteromedial bowing of the tibia and fibula, spontaneous remodeling of an anterolateral bowing deformity is not expected. Intramedullary nailing or the use of a vascularized fibula is reserved for the treatment of a congenital pseudarthrosis of the tibia. Crawford AH Jr, Bagamery N: Osseous manifestations of neurofibromatosis in childhood. J Pediatr Orthop 1986;6:72-88.

The child has a trigger thumb deformity. A trigger thumb is a developmental mechanical problem rather than a congenital deformity. The anomaly generally is not noted at birth. A fixed flexion deformity of the IP joint of the thumb most commonly occurs in children in the first 2 years of life. A stretching and splinting program may correct the deformity in the first year of life, but nonsurgical management after age 3 years results in a success rate of only 50%. Release of the proximal annular pulley of the flexor sheath is recommended at this age. Tan AH, Lam KS, Lee EH: The treatment outcome of trigger thumb in children. J Pediatric Orthop B 2002;11:256-259. Slakey JB, Hennrikus WL: Acquired thumb flexion contracture in children: Congenital trigger thumb. J Bone Joint Surg Br 1996;78:481-483.

PMMA has no adhesive properties and can be more accurately described as grout than glue. It does not chemically bond to bone or implants; however, mechanical bonding is accomplished with porous or coated components and with cancellous bone. PMMA is approximately three times stronger in compression than in tension. Peak blood levels of monomer are usually seen approximately 3 minutes after the cement is placed. The monomer is cleared by the lungs. Associated hypotension is more closely related to diminished blood volume than to circulating monomer levels. High porosity decreases the tensile and fatigue properties of cement. Manually mixed cement may have porosity as high as 27%. Porosity may be reduced to less than 1% through vacuum mixing or centrifugation of the cement. When adding antibiotics to cement, the compressive and tensile forces are not appreciably decreased, but the overall fatigue strength may be reduced. Canale ST (ed): Campbell's Operative Orthopaedics, ed 9. St Louis, MO, Mosby, 1998, pp 221-224.

The Stryker notch view best shows this type of defect. An outlet view helps evaluate acromial shape, a true AP shows joint space narrowing, a serendipity view evaluates the sternoclavicular joint, and a Zanca view helps evaluate the acromioclavicular joint. An internal rotation AP may also depict a Hill-Sachs defect.

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.

While guidelines for predicting fracture risk are at best imprecise, the scoring system by Mirels (pain, anatomic location, and pattern of bony destruction) has been shown to be most predictive of fracture risk. Functional pain, peritrochanteric location, and lytic bone destruction are the greatest risk factors for pathologic fracture. The factors of patient weight, age, soft-tissue mass, and location within bone are all of lesser importance. Frassica FJ, Frassica DA, McCarthy EF, Riley LH III: Metastatic bone disease: Evaluation, clinicopathologic features, biopsy, fracture risk, nonsurgical treatment, and supportive management. Instr Course Lect 2000;49:453-459.

The patient has a single-level deficit by clinical examination but an adjacent level that may be pathologic. Hilibrand and associates, in a review of 374 patients with myeloradiculopathy treated with single-level or multilevel anterior cervical diskectomy and fusion, showed that 25% of patients had an occurrence of new radiculopathy or myelopathy at an adjacent level within 10 years after surgery. Reoperation rates were highest in those patients where the adjacent nonfused segment was C5-6 or C6-7. Those patients who had multilevel fusions had a lower incidence of adjacent segment disease. The authors recommended incorporating an adjacent level in the initial procedure in patients with myelopathy or radiculopathy when significant disease was noted. Posterior keyhole foraminotomy is an excellent procedure for single-level radiculopathy but is not effective in relieving myelopathy. Anterior cervical diskectomy without fusion has an increased incidence of hypermobility and neck pain on long-term follow-up. In a later review, these authors reported improved fusion rates and better clinical outcomes with the use of strut fusions instead of multilevel interbody grafts. Hilibrand AS, Carlson GD, Palumbo MA, Jones PK, Bohlman HH: Radiculopathy and myelopathy at segments adjacent to the site of a previous anterior cervical arthrodesis. J Bone Joint Surg Am 1999;81:519-528. Henderson CM, Hennessy RG, Shuey HM Jr, Shackelford EG: Posterior-lateral foraminotomy as an exclusive operative technique for cervical radiculopathy: A review of 846 consecutively operated cases. Neurosurgery 1983;13:504-512.

Bacitracin is a polypeptide obtained from a strain (Tracy strain) of Bacillus subtilis. It is stable and poorly absorbed from the intestinal tract; its only use is for topical application to skin, wounds, or mucous membranes. Concentrations of 500 to 2,000 units per milliliter of solution or gram of ointment are used for topical application. Bacitracin is mainly bactericidal for gram-positive bacteria, including penicillin-resistant staphylococci. In combination with polymixin B or neomycin, bacitracin is useful for suppression of mixed bacterial flora in surface lesions. Bacitracin is toxic for the kidney, causing proteinuria, hematuria, and nitrogen retention; therefore, it has no place in systemic therapy. Bacitracin is said not to induce hypersensivity readily, but reactions to this agent have been described. Rosenstein BD, Wilson FC, Funderburk CH: The use of bacitracin irrigation to prevent infection in postoperative skeletal wounds: An experimental study. J Bone Joint Surg Am 1989;71:427-430.

Patients require prophylaxis for heterotopic bone after resection to prevent recurrence. The optimal management has been found to be a dose of 700 cGy in one dose delivered either pre- or postoperatively. A dose of 2,000 to 3,000 cGy is considered excessive. Radiation therapy consisting of 1,000 cGy in five doses is an acceptable prophylaxis; however, it will require an extended hospital stay of 3 to 4 days and is more problematic for the patient who must be transported for radiation therapy for 5 days. A dose of 400 cGy is not as effective in prophylaxis for heterotopic bone formation. Healy WL, Lo TC, DeSimone AA, Rask B, Pfeifer BA: Single-dose irradiation for the prevention of heterotopic ossification after total hip arthroplasty: A comparison of doses of five hundred and fifty and seven hundred centigray. J Bone Joint Surg Am 1995;77:590-595. Pelligrini VD Jr, Gregoritch SJ: Preoperative irradiation for the prevention of heterotopic ossification following total hip arthroplasty. J Bone Joint Surg Am 1996;78:870-881.

