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8. Foot and Ankle MCQs

Practice Set 307 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 6121

Topic: 8. Foot and Ankle

A 25-year-old ballet dancer experiences sudden midfoot pain after an axial load with a rotational component while landing from a jump. Radiographs are equivocal, but there is significant tenderness over the tarsometatarsal joint complex, and a small fleck fracture is noted at the base of the second metatarsal. What is the pathognomonic radiological sign of a Lisfranc injury that should be specifically sought out?

. Loss of the normal foot arch.
. Presence of a nutcracker fracture of the cuboid.
. Diastasis between the first and second metatarsal bases.
. Anterior dislocation of the navicular bone.
. Fracture of the lateral cuneiform.

Correct Answer & Explanation

. Diastasis between the first and second metatarsal bases.

Explanation

A Lisfranc injury involves disruption of the tarsometatarsal joint complex. The Lisfranc ligament connects the medial cuneiform to the base of the second metatarsal. The pathognomonic radiological sign for a Lisfranc injury is diastasis (widening) between the base of the first and second metatarsals, particularly on weight-bearing or stress views, or between the medial cuneiform and second metatarsal. A 'fleck sign' (avulsion fracture off the base of the second metatarsal) is also highly indicative. While other fractures can occur, the widening between the first and second metatarsal bases is key. The other options describe different foot injuries or less specific findings.

Question 6122

Topic: 8. Foot and Ankle

A 45-year-old male sustains a direct blow to the lateral aspect of his knee, resulting in a fibular head fracture. He immediately develops foot drop and paresthesia over the dorsum of his foot. Which nerve is most likely injured?

. Saphenous nerve.
. Tibial nerve.
. Common peroneal nerve.
. Superficial peroneal nerve.
. Deep peroneal nerve.

Correct Answer & Explanation

. Common peroneal nerve.

Explanation

The common peroneal nerve courses superficially around the neck of the fibula, making it highly susceptible to injury with fibular head fractures or direct trauma to this area. Damage to the common peroneal nerve results in a 'foot drop' (weakness in ankle dorsiflexion and eversion) and sensory loss over the dorsum of the foot and lateral leg. The common peroneal nerve then divides into the superficial and deep peroneal nerves. The saphenous nerve is a sensory nerve of the medial leg. The tibial nerve supplies the posterior compartment of the leg and plantar sensation. While specific branches (superficial or deep peroneal) could be injured, the global presentation of foot drop points to the common peroneal nerve prior to its division.

Question 6123

Topic: 8. Foot and Ankle

A 40-year-old male sustains a trimalleolar ankle fracture requiring open reduction internal fixation. Two years post-surgery, he presents with chronic ankle pain, stiffness, and crepitus. Radiographs show joint space narrowing and osteophytes. What is the most likely long-term complication?

. Nonunion of the malleoli.
. Infection of the hardware.
. Recurrent ankle instability.
. Post-traumatic ankle arthritis.
. Chronic regional pain syndrome (CRPS).

Correct Answer & Explanation

. Post-traumatic ankle arthritis.

Explanation

Trimalleolar fractures are intra-articular injuries that often involve significant disruption of the ankle joint congruity. Even with optimal surgical reduction and fixation, damage to the articular cartilage and alterations in joint mechanics predispose to the development of post-traumatic ankle arthritis. This is a very common long-term complication, characterized by chronic pain, stiffness, joint space narrowing, and osteophytes. While nonunion, infection, instability, and CRPS are possible complications, post-traumatic arthritis is arguably the most common and debilitating long-term sequela after severe intra-articular ankle fractures. It can eventually necessitate an ankle fusion or arthroplasty.

Question 6124

Topic: 8. Foot and Ankle

A 35-year-old male presents with acute foot drop after a penetrating injury to the posterior aspect of his knee. Which nerve is most likely injured, and what specific muscle group would be affected?

. Tibial nerve, leading to weakness in ankle dorsiflexion.
. Common peroneal nerve, leading to weakness in ankle plantarflexion.
. Sural nerve, leading to weakness in toe extension.
. Common peroneal nerve, leading to weakness in ankle dorsiflexion and eversion.
. Femoral nerve, leading to weakness in knee extension.

Correct Answer & Explanation

. Common peroneal nerve, leading to weakness in ankle dorsiflexion and eversion.

