8. Foot and Ankle MCQs

The initial treatment for peritendinitis should consist of calf stretching in an eccentric mode and physical therapy. This treatment has been found superior to surgical debridement in non-extensive peritendinitis and pantendinitis.

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.

Peroneal tendinitis and stenosis are typically seen following nonsurgical management and results from lateral subfibular impingement, whereby the displaced, expanded lateral wall subluxates the peroneal tendons against the distal tip of the fibula or might even dislocate the tendons. Nonsurgical management of displaced calcaneal fractures offers little chance for return to normal function because of the development of a calcaneal malunion. The articular surface is not reduced, the heel remains shortened and widened, the talus is dorsiflexed in the ankle mortise, and the displaced lateral wall causes impingement and binding of the peroneal tendons.

Patients with reflex sympathetic dystrophy (RSD) have a history of trauma, minor rather than major (eg, Colles fracture), in about 50% to 65% of cases. The condition may also follow a surgical procedure. Patients usually have symptoms and signs of RSD including: pain, described as burning, throbbing, shooting, or aching; hyperalgesia; allodynia; and hyperpathia. There are trophic changes within 10 days of onset of RSD in 30% of the extremities affected, including stiffness and edema and atrophy of hair, nails, and/or skin. Finally there can be autonomic dysfunction, such as abnormal sweating, either in excess or anhydrosis, heat and cold insensitivity, or redness or bluish discoloration of the extremities. Shingles, also called herpes zoster or zoster, is a painful skin rash caused by the varicella zoster virus (VZV). VZV is the same virus that causes chickenpox. After a person recovers from chickenpox, the virus stays in the body. Usually the virus does not cause any problems; however, the virus can reappear years later, causing shingles. Charcot arthropathy is a progressive condition of the musculoskeletal system that is characterized by joint dislocations, pathologic fractures, and debilitating deformities. This disorder results in progressive destruction of bone and soft tissues at weight-bearing joints; in its most severe form, it may cause significant disruption of the bony architecture. In patients with diabetes, the incidence of acute Charcot arthropathy of the foot and ankle ranges from 0.15% to 2.5%. Acute Charcot arthropathy almost always appears with signs of inflammation. Profound unilateral swelling, an increase in local skin temperature (generally, an increase of 3° to 7° above the nonaffected foot's skin temperature), erythema, joint effusion, and bone resorption in an insensate foot are present. These characteristics, in the presence of intact skin and a loss of protective sensation, are often pathognomonic of acute Charcot arthropathy. Cellulitis is an infection of the skin. Examination would reveal erythema, edema, and pain. Osteomyelitis is an infection of the bone. Examination may reveal edema, drainage, and pain.

Discussion: Several conditions must be met before a tendon transfer has the potential to correct a dynamic deformity. If the target joint cannot be passively corrected to neutral, it indicates that a static joint contracture or bony deformity exists that cannot be corrected with a dynamic tendon transfer.

The elongated anterior process of the calcaneus reaching distally toward the navicular is an abnormal finding. Instead of viewing the rounded, blunt distal anterior process of the calcaneus, a bridge extends to the navicular, albeit incomplete. These findings are consistent with a fibrous coalition. CT can reveal a stress fracture of the calcaneus, arthritis of the subtalar joint with subchondral cysts, or an os peroneum disruption in the peroneus longus, but those entities are not shown here. The plantar fascia is intact.

Duchenne's muscular dystrophy is an X-linked recessive disorder.Duchenne's muscular dystrophy is caused by a mutation in the dystrophin gene. X-linked recessive inheritance is a mode of inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be expressed (1) in males (who are necessarily hemizygous for the gene mutation because they have only one X chromosome) and (2) in females who are homozygous for the gene mutation (i.e., they have a copy of the gene mutation on each of their two X chromosomes).Zane reviewed paediatric neuromuscular disorders. Duchenne's muscular dystrophy patients will show markedly elevated CPK levels (10-200x normal). Muscle biopsy will show connective tissue infiltration, foci of necrosis and absent dystrophin with staining.Illustration A shows an illustration of Gowers sign. This indicates weakness of the proximal muscles. It is characteristic of patients with Duchenne's muscular dystrophy.Incorrect Answers:

Cheilectomy has been shown to provide satisfactory pain relief and improved function in long-term studies. It is important to select patients appropriately when choosing a cheilectomy versus an arthrodesis. Pain at the midrange of motion and loss of more than 50% of the metatarsal head cartilage are predictors of a poor outcome following cheilectomy, and these patients should receive an arthrodesis.