The radial head is covered by cartilage on 360 degrees of its circumference. However, with the normal range of forearm rotation of 160 to 180 degrees, there is a consistent area that is nonarticulating. This area is found by palpation of the radial styloid and Lister's tubercle. The hardware should be kept within a 90-degree arc on the radial head subtended by these two structures. Smith GR, Hotchkiss RN: Radial head and neck fractures: Anatomic guidelines for proper placement of internal fixation. J Shoulder Elbow Surg 1996;5:113-117.

The patient has a periprosthetic fracture below the femoral stem. The component is porous coated and well fixed. Open reduction and internal fixation, leaving the stem in place, can be performed when bone quality is good. Plating with or without allograft struts and supplemental cerclage fixation generally is acceptable. If the component is loose, revision to a longer device is recommended with appropriate stabilization of the fracture using the aforementioned methods. If bone loss has occurred, allograft supplementation or a tumor prosthesis may be indicated. Fractures located well below the stem tip can be treated without regard for the prosthesis. Closed reduction and bracing is not associated with good results for periprosthetic femoral fractures. Retrograde intramedullary nailing is not appropriate for this fracture. Duncan CP, Masri BA: Fractures of the femur after hip replacement. Instr Course Lect 1995;44:293-304.

The radiographs reveal a fracture entering the 4-5 intermetatarsal articulation, consistent with a zone 2 injury. This classically is also referred to as a Jones fracture. The history and radiographic findings indicate this is an acute fracture, which guides management. A zone 1 fracture enters the fifth tarsometatarsal joint, and a zone 3 fracture is a proximal diaphyseal fracture distal to the 4-5 articulation. Initial management is usually nonsurgical and consists of non-weight-bearing in a short leg cast. This method has been shown to result in a better healing rate compared to weight bearing as tolerated. Rosenberg GA, Sterra JJ: Treatment strategies for acute fractures and nonunions of the proximal fifth metatarsal. J Am Acad Orthop Surg 2000;8:332-338.

Injury to the sciatic nerve is a relatively rare but serious complication of THA. Dissection of the sciatic nerve is not typically done during primary THA, although the nerve can be identified during the surgical approach. An anterolateral approach to THA would not necessarily be associated with any greater incidence of sciatic nerve injury than other approaches. Screw fixation for the acetabular component is often a matter of surgeon preference. Provided that the anatomic safe zones for screw fixation (posterior inferior and posterior superior) are recognized, injury to the sciatic nerve from acetabular screws can be minimized. Restoration of anatomic length is important in primary THA. Overlengthening can result in sciatic nerve palsy. Developmental dysplasia of the hip can lead to a congenitally shortened extremity with concomitant congenital shortening of the associated neurovascular structures. Overlengthening of the extremity during THA for developmental dysplasia of the hip can lead to sciatic palsy. Osteonecrosis is not an associated risk factor for sciatic nerve palsy. DeHart MM, Riley LH Jr: Nerve injuries in total hip arthroplasty. J Am Acad Orthop Surg 1999;7:101-111.

An enchondroma is the most common primary tumor of the long bones of the hand. The lesion is usually asymptomatic and often is detected when there is a pathologic fracture. Shimizu K, Kotoura Y, Nishijima N, Nakamura T: Enchondroma of the distal phalanx of the hand. J Bone Joint Surg Am 1997;79:898-900.

Myerson and associates studied the outcomes of 19 patients with tarsometatarsal joint injuries during athletic activity. Injuries were classified as first- or second-degree sprains of the tarsometatarsal joint or a third-degree sprain with diastasis between the metatarsals or cuneiforms. Poor functional results were seen in those with a delay in diagnosis and with inadequate treatment. For patients with third-degree sprains, poor results were obtained with nonsurgical management. These patients required open reduction and internal fixation for optimal return to function. The anatomic reduction is critical to the outcome; therefore, open reduction is preferred. Baxter DE: The Foot and Ankle in Sport, ed 1. St Louis, MO, Mosby, 1995, pp 107-123. Curtis MJ, Myerson M, Szura B: Tarsometatarsal joint injuries in the athlete. Am J Sports Med 1993;21:497-502. Kuo RS, Tejwani NC, DiGiovanni CW, et al: Outcome after open reduction and internal fixation of Lisfranc joint injuries. J Bone Joint Surg Am 2000;82:1609-1618.

Breech positioning has been noted as the risk factor that most increases the relative risk of developmental dysplasia of the hip in multiple series and meta-analysis. All the other factors also increase the risk but to a lesser magnitude. Lehmann HP, Hinton R, Morello P, et al: Developmental dysplasia of the hip practice guideline: Technical report. Committee on Quality Improvement, and Subcommittee on Developmental Dysplasia of the Hip. Pediatrics 2000;105:E57.

The MRI scan shows a massive tear of the supraspinatus tendon with medial retraction to the level of the glenoid. This is most likely an attritional tear with a high risk of failure of the repair. The preferred treatment is nonsurgical management for pain and stiffness. Acromioplasty and coracoacromial ligament release in this setting are controversial, as they can result in the devastating complication of anterosuperior subluxation of the humerus. Rockwood CA Jr, Williams GR Jr, Burkhead WZ Jr: Debridement of degenerative, irreparable lesions of the rotator cuff. J Bone Joint Surg Am 1995;77:857-866.

Only the flexor sheaths of the thumb and small finger are continuous from the digit through the carpal canal and into the distal forearm. If one of the sheaths ruptures from synovitis, it may contaminate the other sheath through Parona's space in the distal forearm. This potential space lies superficial to the pronator quadratus and deep to the flexor tendons. Green DP, Hotchkiss RN, Pederson WC (eds): Operative Hand Surgery, ed 4. New York, NY, Churchill Livingstone, 1999, pp 1044-1045.

