8. Foot and Ankle MCQs

The patient has gouty arthropathy of the first metatarsophalangeal joint. This definitive diagnosis is achieved with aspiration of the joint and polarized light microscopy that shows needle-shaped negatively birefringent monosodium urate crystals. Differential diagnoses of infectious arthritis and pseudogout are also definitively made through joint aspiration. Although rheumatoid arthritis is a possibility, a serum rheumatoid factor is not always diagnostic and a patient with rheumatoid arthritis may have concomitant gouty arthritis. The radiographic findings are not typical of diabetes mellitus or of a patient with Charcot arthropathy.

Patients with spondylolysis typically demonstrate increased pain with lumbar extension, not with forward flexion. In the absence of a disk herniation, a straight leg raise test result should be negative. Pain with forward flexion is not common in spondylolysis, and without nerve root impingement there should be no loss of the tendo-Achilles reflex.

In a patient with a drop foot and with 5/5 muscle strength of the posterior tibial tendon, a split posterior tibial tendon transfer would be the most appropriate treatment option based on the options presented. The deep peroneal nerve innervates the anterior tibial tendon. This muscle has been affected by the injury; therefore, the anterior tibial tendon cannot be transferred. A subtalar fusion would help correct inversion and eversion deformities, but is not effective for plantar flexion deformities. The foot drop is caused by a neurologic condition in this patient, not a contracture of the gastrocsoleus complex. Therefore, a recession would not be beneficial. A flexorhallucis longus tendon transfer would not take the deforming force and make it a corrective force.

DISCUSSION: The imaging studies reveal findings typical of the os trigonum syndrome. This condition results from inflammation between the os trigonum and the adjacent talus. The symptoms of posterior ankle pain are exacerbated by plantar flexion, which stresses the fibrous union between these two bones. Definitive management of the high-level athlete involves excision of the os trigonum from a medial approach, although arthroscopic excision has also been described. The os trigonum is not an intra-articular structure; therefore, ankle arthroscopy is neither diagnostic nor therapeutic.

DISCUSSION: Initial management of a young patient with a cavovarus deformity of the foot and a family history of Charcot-Marie-Tooth disease should focus on mobilization and strengthening of the weakening muscular units and an accommodative insert. Surgical intervention should be delayed until progression of the deformity begins to cause symptoms and/or weakness of the muscular units, resulting in contractures of the antagonistic muscle units.

This young, active patient has ankle valgus following previous trauma. A corrective supramalleolar osteotomy of the tibia will provide pain relief and improve range of motion, allowing return to sports. Supramalleolar osteotomy may be performed for varus or valgus ankles. They are suited for near-normal ROM, minimal talar-tilt or varus heel alignment, and asymmetric ankle arthritis.

A tarsal coalition is an abnormal connection of 2 or more bones in the foot. Surgical options include resection with interposition of muscle or fatty tissue from another area of the body or fusions when large (exceeding 50% of the joint), more severe coalitions are encountered.

DISCUSSION: 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. REFERENCES: 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. Skalley TC, Myerson MS: The operative treatment of acquired hallux varus. Clin Orthop 1994;306:183-191.

DISCUSSION: The flexor hallucis longus tendon is at risk during a Chevron-Akin osteotomy because of its close relationship to the base of the proximal phalanx. The radiograph reveals a reduced ability to flex the interphalangeal joint secondary to the flexor hallucis longus laceration. The other complications are not supported by the radiograph. REFERENCES: Tollison ME, Baxter DE: Combination chevron plus Akin osteotomy for hallux valgus: Should age be a limiting factor? Foot Ankle Int 1997;18:477-481. Scaduto AA, Cracchiolo A III: Lacerations and ruptures of the flexor or extensor hallucis longus tendons. Foot Ankle Clin 2000;5:725-736.

The patient has a bunionette with a large 4-5 intermetatarsal angle. This requires not only ostectomy of the lateral prominence but metatarsal osteotomy to decrease the intermetatarsal angle. Excising the head results in a flail joint and creates the possibility of a transfer lesion. Condylectomy can reduce plantar pressures but does not address the bunionette. The joint surface is well maintained, thus there are no indications for resection.

The right syndesmosis appears disrupted on the CT scan when compared to the normal left side. CT can be helpful in determining injury to the syndesmosis, especially with occult clinical findings.

Dynamic supination is a known residual problem after the Ponseti casting technique is used. Ponseti applied the principles of the Garceau procedure and transferred the entire anterior tibialis tendon to the lateral cuneiform. The anterior tibialis continues to act as a dorsiflexor of the foot but with a more advantageous trajectory. Lengthening the anterior tibialis by itself will not redirect the pull of the muscle. Likewise, the posterior tibialis tendon transfer through the interosseous membrane will not address the supinating force of the anterior tibialis. It is used when the anterior and lateral compartment muscles are either not functioning or weak in relationship to the posterior tibialis. The anterior tibialis tendon transfer to the calcaneus has been used successfully in myelodysplasia for calcaneal deformity.

