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8. Foot and Ankle MCQs

Practice Set 321 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 6401

Topic: Forefoot

A 45-year-old female presents with a painful bunion. Weight-bearing radiographs show a hallux valgus angle (HVA) of 45 degrees, an intermetatarsal angle (IMA) of 18 degrees, and hypermobility of the first tarsometatarsal (TMT) joint. Which of the following surgical options is most appropriate?

. Distal chevron osteotomy
. Akin osteotomy alone
. First TMT joint arthrodesis (Lapidus procedure)
. First metatarsophalangeal joint arthrodesis
. Keller arthroplasty

Correct Answer & Explanation

. First TMT joint arthrodesis (Lapidus procedure)

Explanation

A Lapidus procedure (first TMT arthrodesis) is indicated for severe hallux valgus (HVA >40, IMA >15) associated with first TMT joint hypermobility. It corrects the deformity at the apex and stabilizes the medial column.

Question 6402

Topic: 8. Foot and Ankle

A 28-year-old skier presents with posterolateral ankle pain and a snapping sensation behind the lateral malleolus. Physical examination reveals subluxation of the peroneal tendons with resisted eversion. Pathology involves disruption of which of the following structures?

. Anterior talofibular ligament
. Calcaneofibular ligament
. Superior peroneal retinaculum
. Inferior peroneal retinaculum
. Posterior talofibular ligament

Correct Answer & Explanation

. Superior peroneal retinaculum

Explanation

Peroneal tendon subluxation or dislocation is caused by an injury to the superior peroneal retinaculum (SPR), often occurring with sudden, forceful dorsiflexion and eversion. Surgical repair and potential fibular groove deepening is often required for symptomatic instability.

Question 6403

Topic: 8. Foot and Ankle

A 14-year-old boy presents with a rigid, painful flatfoot and a history of recurrent ankle sprains. Radiographs show an elongated anterior process of the calcaneus resembling an anteater's nose on the lateral view. What is the most likely diagnosis?

. Talocalcaneal coalition
. Calcaneonavicular coalition
. Accessory navicular syndrome
. Muller-Weiss disease
. Kohler disease

Correct Answer & Explanation

. Calcaneonavicular coalition

Explanation

The "anteater sign" on a lateral radiograph is highly indicative of a calcaneonavicular coalition. Talocalcaneal coalitions, conversely, typically present with a "C-sign" on lateral radiographs.

Question 6404

Topic: Forefoot

A 45-year-old female presents with a painful bunion. Clinical exam reveals a hypermobile first tarsometatarsal (TMT) joint. Radiographs show a hallux valgus angle of 35 degrees and an intermetatarsal angle of 16 degrees. Which of the following procedures is most appropriate?

. Distal chevron osteotomy
. First MTP joint arthrodesis
. Akin osteotomy alone
. Proximal crescentic osteotomy with distal soft tissue release
. First TMT joint arthrodesis (Lapidus procedure)

Correct Answer & Explanation

. First TMT joint arthrodesis (Lapidus procedure)

Explanation

A Lapidus procedure (first TMT arthrodesis) is indicated for moderate-to-severe hallux valgus associated with first ray hypermobility. It corrects the intermetatarsal angle and stabilizes the medial column, preventing recurrence.

Question 6405

Topic: 8. Foot and Ankle

A 65-year-old male with end-stage ankle osteoarthritis is evaluated for a total ankle arthroplasty (TAA). Which of the following is considered an absolute contraindication to TAA?

. Age greater than 60 years
. Concomitant subtalar arthritis
. Charcot neuroarthropathy of the ankle
. Previous open reduction internal fixation of the ankle
. Coronal plane deformity of 10 degrees

Correct Answer & Explanation

. Charcot neuroarthropathy of the ankle

Explanation

Charcot neuroarthropathy, active infection, and severe avascular necrosis of the talus are absolute contraindications to total ankle arthroplasty due to unacceptably high failure rates. Ankle arthrodesis is the preferred surgical treatment in these patients.

Question 6406

Topic: 8. Foot and Ankle

A 24-year-old football player presents with lateral ankle pain and a snapping sensation behind the lateral malleolus when circumducting the foot. Radiographs demonstrate a small bony avulsion off the posterolateral aspect of the distal fibula. What is the most appropriate surgical treatment?

