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8. Foot and Ankle MCQs

Practice Set 346 of 353

This practice set contains high-yield board review questions covering key concepts in 8. Foot and Ankle. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 6901

Topic: Midfoot & Hindfoot

A 55-year-old patient presents with a painful flatfoot deformity that has failed conservative management. Based on the provided radiographs, the primary site of degenerative collapse and deformity is located at which of the following articulations?

. Subtalar joint
. Talonavicular joint
. Calcaneocuboid joint
. Tarsometatarsal joints
. Metatarsophalangeal joints

Correct Answer & Explanation

. Tarsometatarsal joints

Explanation

Correct Answer: DThe radiographs demonstrate a degenerative collapse of the midfoot through the tarsometatarsal joints with significant forefoot abduction. Because the primary pathology and deformity are at the tarsometatarsal articulation, a midfoot arthrodesis is the required surgical intervention. Procedures targeting the hindfoot (like triple arthrodesis or lateral column lengthening) would not address the primary site of arthritis and deformity.

Question 6902

Topic: 8. Foot and Ankle

A patient presents with the toe deformity shown in the clinical photograph. The pathophysiology of this deformity involves hyperextension at the metatarsophalangeal (MTP) joint and flexion at the interphalangeal (IP) joints. Which of the following best describes the muscular imbalance at the IP joints in this condition?

. Stronger intrinsic muscles overpowering weaker flexors
. Stronger flexors overpowering weaker intrinsic muscles
. Extensor digitorum longus overpowering the lumbricals
. Extensor digitorum brevis overpowering the plantar plate
. Flexor digitorum longus overpowering the flexor digitorum brevis

Correct Answer & Explanation

. Stronger flexors overpowering weaker intrinsic muscles

Explanation

Correct Answer: BThe dynamic forces acting to maintain the position of the proximal phalanx at the head of the metatarsal are a balance between the extensor digitorum longus and the weaker intrinsic muscles. With hyperextension at the metatarsophalangeal joint, the intrinsic muscles become less efficient as plantar flexors. In the interphalangeal joints, the stronger flexors overpower the weaker intrinsic muscles, which act as the extensors. This combination of events leads to hyperextension at the metatarsophalangeal joint and flexion deformities at the interphalangeal joints, resulting in claw toe.

Question 6903

Topic: 8. Foot and Ankle

A 25-year-old rugby player sustains an axial load to a plantarflexed foot. Weight-bearing radiographs reveal a 4 mm diastasis between the medial cuneiform and the base of the second metatarsal. Rupture of which of the following structures is the primary driver of this radiographic finding?

. Spring ligament
. Plantar fascia
. Lisfranc ligament
. Calcaneocuboid ligament
. Bifurcate ligament

Correct Answer & Explanation

. Lisfranc ligament

Explanation

The Lisfranc ligament connects the medial cuneiform to the base of the second metatarsal, stabilizing the tarsometatarsal joint complex. Rupture of this critical ligament leads to midfoot instability, radiographically evident as widening of the 1st-2nd intermetatarsal space.

Question 6904

Topic: 8. Foot and Ankle

A 2-week-old male with idiopathic clubfoot is undergoing serial casting using the Ponseti method. After correcting the cavus deformity by elevating the first ray, the next step in the casting process involves abduction of the foot to correct the adduction and varus deformities. Around which specific anatomical structure must the foot be abducted to achieve proper correction?

. Calcaneocuboid joint
. Head of the talus
. Sustentaculum tali
. Navicular tuberosity
. Lateral malleolus

Correct Answer & Explanation

. Head of the talus

Explanation

Correct Answer: BIn the Ponseti method for clubfoot correction, the foot is abducted around the head of the talus, which acts as the fulcrum. The sequence of correction is C-A-V-E: Cavus, Adductus, Varus, Equinus. The cavus is corrected first by supinating the forefoot and elevating the first ray to align it with the hindfoot. Subsequently, the adduction and varus are corrected simultaneously by abducting the foot while applying counter-pressure over the lateral aspect of the head of the talus. A historical error in clubfoot casting (often referred to as Kite's error) was applying pressure over the calcaneocuboid joint, which blocks the abduction of the calcaneus and prevents correction of the heel varus, leading to a midfoot breach (rocker-bottom deformity).

