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8. Foot and Ankle MCQs

Practice Set 125 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 2481

Topic: Ankle Trauma & Sports

A 28-year-old skier falls forward with her ankles flexed, experiencing a sudden snapping sensation and acute pain posterior to the lateral malleolus. Radiographs demonstrate a small avulsion fracture ('fleck sign') off the posterolateral margin of the distal fibula. This radiographic finding is pathognomonic for an injury to which of the following structures?

. Anterior talofibular ligament (ATFL)
. Calcaneofibular ligament (CFL)
. Anterior inferior tibiofibular ligament (AITFL)
. Inferior extensor retinaculum
. Superior peroneal retinaculum (SPR)

Correct Answer & Explanation

. Superior peroneal retinaculum (SPR)

Explanation

A 'fleck sign' or rim fracture off the posterolateral border of the distal fibula represents an avulsion of the superior peroneal retinaculum (SPR). This injury leads to peroneal tendon subluxation or dislocation. It classically occurs during forceful dorsiflexion and reflex contraction of the peroneal muscles.

Question 2482

Topic: 8. Foot and Ankle

A 32-year-old horseback rider sustains a forced plantarflexion and abduction injury to the midfoot when her foot gets caught in the stirrup during a fall. Radiographs show an intra-articular impaction fracture of the cuboid. This 'nutcracker' fracture mechanism compresses the cuboid between which two osseous structures?

. The navicular and the medial cuneiform
. The talus and the base of the first metatarsal
. The calcaneus and the bases of the fourth and fifth metatarsals
. The lateral cuneiform and the base of the third metatarsal
. The sustentaculum tali and the fibula

Correct Answer & Explanation

. The calcaneus and the bases of the fourth and fifth metatarsals

Explanation

A 'nutcracker' fracture of the cuboid occurs via forceful plantarflexion and abduction of the forefoot. This mechanism forcefully compresses the cuboid bone between the anterior process of the calcaneus proximally and the rigid bases of the fourth and fifth metatarsals distally, leading to a crush or impaction injury.

Question 2483

Topic: Midfoot & Hindfoot

A 26-year-old male sustained a severe midfoot injury during a high-speed motorcycle crash. Radiographs demonstrate a pure dislocation through the transverse tarsal joint. The Chopart joint complex involves dislocations of which of the following specific articulations?

. The tarsometatarsal (Lisfranc) joints
. The talonavicular and calcaneocuboid joints
. The subtalar and tibiotalar joints
. The naviculocuneiform joints
. The medial, intermediate, and lateral cuneiform interosseous joints

Correct Answer & Explanation

. The talonavicular and calcaneocuboid joints

Explanation

The transverse tarsal joint, historically known as the Chopart joint, represents the anatomic boundary between the hindfoot and midfoot. It consists of two distinct articulations: the talonavicular joint medially and the calcaneocuboid joint laterally.

Question 2484

Topic: 8. Foot and Ankle
A 30-year-old pilot survives a small plane crash and presents with a displaced fracture of the talar neck. Radiographs demonstrate dislocation of both the subtalar joint and the ankle (tibiotalar) joint, while the talonavicular joint remains reduced. According to the Hawkins classification and historical literature, what is the approximate rate of avascular necrosis (AVN) of the talar body associated with this specific injury type?
. 0% to 10%
. 20% to 50%
. 40% to 50%
. 80% to 100%
. 10% to 15%

Correct Answer & Explanation

. 80% to 100%

Explanation

The patient has a Hawkins Type III talar neck fracture (fracture of the neck with dislocation of the subtalar and tibiotalar joints). In this severe injury, all three major sources of blood supply to the talar body (artery of the tarsal canal, deltoid branches, and dorsalis pedis branches) are disrupted. Historically, the rate of AVN for Hawkins Type III fractures approaches 80% to 100%.

Question 2485

Topic: Forefoot

A 55-year-old female presents with painful hallux valgus that has failed shoe modification. Standing radiographs reveal a hallux valgus angle (HVA) of 45 degrees and an intermetatarsal angle (IMA) of 18 degrees. To achieve adequate correction and minimize the risk of recurrence, which surgical approach is most biomechanically appropriate?

. A distal chevron osteotomy of the first metatarsal
. A proximal first metatarsal osteotomy or first tarsometatarsal (Lapidus) arthrodesis
. An isolated Akin osteotomy of the proximal phalanx
. A Keller resection arthroplasty
. A simple bunionectomy (Silver procedure) with medial capsulorrhaphy

Correct Answer & Explanation

. A proximal first metatarsal osteotomy or first tarsometatarsal (Lapidus) arthrodesis

Explanation

Severe hallux valgus is defined by a hallux valgus angle (HVA) > 40 degrees and an intermetatarsal angle (IMA) > 15 to 20 degrees. Distal osteotomies (like the Chevron) do not provide sufficient medial translation to correct a large IMA. Therefore, severe deformities necessitate proximal procedures, such as a proximal metatarsal osteotomy (Ludloff, crescentic) or a first TMT joint arthrodesis (Lapidus procedure).