Explanation

Foot drop is characterized by an inability to dorsiflex the ankle. This is primarily controlled by the muscles innervated by the deep peroneal nerve (tibialis anterior, extensor hallucis longus, extensor digitorum longus) and the muscles of eversion (peroneus longus and brevis) innervated by the superficial peroneal nerve. Both of these are branches of the common peroneal nerve. Therefore, injury to the common peroneal nerve (often at the level of the fibular neck or popliteal fossa) is the most likely cause of foot drop with associated weakness in ankle dorsiflexion and eversion. The tibial nerve affects plantarflexion. Sural nerve is purely sensory. Femoral nerve affects knee extension.

Question 6125

Topic: 8. Foot and Ankle

A 28-year-old soccer player presents with acute onset lateral ankle pain after an inversion injury. He reports a 'snapping' sensation and tenderness posterior to the lateral malleolus. Swelling is noted in this area. Plain radiographs are normal. What specific clinical maneuver would best evaluate the suspected injury?

. Anterior drawer test for ATFL instability.
. Talar tilt test for calcaneofibular ligament instability.
. Squeeze test for syndesmotic injury.
. Peroneal tendon subluxation test (forced dorsiflexion and eversion).
. Thompson test for Achilles tendon rupture.

Correct Answer & Explanation

. Peroneal tendon subluxation test (forced dorsiflexion and eversion).

Explanation

The patient's symptoms (lateral ankle pain after inversion, 'snapping' sensation, tenderness posterior to the lateral malleolus) are highly suggestive of a peroneal tendon subluxation or dislocation. This occurs when the peroneal retinaculum is torn. The peroneal tendon subluxation test involves reproducing the injury mechanism: forced dorsiflexion and eversion of the foot against resistance. A palpable or visible subluxation/dislocation of the peroneal tendons from behind the lateral malleolus confirms the diagnosis. The other tests evaluate different structures: anterior drawer and talar tilt for lateral ligament sprains, squeeze test for syndesmosis, and Thompson test for Achilles rupture.

Question 6126

Topic: 8. Foot and Ankle

A 35-year-old male sustains a posterior malleolus fracture as part of a trimalleolar ankle fracture. The fragment involves 30% of the articular surface of the distal tibia. What is the most appropriate management of the posterior malleolus fragment?

. Non-operative management as it is likely insignificant.
. Excision of the fragment to prevent impingement.
. Open reduction and internal fixation (ORIF) if displaced and significant size.
. Closed reduction and casting.
. Arthroscopic debridement.

Correct Answer & Explanation

. Open reduction and internal fixation (ORIF) if displaced and significant size.

Explanation

Posterior malleolus fractures, when they involve a significant portion of the articular surface (typically >25-30% on lateral X-ray or CT scan) and are displaced (usually >2mm), contribute to ankle instability and increased risk of post-traumatic arthritis. In such cases, open reduction and internal fixation (ORIF) is indicated to restore articular congruity and stability. The preferred approach often involves a posterolateral or posteromedial incision. Smaller, non-displaced fragments can sometimes be managed non-operatively. Excision is generally avoided due to the disruption of the tibiofibular syndesmosis attachment. Closed reduction is rarely successful for displaced fragments of this size.

Question 6127

Topic: 8. Foot and Ankle

A 45-year-old weekend warrior feels a sudden 'pop' in his heel during a game of tennis. He complains of severe pain and is unable to push off his foot. On examination, there is a palpable gap in the Achilles tendon, and he has a positive Thompson test. What is the most appropriate management for this injury?

. Non-operative management with a cast in plantarflexion.
. Immediate surgical repair of the Achilles tendon.
. Physical therapy focusing on stretching and strengthening.
. Corticosteroid injection into the tendon.
. Casting in dorsiflexion to stretch the tendon.

Correct Answer & Explanation

. Immediate surgical repair of the Achilles tendon.

Explanation

The patient's presentation (sudden 'pop', pain, inability to push off, palpable gap, positive Thompson test) is classic for an acute Achilles tendon rupture. While non-operative management can be considered for specific patient populations (sedentary, elderly) or very specific tear patterns, for active, middle-aged individuals, immediate surgical repair is generally recommended. Surgical repair provides a stronger repair, reduces the risk of rerupture, and allows for earlier functional rehabilitation compared to non-operative treatment, although both have their roles. Physical therapy would follow initial management. Corticosteroid injections are contraindicated for tendon ruptures due to weakening effects. Casting in dorsiflexion would lengthen the tendon and prevent healing.

Question 6128

Topic: 8. Foot and Ankle

A 60-year-old female presents with forefoot pain, burning, and numbness that radiates into the third and fourth toes. Symptoms are worse with walking in tight shoes. On examination, a positive Mulder's click is elicited. What is the most likely diagnosis?

. Metatarsal stress fracture.
. Plantar fasciitis.
. Tarsal tunnel syndrome.
. Morton's neuroma.
. Hallux valgus.