Question 6905

Topic: 8. Foot and Ankle

A 13-year-old overweight boy presents with an insidious onset of vague hindfoot pain and frequent ankle sprains. Examination reveals a rigid flatfoot and restricted subtalar motion. Radiographs demonstrate a "C sign" on the lateral view. Which of the following is the most appropriate initial management?

. Resection of the coalition with fat graft interposition
. Subtalar arthrodesis
. Triple arthrodesis
. Short leg cast immobilization for 6 weeks
. Medial displacement calcaneal osteotomy

Correct Answer & Explanation

. Short leg cast immobilization for 6 weeks

Explanation

Correct Answer: Short leg cast immobilization for 6 weeksThe patient's presentation of a rigid flatfoot, restricted subtalar motion, and a "C sign" on lateral radiographs is highly indicative of a talocalcaneal coalition. The "C sign" is formed by the medial outline of the talar dome and the posteroinferior outline of the sustentaculum tali, indicating a middle facet coalition. The initial management for a symptomatic tarsal coalition is conservative, consisting of immobilization in a short leg cast or controlled ankle motion (CAM) boot for 4 to 6 weeks to reduce inflammation and pain. If conservative management fails, surgical intervention may be considered. Resection of the coalition with interposition (fat, wax, or muscle) is indicated for patients who fail conservative treatment and do not have advanced degenerative changes. Arthrodesis (subtalar or triple) is reserved for patients with advanced degenerative changes or those who fail resection. A medial displacement calcaneal osteotomy is not a primary treatment for tarsal coalition.

Question 6906

Topic: 8. Foot and Ankle

A 13-year-old boy presents with recurrent ankle sprains and rigid flatfeet. On examination, he has restricted subtalar motion and pain with inversion. A "C-sign" is noted on the lateral radiograph of the foot. Which of the following is the most likely diagnosis, and what is the best imaging modality to confirm and delineate the anatomy?

. A) Calcaneonavicular coalition; MRI
. B) Calcaneonavicular coalition; CT scan
. C) Talocalcaneal coalition; MRI
. D) Talocalcaneal coalition; CT scan
. E) Talonavicular coalition; CT scan

Correct Answer & Explanation

. D) Talocalcaneal coalition; CT scan

Explanation

Correct Answer: DThe clinical presentation of rigid flatfeet, restricted subtalar motion, and recurrent ankle sprains in an adolescent is classic for a tarsal coalition. The "C-sign" on a lateral radiograph is a continuous C-shaped arc formed by the medial outline of the talar dome and the posteroinferior outline of the sustentaculum tali. This sign is highly indicative of a talocalcaneal (subtalar) coalition, specifically involving the middle facet. The gold standard imaging modality to confirm the diagnosis, determine the extent of the coalition (osseous, cartilaginous, or fibrous), and plan surgical resection is a CT scan. Calcaneonavicular coalitions (Options A and B) are best seen on a 45-degree internal oblique radiograph and present with an "anteater nose" sign, not a C-sign. MRI can be used for fibrous or cartilaginous coalitions but CT remains the primary advanced imaging modality for surgical planning of bony coalitions.

Question 6907

Topic: 8. Foot and Ankle

A 14-year-old male presents with a history of recurrent lateral ankle sprains and a rigid, painful flatfoot. On physical examination, he has significantly decreased subtalar motion and experiences pain with passive inversion of the foot. Lateral radiographs of the foot demonstrate a continuous bony bridge between the talus and the calcaneus, creating a "C-sign." Which of the following is the most likely anatomical location of his pathology?

