8. Foot and Ankle MCQs

DISCUSSION: The peroneus brevis is easily identified by its location behind the fibula and its distal muscle belly. Axial MRI images provide a reliable guide even when one of the peroneals is completely ruptured, subluxated out of the peroneal groove, or absent. REFERENCES: Sarrafian SK: Anatomy of the Foot and Ankle: Descriptive, Topographic, Functional, ed 2. New York, NY, Lippincott, 1993, pp 234-235. Sammarco GJ: Peroneus longus tendon tears: Acute and chronic. Foot Ankle Int 1995;16:245-253.

DISCUSSION: The clinical photographs show a patient with a type I hereditary sensory motor neuropathy who has cavus feet with a flexible hindfoot. The Coleman block test shows that the hindfoot corrects into valgus. To prevent progressive cavus, patients with this condition may benefit from soft-tissue releases at a younger age while the foot is flexible. Once there is fixed deformity, combined soft-tissue and bone procedures usually are necessary. Metatarsal osteotomies will correct the cavus, but will do nothing for the drop foot. Transfer of the extensor hallucis longus to the neck of the first metatarsal and modified transfer of the extensor digitorum longus to the dorsum of the foot will prevent further claw toes and improve foot dorsiflexion. Anterior transfer of the posterior tibialis tendon will also aid in dorsiflexion. Calcaneal osteotomy should be reserved for fixed hindfoot varus that does not correct with block testing, and triple arthrodesis should be avoided as long as possible because the long-term outcome is poor.

DISCUSSION: Eccentric gastrocsoleus strengthening (especially with heavy loads) consistently has been shown to be superior in the management of Achilles tendinopathy. Decreases in pain and increases in strength have been demonstrated despite the frequently refractory nature of this condition. REFERENCES: Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2003, pp 91-102. Vora AM, Myerson MS, Oliva F, et al: Tendinopathy of the main body of the Achilles tendon. Foot Ankle Clin 2005;10:293-308.

DISCUSSION: The patient has end-stage midfoot arthritis, with a secondary flatfoot deformity through the midfoot. The ability to perform a single limb heel rise indicates that the posterior tibial tendon is functioning, and the weight-bearing radiographs show normal calcaneal pitch and talar head coverage, thus confirming that the flatfoot deformity is isolated to the midfoot. Therefore, the most appropriate treatment is medial column arthrodesis and heel cord lengthening. The other listed procedures are not indicated because they are used in the management of adult flatfoot from posterior tibial tendon insufficiency. REFERENCES: Toolan BC: Midfoot arthrodesis: Challenges and treatment alternatives. Foot Ankle Clin 2002;7:75-93. Horton GA, Olney BW: Deformity correction and arthrodesis of the midfoot with a medial plate. Foot Ankle 1993;14:493-499.

DISCUSSION: In Charcot-Marie-Tooth disease, the posterior tibialis and peroneus longus tendons remain strong, serving to invert the hindfoot and depress the first metatarsal head thus causing the cavovarus foot associated with this disease. In contrast, the tibialis anterior and peroneus brevis are less functional and therefore cannot dorsiflex the ankle, elevate the first metatarsal, or evert the foot, contributing to the deformity. REFERENCE: Herring JA (ed): Tachjian's Pediatric Orthopedics, ed 3. Philadelphia, PA, WB Saunders, 2002, vol 2, p 984.

DISCUSSION: At the ankle level, the anterior tibial artery lies medial to the EHL tendon. The artery becomes the dorsalis pedis after crossing onto the dorsum of the foot. At this point, the artery lies lateral to the tendon. REFERENCES: Resch S: Functional anatomy and topography of the foot and ankle, in Myerson M (ed): Foot and Ankle Disorders. Philadelphia, PA, WB Saunders, 2000, vol 1, pp 25-49. Sarrafian SK: Anatomy of the Foot and Ankle: Descriptive, Topographic, Functional, ed 2. Philadelphia, PA, JB Lippincott, 1993.

The radiographs reveal nonunion of a talar neck fracture. There is no radiographic evidence of osteonecrosis or significant degenerative arthritis. The results of talectomy are suboptimal. Arthrodesis would be indicated for degenerative arthritis. Revision ORIF is feasible and preserves motion. A vascularized graft should be considered whenever osteonecrosis is present, but the talar body appears viable in this case.

DISCUSSION: The patient has HMSN-III or Dejerine-Sottas syndrome. This form of HMSN progresses very rapidly and frequently results in severe foot deformity in early childhood. The changes are progressive and are the result of muscle imbalance during growth. Balancing of the foot musculature is essential, particularly during the phases of rapid growth of the foot. However, this cannot be accomplished using the anterior tibial muscle because it is already weak and the transfer will further weaken it. Bony procedures also may be required, and tendon transfers cannot be depended on to correct bony deformity. However, these procedures can be deferred until the foot is closer to adult size. Surgeries that lead to joint arthrodesis, such as triple arthrodesis and some midfoot osteotomies, are contraindicated because the feet may lose protective sensation as the disease progresses. Fusions in insensate feet are less successful than realignment procedures that maintain mobility. REFERENCES: Wetmore RS, Drennan JC: Long-term results of triple arthrodesis in Charcot-Marie-Tooth disease. J Bone Joint Surg Am 1989;71:417-422. Roper BA, Tibrewal SB: Soft tissue surgery in Charcot-Marie-Tooth. J Bone Joint Surg Br 1989;71:17-20. Miller GM, Hsu JD, Hoffer MM, Rentfro R: Posterior tibial tendon transfer: A review of the literature and analysis of 74 procedures. J Pediatr Orthop 1982;2:363-370.