. Anterior talofibular ligament (ATFL) reconstruction
. Calcaneofibular ligament (CFL) repair
. Superior peroneal retinaculum (SPR) repair with or without fibular groove deepening
. Peroneus brevis to longus tenodesis
. Sural nerve decompression

Correct Answer & Explanation

. Superior peroneal retinaculum (SPR) repair with or without fibular groove deepening

Explanation

The clinical presentation and "fleck sign" on radiographs indicate a superior peroneal retinaculum (SPR) avulsion leading to peroneal tendon subluxation. Surgical treatment involves SPR repair and often fibular groove deepening to stabilize the tendons.

Question 6407

Topic: 8. Foot and Ankle
A 40-year-old roofer falls from a height and sustains a severely comminuted, displaced intra-articular calcaneus fracture (Sanders Type III). A lateral extensile approach is planned for open reduction and internal fixation. Which nerve is at greatest risk of iatrogenic injury during the surgical approach?
. Deep peroneal nerve
. Medial plantar nerve
. Sural nerve
. Saphenous nerve
. Tibial nerve

Correct Answer & Explanation

. Sural nerve

Explanation

The sural nerve crosses the lateral aspect of the hindfoot and is at highest risk during the standard lateral extensile approach to the calcaneus. Careful full-thickness flap elevation is required to protect it and the vascular supply to the flap.

Question 6408

Topic: 8. Foot and Ankle

A 38-year-old male sustains an acute, closed mid-substance Achilles tendon rupture. After discussing treatment options, he elects for nonoperative management with a functional rehabilitation protocol. Compared to operative repair, nonoperative management with early functional rehab is associated with which of the following?

. Higher risk of deep vein thrombosis
. Similar re-rupture rates but higher risk of wound complications
. Higher re-rupture rates but lower risk of sural nerve injury
. Similar re-rupture rates but lower risk of wound complications
. Significantly lower return to sport rates

Correct Answer & Explanation

. Similar re-rupture rates but lower risk of wound complications

Explanation

Recent literature shows that nonoperative management utilizing early functional weight-bearing rehabilitation has similar re-rupture rates compared to operative repair, while completely avoiding surgical wound complications. Operative repair has historically shown lower re-rupture rates only when compared to prolonged cast immobilization.

Question 6409

Topic: 8. Foot and Ankle

A 22-year-old collegiate basketball player sustains a zone 2 fracture of the proximal fifth metatarsal. Intramedullary screw fixation is planned. To minimize the risk of lateral cortex penetration and hardware failure, the starting point for the screw should be:

. Plantar and lateral on the fifth metatarsal tuberosity
. Dorsal and medial on the fifth metatarsal tuberosity
. Directly central on the articular surface of the cuboid
. High and medial on the tuberosity to avoid the peroneus brevis insertion
. High and lateral to align with the diaphyseal bow

Correct Answer & Explanation

. Dorsal and medial on the fifth metatarsal tuberosity

Explanation

To avoid penetrating the laterally bowed cortex of the fifth metatarsal, the ideal starting point for an intramedullary screw is high (dorsal) and medial on the tuberosity. This trajectory aligns best with the straight intramedullary canal.

Question 6410

Topic: 8. Foot and Ankle

A 14-year-old boy presents with repeated ankle sprains and a rigid, flatfoot deformity. Radiographs show an elongated anterior process of the calcaneus (anteater sign). CT confirms a calcaneonavicular coalition. After 6 months of failed conservative treatment, what is the best surgical option?

. Subtalar arthrodesis
. Triple arthrodesis
. Coalition resection with extensor digitorum brevis (EDB) interposition
. Calcaneal lengthening osteotomy (Evans)
. Medializing calcaneal osteotomy

Correct Answer & Explanation

. Coalition resection with extensor digitorum brevis (EDB) interposition

Explanation

For a symptomatic calcaneonavicular coalition failing nonoperative management without advanced degenerative changes, the gold standard is resection with interposition of the EDB muscle or fat graft to prevent recurrence. Arthrodesis is reserved for cases with severe arthritis or failed resections.

Question 6411

Topic: 8. Foot and Ankle

A 55-year-old diabetic patient presents with a swollen, erythematous, and warm left foot. Radiographs demonstrate severe periarticular fragmentation, debris, and subluxation of the midfoot joints. According to the Eichenholtz classification, what stage does this represent and what is the primary treatment?