. Calcaneonavicular joint
. Talonavicular joint
. Talocalcaneal joint at the middle facet
. Talocalcaneal joint at the posterior facet
. Cuboid-navicular joint

Correct Answer & Explanation

. Talocalcaneal joint at the middle facet

Explanation

Correct Answer: Talocalcaneal joint at the middle facetThe patient's clinical presentation (rigid flatfoot, recurrent sprains, decreased subtalar motion) is classic for a tarsal coalition. The two most common types are calcaneonavicular and talocalcaneal coalitions. The radiographic "C-sign" on a lateral view is formed by the medial outline of the talar dome and the inferior outline of the sustentaculum tali, and it is highly indicative of a talocalcaneal coalition. Talocalcaneal coalitions most frequently occur at the middle facet of the subtalar joint. Calcaneonavicular coalitions (Option A) are best seen on a 45-degree internal rotation oblique radiograph and are associated with the "anteater nose" sign (tubular elongation of the anterior process of the calcaneus). The posterior facet (Option D) is rarely the primary site of a talocalcaneal coalition.

Question 6908

Topic: 8. Foot and Ankle

A 13-year-old boy presents with frequent ankle sprains and rigid flatfeet. Examination reveals restricted subtalar motion and pain with inversion. Oblique radiographs of the foot demonstrate an elongated anterior process of the calcaneus (the "anteater nose" sign). Which of the following is the most likely diagnosis and its typical primary treatment?

. Talocalcaneal coalition; short leg cast for 4-6 weeks.
. Talocalcaneal coalition; immediate surgical resection and interposition.
. Calcaneonavicular coalition; short leg cast for 4-6 weeks.
. Calcaneonavicular coalition; immediate triple arthrodesis.
. Cuboid-navicular coalition; supportive shoe wear.

Correct Answer & Explanation

. Calcaneonavicular coalition; short leg cast for 4-6 weeks.

Explanation

The "anteater nose" sign on an oblique radiograph is pathognomonic for a calcaneonavicular coalition. Initial management of symptomatic tarsal coalitions, regardless of type, typically involves a period of non-operative treatment such as immobilization in a short leg walking cast to reduce inflammation.

Question 6909

Topic: 8. Foot and Ankle

A patient with a chronic history of gouty arthritis presents with multiple, painless, firm, yellowish nodules over the olecranon bursa and Achilles tendon. Chalky white material is extruded from one of the nodules. Which of the following conditions is most strongly associated with this disease process?

. Psoriasis
. Rheumatoid arthritis
. Metabolic syndrome
. Inflammatory bowel disease
. Hyperparathyroidism

Correct Answer & Explanation

. Metabolic syndrome

Explanation

The patient has tophaceous gout. Gout and hyperuricemia are strongly associated with metabolic syndrome, which includes a constellation of hypertension, central obesity, insulin resistance, and dyslipidemia.

Question 6910

Topic: 8. Foot and Ankle

A 60-year-old man presents with chronic foot pain and the following radiographic findings

. What is the classic radiographic description of the erosions associated with this disease process?

. Pencil-in-cup deformity
. Central lytic lesion with a sclerotic rim
. Punched-out erosions with overhanging edges
. Subchondral cysts with joint space narrowing
. Periarticular osteopenia with marginal erosions

Correct Answer & Explanation

. Punched-out erosions with overhanging edges

Explanation

Chronic tophaceous gout is classically characterized by juxta-articular "punched-out" bony erosions. These often feature overhanging cortical edges, also known as Martel's sign, with preservation of the joint space until late in the disease.

Question 6911

Topic: 8. Foot and Ankle

During extensive tibial lengthening, the patient develops a new-onset clawing of the lesser toes. This most likely represents stretching and irritation of which nerve?

. Deep peroneal nerve
. Superficial peroneal nerve
. Tibial nerve
. Sural nerve
. Saphenous nerve

Correct Answer & Explanation

. Tibial nerve

Explanation

Clawing of the toes during tibial lengthening typically indicates a stretch injury to the tibial nerve. This causes dysfunction of the intrinsic foot musculature, leading to an intrinsic minus foot posture.

Question 6912

Topic: 8. Foot and Ankle

A 7-year-old boy with spastic diplegic cerebral palsy underwent a fractional lengthening of the Achilles tendons bilaterally one year ago. He now presents with a worsening gait, walking with increased knee flexion during the stance phase. What is the primary cause of this iatrogenic gait abnormality?