DISCUSSION: The patient has painful lateral and plantar keratoses with metatarsus quintus valgus deformity. This combination of problems is best addressed with an oblique mid-diaphyseal osteotomy that allows the distal metatarsal to be displaced medially and dorsally. Lateral eminence resection alone will not address the painful plantar keratosis. A distal chevron osteotomy has a more limited ability to address the plantar keratosis (if translated medially and slight dorsally). Proximal diaphyseal osteotomies of the fifth metatarsal are associated with an increased risk of delayed union or nonunion secondary to the relative hypovascularity in the proximal diaphysis. Excision of the fifth metatarsal head can result in a floppy fifth toe and transfer metatarsalgia. REFERENCES: Coughlin MJ: Treatment of bunionette deformity with longitudinal diaphyseal osteotomy with distal soft tissue repair. Foot Ankle 1991;11:195-203. Moran MM, Claridge RJ: Chevron osteotomy for bunionette. Foot Ankle Int 1994;15:684-688.

Ultrasound is best at imaging abrupt changes in the density of adjacent tissue and therefore is best at imaging wood in the soft tissues of the foot.

DISCUSSION: Coleman block testing, performed by placing an elevation under the lateral border of the foot, is used to determine if the forefoot and/or plantar flexed first ray is causing a compensatory varus in the hindfoot. The block is placed under the lateral border of the foot, and therefore does not have any relation to the Achilles tendon and suppleness of the hindfoot. REFERENCES: Holmes JR, Hansen ST Jr: Foot and ankle manifestations of Charcot-Marie-Tooth disease. Foot Ankle 1993;14:476-486. Thometz JG, Gould JS: Cavus deformity, in The Child’s Foot and Ankle. New York, NY, Raven Press, 1992, pp 343-353.

The examination findings reveal that there is specific involvement of the medial plantar nerve by the distribution of the pain medially. The symptoms exclude the possibility of plantar fasciitis and anterior tibial tendinitis. Sinus tarsi syndrome would produce anterolateral symptoms rather than medial symptoms.

The patient has subtalar arthrosis, a loss of heel height with anterior ankle impingement. The mechanics of the ankle are impaired, and dorsiflexion is painful and limited. The talar declination angle is measured by drawing a line through the longitudinal axis of the talus and the plane of support of the foot on a weight-bearing lateral radiograph. Anterior impingement is suggested with any value below 20 degrees. By performing a distraction arthrodesis through the subtalar joint, the normal declination of the talus is reestablished, eliminating the anterior ankle impingement. Tibiotalocalcaneal fusion would be inappropriate because the patient does not have arthritic symptoms in the ankle. Ankle arthroscopy or in situ arthrodesis would not reestablish appropriate ankle mechanics, and the osteophytes would be prone to redevelop. Lateral wall ostectomy may help with impingement at the level of the fibula or the lateral ankle but would provide no benefit to anterior ankle impingement.

The patient requires an arthrodesis of the first metatarsophalangeal joint because of the abnormal neuromuscular forces. The more traditional bunionectomies such as a distal chevron bunionectomy, a proximal first metatarsal osteotomy, and a double osteotomy have a high failure rate because of the underlying Down syndrome. The Keller procedure is indicated for older, sedentary individuals and has little role in the management of a neuromuscular bunion.

The MRI scan shows an obvious talocalcaneal coalition of the medial facet. Because nonsurgical management has failed, surgical resection of the coalition is indicated. Arthrodesis would be indicated only if resection fails to relieve pain or if advanced degeneration of the hindfoot joints is present.

The patient has Becker muscular dystrophy. Patients with this condition have a slower rate of progression of disease compared with patients who have Duchenne muscular dystrophy, and walking may continue into the late teens. The creatine kinase level is not as high as in Duchenne muscular dystrophy, which can range from 20,000 to 30,000 IU/L. Becker muscular dystrophy is allelic to Duchenne muscular dystrophy, resulting in a mutation in the dystrophin gene.

With soft-tissue loss, local or free flap coverage may be necessary to treat exposed tendon and bone. However, a vacuum-assisted closure device is a good temporizing dressing. It prevents external contamination, reduces edema around the wound, increases oxygen tension in the wound, and promotes the formation of granulation tissue. The use of this negative pressure device has been described in both acute traumatic and in chronic wound scenarios.

A subchondral radiolucency of the talar dome after a talar neck fracture is known as the 'Hawkins sign' and is a well-described radiographic indication of viability of the talar body. Subchondral atrophy excludes the diagnosis of avascular necrosis. It is unlikely that AVN will develop at a later stage after injury if a Hawkins sign was present.

DISCUSSION: The peroneus brevis and peroneus longus muscles are the main evertors of the hindfoot. As they descend along the posterior fibula, they pass through the retromalleolar sulcus, formed by the concavity of the retromalleolar fibula. This sulcus is deepened by a fibrocartilaginous rim. The superior peroneal retinaculum covers the fibular groove and stabilizes the peroneal tendons within the retromalleolar sulcus. It originates from the posterolateral ridge of the fibula and inserts onto the lateral calcaneus.

Two prospective randomized studies compared primary fusion with ORIF for Lisfranc injuries. Neither study showed worse results with primary fusion, and the rate of secondary surgery was more common in the ORIF group (salvage arthrodesis or hardware removal).