8. Foot and Ankle MCQs

Most patients with a significant recurrent neuroma will not obtain relief with conservative methods. Pain results from a stump neuroma at the weight-bearing area from too short of a resection of the nerve or from regrowth of the remaining nerve end. Revision of the nerve to a more proximal level off of the weight-bearing area is the most likely method to succeed. A plantar approach facilitates identification and ability to revise the nerve to a more proximal level.

The radiographs do not show significant arthrosis of the hallux metatarsophalangeal joint; therefore, arthrodesis is unnecessary. Orthotics will not correct the deformity. A distally based osteotomy will not achieve sufficient correction of the incongruity of deformity, and a Keller resection is not indicated in the younger population. The treatment of choice is a proximal metatarsal osteotomy with second toe correction.

The injury mechanism describes axial loading to a plantar-flexed foot and is classic for Lisfranc injury. If the initial films are not diagnostic as in this case, weight-bearing films are a reasonable next step. Radiographic widening of 2 mm or more between the second metatarsal base and medial cuneiform (as compared to the other side) is diagnostic; occasionally, a "fleck" sign (a small bony fragment noted in the Lisfranc joint) may indicate an avulsion fracture. Clinical signs include plantar ecchymosis, tenderness over the Lisfranc joint, and an inability to bear weight. Anatomic ORIF or fusion are the options for treatment, and results for ligamentous injuries are better when fusion is performed. Better AOFAS scores have been demonstrated with fusion, and a higher incidence of pain and arthritis have been noted with fixation.

The patient is 3 weeks out from TAR. The wound is erythematous, and the tendon is visible. At 3 weeks this is an acute wound breakdown. The preferred treatment is a return to the operating room, an exchange of the polyethylene because the wound appears deep enough to go down to the joint, and a flap for coverage. Removal of the total ankle and placement of an antibiotic spacer should be considered in the settings of subacute (6 weeks postop) or chronic infection following TAR.

DISCUSSION: The patient has a chronic ingrown nail on his great toe, which is not an uncommon occurrence in teenagers because of improper nail care. There is local infection and a foreign body reaction because of the nail. Continued conservative management with soaks and antibiotics will not improve the clinical situation. In the presence of local chronic infection, nail matrix ablation is contraindicated. Additionally, in the absence of a history of an ingrown nail, a nail matrix ablation is not medically indicated. The appropriate treatment is partial removal of the nail plate. With nail plate removal, the inflammation and local infection will resolve rapidly.

Figures 49a and 49b show a severely comminuted, displaced fracture of the distal tibial metaphysis with intra-articular extension, i.e., pilon fracture, or the so-called “distal tibial explosion fracture.” According to the article by Kellam JF and Waddell JP, there are two mechanisms that can cause this fracture: a rotational pronation dorsiflexion force, and an axial compression force with the foot in either neutral or dorsiflexion at the moment of impact. Because of these mechanisms of injury, two fracture patterns were observed in the series of patients reported. The rotational pattern results in several large metaphyseal fragments, and usually a fibular fracture of a short oblique type above the level of the ankle joint. The second and unfortunately the more common fracture pattern is caused by a severe axial compression force which causes marked comminution of the distal tibial metaphysis, loss of bone substance due to impaction, superior migration of the talus, and loss of the ankle cartilage space.

The medial calcaneal branch of the posterior tibial artery is the major vascular supply to the heel pad. Heel pad avulsions are severe injuries associated with high-energy trauma and often carry a poor prognosis because of the potential for heel pad necrosis. The lateral calcaneal artery and the lateral malleolar artery, along with the lateral tarsal artery, provide perfusion to the lateral flap associated with a standard extensile approach to the calcaneus. The artery of the tarsal canal is a branch of the posterior tibial artery, and the artery of the sinus tarsi is a branch of the perforating peroneal artery. Both provide perfusion to the talus.