Correct Answer & Explanation

. Morton's neuroma.

Explanation

The patient's symptoms (forefoot pain, burning, numbness radiating to the third and fourth toes, worse with tight shoes, and a positive Mulder's click) are pathognomonic for Morton's neuroma. This is a common compressive neuropathy of the interdigital nerve, most often between the third and fourth metatarsal heads. A metatarsal stress fracture would typically cause localized bony tenderness and pain with impact. Plantar fasciitis causes heel pain, especially first steps in the morning. Tarsal tunnel syndrome involves the posterior tibial nerve and affects the arch and toes (often sensory only). Hallux valgus is a deformity of the great toe, causing pain at the bunion.

Question 6129

Topic: 8. Foot and Ankle
A 50-year-old male sustains a comminuted, displaced intra-articular fracture of the calcaneus (Sanders Type III). What is the primary goal of surgical management for this fracture?
. Excision of all comminuted fragments.
. Restoration of Böhler's angle and Gissane's angle.
. Early full weight-bearing.
. Primary subtalar fusion.
. Amputation.

Correct Answer & Explanation

. Restoration of Böhler's angle and Gissane's angle.

Explanation

Intra-articular calcaneus fractures are complex injuries. The primary goal of surgical management (typically open reduction internal fixation, ORIF) for displaced, intra-articular calcaneus fractures is the restoration of the anatomy of the posterior facet of the subtalar joint and the overall shape of the calcaneus. This includes restoring parameters like Böhler's angle and Gissane's angle, which are indicators of the calcaneal height and posterior facet reduction. Correcting these angles helps to restore the mechanics of the hindfoot and subtalar joint. Early full weight-bearing is usually contraindicated. Excision of fragments is not appropriate for comminuted fractures. Primary subtalar fusion is a salvage procedure for severe comminution or failed ORIF, not the primary goal. Amputation is a last resort.

Question 6130

Topic: 8. Foot and Ankle

A 55-year-old female presents with acute pain and swelling in the region of the second metatarsal head. She describes a feeling of 'walking on a pebble' and tenderness on palpation of the plantar aspect of the second metatarsal head. Radiographs are normal. What is the most likely diagnosis?

. Morton's neuroma.
. Freiberg's infraction.
. Sesamoiditis.
. Plantar plate rupture.
. Metatarsal stress fracture.

Correct Answer & Explanation

. Plantar plate rupture.

Explanation

The symptoms (pain and swelling in the second metatarsal head region, 'walking on a pebble' sensation, tenderness on the plantar aspect, normal radiographs) are classic for a plantar plate rupture or attenuation. The plantar plate is a fibrocartilaginous structure that supports the metatarsophalangeal joint. Rupture often leads to instability of the joint, hammer toe deformity (often of the second toe), and subluxation of the toe. While Freiberg's infraction (osteochondrosis of the metatarsal head) and stress fracture can cause metatarsal head pain, they would typically involve the bone itself. Morton's neuroma affects the interdigital nerve. Sesamoiditis affects the hallux. The 'walking on a pebble' and tenderness directly on the plantar plate are key.

Question 6131

Topic: 8. Foot and Ankle

A 45-year-old male sustains a crush injury to his foot, resulting in a displaced fracture-dislocation of the naviculocuneiform joints. Which of the following associated injuries should be specifically sought out due to shared mechanism and potential for long-term morbidity?

. Metatarsal stress fracture.
. Achilles tendon rupture.
. Lisfranc (tarsometatarsal) injury.
. Ankle sprain.
. Calcaneus fracture.

Correct Answer & Explanation

. Lisfranc (tarsometatarsal) injury.

Explanation

Naviculocuneiform fracture-dislocations involve the midfoot, similar to Lisfranc injuries (tarsometatarsal joint complex). Both result from high-energy axial loading or twisting forces and can be difficult to diagnose. Given the proximity and shared mechanism, it's crucial to thoroughly evaluate for concomitant Lisfranc injuries. Missing a Lisfranc injury can lead to significant long-term pain, deformity, and arthritis due to instability of the midfoot. While other injuries can occur, a Lisfranc injury is the most critical associated injury in this anatomical region due to its functional implications. Metatarsal stress fractures are chronic, Achilles rupture is a distinct injury, and ankle sprains are more distal.

Question 6132

Topic: 8. Foot and Ankle
A 25-year-old male presents with a painful, swollen ankle after an inversion injury. Radiographs show no fracture. On examination, there is significant swelling and tenderness over the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL). The anterior drawer test is positive, but the talar tilt test is stable. Which grade of ankle sprain does this most likely represent?
. Grade I.
. Grade II.
. Grade III.
. High ankle sprain (syndesmotic).
. Subtalar sprain.

