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8. Foot and Ankle MCQs

Practice Set 191 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 3801

Topic: 8. Foot and Ankle

A 19-year-old football player sustains a high-energy knee injury resulting in an acute knee dislocation. Following closed reduction, his distal pulses are palpable but seem slightly asymmetric. What is the most appropriate next step in management to rule out a sight-threatening complication?

. Immediate surgical exploration of the popliteal artery
. Perform an ankle-brachial index (ABI)
. Discharge with close clinical follow-up in 24 hours
. Immediate MRI of the knee to plan ligamentous repair
. Apply a hinged knee brace and allow partial weight-bearing

Correct Answer & Explanation

. Immediate surgical exploration of the popliteal artery

Explanation

Vascular assessment is critical in the setting of a knee dislocation. If pulses are asymmetric or the ABI is less than 0.9, an immediate CT angiogram or vascular surgery consultation is required to rule out a popliteal artery injury, which carries a high risk of amputation if missed.

Question 3802

Topic: 8. Foot and Ankle

A 30-year-old male sustains a severe hyperextension injury to his knee, resulting in a KD-III multiligament knee dislocation. On examination, he is unable to dorsiflex his ankle or extend his great toe. This neurologic deficit is due to an injury of a nerve structurally tethered at which of the following locations?

. The popliteal crease
. The adductor hiatus
. The fibular neck
. The interosseous membrane

Correct Answer & Explanation

. The popliteal crease

Explanation

The patient has a foot drop, indicating an injury to the common peroneal nerve, which is common in severe knee dislocations (especially posterolateral). The common peroneal nerve is susceptible to traction injury due to its rigid tethering at the fibular neck.

Question 3803

Topic: 8. Foot and Ankle

A 28-year-old patient presents to the emergency department after sustaining a severe hyperextension injury to the knee. Examination reveals gross multi-planar instability consistent with a knee dislocation (KD-III). The dorsalis pedis pulse is palpable but diminished compared to the contralateral side. The Ankle-Brachial Index (ABI) is calculated to be 0.7. What is the most appropriate next step in management?

. Observation and repeat ABI in 4 hours
. Immediate surgical exploration of the popliteal artery
. Duplex ultrasonography of the lower extremity
. CT angiography of the lower extremity
. Application of a hinged knee brace and discharge with vascular precautions

Correct Answer & Explanation

. Observation and repeat ABI in 4 hours

Explanation

An ABI < 0.9 in the setting of a knee dislocation is highly suspicious for a popliteal artery injury. The most appropriate next step to accurately define the lesion prior to intervention is a CT angiogram (or standard arteriogram).

Question 3804

Topic: 8. Foot and Ankle

A 28-year-old male presents to the emergency department with a multiligamentous knee injury following a high-speed motor vehicle collision. Which of the following physical exam findings mandates immediate surgical exploration by vascular surgery?

. Diminished but palpable dorsalis pedis pulse compared to the contralateral side
. An Ankle-Brachial Index (ABI) of 0.85
. Expanding popliteal hematoma with absent pedal pulses
. Foot drop and absent sensation in the first dorsal web space
. Severe pain on passive stretch of the gastrocnemius

Correct Answer & Explanation

. Diminished but palpable dorsalis pedis pulse compared to the contralateral side

Explanation

An expanding popliteal hematoma with absent pedal pulses is a "hard sign" of arterial injury, mandating immediate surgical exploration. An ABI < 0.9 is a "soft sign" that requires further vascular imaging (like a CT angiogram) but not necessarily immediate exploration.

Question 3805

Topic: 8. Foot and Ankle

A 13-year-old girl twists her ankle while playing soccer. Radiographs reveal a fracture of the anterolateral aspect of the distal tibial epiphysis. What is the primary deforming force and mechanism responsible for this specific injury pattern?

. Internal rotation with intact posterior tibiofibular ligament
. External rotation with avulsion by the anterior inferior tibiofibular ligament
. Axial loading with a fixed supinated foot
. Direct lateral impact causing valgus stress
. Plantarflexion with intact calcaneofibular ligament

Correct Answer & Explanation

. Internal rotation with intact posterior tibiofibular ligament

Explanation

The patient has a juvenile Tillaux fracture, which occurs when the anterior inferior tibiofibular ligament (AITFL) avulses the anterolateral distal tibial epiphysis. This injury occurs via an external rotation mechanism during the transitional period of asymmetric distal tibial physeal closure.