Question 2486

Topic: Midfoot & Hindfoot

A 42-year-old marathon runner presents with chronic, severe plantar heel pain that has not improved with 6 months of stretching, orthotics, and cortisone injections. He notes the pain frequently radiates distally and laterally across the plantar aspect of his foot. On exam, there is maximal tenderness over the medial aspect of the heel, and a Tinel's sign is positive just inferior to the medial malleolus. The patient likely suffers from entrapment of which of the following nerves?

. Medial plantar nerve
. Sural nerve
. Deep peroneal nerve
. First branch of the lateral plantar nerve (Baxter's nerve)
. Saphenous nerve

Correct Answer & Explanation

. First branch of the lateral plantar nerve (Baxter's nerve)

Explanation

Entrapment of the first branch of the lateral plantar nerve (often called Baxter's nerve) is a well-recognized cause of chronic heel pain that mimics or coexists with recalcitrant plantar fasciitis. The nerve typically becomes compressed between the deep fascia of the abductor hallucis muscle and the medial head of the quadratus plantae. Symptoms may include radiating pain and sometimes atrophy of the abductor digiti minimi.

Question 2487

Topic: 8. Foot and Ankle

In a patient with Charcot-Marie-Tooth disease presenting with a classic cavovarus foot deformity, which of the following muscle imbalances is the primary driver for the plantarflexed first ray?

. Overpull of the tibialis anterior relative to the peroneus longus
. Overpull of the peroneus longus relative to the tibialis anterior
. Overpull of the tibialis posterior relative to the peroneus brevis
. Overpull of the peroneus brevis relative to the tibialis posterior
. Overpull of the extensor hallucis longus relative to the flexor hallucis longus

Correct Answer & Explanation

. Overpull of the peroneus longus relative to the tibialis anterior

Explanation

The cavovarus foot deformity in Charcot-Marie-Tooth (CMT) disease is primarily driven by specific muscle imbalances. The peroneus longus overpowers the weakened tibialis anterior, driving the first metatarsal into plantarflexion and creating the forefoot-driven cavus. Additionally, the tibialis posterior overpowers the weakened peroneus brevis, contributing to the hindfoot varus.

Question 2488

Topic: 8. Foot and Ankle
A 30-year-old sustains a Hawkins Type III talar neck fracture. Disruption of which of the following arteries places the talar body at the greatest risk for avascular necrosis?
. Artery of the tarsal sinus
. Artery of the tarsal canal
. Dorsalis pedis artery
. Deltoid branch of the posterior tibial artery
. Perforating branch of the peroneal artery

Correct Answer & Explanation

. Artery of the tarsal canal

Explanation

The artery of the tarsal canal (a branch of the posterior tibial artery) provides the majority of the blood supply to the talar body. While the talus also receives supply from the artery of the tarsal sinus and superior neck vessels, disruption of the artery of the tarsal canal significantly increases the risk of avascular necrosis, which is near 100% in Hawkins Type III fractures (talar neck fracture with subtalar and tibiotalar dislocation).

Question 2489

Topic: 8. Foot and Ankle

A 22-year-old football player sustains a midfoot sprain. Radiographs reveal a subtle 'fleck sign' in the first intermetatarsal space. This radiographic finding represents a bony avulsion of the Lisfranc ligament from which of the following anatomical structures?

. Base of the first metatarsal
. Base of the second metatarsal
. Lateral aspect of the medial cuneiform
. Medial aspect of the middle cuneiform
. Plantar aspect of the navicular

Correct Answer & Explanation

. Base of the second metatarsal

Explanation

The Lisfranc ligament is an interosseous ligament that runs from the lateral aspect of the medial cuneiform to the medial aspect of the base of the second metatarsal. The 'fleck sign' on an AP or mortise radiograph pathognomonically represents an avulsion fracture of this ligament, almost always detaching from the base of the second metatarsal.

Question 2490

Topic: 8. Foot and Ankle

A 55-year-old woman presents with a painful, flexible flatfoot. On examination, she is unable to perform a single-leg heel rise. Radiographs demonstrate greater than 40% uncoverage of the talar head on the AP view. Which of the following surgical procedures is most appropriate to address her specific forefoot abduction deformity?