Correct Answer & Explanation

. Grade II.

Explanation

Ankle sprains are graded based on the severity of ligamentous injury. Grade I is a stretch of the ligament without macroscopic tearing, resulting in minimal instability. Grade II involves a partial tear of the ligament, leading to some instability (often a positive anterior drawer test indicating ATFL laxity), but with a firm endpoint and stable talar tilt (CFL usually intact or minimally stretched). Grade III is a complete rupture of one or more ligaments (typically ATFL and CFL), resulting in gross instability (positive anterior drawer and talar tilt with no firm endpoint). A positive anterior drawer with a stable talar tilt indicates a partial tear, typically Grade II. A high ankle sprain involves the syndesmotic ligaments.

Question 6133

Topic: Ankle Trauma & Sports
A 60-year-old female sustains a distal fibula fracture with no medial tenderness or widening of the medial clear space on stress views. The fracture is located 4 cm above the ankle joint, but radiographs show no syndesmotic widening. Which Weber classification best describes this injury?
. Weber A.
. Weber B.
. Weber C.
. Maisonneuve fracture.
. Pilon fracture.

Correct Answer & Explanation

. Weber C.

Explanation

The Weber classification describes the fibular fracture location relative to the syndesmosis. A Weber C fracture involves a fibular fracture proximal to the syndesmosis. Even if the syndesmosis is not widened on static radiographs, a fracture 4 cm above the ankle joint clearly places it proximal to the syndesmosis, making it a Weber C equivalent. This type of fracture inherently suggests potential syndesmotic injury, even if not grossly apparent. Weber A is distal to the syndesmosis, Weber B is at the level of the syndesmosis. A Maisonneuve fracture is a very high Weber C fracture, typically at the fibular neck. Pilon fractures involve the distal tibia.

Question 6134

Topic: 8. Foot and Ankle

A 16-year-old female presents with a distal femoral osteosarcoma that requires resection of the entire distal femur and knee joint. To achieve optimal function, the orthopedic oncologist proposes a 'rotationplasty'. Which ankle movement will be used to control the prosthetic knee joint after this procedure?

. Ankle dorsiflexion and plantarflexion
. Ankle inversion and eversion
. Subtalar joint motion
. Forefoot abduction and adduction
. Toe flexion and extension

Correct Answer & Explanation

. Ankle dorsiflexion and plantarflexion

Explanation

In a rotationplasty (specifically a Van Nes rotationplasty), the resected distal femur and knee joint are replaced by reattaching the tibia and foot rotated 180 degrees. The ankle joint, now rotated, functions as a knee joint. Thus, the patient's existing ankle dorsiflexion and plantarflexion movements are used to control the prosthetic knee joint. Dorsiflexion typically extends the prosthetic knee, and plantarflexion flexes it. The goal is to maximize functional use of the patient's own musculature.

Question 6135

Topic: 8. Foot and Ankle

A 30-year-old male sustains a Lisfranc injury after a fall from height. Radiographs show diastasis between the medial cuneiform and the base of the second metatarsal. What is the most critical component of surgical fixation for a unstable Lisfranc injury?

. Rigid fixation of all metatarsal-cuneiform joints
. Anatomic reduction and rigid fixation of the first and second tarsometatarsal (TMT) joints
. Fusion of the naviculocuneiform joint
. Flexible fixation of all TMT joints to allow motion
. Early weight-bearing to promote healing

Correct Answer & Explanation

. Anatomic reduction and rigid fixation of the first and second tarsometatarsal (TMT) joints

Explanation

The Lisfranc joint complex includes the tarsometatarsal joints. The stability of the midfoot is largely dependent on the integrity of the Lisfranc ligament and the stability of the first and second TMT joints. Anatomic reduction and rigid internal fixation, typically with screws, of the first and second TMT joints are paramount to restore the arch and prevent post-traumatic arthritis. While other joints may be involved, stable fixation of the first and second TMT joints is the most critical. Fusion is generally reserved for chronic instability or arthritis. Flexible fixation and early weight-bearing are inappropriate for acute, unstable Lisfranc injuries.

Question 6136

Topic: 8. Foot and Ankle

A 30-year-old male sustains a bimalleolar ankle fracture (Lauge-Hansen pronation-eversion IV). What is the primary indication for surgical fixation of this injury?

