8. Foot and Ankle MCQs

DISCUSSION: Nonsurgical management has failed to provide relief; therefore, the treatment of choice is arthrodesis with an intramedullary nail. Amputation may be indicated if the arthrodesis fails. The patient does have adequate circulation for an attempt at salvage. Total ankle arthroplasty is not indicated in a neuropathic patient. REFERENCES: Pinzur MS, Kelikian A: Charcot ankle fusion with a retrograde locked intramedullary nail. Foot Ankle Int 1997;18:699-704. Herbst SA: External fixation of Charcot arthropathy. Foot Ankle Clin 2004;9:595-609.

Stress fractures are the result of physiological bone response to increased stress. Increased stress on bone triggers an increase in remodeling, which begins with resorption of bone at the site of stress. Ongoing stress can overwhelm bone strength, resulting in a fracture. In the foot, this most commonly is seen in the second metatarsal at the junction of the middle and distal thirds. Contributing factors to increased loading of the second metatarsal include hallux valgus (decreased hallux loading transfers to the second metatarsal head), hallux rigidus (offloading of the hallux attributable to pain increases second metatarsal loading), and a long second metatarsal (increased duration of contact during push-off in the stance phase).

Clinical studies have shown that smoking cessation for 4 weeks reduces the risk of infection to the level of nonsmokers. Adverse effects on wound healing caused by chemotherapy used to treat rheumatoid arthritis has not been borne out in the literature.

DISCUSSION: The radiographs show a triplane fracture of the ankle. In adolescence, closure of the distal tibial physis starts peripherally at the anteromedial aspect of the medial malleolus and extends posteriorly and laterally. The anterolateral quadrant of the physis is the last to close, making this region the most susceptible to separation. When the foot is twisted into external rotation, the anterolateral portion of the epiphysis is avulsed by the pull of the anterior tibiofibular ligament. When this fragment alone is avulsed, the result is a juvenile Tillaux fracture. When the fracture extends to involve the remainder of the physis and posterior metaphysis, as in this patient, the result is a triplane fracture. REFERENCES: Richards BS (ed): Orthopaedic Knowledge Update: Pediatrics. Rosemont, Ill, American Academy of Orthopaedic Surgeons, 1996, pp 267-272. Dias LS, Giegerich CR: Fractures of the distal tibial epiphysis in adolescence. J Bone Joint Surg Am 1983;65:438-444. Kling TF Jr: Operative treatment of ankle fractures in children. Orthop Clin North Am 1990;21:381-392.

The flexor digitorum longus is the commonly accepted tendon transfer for posterior tibial tendon insufficiency. The flexor hallucis longus has to be carefully rerouted to avoid crossing the neurovascular bundle and has not been shown clinically to provide superior results to flexor digitorum longus transfer. Use of the peroneus longus results in loss of plantar flexion strength of the first metatarsal, contributing to the flatfoot deformity. The anterior tibial tendon is in the anterior compartment and fires out of phase with the posterior tibial tendon.

The literature regarding turf toe sequelae is inconsistent. While some studies suggest hallux rigidus may be a potential long-term complication due to limited range of motion, there is no consensus in the literature identifying a single 'most common' sequela. However, in the context of standard orthopedic board examinations, hallux rigidus is frequently cited as the primary concern for long-term degenerative changes following significant capsuloligamentous injury to the first MTP joint.

This scenario is a classic example of the development of Charcot foot. A red, swollen, deformed foot without ulceration suggests neuroarthropathy. Normal inflammatory marker findings, no history of fever or chills, and radiographs demonstrating bone loss support the diagnosis. Limb elevation with dramatic reduction in erythema is also characteristic of this disease process and does not occur with infection. Total-contact casting is the cornerstone of treatment for acute Charcot disease. Hemoglobin A1C is an indicator of glucose averaged over a 3-month period, providing the most reliable indication of a patient's ongoing glucose control. The pathophysiology of bone destruction is believed to be hypervascularity of bone. Infection and Charcot disease may develop simultaneously, but the combination is rare.

DISCUSSION: An older patient with calcaneal enthesopathy may take a year or more to recover after tendon debridement and calcaneal ostectomy. Young patients, and those with purely tendon pathology, may recover more quickly.

DISCUSSION: Focal scleroderma is characterized by the formation of patches of sclerotic skin, also known as morphea, or streaks of sclerosis (linear scleroderma). Systemic involvement in focal scleroderma is unusual; however, progression during childhood is common. Contracture of underlying tissues is common, often resulting in serious joint contractures. Bony changes similar to those seen in melorheostosis can be seen. This patient has characteristic skin changes, atrophy of the soft tissues, Achilles tendon contractures, and calcaneal deformities. There are no signs of arthrogryposis, which usually presents with bilateral congenital deformities, including equinovarus. Klippel-Trenaunay-Weber syndrome is characterized by venous malformation in association with focal overgrowth.