. Medial displacement calcaneal osteotomy (MDCO)
. Lateral column lengthening (Evans osteotomy)
. First tarsometatarsal (Lapidus) arthrodesis
. Flexor digitorum longus transfer alone
. Subtalar arthrodesis

Correct Answer & Explanation

. Lateral column lengthening (Evans osteotomy)

Explanation

The patient has Stage IIb adult-acquired flatfoot deformity (posterior tibial tendon dysfunction), characterized by a flexible deformity with significant forefoot abduction (evidenced by >40% talonavicular uncoverage). Lateral column lengthening (Evans osteotomy) is specifically indicated to correct the forefoot abduction by lengthening the lateral column.

Question 2491

Topic: Forefoot

In evaluating an athlete with a hyperextension injury of the first metatarsophalangeal (MTP) joint (turf toe), which of the following is considered an absolute indication for surgical intervention?

. Grade 2 sprain with partial plantar plate tear
. Painful range of motion
. Proximal migration of the sesamoids >3 mm
. Minimal ecchymosis over the plantar MTP joint
. 10 degrees loss of maximum dorsiflexion

Correct Answer & Explanation

. Proximal migration of the sesamoids >3 mm

Explanation

Turf toe represents a sprain or tear of the first MTP plantar plate complex. Absolute indications for operative intervention include a large intra-articular fracture, proximal migration of the sesamoids >3 mm (indicating complete disruption of the plantar plate/sesamoid complex), and a traumatic hallux valgus deformity.

Question 2492

Topic: 8. Foot and Ankle

A 13-year-old boy presents with a rigid, painful flatfoot and a history of recurrent lateral ankle sprains. Lateral foot radiographs demonstrate an 'anteater nose' sign. Which of the following is the most likely diagnosis?

. Talocalcaneal coalition
. Calcaneonavicular coalition
. Talonavicular coalition
. Accessory navicular syndrome
. Charcot arthropathy

Correct Answer & Explanation

. Calcaneonavicular coalition

Explanation

The 'anteater nose' sign on a lateral foot radiograph is an anterior tubular elongation of the superior process of the calcaneus, which is pathognomonic for a calcaneonavicular coalition. In contrast, the 'C-sign' on a lateral radiograph is associated with a talocalcaneal coalition.

Question 2493

Topic: Forefoot

A 40-year-old female undergoes evaluation for hallux valgus. Her radiographs show a hallux valgus angle (HVA) of 30 degrees, an intermetatarsal angle (IMA) of 14 degrees, and a Distal Metatarsal Articular Angle (DMAA) of 20 degrees with a congruent MTP joint. Which of the following procedures is necessary to correct the abnormal DMAA?

. Standard Chevron osteotomy
. Lapidus procedure
. Proximal opening wedge osteotomy
. Reverdin (distal closing wedge) osteotomy
. Akin osteotomy

Correct Answer & Explanation

. Reverdin (distal closing wedge) osteotomy

Explanation

A Distal Metatarsal Articular Angle (DMAA) >15 degrees indicates an abnormal lateral slope of the distal metatarsal articular surface. In the presence of a congruent joint and an abnormal DMAA, an extra-articular correction such as a Reverdin (distal medial closing wedge) osteotomy or a biplanar chevron is required to reorient the articular surface while maintaining joint congruency.

Question 2494

Topic: 8. Foot and Ankle

A 60-year-old patient with poorly controlled diabetes mellitus presents with an acute, unilateral, erythematous, swollen, and warm foot. Pedal pulses are bounding. Radiographs of the foot show no fractures or joint subluxations. What is the most appropriate next step in management?

. Intravenous antibiotics and urgent surgical debridement
. MRI of the foot to rule out osteomyelitis
. Non-weight bearing total contact casting
. Immediate Charcot foot reconstruction
. Corticosteroid injection into the affected joints

Correct Answer & Explanation

. Non-weight bearing total contact casting

Explanation

This patient presents with Eichenholtz Stage 0 Charcot arthropathy (acute inflammation with normal radiographs). The most appropriate initial management is strict offloading and non-weight bearing total contact casting to arrest the process and prevent progression to fragmentation (Stage 1) and severe deformity. Bounding pulses reflect the autonomic neuropathy and arteriovenous shunting typical of Charcot.

Question 2495

Topic: 8. Foot and Ankle

When performing an arthrodesis of the first metatarsophalangeal (MTP) joint for severe hallux rigidus, what is the optimal position of fusion to ensure appropriate biomechanics during gait?