DISCUSSION: The nerve to the abductor digiti quinti is the first branch of the lateral plantar nerve. It branches off while the nerve is still on the medial side of the foot and also innervates a portion of the plantar fascia. It can become entrapped beneath the deep fascia of the abductor hallucis muscle and has been associated with some forms of chronic heel pain. REFERENCES: Baxter DE, Pfeffer GB: Treatment of chronic heel pain by surgical release of the first branch of the lateral plantar nerve. Clin Orthop 1992;279:229-236. Schon LC, Glennon TP, Baxter DE: Heel pain syndrome: Electrodiagnostic support for nerve entrapment. Foot Ankle 1993;14:129-135.

DISCUSSION: The motor dysfunction in Charcot-Marie-Tooth disease involves the tibialis anterior muscle. Charcot-Marie-Tooth disorders most commonly cause distal motor dysfunction in the foot intrinsics, anterior compartment musculature, and peroneals. There is evidence that the peroneus brevis is affected selectively and the peroneus longus is spared. This is based on clinical muscle testing, muscle cross-sections on MRI, and electrodiagnostic testing. REFERENCES: Mann RA, Missirian J: Pathophysiology of Charcot-Marie-Tooth disease. Clin Orthop 1988;234:221-228. Tynan MC, Klenerman L, Helliwell TR, Edwards RH, Hayward M: Investigation of muscle imbalance in the leg in symptomatic forefoot pes cavus: A multidisciplinary study. Foot Ankle 1992;13:489-501.

Diseases such as Charcot-Marie-Tooth result in spasticity of the extrinsic flexor tendons. This results in hyperflexion of the proximal and distal interphalangeal joints of the involved toe, as well as hyperextension at the metatarsophalangeal joint. The tendon often becomes contracted with progressive equinus of the ankle. Correction of ankle equinus exaggerates the claw toe deformity. The interosseous tendon plays no role in the etiology of a claw toe but may become contracted in later stages of the disease. Laxity of the volar plate may precipitate a claw toe deformity in a nonspastic situation. In patients with a head injury, claw toe deformities are generally the result of overactivity of the extensor tendons.

The deformity is long-standing, the hindfoot is immobile, and the radiographs reveal severe degenerative arthritis involving the entire hindfoot, severe deformity, and talonavicular dislocation. The “exostosis” responsible for the callus is the talar head; resection would severely destabilize the foot. Degenerative arthritis and fixed deformity preclude lateral column lengthening, medial slide calcaneal osteotomy, and talonavicular arthrodesis. Triple arthrodesis is the only viable option.

A Lisfranc amputation is through the tarsometatarsal joints, except the 2nd metatarsal, which is osteotomized to preserve the stability of the medial cuneiform. To prevent the patient from supinating the foot following this amputation, the evertors of the foot must be maintained. The principal evertors are the peroneus brevis and longus. Therefore, the function of the peroneus brevis must be preserved. Technically, this is done by preserving the soft-tissue envelope (peroneus brevis, tertius, and plantar fascia) around the fifth metatarsal base. The posterior tibialis is the primary supinator of the foot, and releasing it would lead to an eversion deformity. The tibialis posterior tendon attachment to the bases of the second and third metatarsals will be released with this amputation, but the main attachment to the navicular is preserved.

produce higher levels of SMN protein.The other choices are not associated with spinal muscular atrophy.Defects in PMP22 are the cause of 70% to 80% of cases of Charcot-Marie-Tooth disease. Mutations in the dystrophin gene cause Duchenne muscular dystrophy.