DISCUSSION: Most subtalar dislocations can be easily reduced by closed methods. If no fractures or defects are seen on the postreduction radiographs, then the success rate with cast immobilization is good. Medial dislocations have a better prognosis than lateral dislocations. Late instability is rare; therefore, the duration of immobilization should not be excessive. Most subtalar dislocations result in some stiffening of the hindfoot, and painful degenerative arthrosis is the most common serious complication. REFERENCE: Saltzman C, Marsh JL: Hindfoot dislocations: When are they not benign? J Am Acad Orthop Surg 1997;5:192-198.

DISCUSSION: Combination drugs with activity against both aerobic and anaerobic organisms have been determined to be the best approach. The first-generation cephalosporins do not provide adequate coverage for gram-negative and anaerobic organisms. Gentamicin alone would not provide adequate activity against anaerobes, and there is the risk of renal and auditory toxicity. REFERENCES: Pinzur MS, Slovenkai MD, Trepman E: Guidelines for diabetic foot care. Foot Ankle Int 1999;20:695-702. Eckman MH, Greenfield S, Mackey WC, et al: Foot infections in diabetic patients: Decision and cost-effectiveness analyses. JAMA 1995;273:712-720.

DISCUSSION: This is an example of tethering of the flexor hallucis longus/flexor digitorum longus (FHL/FDL) to the fracture site. Additional time and/or physical therapy and bracing would not be expected to be of benefit. Release of the FHL and FDL from the fracture site or retromalleolar lengthening will address the posttraumatic claw toe deformity and Achilles tendon lengthening will address the mild equinus. Posterior tibial tendon transfer is not appropriate as the patient demonstrates a normal heel rise. Midfoot releases and hallux fusion are also not indicated. REFERENCES: Feeny MS, Williams RL, Stephens MM: Selective lengthening of the proximal flexor tendon in the management of acquired claw toes. J Bone Joint Surg Br 2001;83:335-338. Clawson DK: Claw toes following tibial fracture. Clin Orthop Relat Res 1974;103:47-48.

DISCUSSION: 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.

DISCUSSION: The main blood supply to the lateral two thirds of the talar body is derived from the artery of the tarsal canal, a branch of the posterior tibial artery. The peroneal artery helps form a vascular plexus over the posterior tubercle and combines with other arteries to form the artery of the sinus tarsi, which is the principal blood supply of the intrasinus structures of the talus. The anterior tibial arteries send branches to the superior surface of the talar head and give rise to the anterolateral malleolar artery, which may anastomose with other vessels to form the artery of the tarsal sinus.

The history and radiographs indicate a Lisfranc fracture-dislocation of the foot. The radiographs show the classic “fleck sign,” which is an avulsion of the Lisfranc ligament from the base of the second metatarsal. Most authors recommend open reduction and internal fixation of this injury. Closed reduction can be attempted, but anatomic reduction is unlikely because of the interposed bone fragments and soft tissues. Standard radiographs are not reliable in identifying 1 to 2 mm of subluxation of the tarsometatarsal joint. The tarsometatarsal joint has a poor tolerance to even mild subluxation, and the resulting decrease in joint contact area increases the likelihood of posttraumatic arthritis. Open reduction with the joint visible allows more anatomic reduction and internal fixation of larger osteochondral fragments or excision of smaller interposed fragments.

Ankle fusion is perhaps the most predictable surgical treatment for a relatively young, active patient with ankle arthritis. Moreover, there are concerns regarding implant loosening when performing TAA in active patients. Outcome after syndesmosis ORIF has been linked to the quality of the reduction at the index procedure. Syndesmotic malreduction that is severe necessitates osteotomy and revision ORIF.

The patient has a Hawkins type III talar neck fracture-dislocation with a risk of osteonecrosis ranging from 69% to 100%. Anatomic studies have shown that the artery of the tarsal canal supplies the lateral two thirds of the talar body. The other vessels listed provide no significant contribution to the talus.