DISCUSSION: Based on findings of a sudden increase in pain with associated swelling, the most likely diagnosis is a stress fracture. The initial radiographic findings usually will be negative. Morton’s neuroma and transfer metatarsalgia are not associated with swelling. Metatarsophalangeal synovitis usually involves the second metatarsophalangeal joint. Freiberg’s infraction is seen clearly on a radiograph.

DISCUSSION: The arthroscopic views show the lateral side of the ankle as demonstrated by the presence of the tibiofibular articulation. As is typical in chronic anterolateral impingement, synovitis overlies the anteroinferior band of the tibiofibular ligament, the most distal portion of the anterior syndesmosis. Hypertrophic scar formed on or in this ligament can impinge on the lateral margin of the talar dome and has been associated with chronic anterolateral ankle pain.

DISCUSSION: Treatment for pes planus revolves around 2 clinical parameters: pain and rigidity. In the absence of pain, no intervention is warranted. Rigid pes planus is most frequently associated with a tarsal coalition. The initial treatment for painful pes planus, whether flexible or rigid, is immobilization, usually in a walking cast. This often is sufficient to relieve symptoms on a permanent basis. Surgery should be contemplated only when this treatment fails. In stage 3, the pes planus is rigid. If it is painful, surgical treatment, which consists of a triple arthrodesis, may be considered. However, if medical constraints or patient preference preclude surgery, an Arizona brace can provide sufficient support to reduce symptoms to an acceptable level to perform activities of daily living.

DISCUSSION: The CT scan reveals an avulsion of the dorsal beak of the anterior process of the calcaneus. This common fracture is an avulsion of the origin of the bifurcate ligament, which runs from the anterior calcaneal process to both the cuboid and the lateral aspect of the navicular. An inversion mechanism is common, and the fracture is often missed in evaluation for a suspected ankle sprain. MRI may be useful in the diagnosis of these occult injuries, and suspicion should be present when tenderness exists over the superior portion of the anterior process of the calcaneus.

DISCUSSION: The clinical photograph shows a rocker-bottom deformity, and the lateral radiograph suggests a congenital vertical talus deformity. A lateral radiograph of the foot in maximum plantar flexion is needed to demonstrate the fixed position of the deformity with malalignment of the talar-metatarsal axis. A fixed dislocation of the navicular on the talus differentiates a congenital vertical talus from the oblique talus with talonavicular subluxation.

DISCUSSION: Sever disease, or calcaneal apophysitis, is best treated with activity modification that includes rest, restriction from sports and running, and Achilles tendon stretching exercises. The diagnosis is clinical (rendering MRI study unnecessary) and the course is usually self-limited, obviating the need for surgery. Occasionally, children with severe symptoms may benefit from a short period of cast or fracture brace immobilization. RECOMMENDED READINGS: Sullivan RJ. Adolescent foot and ankle conditions. In: Pinzur MD, ED. Orthopaedic Knowledge Update: Foot and Ankle 4. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2008:47-55. Feldman DS. Osteochondrosis. In: Spivak JM, Di Cesare PE, Feldman DS, et al, eds. Orthopaedics: A Study Guide. New York, NY: McGraw-Hill; 1999:765-766.

DISCUSSION: Surgery is not indicated in a patient who has a mild deformity and no pain. Shoe wear modifications should be recommended. REFERENCE: Mann RA, Coughlin MJ: Surgery of the Foot and Ankle, ed 7. St Louis, MO, Mosby, 1999, p 174.

DISCUSSION: Osteochondral lesions of the talar dome can have a traumatic or nontraumatic etiology. Most authors site a probable traumatic etiology for lateral lesions. Stage I and II lesions, which are composed of compressed subchondral bone or a partial detached osteochondral fragment, can be treated initially in a non-weight-bearing short leg cast for 6 weeks. Stage III medial lesions can also be treated in the same manner. If symptoms persist, the treatment of choice is debridement of the fracture, curettage of the lesion, and drilling of the subchondral bone. This treatment also applies to lateral stage III and all stage IV lesions. If the fragment is at least one third of the size of the talar dome, management should consist of open reduction and internal fixation. In patients with more chronic lesions (4 to 6 months of persistent pain), the threshold to proceed with surgery is lower, even in a stage II lesion. REFERENCES: Lutter LD, Mizel MS, Pfeffer GB (eds): Orthopaedic Knowledge Update: Foot and Ankle. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1994, pp 205-226. Pettine KA, Morrey BF: Osteochondral fractures of the talus: A long-term follow-up. J Bone Joint Surg Br 1987;69:89-92.