AAOS Foot & Ankle MCQs (Set 1): Trauma & Degenerative Disorders | ABOS Review

The patient has a discrete callus that overlies a prominent medial sesamoid. Calluses typically occur in response to increased pressure on the skin. Initial treatment should be directed at reducing local pressure with a felt pad. Sesamoid shaving is indicated if the felt pad fails to provide relief. Sesamoidectomy should be reserved for refractory callus given the potential complications of transfer metatarsalgia or callus and hallux valgus. A first metatarsal dorsiflexion osteotomy is more appropriate for a diffuse callus that fails to respond to nonsurgical management. Cryoablation and topical salicylic acid are appropriate for plantar warts, which have a rougher appearance with multiple, small black spots in the lesion. Mann RA, Wapner KL: Tibial sesamoid shaving for treatment of intractable plantar keratosis. Foot Ankle 1992;13:196-198.

The patient's symptoms are typical for gouty arthropathy, and the diagnosis can only be confirmed with aspiration and visualization of the crystals. A concomitant infection also must be ruled out; therefore, it is important to obtain a cell count and culture. Colchicine may have a role in gouty management, but the diagnosis must be confirmed. Allopurinol is not effective in acute gouty arthropathy. Measurement of serum uric acid levels is often not helpful in making a definitive diagnosis. Steroid injections should be deferred until cell count and culture results indicate no accompanying infection. Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 172-173.

The child has an up-to-date tetanus; therefore, a booster is not recommended. Pseudomonas coverage is most likely not needed because the child was barefoot. It is too early to evaluate for abscess or osteomyelitis with MRI, and a formal debridement is rarely indicated without signs of an abscess or a retained foreign body. Radiographs with soft-tissue penetration should be obtained to check for a retained foreign body. Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 199-205.

The stretched peroneus brevis muscle and tendon follow anterior to the fibula and are most likely incarcerated with reduction. The anterior talofibular ligament is too small to prevent reduction of the ankle joint itself. The extensor digitorum brevis originates from the talus; therefore, it is not involved in the tibiotalar joint. The posterior tibial tendon lies medially and would not be interposed into the ankle joint. Similarly, the anterior tibialis tendon also would not be involved. Pehlivan O, Akmaz I, Solakoglu C, et al: Medial peritalar dislocation. Arch Orthop Trauma Surg 2002;122:541-543.

The hallux varus seen in this patient is most likely the result of a combination of causes. Based on the degenerative changes and the significant shortening of the first metatarsal relative to the second metatarsal, a metatarsophalangeal arthrodesis is the treatment of choice. The other surgical approaches are not expected to provide a satisfactory result. Coughlin MJ, Mann RA: Adult hallux valgus, in Coughlin MJ, Mann RA (eds): Surgery of the Foot and Ankle, ed 7. St Louis, MO, Mosby-Year Book, 2000, pp 150-269.

The patient has a supple plantigrade foot that would benefit from a drop foot brace to prevent catching of the toes. Tendon transfer should not be considered until the patient has undergone bracing. Achilles tendon lengthening is not necessary because the foot is plantigrade and flexible. Nerve grafting is not indicated because of the length of time the peroneal nerve palsy has been present. Dehne R: Congenital and acquired neurologic disorders, in Mann RA, Coughlin MJ (eds): Surgery of the Foot and Ankle, ed 7. St Louis, MO, Mosby, 1999, vol 1, pp 552-553.

Removal of both sesamoids is associated with a high incidence of postoperative hallux valgus and cock-up deformity of the great toe because of weakening of the flexor hallucis brevis tendon. The sesamoids lie within these tendons and require meticulous repair following excision. Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2003, pp 17-25.

Fractures of the lateral process of the talus in snowboarders have been thought to result from pure dorsiflexion, inversion, and axial loading. In a cadaveric study, 10 cadavers were placed in fixed dorsiflexion and inversion with an axial load. This was combined with or without external rotation. No fractures occurred after axial loading in the dorsiflexed-inverted position. Fractures of the lateral process of the talus occurred in 75% of the specimens with the addition of external rotation. Boon AJ, Smith J, Zobitz ME, et al: Snowboarder's talus fracture: Mechanism of injury. Am J Sports Med 2001;29:333-338.

This patient appears to have adequate blood supply to heal a Syme's ankle disarticulation but is currently malnourished because of the systemic infection, and is likely to progress to wound failure. Therefore, the initial management of choice is culture-specific antibiotic therapy, open wound management, and nutritional supplementation. If his serum albumin rises to a minimum of 2.5 gm/dL, he can undergo elective Syme's ankle disarticulation. If the serum albumin does not rise within a short period of time, he should undergo transtibial amputation.

Synovial chondromatosis results from chondroid metaplasia within the synovium. Male to female ratio is 2:1, with a peak incidence in early adult life. Radiographs can show speckled cal

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.

All of the above can be associated with myelomeningocele, but talipes equinovarus occurs in 50% to 90% of patients with myelomeningocele. Congenital vertical talus is rarely associated with any neuromuscular diseases other than myelomeningocele but is not the most common deformity in myelomeningocele. Stans AA, Kehl DK: The pediatric foot, in Baratz ME, Watson AD, Imbriglia JE (eds): Orthopaedic Surgery: The Essentials. New York, NY, Thieme, 1999, pp 702-703.

The central one third has been established as the watershed zone by angiographic studies, and has been borne out in clinical conditions involving the navicular, such as stress fractures and osteonecrosis. These findings account for the susceptibility to injury at this level. Nunley JA, Pfeffer GB, Sanders RW, et al (eds): Advanced Reconstruction: Foot and Ankle. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 239-242.