DISCUSSION: The type of deformity described is a type 2 bunionette. A more proximal procedure is necessary to correct the large intermetatarsal angle and the lateral bowing. The osteotomy of choice is a diaphyseal shaft osteotomy. Because this patient has a plantar callosity and a lateral callosity, the osteotomy is angled superiorly to elevate the fifth shaft with the shift, eliminating overload of the plantar metatarsal head and subsequent callus formation.

DISCUSSION: With a gap of less than 4 cm, a V-Y repair would be appropriate without a tendon transfer. For gaps greater than 5 cm, a lengthening with augmentation is the most appropriate treatment. Therefore, the treatment of choice is an Achilles tendon turndown with flexor hallucis longus tendon transfer. The plantaris tendon is not a strong enough repair, and direct repair is not possible given the large defect in the Achilles tendon.

The Achilles tendon insertion encompasses a broad area on the posterior area of the calcaneus. A biomechanical study has shown that up to 50% of the Achilles tendon insertion point can be detached before the strength of the attachment point starts to weaken. It is recommended that if more than this amount is detached to remove the posterior superior calcaneal prominence, consideration should be given to either securing the tendon to the bone with suture anchors or performing a tendon transfer.

Following ORIF of a known osseous injury, stress testing of the syndesmosis is recommended, especially for pronation-external rotation injuries. The Cotton test applies a laterally directed force to the fibula to assess for widening of the distal tibiofibular joint space. A positive Cotton test result indicates that syndesmotic stabilization is indicated. The Thompson test is used to determine Achilles tendon integrity. The squeeze test is a clinical, not intraoperative, assessment of syndesmotic injury. The anterior drawer test assesses the integrity of the anterior talofibular ligament.

DISCUSSION: 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. REFERENCES: Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 172-173. Jahss MH: Disorders of the Foot and Ankle, ed 2. Philadelphia, PA, WB Saunders, 1991, pp 1712-1718.

The first branch of the lateral plantar nerve (Baxter's nerve) innervates the abductor digiti minimi. It is reported to be trapped at the interval between the abductor hallucis and the quadratus plantae muscles.

The history and presentation are consistent with type I Charcot-Marie-Tooth (CMT), the most common form of hereditary peripheral motor sensory neuropathy. Type I CMT is the most common, occurring in 50% of patients with CMT, and is characterized by marked slowing of motor neuron velocities, and inconsistent slowing of sensory neuron velocities. Peroneus longus to brevis transfer is indicated to release the overpull of the peroneus longus, and restore the eversion and dorsiflexion function of the peroneus brevis. A lateralizing calcaneal osteotomy with proximal translation is indicated to correct heel varus given that the Coleman block only allows for partial correction of heel varus. Proximal translation of the posterior tuber corrects for the increased calcaneal dorsiflexion, improving the lever arm for the triceps surae. A medial column closing wedge osteotomy is often required to correct a rigid, or semirigid plantar flexed first ray to allow for a balanced, plantigrade foot. Triple arthrodesis is indicated for rigid, arthritic hindfoot deformities. Transfer of the posterior tibial tendon to the tibialis anterior is not indicated since it is an out-of-phase transfer. Transfer of the posterior tibial tendon, when performed, should be to the lateral aspect of the foot. A medializing calcaneal osteotomy would accentuate the heel varus. There is no indication for Botox in CMT; Botox injection of the calf would further weaken push-off during gait. Bracing of a progressive semirigid or rigid deformity is not recommended.

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.

The Coleman block test is used to evaluate the effect of the forefoot on the rearfoot varus. If the deformity corrects with the block, then the hindfoot deformity is flexible and the varus position is secondary to the plantar flexed first ray or valgus position of the forefoot. A rearfoot orthotic will not correct the forefoot cause of the deformity. The patient still may need a lateralizing calcaneal osteotomy to realign the hindfoot.

DISCUSSION: Posterior ankle impingement or os trigonum syndrome is well described in dancers, and it is often associated with flexor hallucis longus tendinitis. High-quality MRI imaging will reveal the inflammation about the os trigonum and flexor hallucis longus tendinitis. REFERENCES: Mizel MS, Miller RA, Scioli MW (eds): Orthopaedic Knowledge Update: Foot and Ankle 2. Rosemont IL, American Academy of Orthopaedic Surgeons, 1998, pp 315-332. Hamilton WG, Hamilton LH: Foot and ankle injuries in dancers, in Coughlin MJ, Mann RA (eds): Surgery of the Foot and Ankle, ed 7. St Louis, MO, Mosby, 1999, pp 1225-1256.

DISCUSSION: Numerous causes of tarsal tunnel syndrome have been reported. The most favorable outcomes from release of the tarsal tunnel are in patients who have a space-occupying lesion (eg, ganglion, lipoma, or neurilemoma). While electrodiagnostic studies may be abnormal preoperatively, there is a low correlation between clinical outcome and electromyographic findings. Intrinsic weakness is a late finding in long-standing nerve dysfunction. REFERENCES: Beskin JL: Nerve entrapment syndromes of the foot and ankle. J Am Acad Orthop Surg 1997;5:261-269. 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.