100 Orthopedic MCQs: Trauma, Spine, Sports Medicine & Arthroplasty | Comprehensive ABOS Review

Numerous surgical approaches have been used for thoracic diskectomy, including the most recent VATS. One of the first approaches described, posterior laminectomy, involves manipulation of the spinal cord, which the other approaches avoid. The posterior approach had dismal results, including further neurologic deterioration and even paralysis. Belanger TA, Emery SE: Thoracic disc disease and myelopathy, in Frymoyer JW, Wiesel SW (eds): The Adult and Pediatric Spine. Philadelphia, PA, Lippincott Williams and Wilkins, 2004, pp 855-864. Benjamin V: Diagnosis and management of thoracic disc disease. Clin Neurosurg 1983;30:577-605. Russell T: Thoracic intervertebral disc protrusion: Experience of 67 cases and review of the literature. Br J Neurosurg 1989;3:153-160.

The superior gluteal artery is a branch of the posterior division of the internal iliac artery and exits the pelvis through the greater sciatic notch. It can be injured as a result of a pelvic ring fracture or acetabular fracture that has a fracture of the posterior column. Agur AM, Dalley AF (eds): Grant's Atlas of Anatomy, ed 12. Philadelphia, PA, Lippincott Williams and Wilkins, 2008.

The radiographs show a fracture-dislocation with translation in both the coronal and sagittal planes, evidence of significant instability requiring surgical stabilization. Anterior instrumentation is not as effective as posterior instrumentation in restoring stability, and because there is little bony destruction, the anterior column can be successfully reconstructed with simple realignment. The treatment of choice is multisegment posterior fusion with instrumentation. Lewandrowski KU, McLain RF: Thoracolumbar fractures: Evaluation, classification, and treatment, in Frymoyer JW, Wiesel SW (eds): The Adult and Pediatric Spine. Philadelphia, PA, Lippincott Williams and Wilkins, 2004, pp 817-843.

All but the Moberg osteotomy are capable of providing pain relief; however, arthrodesis offers the best long-term results and restores weight bearing and propulsion function to the first ray. Machacek F Jr, Easley ME, Gruber F, et al: Salvage of a failed Keller resection arthroplasty. J Bone Joint Surg Am 2004;86:1131-1138.

The child has the classic findings of Kohler's disease or osteochondrosis of the tarsal navicular. The cause of this condition is not known, but osteonecrosis and mechanical compression have been proposed. Children generally report midfoot pain over the tarsal navicular and limping. Physical findings include tenderness, swelling, and occasionally redness in the region of the tarsal navicular. Radiographs show sclerosis and narrowing of the tarsal navicular. The natural history of the condition is spontaneous resolution and reconstitution of the navicular. Symptomatic treatment with restriction of weight bearing or casting is recommended. Karp M: Kohler's disease of the tarsal scaphoid. J Bone Joint Surg 1937;19:84-96.

The patient has a plexiform neurofibroma and multiple café-au-lait spots, all characteristic of von Recklinghausen's neurofibromatosis. This disease has been linked to a defect of the gene NF1 on chromosome 17. EWS is one of the genes associated with the 11;22 translocation found in Ewing's sarcoma and several other sarcomas. EXT1 is the most common gene affecting patients with multiple hereditary exostosis. P53 and Rb are tumor suppressor genes whose inactivation has been associated with tumors in conditions such as Li-Fraumeni and retinoblastoma, respectively. Theos A, Korf BR, American College of Physicians, et al: Pathophysiology of neurofibromatosis Type 1. Ann Intern Med 2006;144:842-849.

The patient has a degenerative collapse of the midfoot through the tarsometatarsal joints with significant forefoot abduction; therefore, a midfoot arthrodesis is required to address the arthritic joints and deformity at the tarsometatarsal articulation. All of the other procedures correct hindfoot deformities and therefore would not be appropriate treatment. Brage M: Degenerative joint disease of the midfoot. Foot Ankle Clin 1999;4:355-367.

An acetabular reinforcement cage is required infrequently except when there is pelvic discontinuity in which there is no posterior column support of the acetabular cup. A larger cup inserted with cement and morselized bone graft is an effective technique for contained cavitary and anterior wall defects. Zone 1 osteolysis and a medial wall defect are essentially the same as a contained cavitary defect and can be reconstructed using cementless cups. Berry DJ, Lewallen DG, Hanssen A, Cabanela ME: Pelvic discontinuity in revision total hip arthroplasty. J Bone Joint Surg Am 1999;81:1692-1702.

A number of bioabsorbable polymers are used in orthopaedic applications, and all have in common reports of foreign body reactions, which occur in more than 50% of patients in some series. In general, the high cost of these polymers is offset by the elimination of a second surgery to remove the implant. Bioabsorbable polymers are low strength in comparison to metallic alloys but of sufficient strength for many orthopaedic applications. The elastic modulus is not as high as many other orthopaedic biomaterials, making them suitable for applications where lower stiffness is an asset. Ambrose CG, Clanton TO: Bioabsorbable implants: Review of clinical experience in orthopedic surgery. Ann Biomed Eng 2004;32:171-177.

Injuries to the MCL usually result from repetitive high valgus stress on the medial aspect of the elbow joint due to overhead throwing or racquet sports. Excessive stresses during the late cocking and acceleration phase of throwing can injure the anterior band of the MCL. Clinically, the injuries may present as chronic or acute, and a pop may be noted in the latter. Associated ulnar nerve involvement is common. Valgus instability is present in about 25% of patients. Patients typically are athletes who participate in throwing and have localized medial elbow pain and tenderness along the course of a ligament that extends from the medial epicondyle of the distal humerus to the sublime tubercle of the ulna. Surgical reconstruction is the procedure of choice in an athlete desiring a return to a high level of throwing. Miller MD, Cooper DE, Warner JJP (eds): Review of Sports Medicine and Arthroscopy. Philadelphia, PA, WB Saunders, 1995, p 230. Arendt EA (ed): Orthopaedic Knowledge Update: Sports Medicine 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, p 227.

The obturator artery lies closest to the transverse acetabular ligament. The femoral artery is closest to the anterior rim of the acetabulum. No named vessel lies within the substance of the gluteus minimus or superior to the piriformis tendon. The medial femoral circumflex artery lies medial or deep to the quadratus femoris muscle. Hoppenfeld S, deBoer P: Surgical Exposures in Orthopaedics: The Anatomic Approach, ed 1. Philadelphia, PA, JB Lippincott, 1984, Figure 7-53, p 346.

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

A concentric hip with acetabular dysplasia in a symptomatic patient is best treated by periacetabular osteotomy. The Salter osteotomy is less optimal because the method has limited correction, is uniaxial, cannot be tailored to the deformity, and lateralizes the entire hip joint, thereby increasing the joint reactive forces. Because the hyaline cartilage of the joint is histologically normal, rotating the hyaline cartilage into an optimal position is preferable to augmenting the acetabulum with a shelf or by Chiari osteotomy. Varus intertrochanteric osteotomy has no significant role in the treatment of acetabular dysplasia. Total hip arthroplasty may be required in the future but should not be the first choice.