. Spasticity of the rectus femoris.
. Overlengthening of the Achilles tendon causing a loss of the plantarflexion-knee extension couple.
. Underlengthening of the medial hamstrings.
. Progressive hip flexion contractures.
. Weakness of the anterior tibialis muscle.

Correct Answer & Explanation

. Overlengthening of the Achilles tendon causing a loss of the plantarflexion-knee extension couple.

Explanation

Overlengthening the Achilles tendon in a patient with cerebral palsy destroys the plantarflexion-knee extension couple. Without a competent gastroc-soleus complex to control forward advancement of the tibia (second rocker), the tibia collapses forward, leading to an iatrogenic crouch gait.

Question 6913

Topic: 8. Foot and Ankle

A 9-year-old boy is undergoing a 5-cm tibial lengthening via distraction osteogenesis with a circular external fixator. During the consolidation phase, he develops a fixed equinus contracture. What biomechanical factor makes the ankle most susceptible to this specific contracture during tibial lengthening?

. Weakness of the anterior tibialis muscle due to deep peroneal nerve stretch.
. The relative strength and lack of excursion of the triceps surae complex crossing the ankle joint.
. Premature consolidation of the fibular osteotomy.
. Improper placement of the proximal tibial transfixation wires.
. Overactivity of the flexor hallucis longus muscle.

Correct Answer & Explanation

. The relative strength and lack of excursion of the triceps surae complex crossing the ankle joint.

Explanation

Ankle equinus is the most common joint contracture during tibial lengthening. The strong gastrocnemius-soleus complex resists stretching more than the anterior compartment muscles, pulling the foot into plantarflexion unless prevented by aggressive physical therapy or extending the frame to the foot.

Question 6914

Topic: 8. Foot and Ankle

A 25-year-old female undergoes acute correction of a severe valgus deformity of the proximal tibia utilizing an opening wedge osteotomy. In the recovery room, she is found to have a dense foot drop and numbness in the first web space. What is the most appropriate initial management?

. Immediate surgical exploration of the common peroneal nerve.
. Application of an ankle-foot orthosis (AFO) and physical therapy.
. Immediate release of the deformity correction and slight knee flexion.
. Stat MRI of the lumbar spine to rule out epidural hematoma.
. Administration of high-dose intravenous corticosteroids.

Correct Answer & Explanation

. Immediate release of the deformity correction and slight knee flexion.

Explanation

Acute correction of a severe valgus deformity stretches the common peroneal nerve on the lateral side. The immediate treatment for an acute post-operative nerve palsy in this setting is to release the correction (close the wedge or adjust the frame) and flex the knee to relieve nerve tension before irreversible damage occurs.

Question 6915

Topic: 8. Foot and Ankle
A 12-year-old boy with spastic diplegic cerebral palsy presents with an increasingly severe crouch gait. He underwent bilateral isolated Achilles tendon lengthenings at age 6 for toe-walking. Physical examination reveals hip and knee flexion contractures of 25 degrees bilaterally and excessive ankle dorsiflexion. Which of the following surgical strategies is most appropriate?
. Repeat bilateral Achilles tendon lengthenings.
. Bilateral hamstring lengthenings and distal femoral extension osteotomies.
. Bilateral anterior half of the tibialis anterior transfer (SPLATT).
. Bilateral gastrocnemius recessions.
. Botulinum toxin injections to the gastrocnemius-soleus complex.

Correct Answer & Explanation

. Bilateral hamstring lengthenings and distal femoral extension osteotomies.

Explanation

Crouch gait in this scenario was exacerbated by prior isolated Achilles lengthenings, leading to excessive dorsiflexion and uncontrolled forward progression of the tibia. Proper management must address the knee and hip flexion contractures (hamstrings/psoas) and osseous deformities (distal femoral extension osteotomy) while avoiding further weakening of the plantarflexors.