The patient has posttraumatic arthritis of the elbow; therefore, the treatment of choice is hardware removal and soft-tissue releases with splinting to avoid recurrence of contractures. The combination of pain and stiffness in an elbow that has sustained significant joint surface damage renders it unresponsive to simple soft-tissue releases and heterotopic bone excision. Joint distraction and interposition arthroplasty offer the possibility of maintaining motion and relieving pain as a later salvage procedure. Joint replacement should not be performed in young, active, strong individuals because the prosthesis will fail quickly and complications will develop. Synovectomy and radial head excision are not indicated. Morrey BF: Distraction arthroplasty: Clinical applications. Clin Orthop 1993;293:46-54.

Continuous fluoroscopy and cine radiography expose the patient and personnel to markedly increased levels of direct and scatter radiation exposure. Continuous fluoroscopy should be limited to only what is absolutely needed for safe completion of the procedure. By orienting the cathode ray tube beneath the patient and placing the image intensifier as close as clinically possible to the patient, scatter radiation exposure to the personnel is minimized.

The radiographs show localized diffuse cortical thickening that is characteristic of melorheostosis. The condition may be monostotic or it may involve many bones in one extremity (monomelic) in the distribution of a sclerotome. Bone scans will show increased uptake at the site or sites of skeletal involvement. Long tubular bones are most commonly involved. Melorheostosis is usually asymptomatic and requires no treatment. On rare occasions, there may be associated soft-tissue contractures. Dorfman H, Czerniak B: Bone Tumors. St Louis, MO, Mosby Inc, 1998, pp 1105-1107. 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.

The figure shows a supracondylar process, which is a normal anatomic variant. An osteochondroma tends to occur more toward the end of bones, and the medullary space of the underlying bone extends into the base of the osteochondroma. The presence of a supracondylar process is usually asymptomatic. However, the ligament of Struthers that always extends from the supracondylar process to the medial epicondyle can result in median nerve entrapment secondary to trauma. Last RJ: Anatomy: Regional and Applied, ed 6. London, England, Churchill Livingstone, 1978, pp 132-133.

In Young's modulus of elasticity, E is a measure of the stiffness of a material and its ability to resist deformation. In the elastic region of the stress-stain curve, E = stress/strain. The moduli of elasticity for these materials are alumina ceramic = 380 Gigapascals (GPa), cobalt-chromium = 210 GPa, stainless steel = 190 GPa, titanium = 116 GPa, and PMMA = 1.1 to 4.1 GPa. Buckwalter JA, Einhorn TA, Simon SR (eds): Orthopaedic Basic Science, ed 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2000, pp 182-215.

En bloc excision is the recommended treatment of osteoblastoma. Treatment should consist of en bloc removal of the lamina, facet, and spinous process. Facet removal would necessitate fusion. Radiation therapy is not recommended. Intralesional curettage has a high rate of recurrence. Bridwell KH, Ogilvie JW: Primary tumors of the spine, in Bridwell KH, DeWald RL (eds): The Textbook of Spinal Surgery. Philadelphia, PA, JB Lippincott, 1991, vol 2, pp 1143-1174.

Progressive scoliosis develops in most patients with Duchenne muscular dystrophy. The onset of spinal deformity typically follows the cessation of walking, and curves can be expected to progress about 10 degrees per year. Posterior spinal fusion with instrumentation should be performed as soon as a curve of 25 degrees or greater is documented and before deterioration of pulmonary function (a FVC of less than 30%) precludes surgery. Patients with kyphotic posture tend to progress more rapidly than those with lordotic posture. Brace treatment is contraindicated because it is not definitive and it may mask curve progression while pulmonary function is concomitantly worsening. Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, Ill, American Academy of Orthopaedic Surgeons, 1999, pp 635-651.

The first branch of the lateral plantar nerve is susceptible to entrapment beneath the deep fascia of the adductor hallucis muscle adjacent to the calcaneal attachment of the plantar fascia. This can be a cause of chronic heel pain. Additionally, the nerve is vulnerable to injury by a blind dissection in releasing the plantar fascia. The dorsal cutaneous branch of the superficial peroneal nerve supplies sensation to the dorsum of the foot. The medial calcaneal branch of the posterior tibial nerve lies in the subcutaneous tissues and innervates the skin of the heel. It is vulnerable to injury from skin incisions on the medial side of the heel. The lateral branch of the medial plantar nerve forms the second and third common digital nerves. Entrapment of the proper medial plantar nerve can occur at the master knot of Henry. This is well distal to the calcaneal attachment of the plantar fascia, and the pain usually radiates more distally in the arch, separate from heel pain. The communicating branch of the fourth common digital nerve crosses to the third common digital nerve. Therefore, the third common digital nerve receives supply from both the lateral and medial plantar nerves. This dual supply has been implicated in the increased incidence of digital neuroma of the third common digital nerve. Bordelon RL: Heel pain, in Mann RA, Coughlin MJ (eds): Surgery of the Foot and Ankle, ed 6. St Louis, MO, CV Mosby, 1993, pp 837-857. Mann RA, Baxter DE: Diseases of the nerves, in Mann RA, Coughlin MJ (eds): Surgery of the Foot and Ankle, ed 6. St Louis, MO, CV Mosby, 1993, pp 543-574.

Scoliosis is a common occurrence in children with myelomeningocele, with the incidence increasing as the neurologic level moves cephalad. The rate of pseudarthrosis for isolated anterior or posterior fusions has been reported as high as 75%. The combination of anterior and posterior fusions with some type of instrumentation has been shown to decrease the rate of pseudarthrosis to 20%. Brace treatment in smaller curves can be used as a temporizing measure to delay surgery, but as with idiopathic scoliosis, the brace is ineffective for larger curves. Observation is not indicated with a curve of this magnitude. Ward WT, Wenger DR, Roach JW: Surgical correction of myelomeningocele scoliosis: A critical appraisal of various spinal instrumentation systems. J Pediatr Orthop 1989;9:262-268.