Question 3806

Topic: Ankle Trauma & Sports
A 13-year-old girl sustains an inversion and external rotation injury to her ankle. Radiographs show a Salter-Harris III fracture of the anterolateral distal tibial epiphysis. Avulsion of which ligament is responsible for this specific fracture pattern?
. Anterior talofibular ligament (ATFL)
. Calcaneofibular ligament (CFL)
. Deltoid ligament
. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

This is a Tillaux fracture, caused by external rotation forces. The anterior inferior tibiofibular ligament (AITFL) is stronger than the anterolateral distal tibial physis in adolescents, resulting in an avulsion fracture as the central and medial physis has already closed.

Question 3807

Topic: 8. Foot and Ankle

An 11-year-old boy presents with a 6-month history of bilateral foot pain and recurrent ankle sprains. Examination reveals rigid flatfeet with absent subtalar motion and peroneal spasticity. Computed tomography (CT) confirms bilateral talocalcaneal coalitions involving approximately 25% of the posterior facet, with no degenerative changes. Nonoperative management with casting and orthotics has failed to relieve his symptoms. What is the most appropriate surgical intervention?

. Resection of the coalition with interposition of fat or muscle
. Subtalar arthrodesis
. Triple arthrodesis
. Calcaneal lengthening osteotomy
. Medial displacement calcaneal osteotomy

Correct Answer & Explanation

. Resection of the coalition with interposition of fat or muscle

Explanation

Talocalcaneal coalitions commonly present in late childhood or early adolescence as a rigid, painful flatfoot. If conservative management fails, surgical resection with interposition (e.g., fat graft or extensor digitorum brevis) is indicated, provided the coalition involves less than 50% of the posterior facet and there are no significant degenerative changes in the subtalar or surrounding joints.

Question 3808

Topic: 8. Foot and Ankle

A 13-year-old boy presents with a painful, rigid flatfoot and a history of recurrent ankle sprains. Examination shows a lack of subtalar motion and peroneal muscle spasm. Radiographs show a continuous C-shaped radiodense line formed by the medial outline of the talar dome and the posteroinferior aspect of the sustentaculum tali. Which of the following is the most likely diagnosis?

. Calcaneonavicular coalition
. Talocalcaneal coalition
. Accessory navicular
. Congenital vertical talus
. Posterior tibial tendon dysfunction

Correct Answer & Explanation

. Calcaneonavicular coalition

Explanation

The clinical presentation of a rigid flatfoot with peroneal spasticity in an adolescent is classic for a tarsal coalition. The 'C-sign' on a lateral radiograph is highly indicative of a talocalcaneal coalition (specifically involving the middle facet). Calcaneonavicular coalitions are typically seen on an oblique radiograph as an 'anteater nose' sign.

Question 3809

Topic: 8. Foot and Ankle

A 14-year-old boy complains of recurrent right ankle sprains and deep midfoot pain that worsens with activity. Examination reveals a rigid flat foot, prominent peroneal tendons, and limited subtalar inversion and eversion. Lateral radiographs show an elongated anterior process of the calcaneus (the 'anteater nose' sign). What is the most likely diagnosis?

. Talocalcaneal coalition
. Calcaneonavicular coalition
. Accessory navicular syndrome
. Congenital vertical talus
. Flexible pes planovalgus

Correct Answer & Explanation

. Talocalcaneal coalition

Explanation

The clinical presentation of a rigid flatfoot with peroneal spasticity in an adolescent is classic for a tarsal coalition. The 'anteater nose' sign on the lateral foot radiograph is the pathognomonic finding of a calcaneonavicular coalition, representing a tubular elongation of the anterior process of the calcaneus attempting to bridge to the navicular. Talocalcaneal coalitions are typically best seen on a Harris axial view or CT scan and may show a 'C-sign' on the lateral radiograph.

Question 3810

Topic: 8. Foot and Ankle

A 12-year-old boy presents with a history of recurrent ankle sprains and rigid flatfeet. On examination, he has decreased subtalar motion and peroneal spasticity. Radiographs demonstrate a C-sign on the lateral view of the foot. Which of the following is the most appropriate initial management?