Question.1 .A 49-year-old weekend athlete has a 4-week history of pain in his unilateral plantar heel that is most severe for the first 20 steps upon arising in the morning. He has an area of maximal tenderness on the plantar medial aspect of the heel pad at the origin of the plantar fascia. He has only improved 30% after a 3-week course of physical therapy with toe intrinsic muscle strengthening and arch- and tendo-Achilles stretching. What is the best next treatment step?Release the plantar fascia.Inject the plantar fascia with platelet-rich plasma.Prescribe a night splint and continue physical therapy.Administer extracorporeal shockwave therapy to the heel.Perform a series of 3 steroid injections into the plantar fascia.Question.2 .Figures 16a and 16b are the radiographs of a 38-year-old carpenter with progressively worsening ankle pain; 14 years ago, he was involved in an all-terrain vehicle collision. Anti-inflammatory medication,corticosteroid injections, and bracing no longer effectively control his pain. The pain now interferes with his work and family responsibilities. Examination reveals an antalgic limp, varus deformity, limited ankle motion, limited eversion, and normal strength. Treatment should now consist ofankle arthrodesis.total ankle arthroplasty.distal tibia osteotomy.lateral ligament repair.deltoid ligament release.Question. 3 .A 48-year-old woman had total knee arthroplasty. She is unable to “lift her toes or ankle to her nose.”After 2 months of physical therapy, she has a slapping gait. What is the best next treatment step?Ankle fusionAnkle-foot orthosisSural nerve graftMedial heel postLaminectomy of L4/5Question. 4 .Figures 46a through 46c are the CT scans of an 18-year-old who sustained an injury 3 weeks ago and now has ankle pain. Examination reveals an ankle effusion and painful range of motion. Recommended treatment should consist oftranstalar drilling.fixation of the fragment.osteochondral autograft.weight bearing in a boot with early range of motion.cast immobilization and nonweight-bearing activity for 6 weeks.Question. 5 .A 47-year-old woman has a closed, displaced, Weber C bimalleolar ankle fracture. Past medical history includes diabetes mellitus for 7 years controlled with diet and an oral hypoglycemic agent. Semmes-Weinstein sensory testing reveals absence of sensation to the 5.07/10-gm monofilament on the plantar aspect of both feet. The skin is intact with 2+ pedal pulses. Treatment should includeopen reduction with limited internal fixation.closed reduction and application of an external fixator.closed reduction and total contact cast immobilization.retrograde intramedullary rod fixation with ankle fusion.internal fixation and an extended period of immobilization.Question. 6 .Figures 68a and 68b are the clinical photographs of a 55-year-old woman who had a right hindfoot fusion 3 years ago for a pes planovalgus deformity. Since the surgery, she has had lateral hindfoot pain and places most of the weight-bearing load on the lateral border of her foot when walking. What is the most likely cause of her symptoms?Deltoid insufficiencyExcessive forefoot abductionResidual heel valgusResidual Achilles tendon contractureMalposition of the transverse tarsal joint

DISCUSSION: The patient’s clinical picture is considered the classic presentation for psoriatic arthritis. The other answers are not applicable for the constellation of findings. REFERENCES: Jahss MH: Disorders of the Foot and Ankle, ed 2. Philadelphia, PA, WB Saunders, 1991, pp 1691-1693. Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 172-173.

DISCUSSION: The orthosis shown is a carbon reinforced Morton’s extension, and it is commonly used for hallux rigidus. It decreases motion of the first metatarsophalangeal joint and subsequently decreases pain. REFERENCE: Clanton TO: Athletic injuries to the soft tissues of the foot and ankle, in Coughlin MJ, Mann RA (eds): Surgery of the Foot and Ankle, ed 7. St Louis, MO, Mosby, 1999, vol 2, p 1185.

DISCUSSION: The strongest biomechanical construct is posterior to anterior fixation with the entry point being at the level of the posterolateral tubercle of the talus. This uses the interval between the peroneus brevis and the flexor hallucis longus. The interval between the flexor digitorum longus and the flexor hallucis longus with entry at the posteromedial tubercle of the talus is not an accepted approach for fixation of talar neck fractures. All of the other options use screw placements from anterior to posterior. REFERENCES: Swanson TV, Bray TJ, Homes GB Jr: Fractures of the talar neck: A mechanical study of fixation. J Bone Joint Surg Am 1992;74:544-551. Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 37-38.

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.

The sustentaculum tali remains in its anatomic position because of its supporting ligamentous structures. This provides the key to the reconstruction of the calcaneus. The posterior facet is reduced to the sustentaculum tali and then fixed to it for stability. All of the other components of the calcaneus are then reduced to this complex.

Continuous fluoroscopy and cine radiography expose the patient and personnel to markedly increased levels of direct and scatter radiation exposure. Continuous fluoroscopy should be limited to only what is absolutely needed for safe completion of the procedure. By orienting the cathode ray tube beneath the patient and placing the image intensifier as close as clinically possible to the patient, scatter radiation exposure to the personnel is minimized.