Type I fractures are trochanteric fractures usually secondary to osteolysis. Type II fractures are located around the stem. Type III fractures are distal to the stem. If the fracture and prosthesis are stable, the fracture can be treated nonsurgically. If the fracture is unstable, the stability of the prosthesis should be assessed. If the prosthesis is unstable (type IIB), treatment should consist of revision to a long stem prosthesis that bypasses the fracture by two cortical diameters. If, as in this patient, the prosthesis is not loose (type IIA), open reduction and internal fixation is the appropriate option. Proximal femoral allograft is appropriate for type IIIC fractures in which the proximal bone is significantly compromised and the femoral component is loose. Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 455-492.

Intrafocal pinning allows the Kirschner wires to be placed through a site of comminution and then drilled through intact cortex. Generally Kapandji intrafocal pinning is done for dorsal comminuted extra-articular dorsal bending fractures, but it also may be used to elevate and buttress radial comminution. Simple intra-articular fractures can also be treated with pinning alone. Intrafocal pinning works best as a dorsal or radial buttress to prevent shortening. When there is volar comminution, the fracture is prone to shortening and supplemental external fixation or plating is recommended. Trumble TE, Wagner W, Hanel DP, et al: Intrafocal (Kapandji) pinning of distal radius fractures with and without external fixation. J Hand Surg Am 1998;23:381-394. Choi KY, Chan WS, Lam TP, et al: Percutaneous Kirschner-wire pinning for severely displaced distal radial fractures in children: A report of 157 cases. J Bone Joint Surg Br 1995;77:797-801.

The correct progression of the annular and cruciform pulley in the digits is A1, A2, C1, A3, C2, A4, C3. The two cruciform pulleys are collapsible elements adjacent to the more rigid annular pulleys of the flexor tendon sheath. This arrangement enables unrestricted flexion of the proximal interphalangeal joint. Hoppenfeld S, deBoer P: Surgical Exposures in Orthopaedics, ed 2. Philadelphia, PA, Lippincott-Raven, 1994, pp 176-186.

In childhood, the more common soft-tissue sarcomas are rhabdomyosarcoma, synovial sarcoma, and fibrosarcoma. Rhabdomyosarcoma, treated with radiation therapy and chemotherapy, is a round cell tumor and is inconsistent with this patient's histologic findings. Synovial sarcoma can be monophasic or biphasic with both spindle and epithelial-like cells and is associated with the characteristic reciprocal chromosomal translocation of t(x:18)(p11;q11) which is not found in fibrosarcoma. Synovial sarcoma also can be associated with cystic loculated areas best seen in a T2-weighted MRI scan. Nonrhabdomyosarcoma childhood soft-tissue sarcomas are treated with surgical excision in conjunction with chemotherapy and/or radiation therapy. The histology reveals no inflammatory cells to suggest an abscess; therefore, antibiotics and drainage are unnecessary. The MRI scans clearly show a mass of soft tissue and no bone involvement; therefore, proximal femoral resection is not appropriate. Serial observation is not appropriate because of the history of enlargement and insidious onset. Enzinger FM, Weiss SW: Soft Tissue Tumors, ed 3. St Louis, MO, Mosby Year Book, 1995, p 757.

The MRI scans show hypertrophy of the left L4-L5 facet joint and ligamentum flavum, with a synovial cyst. Appropriate surgical management consists of a hemilaminectomy and direct decompression of the neural elements. Fusion, in addition to the decompression, may be considered, particularly in patients with an associated spondylolisthesis. Epstein NE: Lumbar laminectomy for the resection of synovial cysts and coexisting lumbar spinal stenosis or degenerative spondylolisthesis: An outcome study. Spine 2004;29:1049-1055.

The radiograph shows an eccentric, cortically based lytic lesion in the proximal fibula. The CT and MRI scans confirm that it is well circumscribed and cortically based with significant surrounding edema. The radiographic differential diagnosis would be a Brodie's abscess or osteoid osteoma. An osteoblastoma would have to be greater than 2 cm in size. A chondroblastoma may also have significant edema around it, but it is an epiphyseal-based lesion, not cortically based. The well-circumscribed nature of the lesion is not consistent with osteosarcoma. The pathology shows a very cellular and vascular stroma with plump, but not atypical osteoblast cells making a matrix of immature woven bone. There are no abundant inflammatory cells or dead bone suggestive of osteomyelitis or a Brodie's abscess. Therefore, the clinical and histologic picture is most consistent with an osteoid osteoma. Percutaneous radiofrequency ablation, usually with CT guidance, has become the preferred method for treating most cases of osteoid osteoma. Rosenthal DI: Radiofrequency treatment. Orthop Clin North Am 2006;37:475-484.

The radiograph and MRI scan show osteochondritis dissecans of the capitellum, and the patient's history suggests a loose body. The treatment of choice is arthroscopic removal of the loose body and microfracture of the crater. Excision of the radial head, a cortisone injection, or tennis elbow release does not treat the pathology in the capitellum. Nonsurgical treatment would not relieve the mechanical symptoms of the loose body or promote healing in the crater. Baumgarten TE, Andrews JR, Satterwhite YE: The arthroscopic classification and treatment of osteochondritis dissecans of the capitellum. Am J Sports Med 1998;26:520-530. Jackson DW, Silvino N, Reiman P: Osteochondritis in the female gymnast's elbow. Arthroscopy 1989;5:129-136.

The patient has a fixed deformity of the hindfoot and an Achilles tendon contracture; therefore, the treatment of choice is triple arthrodesis with Achilles tendon lengthening. Further bracing will not be helpful. Amputation is not indicated, and ankle arthrodesis will not address the hindfoot deformity. Palliative management would be more appropriate if the knee was unstable or the quadriceps were weak, because the equinus balances the ground reaction force across the knee. Perry J, Fontaine JD, Mulroy S: Findings in post-poliomyelitis syndrome: Weakness of muscles of the calf as a source of late pain and fatigue of muscles of the thigh after poliomyelitis. J Bone Joint Surg Am 1995;77:1148-1153.