. 0 degrees of dorsiflexion, 0 degrees of valgus
. 10-15 degrees of dorsiflexion, 10-15 degrees of valgus
. 25-30 degrees of dorsiflexion, neutral valgus
. Neutral dorsiflexion, 20 degrees of valgus
. 5 degrees of plantarflexion, 10 degrees of valgus

Correct Answer & Explanation

. 10-15 degrees of dorsiflexion, 10-15 degrees of valgus

Explanation

The optimal position for a first MTP joint arthrodesis is 10-15 degrees of valgus and 10-15 degrees of dorsiflexion relative to the floor (or about 20-25 degrees relative to the first metatarsal axis). This position allows the hallux to clear the ground during the swing phase and provides a stable platform during toe-off without excessive pressure on the interphalangeal joint.

Question 2496

Topic: 8. Foot and Ankle

A 24-year-old snowboarder sustains an ankle injury after landing hard from a jump. He has focal tenderness inferior to the lateral malleolus. Radiographs reveal a fracture of the lateral process of the talus. What is the most common mechanism for this specific injury?

. Plantarflexion and inversion
. Dorsiflexion and inversion
. Plantarflexion and eversion
. Dorsiflexion and eversion
. Pure axial load

Correct Answer & Explanation

. Dorsiflexion and inversion

Explanation

A fracture of the lateral process of the talus is famously known as 'snowboarder\'s fracture'. It classically occurs from a mechanism involving forced dorsiflexion and inversion of the ankle, often accompanied by an axial load. It is frequently misdiagnosed as an ankle sprain.

Question 2497

Topic: Ankle Trauma & Sports

A 14-year-old male sustains an ankle injury resulting in a juvenile Tillaux fracture. Which of the following ligaments is responsible for the avulsion of the anterolateral distal tibial epiphysis?

. Anterior talofibular ligament (ATFL)
. Calcaneofibular ligament (CFL)
. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Deltoid ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

A juvenile Tillaux fracture is an avulsion of the anterolateral distal tibial epiphysis. It occurs in adolescents because the distal tibial physis closes from medial to lateral. The open anterolateral physis remains vulnerable to avulsion by the anterior inferior tibiofibular ligament (AITFL) during an external rotation injury.

Question 2498

Topic: 8. Foot and Ankle

The Achilles tendon is susceptible to rupture at its watershed area, located 2 to 6 cm proximal to its insertion on the calcaneus. The primary blood supply to this specific watershed region is derived from which of the following?

. Intramuscular branches of the gastrocnemius
. Osseous branches from the calcaneal tuberosity
. Extrinsic vessels traversing the paratenon
. The sural artery
. The medial plantar artery

Correct Answer & Explanation

. Extrinsic vessels traversing the paratenon

Explanation

The Achilles tendon lacks a true synovial sheath and is enveloped by a paratenon. The blood supply to its relatively hypovascular watershed region (2-6 cm proximal to the calcaneal insertion) is predominantly extrinsic, coming from vessels that traverse the paratenon, primarily branching from the posterior tibial artery.

Question 2499

Topic: 8. Foot and Ankle

A 15-year-old female dancer presents with insidious onset of pain over the dorsal forefoot. Radiographs show flattening, sclerosis, and fragmentation of the second metatarsal head. What is the most likely diagnosis?

. Kohler's disease
. Sever's disease
. Freiberg's infraction
. Iselin's disease
. Mueller-Weiss disease

Correct Answer & Explanation

. Freiberg's infraction

Explanation

Freiberg's infraction is avascular necrosis of the metatarsal head, most commonly affecting the second metatarsal. It frequently occurs in adolescent females and high-demand athletes (like dancers). Kohler's disease affects the navicular; Sever's is calcaneal apophysitis; Iselin's affects the 5th metatarsal base; Mueller-Weiss is spontaneous AVN of the adult navicular.

Question 2500

Topic: 8. Foot and Ankle

A 68-year-old man presents with a 'slapping' gait and a mild foot drop. He notes a recent pop anteriorly at the ankle while walking downstairs. Examination reveals a palpable mass over the anterior ankle and inability to actively dorsiflex the ankle past neutral, although toe extension is preserved. What is the classic 'triad' associated with this diagnosis?

. Pseudotumor, loss of active dorsiflexion, and extensor hallucis longus overactivity
. Pseudotumor, loss of active dorsiflexion, and steppage gait
. Hindfoot varus, forefoot abduction, and flatfoot
. Pain, pallor, and pulselessness
. Ankle equinus, cavus foot, and claw toes

Correct Answer & Explanation

. Pseudotumor, loss of active dorsiflexion, and steppage gait

Explanation

This patient has a spontaneous rupture of the tibialis anterior tendon. The classic triad of a tibialis anterior tendon rupture includes: 1) a soft tissue mass (pseudotumor) at the anterior ankle representing the retracted tendon stump, 2) loss of active ankle dorsiflexion, and 3) a steppage gait (foot drop). EHL overactivity may be a compensatory sign, but the accepted classic triad includes the steppage gait.

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