. Stage 0; observation and NSAIDs
. Stage 1; total contact casting and non-weight-bearing
. Stage 2; surgical midfoot fusion
. Stage 3; custom accommodating footwear
. Stage 4; below-knee amputation

Correct Answer & Explanation

. Stage 1; total contact casting and non-weight-bearing

Explanation

Eichenholtz Stage 1 (Developmental/Fragmentation) is characterized by clinical erythema, swelling, and radiographic fragmentation and debris. The gold standard treatment in this active phase is immobilization and offloading, typically with a total contact cast, until the joints coalesce.

Question 6412

Topic: 8. Foot and Ankle

During open reduction and internal fixation of a pronation-external rotation (PER-4) ankle fracture, the surgeon assesses the syndesmosis using the external rotation stress test. Which radiographic parameter on the mortise view most reliably indicates syndesmotic instability requiring fixation?

. Tibiofibular overlap greater than 1 mm
. Medial clear space greater than 4 mm
. Talar tilt of 2 degrees
. Tibiofibular clear space greater than 5 mm
. Decrease in the talocrural angle

Correct Answer & Explanation

. Medial clear space greater than 4 mm

Explanation

An increase in the medial clear space (>4 mm) with external rotation stress is the most reliable radiographic indicator of deep deltoid ligament insufficiency and syndesmotic instability. The tibiofibular clear space is less reproducible due to variability in rotational positioning.

Question 6413

Topic: 8. Foot and Ankle

A 24-year-old athlete sustains a hyper-plantarflexion injury to his midfoot.

A Lisfranc injury is suspected. The primary stabilizing ligament of the Lisfranc joint complex connects which two bones?

. Medial cuneiform and the base of the first metatarsal
. Medial cuneiform and the base of the second metatarsal
. Middle cuneiform and the base of the second metatarsal
. Lateral cuneiform and the cuboid
. Navicular and the medial cuneiform

Correct Answer & Explanation

. Medial cuneiform and the base of the second metatarsal

Explanation

The Lisfranc ligament is an interosseous ligament that serves as the primary and strongest stabilizer of the tarsometatarsal articulation. It originates on the lateral aspect of the medial cuneiform and inserts onto the medial base of the second metatarsal. There is no direct transverse ligamentous connection between the bases of the first and second metatarsals.

Question 6414

Topic: 8. Foot and Ankle

Charcot neuroarthropathy is a devastating complication in patients with long-standing diabetes mellitus. Which of the following pathophysiologic mechanisms best describes the 'neurovascular theory' of Charcot arthropathy development?

. Repeated unrecognized microtrauma due to loss of protective sensation
. Autonomic neuropathy leading to increased extremity blood flow and active osteoclastic bone resorption
. Direct bacterial invasion of the joint space resulting in smoldering osteomyelitis
. Ischemia secondary to peripheral arterial microvascular disease causing avascular bone necrosis
. Autoimmune destruction of the articular cartilage triggered by advanced glycation end products

Correct Answer & Explanation

. Autonomic neuropathy leading to increased extremity blood flow and active osteoclastic bone resorption

Explanation

The neurovascular theory postulates that autonomic neuropathy causes a loss of sympathetic tone, resulting in arteriovenous shunting and a hyperemic state in the foot. This increased blood flow stimulates active osteoclastic bone resorption and localized osteopenia, making the bones highly susceptible to fracture and collapse.

Question 6415

Topic: 8. Foot and Ankle

A 22-year-old collegiate football player sustains an acute midfoot injury when tackled with his foot plantarflexed. An AP weight-bearing radiograph reveals a small osseous avulsion in the space between the base of the first and second metatarsals ('fleck sign'). This represents an avulsion of the Lisfranc ligament, which anatomically connects which two bones?

. First metatarsal base and second metatarsal base
. Medial cuneiform and second metatarsal base
. Middle cuneiform and first metatarsal base
. Navicular and medial cuneiform
. Talus and navicular

Correct Answer & Explanation

. Medial cuneiform and second metatarsal base

Explanation

The 'fleck sign' is pathognomonic for a Lisfranc injury. It represents a bony avulsion of the strong intra-articular Lisfranc ligament, which spans from the lateral aspect of the medial cuneiform to the medial base of the second metatarsal, stabilizing the midfoot arch.

Question 6416

Topic: 8. Foot and Ankle

A 10-year-old child with spastic diplegic cerebral palsy presents with progressive crouch gait. He underwent an isolated tendo-Achilles lengthening at age 5 for toe-walking. Physical examination reveals bilateral knee flexion contractures of 15 degrees and excessive ankle dorsiflexion during the stance phase of gait. What is the most likely primary underlying etiology of his current gait deterioration?