The symptoms are consistent with tarsal tunnel syndrome. Ganglion cysts are a well-known cause of tarsal tunnel syndrome. The MRI scans show a high intensity, well-circumscribed mass in the tarsal tunnel that is consistent with a fluid-filled cyst. Patients usually respond well to excision of the ganglion and resolution of the tarsal tunnel symptoms. The surrounding fat is a different signal intensity on the MRI scans, which rules out a lipoma. Synovial cell sarcoma has a heterogeneous appearance on an MRI scan. Metastatic tumors are most commonly found in the osseous structures of the foot, not the soft tissues. Rozbruch SR, Chang V, Bohne WH, et al: Ganglion cysts of the lower extremity: An analysis of 54 cases and review of the literature. Orthopedics 1998;21:141-148. Llauger J, Palmer J, Monill JM, et al: MR imaging of benign soft-tissue masses of the foot and ankle. Radiographics 1998;18:1481-1498.

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

In most patients with symptomatic talocalcaneal coalition involving less than 50% of the subtalar joint, resection with fat graft interposition is preferred over a subtalar or triple arthrodesis, especially if reasonable range of motion can be achieved. This patient has a synchondrosis that is partially cartilaginous. Although patients may have a residual gait abnormality, most report pain relief after surgery. Scranton PE Jr: Treatment of symptomatic talocalcaneal coalition. J Bone Joint Surg Am 1987;69:533-539. Kitaoka HB, Wikenheiser MA, Schaughnessy WJ, et al: Gait abnormalities following resection of talocalcaneal coalition. J Bone Joint Surg Am 1997;79:369-374.

Most of these injuries occur in young, active patients. Success rates for nonsurgical management are only marginally better than 50%. The treatment of choice is early surgery for patients who desire a quick return to a sport or active lifestyle. Subluxation of the peroneal tendons leads to longitudinal tears over time. McLennan JG: Treatment of acute and chronic luxations of the peroneal tendons. Am J Sports Med 1980;8:432-436.

Achilles tendon tension is not affected by knee position when the ankle is in 20 degrees to 25 degrees of plantar flexion. Skin perfusion overlying the Achilles tendon is maximal in 20 degrees of plantar flexion and is reduced beyond 20 degrees of plantar flexion. Neutral flexion or any amount of dorsiflexion compromises the repair.

The patient has advanced arthrosis of the midfoot, and orthotic management has failed to provide relief. Therefore, the treatment of choice is midfoot arthrodesis. Shock wave treatment has not been shown to be beneficial for arthritis. An ankle-foot orthosis would not be appropriate based on findings of a normal ankle joint. Triple arthrodesis would not be helpful because the hindfoot joint is not affected in a Lisfranc injury. Sangeorzan BJ, Veith GR, Hansen ST Jr: Salvage of Lisfranc's tarsometatarsal joints by arthrodesis. Foot Ankle 1990;10:193-200.

The Lisfranc ligament arises from the lateral surface of the first (medial) cuneiform and is directed obliquely outward and slightly downward to insert on the medial surface of the second metatarsal base. It is the strongest of the tarsometatarsal interosseous ligaments. Sarrafian SK: Anatomy of the Foot and Ankle: Descriptive, Topographic, Functional, ed 2. Philadelphia, PA, JB Lippincott, 1993.

The patient has the classic symptoms, examination findings, and radiographs for a painful accessory navicular. Initial treatment should always be nonsurgical, specifically cast immobilization. Surgery should be reserved for those patients who fail nonsurgical management. Corticosteroids should not be injected into a posterior tibial tendon or insertion point because they can weaken the tendon and possibly cause tendon rupture. Triple arthrodesis and biopsy have no role in the management of a painful accessory navicular.

The displaced talar neck fracture should be treated with open reduction and internal fixation using screws. Closed reduction and casting will not maintain position, and percutaneous pinning is not able to maintain reduction to allow union. External fixation and amputation are not necessary for this injury unless there is severe soft-tissue loss.

Rheumatoid arthritis commonly affects the metatarsophalangeal joints, which become destabilized with time resulting in hallux valgus and dislocated lesser claw toes. The result is metatarsalgia as the dislocated claw toes "pull" the fat pad distally. Severe hallux valgus reduces first ray load, which compounds the metatarsalgia because the load is transferred to the lesser metatarsal heads. First metatarsophalangeal arthrodesis restores weight bearing medially and corrects the painful bunion. Metatarsal head resection slackens the toe tendons to allow correction of the claw toes by whatever means necessary and decreases plantar load over the forefoot. Rheumatoid arthritis in the first metatarsophalangeal joint will continue to progress if osteotomies or a Lapidus procedure are performed. Keller resection arthroplasty increases transfer metatarsalgia and reduces push-off power during gait. Flexor-to-extensor tendon transfer of the lesser toes does not address the metatarsalgia and does not correct the dislocation of the metatarsophalangeal joint. Coughlin MJ: Arthritides, in Coughlin MJ, Mann RA (eds): Surgery of the Foot and Ankle, ed 7. St Louis, MO, Mosby, 1999, p 572.

The dislocation is between the medial and middle cuneiform. Although the first and second tarsometatarsal joints are aligned, there is a gap between the cuneiforms. The radiograph shows a Lisfranc dislocation variant. In a healthy active individual, open reduction and internal fixation yields the best results. The reestablishment of the normal arch and medial column support with anatomic reduction is critical to obtaining the best possible outcome from these injuries. Teng AL, Pinzur MS, Lomasney L, et al: Functional outcome following anatomic restoration of the tarsal-metatarsal fracture dislocation. Foot Ankle Int 2002;23:922-926.

The patient's clinical picture is considered the classic presentation for psoriatic arthritis. The other answers are not applicable for the constellation of findings. Jahss MH: Disorders of the Foot and Ankle, ed 2. Philadelphia, PA, WB Saunders, 1991, pp 1691-1693.