Any patient who is severely symptomatic this quickly after surgery must be evaluated for infection. Loosening is also a possible cause, but infection must be ruled-out. Bone scans are not helpful at this early postoperative stage. Normal laboratory values argue strongly against infection, but when abnormal, need to be supplemented with a hip aspiration. Aspiration remains the most selective and sensitive measure, especially when linked to a WBC count of the synovial tissues in the joint. There is no indication for an antiobiotic trial because it may make future culture sensitivity more difficult. Drancourt M, Stein A, Argenson JN, et al: Oral rifampin plus ofloxacin for treatment of staphylococcus-infected orthopedic implants. Antimicrob Agents Chemother 1993;37:1214-1218. Duncan CP, Beauchamp C: A temporary antibiotic-loaded joint replacement system for the management of complex infections involving the hip. Orthop Clin North Am 1993; 24: 751-759.

The MRI scan reveals a rudimentary disk at the L5-S1 level, suggesting transitional anatomy. There is a posterior disk bulge at L3-4. At L4-5, there is disk desiccation and loss of disk height, with a posterior disk bulge and a high intensity zone in the posterior annulus, suggesting an annular tear. While these and similar radiographic findings have been associated with the severity of a patient's pain, they are also commonly found in cross-sectional studies of asymptomatic subjects. Carragee and associates found 59% of symptomatic patients undergoing diskography have high intensity zones as compared to 25% of asymptomatic subjects of a similar patient profile. Diskographic injections provoked pain in disks with high intensity zones approximately 70% of the time whether the individual was previously symptomatic or not. This patient's non-specific pain pattern does not require further work-up as she is not a surgical candidate. Carragee EJ, Paragioudakis SJ, Khurana S: 2000 Volvo Award winner in clinical studies: Lumbar high-intensity zone and discography in subjects without low back problems. Spine 2000;25:2987-2992. Pneumaticos SG, Reitman CA, Lindsey RW: Diskography in the evaluation of low back pain. J Am Acad Orthop Surg 2006;14:46-55. Brox JI, Sorensen R, Friis A, et al: Randomized clinical trial of lumbar instrumented fusion and cognitive intervention and exercises in patients with chronic low back pain and disc degeneration. Spine 2003;28:1913-1921.

Surgical curettage or en bloc resection is the treatment of choice for osteoid osteoma. Night pain and relief of symptoms with nonsteroidal anti-inflammatory drugs are classic findings for osteoid osteoma. Donley BG, Philbin T, Rosenberg GA, Schils JP, Recht M: Percutaneous CT guided resection of osteoid osteoma of the tibial plafond. Foot Ankle Int 2000;21:596-598. Kenzora JE, Abrams RC: Problems encountered in the diagnosis and treatment of osteoid osteoma of the talus. Foot Ankle 1981;2:172-178.

To mobilize the common iliac vessels across the midline, the iliolumbar vein must be ligated. It has a short trunk and can be torn if mobilization is attempted without ligation. It is the only branch off the common iliacs (there are no arterial branches) prior to the terminal branches, the internal (hypogastric) and external iliacs. The middle sacral vessels run distally from the axilla of the bifurcation and are a factor when accessing the L5-S1 disk. Baker JK, Reardon PR, Reardon MJ, et al: Vascular injury in anterior lumbar surgery. Spine 1993;18:2227-2230.

The most likely diagnosis is a stress fracture of the calcaneus and is supported by the history of running, female gender, and amenorrhea. Reproducing pain with medial and lateral compression of the heel also supports the diagnosis. A bone scan or MRI would most likely confirm the diagnosis. Plantar fasciitis would result in pain on the bottom of the heel with point tenderness. The lack of other areas of involvement or other symptoms does not support a seronegative inflammatory arthritis. Tarsal tunnel syndrome and peripheral neuropathy are unlikely because of the normal neurologic examination. Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 597-612.

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

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.

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

When performing a gastrocnemius slide at the tendinous portion of the gastrocnemius insertion, the sural nerve and saphenous vein, which tend to run midline posterior at this level, must be protected and retracted laterally. An anatomic study of the sural nerve at this level localized the nerve superficial to the deep fascia overlying the gastrocnemius in 42.5% of the cases; deep to the superficial fascia in 57.5% of the cases, and directly applied to the gastrocnemius tendon in 12.5% of cases. Pinney SJ, Sangeorzan BJ, Hanen ST Jr: Surgical anatomy of the gastrocnemius resection (Strayer procedure). Foot Ankle Int 2004;25:247-250.

The patient has a bucket-handle fracture of the distal femur with bilateral corner fractures of the distal femur and a transverse fracture of the proximal tibia. These fractures are virtually pathognomonic of child abuse. The infant should be admitted to the hospital, and child protection services should be notified for investigation of possible abuse. A skeletal survey should be obtained, along with laboratory studies that include a CBC, a platelet count, a prothrombin time, a partial thromboplastin time, and a bleeding time. Akbarnia BA: The role of the orthopaedic surgeon in child abuse, in Morrissy RT, Weinstein SL (eds): Lovell & Winter's Pediatric Orthopaedics, ed 4. Philadelphia, Pa, Lippincott-Raven, 1996, pp 1315-1334.

An epidural abscess with neurologic deficit represents a medical and surgical emergency. The prognosis is related to the timeliness of diagnosis and treatment. Once identified, the primary treatment is surgical decompression of the abscess, followed by organism-specific antibiotics. In the absence of a significant anterior process such as diskitis or vertebral osteomyelitis, lumbar epidural abscesses generally can be drained through a posterior approach. Delayed stabilization usually is not required unless, in the course of decompression, removal of too much of the facets creates an instability; this is an uncommon occurrence. Garfin SR, Vaccaro AR (eds): Orthopaedic Knowledge Update: Spine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1997, pp 257-271.

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.

In a traditional plate system, fracture security depends on the friction between the plate and the underlying bone. Bicortical fixation will decrease the toggle and improve stability. Locking plates absorb axial forces transmitted from the screws. Such plates do not require plate compression against the bone, thus preserving periosteal blood supply. Nana AD, Joshi A, Lichtman DM: Plating of the distal radius. J Am Acad Orthop Surg 2005;13:159-171.

The successful treatment of necrotizing soft-tissue infections such as clostridial myonecrosis depends on prompt recognition and aggressive surgical debridement of all involved muscle, fascia, and soft tissue, resecting to a clearly normal healthy, viable margin. The effective antibiotic regimen for clostridial infection is high-dose penicillin; however, necrotizing infections are frequently polymicrobial so initially broad-spectrum antibiotics are indicated. Hyperbaric oxygen therapy may be used as an adjunct to surgical treatment but is insufficient as a primary therapy. Prolonged application of tourniquets and wound closure should be avoided. Pellegrini VD, Evarts CM: Complications, in Rockwood CA Jr, Green DP (eds): Fractures in Adults, ed 3. Philadelphia, PA, JB Lippincott, 1991, pp 365-370. Gerding DN, Peterson LR: Infections caused by anaerobic bacteria, in Shulman ST, Phair JP, Peterson LR, Warren JR (eds): Infectious Diseases, ed 5. Philadelphia, PA, WB Saunders, 1997, pp 416-417.