. Calcaneal lengthening osteotomy
. Subtalar arthrodesis
. Resection of the talocalcaneal coalition with fat graft interposition
. Short leg walking cast for 4 to 6 weeks
. Resection of the calcaneonavicular coalition

Correct Answer & Explanation

. Calcaneal lengthening osteotomy

Explanation

Tarsal coalition is a fusion between two or more tarsal bones, most commonly talocalcaneal or calcaneonavicular. The C-sign on a lateral foot radiograph is a radiographic indicator of a talocalcaneal coalition, formed by the continuous outline of the medial outline of the talar dome and the posterior outline of the sustentaculum tali. The initial management for a symptomatic tarsal coalition is non-operative, focusing on resting the foot and breaking the pain cycle with immobilization, typically in a short leg walking cast or a controlled ankle motion (CAM) boot for 4 to 6 weeks.

Question 3811

Topic: 8. Foot and Ankle

A 13-year-old boy complains of frequent ankle sprains and lateral foot pain. Examination reveals a rigid flatfoot with peroneal spasticity. Oblique radiographs of the foot demonstrate an 'anteater sign.'

If a 6-month trial of short leg casting and orthotics fails to relieve his symptoms, and no degenerative changes are noted on CT scan, what is the most appropriate definitive surgical management?

. Calcaneal lengthening osteotomy
. Subtalar arthrodesis
. Resection of the coalition with interposition of the extensor digitorum brevis
. Triple arthrodesis
. Talonavicular arthrodesis

Correct Answer & Explanation

. Calcaneal lengthening osteotomy

Explanation

The patient's clinical presentation and the 'anteater sign' (an elongated anterior process of the calcaneus) on oblique radiographs are classic for a calcaneonavicular coalition. Initial treatment consists of conservative measures (cast immobilization, orthotics). If symptoms persist in the absence of degenerative arthritic changes, the gold standard surgical treatment is resection of the calcaneonavicular bar with interposition of a tissue spacer, most commonly the extensor digitorum brevis (EDB) muscle belly or fat, to prevent recurrence.

Question 3812

Topic: 8. Foot and Ankle

A 35-year-old man presents to the emergency department following a high-speed motor vehicle collision with his knee striking the dashboard. On physical examination, his right lower extremity is shortened, flexed, adducted, and internally rotated. Which of the following neurologic deficits is most commonly associated with this specific injury pattern?

. Inability to extend the knee against resistance
. Inability to actively plantarflex the ankle
. Inability to actively dorsiflex the ankle
. Loss of sensation over the medial aspect of the thigh
. Weakness of active hip adduction

Correct Answer & Explanation

. Inability to extend the knee against resistance

Explanation

This patient has a classic presentation for a posterior hip dislocation. The sciatic nerve is injured in 10-20% of posterior hip dislocations, with the peroneal division being disproportionately affected, leading to foot drop (inability to dorsiflex the ankle).

Question 3813

Topic: 8. Foot and Ankle

A 28-year-old restrained driver presents after a motor vehicle collision with a posterior hip dislocation. Which neurologic deficit is most commonly associated with this specific injury?

. Weakness in ankle dorsiflexion
. Weakness in knee extension
. Numbness over the medial thigh
. Weakness in hip adduction
. Decreased patellar reflex

Correct Answer & Explanation

. Weakness in ankle dorsiflexion

Explanation

Posterior hip dislocations are most commonly associated with sciatic nerve injuries, particularly affecting the peroneal division. This typically presents clinically as a foot drop or weakness in ankle dorsiflexion.

Question 3814

Topic: 8. Foot and Ankle

During a complex reconstruction of the midfoot, a surgeon dissects the plantar aspect of the foot and identifies the Master Knot of Henry. At this anatomical landmark, which tendon crosses dorsal (deep) to the flexor digitorum longus (FDL)?

. Flexor hallucis longus (FHL)
. Tibialis posterior
. Peroneus longus
. Tibialis anterior
. Plantaris

Correct Answer & Explanation

. Flexor hallucis longus (FHL)

Explanation

The Master Knot of Henry is located in the medial plantar midfoot at the level of the navicular. Here, the flexor hallucis longus (FHL) tendon reliably crosses dorsal (deep) to the flexor digitorum longus (FDL) tendon.