DISCUSSION: The radiograph shows posttraumatic tibiofibular synostosis. This condition typically follows an eversion (high) ankle sprain that results in disruption of the interosseous membrane. Ossification usually develops within 6 to 12 months after the injury. Return to sports is possible despite the lack of normal ankle dorsiflexion and mobility between the tibia and fibula. Surgical excision is reserved for persistent pain that fails to respond to nonsurgical management once the ossification is cold on bone scintigraphy. REFERENCES: Whiteside LA, Reynolds FC, Ellsasser JC: Tibiofibular synostosis and recurrent ankle sprains in high performance athletes. Am J Sports Med 1978;6:204-208. Henry JH, Andersen AJ, Cothren CC: Tibiofibular synostosis in professional basketball players. Am J Sports Med 1993;21:619-622. Andrish J: The leg, in Drez D, DeLee JD, Miller MD (eds): Orthopaedic Sports Medicine Principles and Practice, ed 2. Philadelphia, PA, WB Saunders, 2003, pp 2155-2181.

This patient has undergone ORIF of the lateral malleolus with shortening of the lateral malleolus and lateral tibiotalar tilt. Revision surgery would entail bone grafting and re-plating of the fibula.Malunion of the fibula component of ankle fractures lead to tibiotalar instability and post-traumatic ankle arthritis. The distal fragment is usually shortened and externally rotated. The osteotomy can restore length and correct rotation. Markers for potential instability include: (1) asymmetry of the medial-lateral clear spaces, (2) talar tilt>2mm, (3) talar subluxation, (4) abnormal talocrural angle (normal, 75-86deg).Chu et al. opined that reconstruction for distal fibula malunions should include: (1) osteotomy, (2) +/- syndesmotic fixation and (3) autologous bone graft. They recommend: (1) low oblique osteotomy for fractures below the syndesmosis, (2) transverse osteotomy above the syndesmosis for high fractures (PER4) and low fractures with tibiofibular instability, (3) inspection of the tibiofibular joint through an anterolateral window to ensure anatomic reduction.Weber et al. described a method of corrective lengthening osteotomy of the fibula in 23 cases. They described 3 criteria for assessing normal fibular length. Seventeen patients had good-excellent results, and 6 had fair-poor results (1 of these 6 needed ankle fusion).Figure A is an AP radiograph of a distal fibula fracture fixed in a shortened position with lateral talar tilt and degenerative changes at the anterolateral tibiotalar joint. Illustration A is an anteroposterior radiograph after fibular osteotomy and correctionwith medial distal tibial autograft to correct talar tilt and restore anatomic fibular length. Illustration B shows the normal talocrural angle. Illustration C shows the Weber-Simpson method of fibula lengthening used in Illustration A.Incorrect Answers:

DISCUSSION: The plantar intrinsic muscles are divided into four layers with respect to depth from the plantar fascia. They are (from superficial to deep): 1) abductor hallucis, flexor digitorum brevis, abductor digiti minimi; 2) quadratus plantae, lumbricals; 3) flexor digiti minimi, flexor hallucis brevis, adductor hallucis; and 4) dorsal and plantar interosseous muscles. The flexor hallucis brevis and adductor hallucis originate from the midtarsal bones, encompass the sesamoids, and insert into the base of the proximal phalanx. The adductor hallucis consists of two muscle bellies forming a conjoined tendon and inserting into the lateral portion of the proximal phalanx and the lateral sesamoid. The adductor hallucis is stronger than the abductor hallucis, which may contribute to hallux valgus. The flexor digitorum minimi travels under the fifth metatarsal, arising at the base and inserting into the lateral base of the fifth proximal phalanx. REFERENCE: Resch S: Functional anatomy and topography of the foot and ankle, in Myerson MS (ed): Foot and Ankle Disorders. Philadelphia, PA, WB Saunders, 2000, pp 32-33.

DISCUSSION: A discrete or focal callus is a response to excessive weight-bearing stress beneath the lateral (fibular) condyle of a lesser metatarsal head (most commonly second). The other structures generally have not been associated with a discrete callus. REFERENCES: Coughlin MJ, Mann RA: Keratotic disorders of the plantar skin, in Coughlin MJ, Mann RA (eds): Surgery of the Foot and Ankle, ed 6. St Louis, MO, Mosby-Year Book, 1993, pp 413-465. Cracchiolo A: Surgical procedures of the lateral metatarsals, in Jahss MH (ed): Disorders of the Foot and Ankle, ed 2. Philadelphia, PA, WB Saunders, 1991, pp 1269-1283.