The patient has a stable flexion-compression injury of the cervical spine. The fracture occurs as a result of compression failure of the vertebral body. If the force continues, a tension failure of the posterior structures occurs, leading to potential dislocation. Immobilization in a rigid cervical orthosis will allow this fracture to heal. Clark CR (ed): The Cervical Spine, ed 3. Philadelphia, PA, Lippincott-Raven, 1998, pp 457-464.

Success of a meniscal allograft transplantation is strongly dependent on accurate graft sizing, typically within 5% of the native meniscus. Previous studies have established that donor cell viability is not mandatory for the survival of these grafts since they are replaced by the recipient's cells (at least peripherally) within several weeks. Thus, cryopreservation of the graft to ensure cell viability is not necessary. There is a limited immune response to musculoskeletal allografts; therefore, immunosuppression, as is required for visceral organ transplantation, is not indicated. Wirth CA, Kohn D: Meniscal transplantation and replacement, in Fu FH, Harner CD, Vince JG (eds): Knee Surgery. Baltimore, MD, Williams & Wilkins, 1994, vol 1, pp 631-641. Brautigan BE, Johnson DL, Caborn DM, et al: Allograft tissues, in Drez D, DeLee JD, Miller MD (eds): Orthopaedic Sports Medicine: Principles and Practice, ed 2. Philadelphia, PA, WB Saunders, 2003, pp 205-213.

These lesions are emboli related to the cardiac surgery, and the patient is already on anticoagulation medication. The foot reveals no signs consistent with gangrene or infection. Unless the patient shows local or systemic signs of sepsis, the best management is observation. It is unlikely that formal debridement will be necessary. Bowker JH, Pfeiffer MA (eds): The Diabetic Foot. St Louis, MO, Mosby, 2001, pp 219-260.

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

Open reduction and internal fixation is the treatment of choice for accurate reduction of the disrupted intercarpal ligaments. In addition, the displaced scaphoid fracture will require open reduction and internal fixation and possible bone grafting. Closed reduction and long arm casting will not allow accurate reduction of the dislocated intracarpal intervals, and it is unlikely to allow accurate reduction of the scaphoid. The maneuver required to effect closed reduction of a displaced scaphoid fracture will most likely cause the scaphoid lunate interval to displace. Closed reduction with percutaneous pin fixation or with an external fixator is unable to effect anatomic reduction of the injury. Proximal row carpectomy is used as a salvage procedure for a variety of degenerative and posttraumatic problems of the wrist. Kozin SH: Perilunate injuries: Diagnosis and treatment. J Am Acad Orthop Surg 1998;6:114-120. Herzberg G, Comtet JJ, Linscheid RL, Amadio PC, Cooney WP, Stalder J: Perilunate dislocations and fracture-dislocations: A multicenter study. J Hand Surg Am 1993;18:768-779.

The history, examination, and MRI scan findings are consistent with a midsubstance partial rupture of the rectus femoris muscle. This is an injury masquerading as a "pseudo tumor." The lack of an appreciable mass effect on the T1-weighted MRI scan, the defined fluid signal on the T2-weighted scans, and the lack of significant contrast enhancement after gadolinium are all most consistent with injury rather than a neoplasm. Most of these injuries respond to nonsurgical management; a few will benefit from late debridement and repair if symptoms fail to resolve in 3 to 6 months. The treatment of choice is nonsurgical management with a follow-up MRI scan to verify that the findings are resolving. Hughes C IV, Hasselman CT, Best TM, et al: Incomplete, intrasubstance strain injuries of the rectus femoris muscle. Am J Sports Med 1995;23:500-506.

The best method of preventing wrong-site surgery is for the surgeon to initial the surgical site in the preoperative holding area after discussion and confirmation of the site with the patient. This should be done before sedating medications are administered. A recent study found that patient noncompliance with specific preoperative instructions to mark the site with a "yes" at home was surprisingly high; only 59% of the patients marked the extremity correctly and 37% made no mark. Noncompliance was higher in those with workers' compensation claims (70%) and those with previous related surgery (51%). DeGiovanni CW, Kang L, Manuel J: Patient compliance in avoiding wrong site surgery. J Bone Joint Surg Am 2003;85:815-819.

The surgeon perforated the anterior longitudinal ligament and injured the common iliac artery. Bingol and associates described injuries to the vascular structures during lumbar disk surgery. The common iliac artery was most commonly affected and constituted 76.9% of injuries.

Because the patient has sustained a tarsometatarsal injury with midfoot sag, the treatment of choice is a tarsometatarsal arthrodesis. The cause of his flatfoot deformity is secondary to the tarsometatarsal injury and not from posterior tibialis tendon deficiency. Lateral column lengthening, double arthrodesis, and calcaneal osteotomy are not indicated. Although open reduction and internal fixation may be performed late when arthritis is present, these procedures are less likely to succeed. Komenda GA, Myerson MS, Biddinger KR: Results of arthrodesis of the tarsometatarsal joints after traumatic injury. J Bone Joint Surg Am 1996;78:1665-1676.

The posterior circumflex artery provides blood supply only to the posterior portion of the greater tuberosity and a small posteroinferior portion of the humeral head. The humeral head is supplied primarily by the anterolateral ascending branch of the anterior circumflex artery; the terminal branch of this artery is termed the arcuate artery. Norris TR (ed): Orthopaedic Knowledge Update: Shoulder and Elbow 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 267-274.

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

The superior glenohumeral ligament (SGHL) and coracohumeral ligament serve as primary static restraints against inferior translation of the arm when the shoulder is in 0 degrees of abduction. Of these, the coracohumeral ligament has been shown to have a greater cross-sectional area, greater stiffness, and greater ultimate load than the SGHL. The inferior glenohumeral ligament plays a greater stabilizing role with increasing abduction of the arm. The coracoacromial ligament may help provide superior stability, especially when the rotator cuff is deficient. The coracoclavicular ligaments stabilize the acromioclavicular joint. Boardman ND, Debski RE, Warner JJ, et al: Tensile properties of the superior glenohumeral and coracohumeral ligaments. J Shoulder Elbow Surg 1996;5:249-254.

Flexion contractures and angular deformities of a limb cause inaccurate limb-length measurement results with most clinical methods. A CT scanogram is more accurate than standard scanograms for determining limb length in patients with knee flexion contractures of 30 degrees or more. The cost and time necessary to complete the examinations are comparable, but the CT scanogram delivers only 20% of the radiation needed for standard scanograms. Aaron A, Weinstein D, Thickman D, Eilert R: Comparison of orthoroentgenography and computed tomography in the measurement of limb-length discrepancy. J Bone Joint Surg Am 1992;74:897-902.

Because the patient is skeletally mature with a curve of less than 40 degrees, there is no benefit to bracing and surgery is not indicated. Management should consist of observation and follow-up radiographs in 6 months. Lonstein JE, Carlson JM: The prediction of curve progression in untreated idiopathic scoliosis during growth. J Bone Joint Surg Am 1984;66:1061-1071.