Popliteal artery injury during total knee arthroplasty is relatively rare. Knee flexion, the position that occurs during most of the arthroplasty procedure, allows the popliteal vessels to fall posteriorly, further away from harm. Anatomically, the popliteal artery lies anterior to the popliteal vein and 9 mm posterior to the posterior aspect of the tibial plateau in 90 degrees of flexion. Barrack RL, Booth RE Jr, Lonner JH, et al (eds): Orthopaedic Knowledge Update: Hip and Knee Reconstruction 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, p 151.

Naranja and associates reviewed 37 knees (35 patients, with 28 women and 7 men) without any motion that were converted to total knee arthroplasties. After an average follow-up of 90 months, the patients lacked an average of 7 degrees of extension and had 62 degrees of flexion. Results showed a short-term complication rate of 24% (stiffness requiring manipulation, delayed wound healing, and recurrent hemarthrosis), a major complication rate of 35% (patellar tendon or tibial tubercle avulsion, persistent pain requiring arthrodesis, loosening, and joint stiffness requiring arthrotomy for excision of scar tissue), and an infection rate of 14%. The total complication rate was 57%. A satisfactory outcome (no pain and an unlimited ambulation distance) was obtained in only 10 patients (29%). There was no relationship between results and the angle at which the knee was ankylosed preoperatively. This study revealed that although success in reconstructing a previously ankylosed or arthrodesed knee is possible, the lack of consistent adequate motion and the complication rate may suggest that the surgeon reconsider the risks and benefits of this difficult procedure.

The patient has a locked knee that cannot be fully extended. This is most likely the result of the mechanical block of a bucket-handle tear that has flipped into the notch. Also, the pain may be so severe that the muscle spasm prevents the knee from straightening out. When the patient is anesthetized, the muscle spasm relaxes and the meniscus can be reduced out of the notch. Arthroscopy is the treatment of choice. A meniscal repair is usually possible in large bucket-handle tears because the meniscus is torn in the red-red zone where most of the vascular supply is located. If the handle portion is badly frayed or damaged, a partial meniscectomy should be performed. The classic finding on MRI is a "double PCL sign." This is due to the flipped portion of the meniscus in the notch. Critchley IJ, Bracey DJ: The acutely locked knee: Is manipulation worthwhile? Injury 1985;16:281-283.

One possible reason for improved efficacy of LMWHs is the relative improved bioavailability compared with that of unfractionated heparin. This is, in part, the result of a more predictable dose response and a longer half-life. There is no alteration of venous flow, and the rate of bleeding complications is the same or slightly higher than that of other prophylactic agents. Colwell CW Jr, Spiro TE, Trowbridge AA: Use of enoxaparin, a low-molecular weight heparin, and unfractionated heparin for the prevention of deep venous thrombosis after elective hip replacement: A clinical trial comparing efficacy and safety. J Bone Joint Surg Am 1994;76:3-14. Bara L, Billaud E, Kher A, Samama M: Increased anti-Xa bioavailability for a low-molecular weight heparin (PK 10169) compared with unfractionated heparin. Semin Thromb and Hemost 1985;11:316-317.

Without more distal immobilization such as a thigh extension, the lower two lumbar segments generally show the same or even increased mobility with a TLSO. White AA, Panjabi MM: Clinical Biomechanics of the Spine, ed 2. Philadelphia, PA, JB Lippincott, 1990, pp 475-509.

Shoe wear modification is the most appropriate management based on the patient's age, high activity level, and relatively minor symptoms. She also has a mild hallux valgus. Normal radiographic measurements are an intermetatarsal angle of less than 9 degrees, a hallux valgus angle of less than 15 degrees, and a distal metatarsal articular angle of less than 9 degrees. Surgical procedures should be reserved for patients with more severe or progressive deformities. Stephens HM: Bunions, in Fitzgerald RH, Kaufer H, Malkani AL (eds): Orthopaedics. St Louis, MO, Mosby, 2002, pp 1510-1519.

DEXA can provide data on bone mineral content and soft-tissue composition, and requires cross-sectional dimension for accuracy. DEXA provides a quantitative, not qualitative, measurement of bone mineral content and is incapable of differentiating between trabecular and cortical bone. Osteoarthritis falsely elevates the values, especially in the AP spinal analysis. Genant HK, Faulkner KG, Gluer CC: Measurement of bone mineral density: Current status. Am J Med 1991;91:49S-53S. Genant HK, Engelke K, Fuerst T, et al: Review: Noninvasive assessment of bone mineral density and stature: State of the art. J Bone Miner Res 1996;11:707-730.

Cadaver and clinical studies have shown that the sural nerve is at the highest risk for injury with a percutaneous repair of the Achilles tendon.

Chondrolysis may be associated with unrecognized permanent penetration of the joint space by a pin or screw. However, transient penetration by the guide wire or screw is not associated with this problem. One study described 11 hips in which there was transient intraoperative penetration of the joint space by a guide wire or screw. These patients were followed for at least 2 years, with none showing any clinical or radiographic evidence of chondrolysis. Another retrospective study of 55 slipped epiphyses described 11 hips with transient intraoperative pin penetration, with none showing development of chondrolysis. There are no studies to suggest that transient pin penetration leads to osteonecrosis, stiffness, or premature physeal closure. Zionts LE, Simonian PT, Harvey JP Jr: Transient penetration of the hip joint during in situ cannulated-screw fixation of slipped capital femoral epiphysis. J Bone Joint Surg Am 1991;73:1054-1060.