Question 6916

Topic: 8. Foot and Ankle

A 14-year-old girl is undergoing a 4 cm tibial lengthening using a circular external fixator. During the distraction phase, she is at highest risk for developing an equinus contracture. Which of the following is the most effective prophylactic intraoperative measure to prevent this complication?

. Prophylactic Achilles tendon lengthening at the time of frame application
. Performing the corticotomy in the distal diametaphysis instead of the proximal tibia
. Administering botulinum toxin to the anterior compartment musculature
. Using a higher distraction rate of 1.5 mm per day
. Extending the external fixator to include the foot

Correct Answer & Explanation

. Extending the external fixator to include the foot

Explanation

Tibial lengthening severely tensions the gastrocnemius-soleus complex, risking a resistant equinus contracture. Extending the fixator to include the foot rigidly maintains the ankle in neutral during the lengthening process.

Question 6917

Topic: 8. Foot and Ankle

A 15-year-old male is undergoing proximal tibial lengthening. Two weeks into the distraction phase, he reports new-onset numbness on the dorsum of his foot and weakness in great toe extension. What is the most appropriate initial management?

. Halt the distraction process immediately and observe closely
. Increase the rate of distraction to expedite the procedure
. Perform an immediate complete peroneal nerve decompression
. Administer high-dose intravenous corticosteroids
. Prescribe a rigid ankle-foot orthosis and continue distraction

Correct Answer & Explanation

. Halt the distraction process immediately and observe closely

Explanation

Numbness and extensor hallucis longus weakness indicate early deep peroneal nerve stretch palsy. The initial step is to immediately halt the distraction; if symptoms do not improve, slight shortening of the frame is indicated.

Question 6918

Topic: 8. Foot and Ankle

A 7-year-old child with spastic diplegic cerebral palsy presents with a 'crouch gait'. During the stance phase of gait analysis, what classic combination of lower extremity joint positions is diagnostic of this gait pattern?

. Hip extension, knee extension, and ankle plantarflexion
. Excessive hip and knee flexion with ankle dorsiflexion
. Hip internal rotation, knee recurvatum, and ankle equinus
. Hip abduction, knee extension, and hindfoot valgus
. Excessive hip and knee flexion with ankle plantarflexion

Correct Answer & Explanation

. Excessive hip and knee flexion with ankle dorsiflexion

Explanation

Crouch gait is characterized by excessive hip and knee flexion combined with excessive ankle dorsiflexion during the stance phase. This is often seen in cerebral palsy following isolated Achilles tendon lengthening without addressing hamstring/psoas spasticity.

Question 6919

Topic: 8. Foot and Ankle

During the loading response phase of the normal gait cycle, which muscle group contracts eccentrically to control the descent of the foot and prevent a 'foot slap'?

. Gastrocnemius-soleus complex
. Tibialis anterior
. Quadriceps femoris
. Hamstrings
. Gluteus medius

Correct Answer & Explanation

. Tibialis anterior

Explanation

During the loading response (heel strike to foot flat), the ankle dorsiflexors, primarily the tibialis anterior, contract eccentrically. This controlled lengthening lowers the forefoot smoothly to the ground.

Question 6920

Topic: 8. Foot and Ankle

A patient is undergoing evaluation for a varus deformity of the lower extremity. Which of the following correctly describes the normal mechanical axis of the lower limb?

. It passes from the anterior superior iliac spine through the patella to the first web space.
. It passes from the center of the femoral head to the center of the ankle, normally passing slightly lateral to the center of the knee joint.
. It passes from the center of the femoral head to the center of the ankle, normally passing slightly medial to the center of the knee joint.
. It runs parallel to the anatomical axis of the femur.
. It is formed by a line drawn from the greater trochanter to the lateral malleolus.

Correct Answer & Explanation

. It passes from the center of the femoral head to the center of the ankle, normally passing slightly medial to the center of the knee joint.

Explanation

The mechanical axis of the lower limb connects the center of the femoral head to the center of the ankle plafond. In a normal limb, it passes slightly medial (about 8-10 mm) to the center of the knee joint.

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