Osteoporotic vertebral compression fractures are associated with neurologic complications in less than 1% of patients. After the initial fracture however, patients have a 20% risk of further fractures. The mortality rate of patients with vertebral fractures exceeds that of patients with hip fractures when they are followed beyond 6 months. Gass M, Dawson-Hughs B: Preventing osteoporosis-related fractures: An overview. Am J Med 2006;119:S3-S11. Lindsay R, Silverman SL, Cooper C, et al: Risk of new vertebral fracture in the year following a fracture. JAMA 2001;285:320-323.

The radiographs show polyethylene wear, but exchange of this will not necessarily provide pain relief. The presence of pain suggests the possibility of occult loosening, and the surgeon must be prepared for this option intraoperatively. There is little evidence of infection. Rand JA, Peterson LF, Bryan RS, Ilstrup DM: Revision total knee arthroplasty, in Anderson LD (ed): Instructional Course Lectures XXXV. Park Ridge, IL, American Academy of Orthopaedic Surgeons, 1986, pp 305-318.

The patient has a dislocation of the elbow with displaced coronoid process and radial head fractures. The elbow is extremely unstable after this injury, and recurrent dislocation in a splint is the most common early complication. Skeletal stabilization of the fractures is required to restore stability of the joint. Characteristics of the fractures will determine the techniques required to restore stability. Ring D, Jupiter JB, Zilberfarb J: Posterior dislocation of the elbow with fractures of the radial head and coronoid. J Bone Joint Surg Am 2002;84:547-551.

All of the options, except cementing the metaphyseal portion and press fitting the keel of the tibial component, have been shown to create strong and long-lasting constructs; however, cementing of both the platform and the keel offers the most predictable solution. Cementing the platform and not the keel has been shown to have a higher loosening rate than the more traditional methods of fully cementing or using screws to augment fixation.

Although opinions differ on whether a decompression is indicated in a patient with symptomatic basilar invagination, it is generally agreed that occipitocervical stabilization is indicated. This has been done with and without concomitant arthrodesis. Crockard HA, Grob D: Rheumatoid arthritis upper cervical involvement, in Clark CR (ed): The Cervical Spine, ed 3. Philadelphia, PA, Lippincott Raven, 1998, p 701.

Zirconia as a bearing surface is "metastable," meaning that, in the microstructure of the material the zirconia molecules are ordered in a tetragonal fashion, but they can easily transform to a monoclinic microstructure that is less wear resistant. Transformation can occur with input of enough energy (eg, thermal energy imparted by steam sterilization or mechanical energy at the bearing surface). Zirconia was introduced as an alternative to alumina because it has a higher toughness, making it less susceptible to gross fracture (ceramics do not undergo fatigue fracture, but rather fail from a process of slow crack growth). Zirconia is highly biocompatible (as are many ceramics) and is essentially immune to corrosive processes that can plague metallic alloys such as stainless steel. Clarke IC, Manaka M, Green DD, et al: Current status of zirconia used in total hip implants. J Bone Joint Surg Am 2003;85:73-84. Haraguchi K, Sugano N, Nishii T, et al: Phase transformation of a zirconia ceramic head after total hip arthroplasty. J Bone Joint Surg Br 2001;83:996-1000.

In local gigantism, a ray resection allows proper fitting of shoes. The ray resection narrows the foot and shortens the length. The foot may require further surgery with growth. Debulking, physeal arrest, and distal phalanx amputation are unlikely to be effective. Turra S, Santini S, Cagnoni G, Jacopetti T: Gigantism of the foot: Our experience in seven cases. J Pediatr Orthop 1998;18:337-345.

The most common clinical presentation of a patient with a malignant bone tumor is pain. Malignant bone tumors rarely are diagnosed as an incidental finding or pathologic fracture. In patients who have a pathologic fracture on initial presentation, a history of increasing pain prior to the fracture is typical. While 90% of malignant bone tumors are associated with a soft-tissue mass, in many patients the soft-tissue component of the tumor is not clinically apparent. Buckwalter JA: Musculoskeletal neoplasms and disorders that resemble neoplasms, in Weinstein SL, Buckwalter JA (eds): Turek's Orthopaedics: Principles and Their Application, ed 5. Philadelphia, PA, JB Lippincott, 1994, pp 290-295.

The MRI scans clearly show an extruded L4-5 disk that is affecting the L5 nerve root on the left side. In addition, the L5 nerve root has a cutaneous distribution in the first dorsal web space. S1 affects the lateral foot. L4 affects the medial calf.

Four years after surgery, more than 90% of patients are satisfied with the cosmetic appearance of the iliac donor site scar. Approximately 25% still have pain and/or functional difficulty, including 12.7% who still report difficulty with ambulation, 11.9% difficulty with recreational activities, 7.5% with sexual intercourse, and 11.2% require pain medication for iliac donor site symptoms. Silber JS, Anderson DG, Daffner SD, et al: Donor site morbidity after anterior iliac crest bone harvest for single-level anterior cervical discectomy and fusion. Spine 2003;28:134-139.

Approximately one half of patients with juvenile rheumatoid arthritis (JRA) have the pauciarticular form, which by definition includes only patients with fewer than five joints involved. The peak period of onset is between the ages of 2 and 4 years, with half of the affected children coming to medical attention before age 4 years. The knee is most often affected, with the ankle-subtalar and elbow joints next in frequency. The average duration of the disease is 2 years and 9 months, with half the cases lasting less than 2 years. Arthritis, in Herring JA (ed): Tachdjian's Pediatric Orthopaedics, ed 3. St Louis, MO, WB Saunders, 2002, pp 1811-1839.

Latissimus dorsi tendon transfer is considered a surgical option for treatment in patients with chronic supraspinatus and infraspinatus tendon tears. Preoperative subscapularis function is necessary for good clinical results. Additionally, men with active elevation to shoulder level and active external rotation to 20 degrees have predictably good results. Women with active shoulder elevation limited to below chest level have poor results from this procedure and should not be considered candidates. Postoperatively they lack pain control, active elevation, and active external rotation. Muscular atrophy in the latissimus dorsi does not occur, and glenohumeral arthritic changes frequently develop postoperatively. Gerber C, Maquieira G, Espinosa N: Latissimus dorsi transfer for the treatment of irreparable rotator cuff tears: Factors affecting outcome. J Bone Joint Surg Am 2006;88:113-120.

Although the classic radiographic appearance of fibrous dysplasia is one of a central metaphyseal lesion with ground glass matrix, it is not unusual to see either a more radiodense-appearing lesion or a more peripheral location. The histologic finding of spicules of woven bone without osteoblastic rimming in a bland fibrous background is diagnostic of fibrous dysplasia. The imaging studies could be consistent with low-grade osteosarcoma, osteoblastoma, or osteomyelitis, but all have a very different histologic picture. Observation is indicated in the absence of symptoms, impending fracture, or deformity. Fibrous dysplasia most commonly occurs in the proximal femur. Huvos AG: Bone Tumors: Diagnosis, Treatment, and Prognosis. Philadelphia, PA, WB Saunders, 1991, pp 30-43.