The radiographs reveal a geographic, diaphyseal lesion with very subtle cortical expansion, cortical thinning, relatively sharp demarcation, and angular rather than rounded borders, suggesting a fibrous bone lesion. This lesion demonstrates the classic ground glass appearance of fibrous dysplasia. Ewing's sarcoma, metastases, and aneurysmal bone cyst all typically have a more aggressive appearance. Parsons TW: Benign bone tumors, in Fitzgerald RH, Kaufer H, Malkani AL (eds): Orthopaedics. St Louis, MO, Mosby, 2002, pp 1027-1035.

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.

Embolization of fat and bone marrow elements during total hip arthroplasty has been studied intraoperatively using transesophageal echocardiography. These studies showed the occurrence of a large number of embolic events during the insertion of a cemented femoral stem. Embolic events were rare during insertion of a cementless stem. Femoral broaching caused some embolic events, but they were not nearly as significant as those that occurred following insertion of a cemented stem. Additionally, relocation of the cemented hip was accompanied by significant embolic events. This may be related to the untwisting of blood vessels, with the subsequent release of emboli that were most likely generated during insertion of a cemented femoral stem. Pitto RP, Koessler M, Kuehle JW: Comparison of fixation of the femoral component without cement and fixation with use of a bone-vacuum cementing technique for the prevention of fat embolism during total hip arthroplasty. J Bone Joint Surg Am 1999;81:831-843.

To date, only the percent of necrosis after induction chemotherapy in high-grade osteosarcomas seems to be of prognostic value. The value in soft-tissue sarcoma and rhabdomyosarcoma is being evaluated but has not been substantiated. Chondrosarcomas and parosteal osteosarcomas are not treated with chemotherapy. Rosen G, Marcove RC, Caparros B, Nirenberg A, Kosloff C, Huvos AG: Primary osteogenic sarcoma: The rationale for pre-operative chemotherapy and delayed surgery. Cancer 1979,43:2163-2177. Davis AM, Bell RS, Goodwin PJ: Prognostic factors in osteosarcoma: A critical review. J Clin Oncol 1994;12:423-431.

Absence of the rotator cuff results in superior migration of the humeral head because of unopposed deltoid function. This proximal migration results in eccentric loading of glenoid components with early loosening. Hemiarthroplasty yields good pain relief with limited goals of active elevation of 90 degrees. The coracoacromial arch should be preserved. Achieving satisfactory subscapularis tension is preferred to the use of an oversized humeral component. Zeman CA, Arcand MA, Cantrell JS, Skedros JG, Burkhead WZ Jr: The rotator cuff-deficient arthritic shoulder: Diagnosis and surgical management. J Am Acad Orthop Surg 1998;6:337-348. Arntz CT, Jackins S, Matsen FA III: Prosthetic replacement of the shoulder for the treatment of defects in the rotator cuff and the surface of the glenohumeral joint. J Bone Joint Surg Am 1993;75:485-491. Williams GR Jr, Rockwood CA Jr: Hemiarthroplasty in rotator cuff-deficient shoulders. J Shoulder Elbow Surg 1996;5:362-367.

Monteggia fractures in children must be recognized. Early appropriate treatment is much easier than delayed reconstruction for a missed radial head dislocation. In younger children, attempts should be made to reduce the ulna fracture and radial head dislocation with traction and manual manipulation. Anterior Monteggia fractures are the most common, and in this variety the radius is much better stabilized in elbow flexion. Posterior Monteggia fractures are less common and may be managed in elbow extension. Closed reduction is much more successful in younger children; ulnar fixation with a rod or plate may be needed in older patients with unstable fractures. Annular ligament repair is rarely needed in the acute fracture. Wilkins KE: Changes in the management of Monteggia fractures. J Pediatr Orthop 2002;22:548-554. Kay RM, Skaggs DL: The pediatric Monteggia fracture. Am J Orthop 1998;27:606-609.

These are classic findings of osteonecrosis of the hip. The radiograph reveals the subchondral sclerotic pattern commonly seen in osteonecrosis and is quite extensive in this patient. The MRI scan reveals the typical serpentine-like region of low signal intensity with a central zone where the signal is similar to fat. Resnick D (ed): Diagnosis of Bone and Joint Disorders. Philadelphia, PA, WB Saunders, 2002, pp 3160-3162.

The fracture pattern shown in the radiograph involves both a talar neck fracture and a talar body fracture. The body fracture propagates into the subtalar joint, with significant risk for the development of arthritis in that surface even with an anatomic reduction. In addition, Canale and Kelly reported a 25% incidence of malunion of talar neck fractures, with varus angulation occurring most frequently. Of these patients, 50% required a secondary surgical procedure because of the development of degenerative joint disease of the subtalar joint. Canale ST, Kelly FB Jr: Fractures of the neck of the talus: Long-term evaluation of seventy-one cases. J Bone Joint Surg Am 1978;60:143-156.

In secondary amenorrhea, women do not receive the estrogen needed to maintain adequate bone mineralization. This hypoestrogenic state affects bone density, and there is evidence that stress fractures are more frequent in amenorrheic than eumenorrheic athletes. The other conditions are not seen with increased frequency in amenorrheic athletes. Warren MP: Health issues for women athletes: Exercise-induced amenorrhea. J Clin Endocrinol Metab 1999;84:1892-1896.

The area of the tendon degeneration is greater than 50% of the width so a supplemental tendon transfer is needed. Debridement and repair alone do not provide adequate strength. Injection risks tendon rupture. Brisement is indicated for peritendinitis, not tendinosis. Nonsurgical management is unlikely to be of benefit after 12 months. Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 94-95.

In most orthopaedic applications, the materials are strong enough to withstand a single cycle of loading in vivo. However, these loads may be large enough to initiate a small crack in the implant that can grow slowly over thousands or millions of cycles, eventually leading to gross failure. Such fatigue failure has occurred with virtually every type of implant, including stainless steel fracture plates and screws, bone cement in joint arthroplasty, and polyethylene inserts in total knee arthroplasty. Lewis G: Fatigue testing and performance of acrylic bone-cement materials: State-of-the-art review. J Biomed Mater Res Br 2003;66:457-486. Stolk J, Verdonschot N, Huiskes R: Stair climbing is more detrimental to the cement in hip replacement than walking. Clin Orthop 2002;405:294-305.