. Undiagnosed bilateral hip dislocations
. Spasticity of the posterior tibial tendon
. Fixed ankle equinus contracture
. Overactive quadriceps muscle
. Iatrogenic calf muscle weakness

Correct Answer & Explanation

. Iatrogenic calf muscle weakness

Explanation

Crouch gait in patients with cerebral palsy is characterized by excessive hip and knee flexion with excessive ankle dorsiflexion during the stance phase. A common iatrogenic cause is isolated lengthening of the Achilles tendon (without addressing concomitant hamstring spasticity). This leads to weakness of the gastrosoleus complex, removing the plantarflexion-knee extension couple. The tibia falls forward over the foot into excessive dorsiflexion, which secondarily increases knee and hip flexion, worsening the crouch.

Question 6417

Topic: 8. Foot and Ankle

A 13-year-old boy presents with a painful, rigid flatfoot and a history of recurrent ankle sprains. Physical examination reveals severely restricted subtalar motion and palpable spasm of the peroneal tendons. A lateral radiograph demonstrates an elongation of the anterior process of the calcaneus, known as the 'anteater sign'.

What is the most likely diagnosis?

. Talocalcaneal coalition
. Calcaneonavicular coalition
. Congenital vertical talus
. Symptomatic accessory navicular
. Kohler disease

Correct Answer & Explanation

. Calcaneonavicular coalition

Explanation

The 'anteater sign' on a lateral radiograph is pathognomonic for a calcaneonavicular coalition. This is a common cause of rigid flatfoot and peroneal spasticity in adolescents (typically becoming symptomatic between ages 8 and 12). In contrast, a talocalcaneal coalition typically becomes symptomatic slightly later (ages 12-16) and is associated with the 'C-sign' on a lateral radiograph.

Question 6418

Topic: 8. Foot and Ankle

A 13-year-old boy presents with frequent lateral ankle sprains and rigid, flat feet. On examination, subtalar motion is markedly restricted. Which of the following radiographic findings is most characteristic of a calcaneonavicular coalition?

. C-sign on a lateral radiograph
. Talar beak sign on an AP radiograph
. Anteater nose sign on a 45-degree internal oblique radiograph
. Double density sign on a Harris axial radiograph
. Too-many-toes sign on a weight-bearing AP view

Correct Answer & Explanation

. Anteater nose sign on a 45-degree internal oblique radiograph

Explanation

The 'anteater nose sign' represents an elongation of the anterior process of the calcaneus, which is the classic radiographic finding for a calcaneonavicular coalition, best visualized on a 45-degree internal oblique radiograph of the foot. The 'C-sign' is seen on lateral radiographs in talocalcaneal coalitions.

Question 6419

Topic: 8. Foot and Ankle

Which of the following best describes the fundamental pathoanatomy of congenital vertical talus?

. Rigid plantarflexion of the talus with dorsal dislocation of the navicular
. Rigid dorsiflexion of the talus with plantar dislocation of the navicular
. Flexible equinus of the calcaneus with medial subluxation of the navicular
. Medial deviation of the talar neck with forefoot adduction
. Rigid adduction of the midfoot with fixed calcaneal varus

Correct Answer & Explanation

. Rigid plantarflexion of the talus with dorsal dislocation of the navicular

Explanation

Congenital vertical talus is characterized by a fixed, rigid plantarflexed talus with an irreducible dorsal dislocation of the navicular on the talar neck. The calcaneus is in fixed equinus and valgus, distinguishing it from oblique talus, where the navicular dislocation is reducible.

Question 6420

Topic: 8. Foot and Ankle

A 12-year-old boy presents with a history of recurrent ankle sprains and a painful, rigid flatfoot. A lateral radiograph of the foot demonstrates an elongated anterior process of the calcaneus, known as the "anteater nose" sign. Which of the following conditions is the most likely diagnosis?

. Talocalcaneal coalition
. Calcaneonavicular coalition
. Talonavicular coalition
. Calcaneocuboid coalition
. Naviculocuneiform coalition

Correct Answer & Explanation

. Calcaneonavicular coalition

Explanation

The "anteater nose" sign on a lateral foot radiograph is pathognomonic for a calcaneonavicular coalition. This condition typically presents between 8 and 12 years of age as the cartilaginous bar begins to ossify, causing a rigid, painful flatfoot.

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