The radiographic appearance shows a slightly expansile lesion in the proximal phalanx of the fifth digit typical of an enchondroma. There is a stippled appearance within the bone and no evidence of cortical destruction. The biopsy reveals a cartilage lesion with basophilic cytoplasm. There are some hypercellular areas but no evidence of pleomorphism. Enchondromas in the tubular bones of the hand are usually more cellular than their counterparts in the femur and humerus and should not be considered malignant. No other lesions are noted in the radiograph, so a diagnosis of Ollier's disease cannot be made. An osteochondroma is a benign surface cartilage tumor. Brown tumor and osteomyelitis can be differentiated from enchondroma based on the histology. Wold LE, Adler CP, Sim FH, et al: Atlas of Orthopedic Pathology, ed 2. Philadelphia, PA, WB Saunders, 2003, p 225.

Large cementless acetabular components have been shown to perform well in revision acetabular reconstruction. The use of such components is predicated on the presence of adequate anterior and posterior column bone. If a good press-fit can be achieved between the anterior and posterior columns, typically, the remaining defects can be filled with morcellized bone graft. Protrusio cages are typically used in situations where it is not possible to obtain adequate fixation with a large acetabular component. The use of a high hip center with small sockets is more typical of primary arthroplasty in patients with developmental dysplasia of the hip. Bulk acetabular allografts for large segmental defects might be necessary in certain situations, although the use of bulk allografts has resulted in a high failure rate after 5 years. Early results of the use of protrusio cages and bone grafting for large segmental defects have been favorable. Petrera P, Rubash HE: Revision total hip arthroplasty: The acetabular component. J Am Acad Orthop Surg 1995;3:15-21.

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.

Prosthetic shoulder arthroplasty has been shown to provide predictable results for treating stage III and stage IV osteonecrosis of the humeral head. The decision to resurface the glenoid (total shoulder arthroplasty versus humeral hemiarthroplasty) usually is made based on the radiographic and intraoperative appearance of the glenoid. Core decompression of the humeral head has been reported to be effective for earlier stages (pre collapse) but would not be appropriate for a patient with stage IV disease. Hattrup SJ, Cofield RH: Osteonecrosis of the humeral head: Results of replacement. J Shoulder Elbow Surg 2000;9:177-182. L'Insalata JC, Pagnani MJ, Warren RF, et al: Humeral head osteonecrosis: Clinical course and radiographic predictors of outcome. J Shoulder Elbow Surg 1996;5:355-361.

The modified Hardinger approach includes a partial anterior trochanteric osteotomy creating a trochanteric wafer (as seen on the radiograph) that is displaced anterior and medial in continuity with the gluteus medius and vastus lateralis. Failure of abductor reattachment, migration of the trochanter, nonunion of the osteotomy site, and excessive splitting of the gluteus medius muscle causing injury to the inferior branch of the superior gluteal nerve can result in weakness of the abductor mechanism. Abductor strength should be evaluated with the patient lying on the opposite side and elevating the affected limb. Although slight weakness may manifest itself as a limp only after prolonged muscular activity, significant weakness results in a constant limp without associated discomfort. Morrey BF (ed): Joint Replacement Arthroplasty. New York, NY, Churchill Livingstone, 1991, pp 512-526.

Morphologic and anatomic studies confirm the pedicle is smaller on the concave side of thoracic curves. The dura is also closer to the pedicle on the concave side of the curves. Liljenqvist U, Allkemper T, Hackenberg L, et al: Analysis of vertebral morphology in idiopathic scoliosis with use of magnetic resonance imaging and multiplanar reconstruction. J Bone Joint Surg Am 2002;84:359-368.

The floating elbow is best managed with early open reduction and internal fixation of the humeral and forearm fractures, followed by early range of motion. These fractures predispose the elbow to stiffness, and early range of motion is recommended. Solomon HB, Zadnik M, Eglseder WA: A review of outcomes in 18 patients with floating elbow. J Orthop Trauma 2003;17:563-570.

The inability to single leg hop is considered the best indicator of a syndesmosis ankle sprain without diastasis. Tenderness along the syndesmosis, the deltoid, or over the anterior talofibular ligament or anterior distal tibia/fibula may present later, following the initial injury. The squeeze test and tenderness with dorsiflexion and external rotation may be positive but often are not present initially. The best determinant for prediction of return to play is the amount of tenderness along the syndesmosis, measured from the distal fibula up the syndesmosis. Nussbaum ED, Hosea TM, et al: Prospective evaluation of syndesmosis ankle sprains without diastasis. Am J Sports Med 2001;29:31-35. Miller CD, Shelton WR, Barrett GR, et al: Deltoid and syndesmosis ligament injury of the ankle without fracture. Am J Sports Med 1985;23:746-750.

Ewing's sarcoma typically can occur in the diaphysis of the long bones (50% to 55%). It is often accompanied by a large soft-tissue mass. Abnormal findings are common, including a low-grade fever, an elevated ESR, and leukocytosis. The histology is consistent with a small round blue cell tumor. The unique pathology and other findings exclude osteosarcoma. Giant cell tumor and chondrosarcoma have a different histologic appearance and typically are more metaphyseal in location. Chondrosarcoma typically is found in older age groups, has a different histologic pattern, and rarely occurs in the midshaft of the femur.

The patient was admitted to the hospital with sepsis. The sepsis has resolved, leaving the patient with a negative nitrogen balance. Now that the patient is stable, metabolic support should be used to optimize his nutrition. If the serum albumin can be increased to 2.5 g/dL, he has an excellent potential to heal an amputation at the Syme ankle disarticulation level; a level that will optimize his functional independence. Pinzur MS, Stuck RR, Sage R, et al: Syme ankle disarticulation in patients with diabetes. J Bone Joint Surg Am 2003;85:1667-1672.

Contraindications to primary total knee arthroplasty include active infection, an incompetent extensor mechanism, compromised vascularity in the extremity, and local neurologic disruption affecting the competence of the musculature about the knee. Anterior cruciate, posterior cruciate, or lateral ligament incompetence can be managed with primary total knee arthroplasty. Mild flexion contracture and previous high tibial valgus osteotomy are not contraindications to primary total knee arthroplasty.

Full exposure of the volar plate of the proximal interphalangeal joint of the finger is best accomplished by incision of the distal C1, A3, and proximal C2 pulleys; followed by gentle retraction of the flexor digitorum superficialis and profundus tendons. Sacrifice of the A3 pulley, although associated with some biomechanic disadvantage, can be tolerated without causing functionally limiting bowstringing of the flexor tendon. Sacrifice of even a portion of the A2 or A4 pulleys can decrease the biomechanic leverage provided by the flexor tendon sheath, leading to bowstringing of the flexor tendons. Hoppenfeld S, deBoer P: Surgical Exposures in Orthopaedics, ed 2. Philadelphia, PA, Lippincott-Raven, 1994, pp 176-186. Strickland J: Flexor tendon-acute injuries, in Green DP, Hotchkiss RN, Pederson WC (eds): Green's Operative Hand Surgery, ed 4. New York, NY, Churchill Livingstone, 1999, vol 2, pp 1853-1855.