The patient has infantile fibrosarcoma. For unresectable lesions, the treatment of choice is chemotherapy with vincristine, actinomycin-D, and cyclophosphamide, followed by excision if there is an adequate decrease in the size of the lesion.

The meniscofemoral ligaments connect the posterior horn of the lateral meniscus to the intercondylar wall of the medial femoral condyle. The ligament of Humphrey (arrow) passes anterior to the posterior cruciate ligament, whereas the ligament of Wrisberg passes posterior to the posterior cruciate ligament. One or the other has been identified in 71% to 100% of cadaver knees, with the ligament of Wrisberg being more common. Clarke HD, Scott WN, Insall JN, et al: Anatomy, in Insall JN, Scott WN (eds): Surgery of the Knee, ed 4. Philadelphia, PA, Churchill Livingstone, 2006, vol 1, pp 3-66.

Warfarin acts by inhibiting clotting factors II, VII, IX, X. The actual mechanism of action is by inhibition of hepatic enzymes, vitamin K epoxide, and perhaps vitamin K reductase. This inhibition results in lack of carboxylation of vitamin K-dependent proteins (II, VII, IX, X). The anticoagulant effect of warfarin can be reversed with vitamin K or fresh-frozen plasma. The use of alcohol may lead to liver dysfunction and an even more limited margin of available factors. Lieberman JR, Wollaeger J, Dorey F, et al: The efficacy of prophylaxis with low-dose warfarin for prevention of pulmonary embolism following total hip arthroplasty. J Bone Joint Surg Am 1997;79:319-325.

The ratio of displacement from CD to AB normally equals 1.0. If the ratio is greater than 1.0, an anterior atlanto-occipital dislocation may exist. Ratios slightly less than 1.0 are normal except in posterior dislocations, fractures of the odontoid process or ring of the atlas, or congenital abnormalities of the foramen magnum. In these conditions, the ratio may approach 0.7. Powers B, Miller MD, Kramer RS, et al: Traumatic anterior atlanto-occipital dislocation. Neurosurgery 1979;4:12-17.

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 shows tuberosity malposition. The effect of improper prosthetic placement has also been associated with poor outcomes. However, the malposition of the tuberosity seen on the radiograph clearly explains loss of motion in this patient. It has been demonstrated that the functional results after hemiarthroplasty for three- and four-part proximal humeral fractures appear to be directly associated with tuberosity osteosynthesis. The most significant factor associated with poor and unsatisfactory postoperative functional results was malposition and/or migration of the tuberosities. Factors associated with a failure of tuberosity osteosynthesis in a recent study were poor initial position of the prosthesis, poor position of the greater tuberosity, and women older than age 75 years (most likely with osteopenic bone). Greater tuberosity displacement has been identified by Tanner and Cofield as being the most common complication after prosthetic arthroplasty for proximal humeral fractures. Furthermore, Bigliani and associates examined the causes of failure after prosthetic replacement for proximal humeral fractures and found that although almost all failed cases had multiple causes, the most common single identifiable reason was greater tuberosity displacement. Bigliani LU, Flatow EL, McCluskey G, et al: Failed prosthetic replacement for displaced proximal humeral fractures. Orthop Trans 1991;15:747-748. Boileau P, Krishnan SG, Tinsi L, et al: Tuberosity malposition and migration: Reasons for poor outcomes after hemiarthroplasty for displaced fractures of the proximal humerus. J Shoulder Elbow Surg 2002;11:401-412.

The standard approach to the volar aspect of the distal radius is the Henry approach. Following incision of the skin and subcutaneous tissues, the forearm fascia is incised. The radial artery and venae comitantes lie in the interval between the tendons of the flexor carpi radialis muscle and the brachioradialis muscle. This interval is developed, and the radial artery and veins are retracted in a radial direction. Hoppenfeld S, deBoer P: Surgical Exposures in Orthopaedics, ed 2. Philadelphia, PA, Lippincott-Raven, 1994, pp 118-131.

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.

This issue has been debated since Inman published his classic study on clavicular rotation in 1944. Subsequently, it has been shown by several authors that the clinical evaluation of patients with either coracoclavicular screws in place or with arthrodesis of the coracoclavicular reveals little to no loss of shoulder motion. This is most likely the result of synchronous motion of the scapula and clavicle in shoulder movements. Flatow EL: The biomechanics of the acromioclavicular, sternoclavicular, and scapulothoracic joints. Instr Course Lect 1993;42:237-245. Kenedy JC, Cameron H: Complete dislocation of the acromioclavicular joint. J Bone Joint Surg Br 1954;36:202-208. Rockwood CA Jr, Williams GR, Young CD: Disorders of the acromioclavicular joint, in Rockwood CA Jr, Matsen FA III (eds): The Shoulder. Philadelphia, PA, WB Saunders, 1998, vol 1, pp 483-553.

A muscle that lengthens as it is activated is an eccentric contraction. Isometric contraction involves no change in length. Concentric contraction occurs while the muscle is shortening. In isotonic contraction, the force remains constant through the contraction range. Isokinetic muscle contraction occurs at a constant rate of angular change of the involved joint. Garrett WE, Speer KP, Kirkendall DT (eds): Principles & Practice of Orthopaedic Sports Medicine. Philadelphia, PA, Lippincott Williams & Wilkins, 2000, pp 12-13.

The patient has an aneurysmal bone cyst. The fluid-fluid levels seen on the MRI scan are typical for aneurysmal bone cyst, and the histology is consistent with a cystic lining. Vascular lakes, multinucleated giant cells, reactive bone, fibrovascular tissue, and an absence of atypical cells or numerous mitoses are seen histologically. Aneurysmal bone cysts will typically continue to grow and cause further bone destruction; therefore, observation is not recommended. Steroid injections are not effective. A thorough curettage of the cyst lining and bone grafting are required. Wide resection and chemotherapy are reserved for more aggressive tumors. There is no evidence of infection radiographically or histologically. Telangiectatic osteosarcoma should also be considered in the differential diagnosis; therefore, biopsy is an important part of the work-up. Wold LA, et al: Atlas of Orthopaedic Pathology. Philadelphia, PA, WB Saunders, 1990, pp 232-233.