. Pain control
. Prevention of deep vein thrombosis
. Restoration of ankle joint stability and congruent articular surfaces
. Early return to sports
. Reduction of swelling

Correct Answer & Explanation

. Restoration of ankle joint stability and congruent articular surfaces

Explanation

The primary indication for surgical fixation of unstable ankle fractures, such as a bimalleolar fracture, is to restore anatomic alignment of the articular surfaces and achieve stability of the ankle mortise. This prevents post-traumatic arthritis, malunion, and chronic instability. While surgery can help with pain control and facilitate rehabilitation, these are secondary benefits. It also helps reduce swelling indirectly but isn't the primary goal. Prevention of DVT is addressed by prophylaxis, not surgery itself. Early return to sports is a desirable outcome but not the primary surgical indication.

Question 6137

Topic: 8. Foot and Ankle

A 70-year-old female presents with a distal fibula fracture and a widened medial clear space on ankle radiographs, indicating syndesmotic disruption. What additional finding, if present, would prompt consideration for a posterior malleolus fracture?

. Talonavicular joint subluxation
. Shortening of the fibula
. Anterior talar dome injury
. Posterior subluxation of the talus
. Lisfranc injury

Correct Answer & Explanation

. Posterior subluxation of the talus

Explanation

Posterior subluxation of the talus on lateral radiographs in the context of an ankle fracture-dislocation or syndesmotic injury strongly suggests an associated posterior malleolus fracture. The posterior malleolus is a critical stabilizer of the ankle joint, and its fracture can lead to posterior talar displacement and compromise the posterior tibiofibular ligament. Shortening of the fibula is common with syndesmotic injury but doesn't specifically indicate a posterior malleolus fracture. Talonavicular subluxation and Lisfranc injury are midfoot/forefoot injuries. Anterior talar dome injury is less specific for a posterior malleolus fracture.

Question 6138

Topic: Midfoot & Hindfoot

A 40-year-old male presents with an isolated subtalar dislocation without associated fracture. After closed reduction, what is the most appropriate next step in management?

. Immediate weight-bearing in a walking boot
. Surgical exploration to repair torn ligaments
. CT scan to rule out occult fractures and assess reduction
. MRI to assess deltoid ligament integrity
. Long-term immobilization in a non-weight-bearing cast for 12 weeks

Correct Answer & Explanation

. CT scan to rule out occult fractures and assess reduction

Explanation

After successful closed reduction of a subtalar dislocation, a CT scan is essential. It is critical to rule out any occult osteochondral fragments, incarcerated soft tissue, or small fractures (e.g., talar or calcaneal) that may not be visible on plain radiographs and could impede congruity or stability. While ligamentous injury is expected, surgical repair is rarely indicated unless instability persists after reduction. Immobilization is necessary but typically for 4-6 weeks, not 12 weeks. Immediate weight-bearing is inappropriate.

Question 6139

Topic: Midfoot & Hindfoot

Which of the following describes a key differentiating feature between a Lisfranc fracture-dislocation and a simple midfoot sprain on plain radiographs?

. Presence of a fleck sign
. Fracture of the cuboid
. Fracture of the navicular
. Talonavicular joint subluxation
. Widening of the tibiotalar joint

Correct Answer & Explanation

. Presence of a fleck sign

Explanation

A 'fleck sign' refers to an avulsion fracture off the base of the second metatarsal or the medial cuneiform, within the Lisfranc ligament complex. Its presence is highly indicative of a Lisfranc injury (fracture-dislocation) and suggests significant instability that requires surgical intervention. Cuboid or navicular fractures can occur in the midfoot but are not specific to Lisfranc injury. Talonavicular subluxation is a hindfoot/midfoot injury but not diagnostic of Lisfranc. Widening of the tibiotalar joint indicates ankle, not midfoot, pathology.

Question 6140

Topic: 8. Foot and Ankle

Which of the following physical examination findings is most indicative of a syndesmotic injury (high ankle sprain) in an acute ankle injury?

. Pain and swelling over the deltoid ligament
. Positive anterior drawer test
. Pain with palpation of the distal fibula
. Positive squeeze test (distal fibula and tibia compression)
. Ecchymosis around the lateral malleolus

Correct Answer & Explanation

. Positive squeeze test (distal fibula and tibia compression)

Explanation

A positive squeeze test (or fibular compression test), where compression of the tibia and fibula together at mid-calf level elicits pain distally at the syndesmosis, is a highly indicative physical examination finding for a syndesmotic injury. Other tests like external rotation stress test can also be positive. Pain over the deltoid ligament and positive anterior drawer test are indicative of medial and lateral ligamentous injuries, respectively. Pain with palpation of the distal fibula suggests a fibular fracture, and ecchymosis is a general sign of trauma.

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