The strongest biomechanical construct is posterior to anterior fixation with the entry point being at the level of the posterolateral tubercle of the talus. This uses the interval between the peroneus brevis and the flexor hallucis longus. The interval between the flexor digitorum longus and the flexor hallucis longus with entry at the posteromedial tubercle of the talus is not an accepted approach for fixation of talar neck fractures. All of the other options use screw placements from anterior to posterior. Swanson TV, Bray TJ, Homes GB Jr: Fractures of the talar neck: A mechanical study of fixation. J Bone Joint Surg Am 1992;74:544-551.

Measurements of compartment pressures in patients with tibial fractures and compartment syndrome reveal that the highest tissue pressures are recorded at the level of the fracture or within 5 cm of the fracture. Tissue pressures show a statistically significant decrease when they are recorded at increasing distances proximal and distal to the site of the highest pressure recorded. To reliably determine the location of the highest tissue pressure in patients with tibial fractures, measurements should be obtained, at a minimum, in both the anterior and deep posterior compartments at the level of the fracture, as well as at locations proximal and distal. The highest tissue pressure recorded should serve as a basis for determining the need for fasciotomy. Heckman MM, Whitesides TE Jr, Grewe SR, Rooks MD: Compartment pressure in association with closed tibial fractures: The relationship between tissue pressure, compartment, and the distance from the site of the fracture. J Bone Joint Surg Am 1994;76:1285-1292.

The dorsal digital cutaneous nerve of the great toe is a branch of the medial branch of the superficial peroneal nerve. The deep peroneal nerve supplies the first web space. McMinn RMH, Hutchings RT, Logan BM: Color Atlas of Foot and Ankle Anatomy. Weert, Netherlands, Wolfe Medical Publications, 1982, p 50.

The etiology of hip fractures in the elderly is multifactorial, and intervention and prevention can occur at multiple points. Events leading to hip fracture from a fall include fall initiation (during which the individual's neuromuscular status, cognitive status, and vision come into play along with environmental hazards); fall descent (fall direction toward the side being the most influential, energy content of the fall, and fall height, along with muscle activity of the muscles of the thigh); impact (impact location, soft-tissue attenuation such as from trochanteric padding or from overlying fat, impact surface, and muscle activity); and the structural capacity of the femur (bone mineral density, bone geometry, and bone architecture). Hayes and Myers noted that striking the ground in a stiff state with the trunk muscles contracted actually increased the peak impact force, whereas falling in a relaxed state actually reduced peak impact force. Flexion of the trunk at impact had no bearing on the impact force. Direction of the fall was important; falls to the side, not forward, were associated with an increased risk of hip fracture. Increased muscle activity about the hip is thought to be associated with spontaneous fractures of the hip and may actually account for up to 25% of hip fractures; however, it is not related to fractures resulting from a fall.

The degree of acetabular dysplasia and the age of the child are important considerations when choosing what type of osteotomy to perform. The ability to obtain concentric reduction is a prerequisite of all osteotomies that redirect the acetabulum. Procedures that cut all three pelvic bones allow more displacement and, therefore, correction of acetabular dysplasia. The closer the osteotomy is to the acetabulum, the greater the coverage of the femoral head. Compared with the other acetabular osteotomies, the Ganz periacetabular osteotomy provides the greatest potential for correcting acetabular deficiency because there are no bone or ligamentous restraints to limit correction, but it has the disadvantage of being a technically demanding procedure. The amount of coverage provided by the Salter osteotomy is limited. Millis MB, Poss R, Murphy SB: Osteotomies of the hip in the prevention and treatment of osteoarthritis, in Eilert RE (ed): Instructional Course Lectures XLI. Rosemont, Ill, American Academy of Orthopaedic Surgeons, 1992, pp 145-154.

The CT scans show large cystic lesions in the talus and calcaneus with complete subluxation of the subtalar joint, allowing the calcaneus to slide laterally until it becomes blocked by the fibula. The cause of this subluxation is severe posterior tibial tendon dysfunction. Although no fibular fracture has yet appeared, it can occur with continued stress from the calcaneus. There is, however, a pathologic fracture in the medial calcaneus through a medial degenerative cyst. The joint space is irregular and not symmetrical as would be seen in an inflammatory arthropathy. Cystic lesions are not present in the tibia. No stress fracture is seen in the talus. Coughlin MJ: 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 437-499.

The patient has a displaced radial neck fracture. Displaced radial neck fractures with angulation of more than 30 to 45 degrees require reduction. Methods of attempted closed reduction include wrapping the arm with an Esmarch's bandage and applying direct pressure over the maximum deformity of the radial head. More aggressive methods include a Kirschner wire used as a joystick or intramedullary reduction as described by the Metaizeau technique. Open reduction should be avoided because of complications such as stiffness or osteonecrosis. Indications for open reduction are irreducible displacement of more than 45 degrees with severe restriction of forearm rotation. 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. Radomisli TE, Rosen AL: Controversies regarding radial neck fractures in children. Clin Orthop 1998;353:30-39. Skaggs DL, Mirzayan R: The posterior fat pad sign in association with occult fracture of the elbow in children. J Bone Joint Surg Am 1999;81:1429-1433.

Posterior screw fixation of the upper cervical spine has gained a great deal of popularity due to its stable fixation, obviating the use of halo vest immobilization, and its high fusion rates. The use of screws in this location, however, has introduced a whole new set of potential complications. Vertebral artery injury is one of the most feared complications associated with screws in the C1/C2 region. This structure, however, is lateral and posterior at the C2 level and then penetrates the foramen transversarium of C1 to lie cephalad to the arch of C1 before entering the foramen magnum. It is the internal carotid artery that lies immediately anterior to the arch of C1 that is particularly at risk by anterior penetration of C1 lateral mass or C1-C2 transarticular screws as demonstrated by Currier and associates. The internal carotid artery lies posterior to the pharynx. The external carotid artery and the glossopharyngeal nerve are not at risk with this method of fixation. Currier BL, Todd LT, Maus TP, et al: Anatomic relationship of the internal carotid artery to the C1 vertebra: A case report of cervical reconstruction for chordoma and pilot study to assess the risk of screw fixation of the atlas. Spine 2003;28:E461-E467. Grant JC: Grant's Atlas of Anatomy, ed 6. Baltimore, MD, Williams & Wilkins, 1972.

Because the patient has clinical and radiographic signs of AC arthritis and subacromial impingement, the treatment of choice is anterior acromioplasty and distal clavicle excision. Arthroscopic acromioplasty alone would not address the AC arthritis. The rotator cuff is intact; therefore, rotator cuff repair is not indicated. An open Mumford procedure would address the AC arthritis only and not the impingement symptoms. Immobilization might lead to stiffness of the shoulder and is not recommended for treating impingement.

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.

The radiographs show multiple carpometacarpal dislocations. Reduction is often obtainable but difficult to maintain. Internal fixation is required to maintain the reduction, preferably with Kirschner wires. Closed reduction and percutaneous pinning is preferred by some surgeons. Others recommend open reduction to remove irreconstructable osteochondral fragments from the individual joints and to ensure correct reduction of the carpometacarpal joints. Kirschner wires are removed at 6 to 8 weeks. Prokuski LJ, Eglseder WA Jr: Concurrent dorsal dislocations and fracture-dislocations of the index, long, ring, and small (second to fifth) carpometacarpal joints. J Orthop Trauma 2001;15:549-554.