The results of TKA for patients with a prior UTO are reported to be slightly suboptimal. The major problems are patella baja, difficulty in exposure, and instability. Most of the patients exhibit some degree of instability prior to TKA, and ligamentous balancing may be difficult. Ligamentous structures are at risk of rupture during the difficult exposure. The problem of ligamentous balancing is exacerbated by the change in the joint slope that can occur after UTO. Parvizi J, Hanssen AD, Spangehl MJ: Total knee arthroplasty following proximal tibial osteotomy: Risk factors for failure. J Bone Joint Surg Am 2004;86:474-479.

The radiographs show a triplane fracture of the ankle. In adolescence, closure of the distal tibial physis starts peripherally at the anteromedial aspect of the medial malleolus and extends posteriorly and laterally. The anterolateral quadrant of the physis is the last to close, making this region the most susceptible to separation. When the foot is twisted into external rotation, the anterolateral portion of the epiphysis is avulsed by the pull of the anterior tibiofibular ligament. When this fragment alone is avulsed, the result is a juvenile Tillaux fracture. When the fracture extends to involve the remainder of the physis and posterior metaphysis, as in this patient, the result is a triplane fracture. Richards BS (ed): Orthopaedic Knowledge Update: Pediatrics. Rosemont, Ill, American Academy of Orthopaedic Surgeons, 1996, pp 267-272. Dias LS, Giegerich CR: Fractures of the distal tibial epiphysis in adolescence. J Bone Joint Surg Am 1983;65:438-444.

Open release allows lengthening of the shortened subscapularis and is preferred when there are extra-articular contractures. Arthroscopic release, combined with the use of an interscalene catheter postoperatively, is an excellent treatment for capsular contractures but is contraindicated after procedures that result in extracapsular shortening (ie, Magnuson-Stack, Putti-Platt). Additional physical therapy or manipulation under anesthesia is not likely to be helpful. Shoulder hemiarthroplasty is contraindicated with normal articular surfaces, but prosthetic arthroplasty is sometimes necessary for arthritis associated with instability or overly tight instability repairs. Harryman DT II, Matsen FA III, Sidles JA: Arthroscopic management of refractory shoulder stiffness. Arthroscopy 1997;13:133-147. Warner JJ: Frozen shoulder: Diagnosis and management. J Am Acad Orthop Surg 1997;5:130-140. Warner JJ, Allen AA, Marks PH, Wong P: Arthroscopic release of postoperative capsular contracture of the shoulder. J Bone Joint Surg Am 1997;79:1151-1158.

The radiographs show a halo-like sclerotic margin around the tibial stem and lucency under the baseplate. The bone scan shows markedly increased uptake under the tibial component, particularly on the medial side (not diffusely through the knee as seen with infection). These studies indicate lack of bone ingrowth fixation of the cementless porous-coated tibial component. The recent report of Fehring and associates has identified failure of ingrowth of a porous-coated implant as a dominant mode of early failure of total knee arthroplasties. Fehring TK, Odum S, Griffin WL, Mason B, Nadaud M: Early failures of total knee arthroplasty. Clin Orthop 2001;392:315-318.

Traditional surgeries for anterior cruciate ligament-deficient knees carry the potential risk of premature physeal closure in young athletes. Therefore, most surgeons are reluctant to recommend intra-articular reconstruction using bone tunnels with bone-patellar tendon-bone autografts or hamstring tendons. The current recommendation for young athletes is activity modification, rehabilitation, and functional bracing until the patient is near skeletal maturity. At that time, for the very symptomatic patient, the treatment of choice is intra-articular repair of the anterior cruciate ligament. If a skeletally immature patient continues to have instability despite rehabilitation and bracing, a modification of the femoral tunnel to the over-the-top position will not place the lateral femoral physis at risk for premature closure and deformity. A centrally placed tibial tunnel will minimize the risk of angular deformity and minimize limb-length discrepancy if physeal arrest occurs. Barry P: Anterior cruciate ligament injuries, in Andrews JR, Timmerman LA (eds): Diagnostic and Operative Arthroscopy. Philadelphia, Pa, WB Saunders, 1997, p 358. McCarroll JR, Shelbourne KD, Porter DA, Rettig AC, Murray S: Patellar tendon graft reconstruction for midsubstance anterior cruciate ligament rupture in junior high school athletes: An algorithm for management. Am J Sports Med 1994;22:478-484. Nottage WM, Matsuura PA: Management of complete traumatic anterior cruciate ligament tears in the skeletally immature patient: Current concepts and review of the literature. Arthroscopy 1994;10:569-573.

Nodular fasciitis is a benign soft-tissue lesion that usually arises from the fascia and is often misdiagnosed as a sarcoma. Desmoid tumors (aggressive fibromatosis) are also benign tumors with a greater tendency for local recurrence. Desmoid tumors have more spindle-shaped fibroblasts in an abundant collagenous matrix. Malignant fibrous histiocytoma is a hypercellular pleomorphic sarcoma more commonly found in adults. The histology is not consistant with a fatty tumor.

The use of anabolic steroids causes a decrease in high-density lipoprotein levels but has no effect on low-density lipoprotein levels. An abnormally low high-density lipoprotein level should alert the physician to the possibility of steroid use in an athlete. Hartgens F, Rietjens G, Keizer HA, et al: Effects of androgenic-anabolic steroids on apolipoproteins and lipoprotein (a). Br J Sports Med 2004;38:253-259.

The vascularity of the dorsal portion of the digital flexor tendons is considerably richer than the volar portion. The other regions are not preferentially more vascular. Hunter JM, Scheider LH, Makin EJ (eds): Tendon Surgery in the Hand. St Louis, MO, Mosby, 1987, pp 91-99.