Question 3815

Topic: 8. Foot and Ankle
A 28-year-old male sustains a displaced talar neck fracture (Hawkins Type III). Which of the following arteries provides the primary blood supply to the body of the talus, placing it at high risk for avascular necrosis in this injury?
. Anterior tibial artery
. Dorsalis pedis artery
. Artery of the tarsal canal
. Peroneal artery
. Artery of the tarsal sinus

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. Displaced neck fractures disrupt this supply, leading to a high rate of avascular necrosis.

Question 3816

Topic: 8. Foot and Ankle

A 22-year-old football player sustains a midfoot injury. Imaging reveals a widening of the space between the first and second metatarsals. The primary stabilizing ligament of this articulation connects the base of the second metatarsal to which of the following structures?

. First metatarsal base
. Medial cuneiform
. Intermediate cuneiform
. Navicular
. Cuboid

Correct Answer & Explanation

. First metatarsal base

Explanation

The Lisfranc ligament is a strong interosseous ligament that connects the lateral aspect of the medial cuneiform to the medial base of the second metatarsal. It is critical for the stability of the tarsometatarsal joint complex.

Question 3817

Topic: 8. Foot and Ankle

A 25-year-old runner suffers an external rotation injury to his right ankle, resulting in a high ankle sprain. Which of the following ligaments is typically the first to tear in a syndesmotic injury?

. Posterior inferior tibiofibular ligament (PITFL)
. Anterior inferior tibiofibular ligament (AITFL)
. Interosseous ligament
. Deltoid ligament
. Calcaneofibular ligament

Correct Answer & Explanation

. Posterior inferior tibiofibular ligament (PITFL)

Explanation

The anterior inferior tibiofibular ligament (AITFL) is the weakest of the syndesmotic ligaments. It is typically the first structure to rupture during an external rotation force applied to the dorsiflexed ankle.

Question 3818

Topic: Midfoot & Hindfoot

Surgical dissection in the plantar midfoot requires navigating the Master Knot of Henry. Which of the following describes the correct anatomic relationship at this intersection?

. The flexor digitorum longus (FDL) tendon crosses dorsal to the flexor hallucis longus (FHL) tendon.
. The flexor hallucis longus (FHL) tendon crosses dorsal to the flexor digitorum longus (FDL) tendon.
. The posterior tibial tendon crosses plantar to the flexor hallucis longus (FHL) tendon.
. The flexor hallucis longus (FHL) tendon crosses plantar to the peroneus longus tendon.
. The flexor digitorum longus (FDL) tendon merges directly with the tibialis posterior tendon.

Correct Answer & Explanation

. The flexor digitorum longus (FDL) tendon crosses dorsal to the flexor hallucis longus (FHL) tendon.

Explanation

At the Master Knot of Henry, the flexor hallucis longus (FHL) crosses dorsal (deep) to the flexor digitorum longus (FDL). This is a critical landmark when harvesting the FDL or FHL tendons.

Question 3819

Topic: Ankle Trauma & Sports

In an unstable syndesmotic injury of the ankle, multiple ligamentous structures are disrupted. Which structure provides the greatest resistance to lateral displacement (diastasis) of the distal fibula relative to the tibia?

. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Interosseous membrane
. Deltoid ligament
. Anterior talofibular ligament (ATFL)

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

Biomechanical studies have shown that the posterior inferior tibiofibular ligament (PITFL) provides the strongest restraint to diastasis of the distal tibiofibular syndesmosis, accounting for approximately 42% of the resistance.

Question 3820

Topic: 8. Foot and Ankle

The Lisfranc ligament is critical for maintaining the structural integrity of the midfoot. Between which two osseous structures does this ligament course?

. Medial cuneiform and first metatarsal base
. Medial cuneiform and second metatarsal base
. Middle cuneiform and second metatarsal base
. Lateral cuneiform and third metatarsal base
. Cuboid and fourth metatarsal base

Correct Answer & Explanation

. Medial cuneiform and first metatarsal base

Explanation

The Lisfranc ligament is an oblique interosseous ligament connecting the lateral aspect of the medial cuneiform to the medial base of the second metatarsal. Disruption of this ligament leads to tarsometatarsal instability.

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