The overriding factor determining treatment in this case is the appearance of the surgical wound. Based on MacPhearson's work, this "C" wound is best managed with two-stage exchange. The functional outcome is markedly diminished following a knee arthrodesis compared to revision knee arthroplasty. Harwin SF: The diagnosis and management of infected total knee replacement. Seminars Arthroplasty 2002;13:9-22. Goldmann RT, Scuderi GR, Insall JN: 2-stage reimplantation for infected total knee replacement. Clin Orthop 1996;331:118-124.

The patient has symptomatic grade IV Brooker heterotopic ossification. Once the bone has matured, it can be excised. Surgical excision should be combined with postoperative irradiation to avoid recurrence. Pharmacologic and irradiation intervention are not successful beyond the perioperative period unless they are combined with surgical excision of mature heterotopic ossification. Koval KJ (ed): Orthopaedic Knowledge Update 7. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 417-451.

Any of the above conditions is credible with a limited history. The MRI scan unequivocally shows the stress fracture in the distal tibia. Most tibial stress fractures can be managed with rest and immobilization. Boden BP, Osbahr DC: High risk stress fractures: Evaluation and treatment. J Am Acad Orthop Surg 2000;8:344-353.

The most likely diagnosis is transient synovitis. Initial management should consist of bed rest and serial observation to rule out atypical septic arthritis of the hip. In an unreliable family situation, hospitalization for bed rest and observation may be indicated. Other disorders such as proximal femoral osteomyelitis, leukemia, juvenile rheumatoid arthritis, pelvic osteomyelitis, diskitis, and arthralgia secondary to other inflammatory disorders should be considered. However, these disorders are unlikely because of the paucity of abnormal clinical signs exhibited by the patient. On the other hand, transient synovitis of the hip in children is a diagnosis of exclusion; other possibilities should be explored if the patient's symptoms do not follow a typical course and resolve in 4 to 21 days.

The patient has a severe Sanders type 4 calcaneus fracture. By far the most common complication associated with surgical treatment of calcaneus fractures is wound dehiscence. Sanders R: Displaced intra-articular fractures of the calcaneus. J Bone Joint Surg Am 2000;82:225-250.

Although thoracic disk herniations have been reported at all levels of the thoracic spine, more than two thirds are found at T9-T12, which is the more mobile lower third of the thoracic region. Belanger TA, Emery SE: Thoracic disc disease and myelopathy, in Frymoyer JW, Wiesel SW (eds): The Adult and Pediatric Spine. Philadelphia, PA, Lippincott Williams and Wilkins, 2004, pp 855-864.

Positioning of the femoral and tibial components is a common cause of early failure of total knee arthroplasty. Two modes of possible position are raising or lowering the joint line from its anatomic level. Raising or lowering the joint line beyond an established threshold can cause limited range of motion, poor patellar function, and possible instability. It has been determined that a threshold of approximately 8 mm provides consistently good results after knee arthroplasty.

Engh and associates reported on the results of 63 knees (56 patients) following polyethylene exchange. The mean interval between exchange and the index total knee arthroplasty was 59 months. The mean follow-up after exchange was 7.4 years. Seven of 48 knees with adequate follow-up failed. Greater failure occurred if there was more severe wear before the exchange. Greater undersurface wear also resulted in a higher failure rate. Perioperative osteolysis or intraoperative observation of metallosis did not have an impact on the failure of polyethylene exchange. The risk of infection is no different from other total knee arthroplasty revisions. Wasielewski RC, Parks N, Williams I, et al: Tibial insert undersurface as a contributing source of polyethylene wear debris. Clin Orthop 1997;345:53-59.

Long-term radiographic analysis of cemented total hips supports the creation of a 2- to 5-mm cement mantle in the proximal medial region. Autopsy studies have shown that the incidence of crack formation was greatest when the cement mantle was less than 2 mm. Ebramzadeh E, Sarmiento A, McKellop HA, Llinas A, Gogan W: The cement mantle in total hip arthroplasty: Analysis of long-term radiographic results. J Bone Joint Surg Am 1994;76:77-87. Jasty M, Maloney WJ, Bragdon CR, O'Connor DO, Haire T, Harris WH: The initiation of failure in cemented femoral components of hip arthroplasty. J Bone Joint Surg Br 1991;73:551-558.

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

This is a nonossifying fibroma of the proximal tibia. The lesion is eccentric, cortically based, with sclerotic margins and no evidence of a soft-tissue mass. Nonossifying fibromas are benign lesions that need no biopsy or surgical treatment when classic findings appear on radiographs. A follow-up radiograph should be performed 2 to 3 months after the initial presentation to ensure that the lesion is not progressive. Surgery is reserved for large lesions with risk of pathologic fracture or for cases where a displaced pathologic fracture has occurred and internal fixation is needed for fracture treatment. Nondisplaced pathologic fractures through nonossifying fibromas are best treated by allowing the fracture to heal and observation of the lesion. Vaccaro AR (ed): Orthopaedic Knowledge Update 8. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2005, pp 197-215.

Boden and associates' recent article presents significant evidence that patients with rheumatoid arthritis, neurologic deterioration, and C1-2 instability are more likely to improve after surgery if the posterior alanto-odontoid interval is greater than 10 mm preoperatively. The accepted safe range for the posterior atlanto-odontoid interval is 14 mm. This measurement is believed to better represent the space available for the cord than the anterior alanto-odontoid interval. Garfin SR, Vaccaro AR (eds): Orthopaedic Knowledge Update: Spine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1997, pp 273-279. Boden SD, Dodge LD, Bohlman HH, Rechtine GR: Rheumatoid arthritis of the cervical spine: A long-term analysis with predictors of paralysis and recovery. J Bone Joint Surg Am 1993;75:1282-1297.

The failure load of an evenly tensioned four-stranded hamstring tendon autograft has been reported to be 4,500 Newtons. The failure load of a 10-mm patellar tendon autograft has been estimated at 2,600 Newtons. The intact anterior cruciate ligament failure load has been calculated at 1,725 Newtons. Corry IS, Webb JM, Clingeleffer AJ, Pinczewski LA: Arthroscopic reconstruction of the anterior cruciate ligament: A comparison of patellar tendon autograft and four-strand hamstring tendon autograft. Am J Sports Med 1999;27:448-454. Hamner DL, Brown CH Jr, Steiner ME, et al: Hamstring tendon grafts for reconstruction of the anterior cruciate ligament: Biomechanical evaluation of the use of multiple strands and tensioning techniques. J Bone Joint Surg Am 1999;81:549-557.

The CT scans show evidence of a lateral wall blowout and malunion without significant arthrosis of the subtalar joint. In a young patient, it is preferable to avoid a fusion and allow residual motion by performing an exostectomy that decompresses the lateral subtalar joint and peroneal tendons. Chandler JT, Bonar SK, Anderson RB, et al: Results of in situ subtalar arthrodesis for late sequelae of calcaneus fractures. Foot Ankle Int 1999;20:18-24.

In general, soft-tissue metastases to regional nodes are a relatively rare occurrence (less than 5% overall). The incidence of lymphatic metastasis is highest for synovial sarcoma, rhabdomyosarcoma, clear cell sarcoma, and epithelioid sarcoma. Regional nodes should be assessed clinically. CT is not used to routinely assess regional nodes. Evaluation of a sentinal node is not indicated because of the low incidence of regional nodal involvement. Fine needle aspiration may be indicated to assess clinically suspicious nodes. Prophylactic inguinal node dissection is contraindicated because it may lead to unnecessary complications such as lymphedema.

In approximately 15% of children with Down syndrome, atlantoaxial instability develops because of ligament laxity, making them susceptible to spinal cord injury with relatively minor trauma. The American Academy of Pediatrics recommends lateral flexion-extension views of the cervical spine in any patient with Down syndrome who wishes to participate in sports. A normal ADI is up to 4 mm. Patients with Down syndrome with an ADI of more than 5 mm should not participate in contact sports or sports with a high risk for neck injury, such as diving, gymnastics, high jump, or butterfly stroke. Cervical fusion has a very high rate of complications in patients with Down syndrome and is recommended only for patients who have myelopathic signs or symptoms. Atlantoaxial instability in Down syndrome: Subject review. American Academy of Pediatrics Committee on Sports Medicine and Fitness. Pediatrics 1995;96:151-154. Tredwell SJ, Newman DE, Lockitch G: Instability of the upper cervical spine in Down syndrome. J Pediatr Orthop 1990;10:602-606.

The majority of mallet fractures can be treated nonsurgically with a distal interphalangeal joint extension splint. Excellent results can be obtained in most patients with splinting alone. The fragment size, amount of displacement, and degree of articular incongruity usually do not affect final outcome, as long as the joint is reduced. Surgical fixation takes on several forms but is fraught with complications including skin/wound problems, loss of fixation, nonunion, and stiffness of the distal interphalangeal joint. Volar subluxation of the distal phalanx remains the primary indication for surgical treatment. Green DP, Butler TE Jr: Fractures and dislocations in the hand, in Rockwood CA, Green DP, Bucholz RW, Heckman JD (eds): Rockwood and Green's Fractures in Adults, ed 4. Philadelphia, PA, Lippincott-Raven, 1996, pp 621-623.

Scuderi and associates reported on patellar height after a high tibial osteotomy. Eighty-nine percent of the patellae, as measured by the Insall-Salvati index, and 76.3 percent, as measured by the Blackburne-Peel index, were observed to be lowered. More recently, Wright and associates reported a 64% incidence of patella baja in patients undergoing a medial opening wedge osteotomy. The incidence of intra-articular fracture during medial opening wedge osteotomy has been reported to be as high as 11% by Hernigou and associates, whereas the incidence of intra-articular fracture during lateral closing wedge high tibial osteotomy has been reported to be 10% to 20% by Matthews and associates. The incidence of peroneal nerve palsy with a lateral closing wedge high tibial osteotomy ranges from 0% to 20%, according to Marti and associates, whereas the incidence of peroneal palsy following a medial opening wedge osteotomy has been reported to be 15.7% by Flierl and associates. The exact incidence of compartment syndrome after a high tibial osteotomy is not known; however, it does not reach the level of patella baja. The incidence of deep infection after a lateral closing wedge high tibial osteotomy ranges from 0% to 4% according to Billings and associates. Scuderi GR, Windsor RE, Insall JN: Observations on patellar height after proximal tibial osteotomy. J Bone Joint Surg Am 1989;71:245-248. Wright JM, Crockett HC, Slawski DP, et al: High tibial osteotomy. J Am Acad Orthop Surg 2005;13:279-289. Hernigou P, Medevielle D, Debeyre J, et al: Proximal tibial osteotomy for osteoarthritis with varus deformity: A ten to thirteen-year follow-up study. J Bone Joint Surg Am 1987;69:332-354. Matthews LS, Goldstein SA, Malvitz TA, et al: Proximal tibial osteotomy: Factors that influence the duration of satisfactory function. Clin Orthop 1988;229:193-200. Marti CB, Gautier E, Wachtl SW, et al: Accuracy of frontal and sagittal plane correction in open-wedge high tibial osteotomy. Arthroscopy 2004;20:366-372. Marti RK, Verhigan RA, Kerkhoffs GM, et al: Proximal tibial varus osteotomy: Indications, technique, and five to twenty-one-year results. J Bone Joint Surg Am 2001;83:164-170. Flierl S, Sabo D, Hornig K, et al: Open wedge high tibial osteotomy using fractioned drill osteotomy: A surgical modification that lowers the complication rate. Knee Surg Sports Traumatol Arthrosc 1996;4:149-153.

Complete rupture of the PCL leads to increased contact pressures in the patellofemoral and medial compartments of the knee. However, whether degenerative arthritis will develop and in which compartments still remains controversial.

The oblique nature of the fracture and extension of the fracture to the condyles implies an unstable fracture. Lag screw fixation provides an excellent chance of union, and the ability to start early range of motion. Stern PJ: Fractures of the metacarpals and phalanges, in Green DP, Hotchkiss RN, Pederson WC, et al (eds): Green's Operative Hand Surgery, ed 5. Philadelphia, PA, Elsevier, 2005, p 281.

In adults, a direct blow on the acromion usually results in an acromioclavicular dislocation. In children, however, the usual injury from this mechanism is a physeal fracture of the lateral clavicle. The clavicular shaft fragment, analogous to the metaphyseal portion of a physeal fracture, herniates through the periosteum, leaving the distal periosteal sleeve in contact with the lateral (distal) physeal fragment. The treatment of choice is immobilization until the patient is pain-free. Falstie-Jensen S, Mikkelsen P: Pseudodislocation of the acromioclavicular joint. J Bone Joint Surg Br 1982;64:368-369.

Rib penciling is the only singular factor; 87% of the curves progressed significantly in patients with three or more penciled ribs. Modulation in neurofibromatosis scoliosis implies the change from an idiopathic type to a dysplastic type of curve with rapid progression and the need for aggressive stabilization by fusion. Crawford AH, Schorry EK: Neurofibromatosis in children: The role of the orthopaedist. J Am Acad Orthop Surg 1999;7:217-230.

The radiographs reveal a scaphoid fracture with displacement and comminution and an unstable fracture pattern. Treatment should consist of open reduction and internal fixation. In displaced scaphoid fractures and fractures with unstable fracture patterns, closed reduction is ineffective and is likely to lead to nonunion. Limited intercarpal fusion and proximal row carpectomy are used to correct a variety of traumatic and posttraumatic problems of the wrist. Amadio PC, Taleisnik J: Fractures of the carpal bone, in Green DP, Hotchkiss RN, Pederson WC (eds): Green's Operative Hand Surgery, ed 4. Philadelphia, PA, 1999, pp 809-823. Rettig ME, Kozin SH, Cooney WP: Open reduction and internal fixation of acute displaced scaphoid waist fractures. J Hand Surg Am 2001;26:271-276. Cooney WP, Dobyns JH, Linscheid RL: Fractures of the scaphoid: A rational approach to management. Clin Orthop 1980;149:90-97.