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8. Foot and Ankle MCQs

Practice Set 106 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 2101

Topic: 8. Foot and Ankle

A 28-year-old male presents with a highly comminuted, displaced coronal shear fracture of the talar body. Open reduction and internal fixation are required. To achieve perpendicular visualization and adequate access for hardware placement on the medial aspect of the talar dome and body, which of the following approaches or osteotomies is most frequently utilized?

. Lateral malleolar osteotomy
. Medial malleolar osteotomy
. Anterior tibial osteotomy
. Z-lengthening of the Achilles tendon
. Extensile lateral approach

Correct Answer & Explanation

. Lateral malleolar osteotomy

Explanation

Fractures of the talar body are intra-articular and notoriously difficult to expose. For direct visualization of the medial and central talar dome and body to achieve anatomic reduction, a medial malleolar osteotomy (typically a chevron type) is the workhorse approach. It allows the medial malleolus to be reflected inferiorly on the deltoid ligament, granting excellent exposure to the talus, and is later fixed with lag screws.

Question 2102

Topic: 8. Foot and Ankle

A 24-year-old male presents with persistent lateral ankle pain 3 weeks after a snowboarding accident. Initial plain radiographs were reported as negative for fracture. Clinical examination reveals tenderness inferior and anterior to the lateral malleolus. Which of the following injuries is most likely present and best diagnosed with a CT scan?

. Anterior process of the calcaneus fracture
. Osteochondral lesion of the talar dome
. Lateral process of the talus fracture
. Sustentaculum tali fracture
. Base of the 5th metatarsal fracture

Correct Answer & Explanation

. Lateral process of the talus fracture

Explanation

Fractures of the lateral process of the talus ("snowboarder's fracture") often result from dorsiflexion and inversion of the ankle. They are notoriously missed on initial plain radiographs (missed in up to 40% of cases). The classic presentation is persistent lateral ankle pain mistaken for a severe sprain. A CT scan is the best modality for definitive diagnosis and assessing displacement and comminution.

Question 2103

Topic: 8. Foot and Ankle

A 38-year-old male undergoes ORIF of a displaced intra-articular calcaneus fracture via an extensile lateral approach.

Postoperatively, the patient reports numbness over the lateral aspect of the foot and lateral heel. Which nerve is most likely at risk during the distal extension of this surgical approach?

. Superficial peroneal nerve
. Sural nerve
. Deep peroneal nerve
. Medial plantar nerve
. Lateral plantar nerve

Correct Answer & Explanation

. Sural nerve

Explanation

The extensile lateral approach to the calcaneus places the sural nerve at risk. The sural nerve provides sensory innervation to the posterolateral lower leg, lateral heel, and lateral border of the foot. It typically crosses the lateral border of the Achilles tendon and runs distally along the lateral aspect of the calcaneus, making it vulnerable during the inferior and distal limbs of the incision.

Question 2104

Topic: Midfoot & Hindfoot

A 45-year-old manual laborer sustains a purely ligamentous Lisfranc injury involving the 1st, 2nd, and 3rd tarsometatarsal joints. Which of the following statements regarding the definitive surgical management is most supported by current orthopedic literature?

. Primary open reduction and internal fixation (ORIF) offers superior functional outcomes compared to primary arthrodesis
. Primary arthrodesis of the 1st, 2nd, and 3rd TMT joints decreases the need for secondary surgeries compared to ORIF
. Bridge plating without articular cartilage debridement is contraindicated
. K-wire fixation should be maintained for a minimum of 12 weeks
. The fourth and fifth TMT joints must always be included in the primary arthrodesis construct

Correct Answer & Explanation

. Primary arthrodesis of the 1st, 2nd, and 3rd TMT joints decreases the need for secondary surgeries compared to ORIF

Explanation

Multiple randomized controlled trials have demonstrated that for purely ligamentous Lisfranc injuries, primary arthrodesis of the medial column (1st, 2nd, and 3rd TMT joints) results in comparable or superior functional outcomes and a significantly lower rate of secondary surgeries (due to hardware removal or subsequent post-traumatic arthritis) when compared to ORIF.

Question 2105

Topic: 8. Foot and Ankle

A 30-year-old male is brought to the emergency department after a motor vehicle collision. He has severe midfoot swelling and deformity. Radiographs confirm a dorsal dislocation of the navicular from the talus and the cuboid from the calcaneus, without fracture. What is this specific injury pattern known as?

. Lisfranc dislocation
. Chopart dislocation
. Subtalar dislocation
. Pantalar dislocation
. Nutcracker injury

Correct Answer & Explanation

. Chopart dislocation

Explanation

The Chopart joint complex, or transverse tarsal joint, consists of the talonavicular and calcaneocuboid joints. A dislocation through these joints is a Chopart dislocation. Subtalar dislocation involves the talocalcaneal and talonavicular joints (the talus remains in the mortise). Lisfranc involves the tarsometatarsal joints.

Question 2106

Topic: 8. Foot and Ankle

A horseback rider sustains a crush injury to the foot when her horse falls on her. She presents with lateral column foot pain. Radiographs reveal a comminuted fracture of the cuboid with shortening of the lateral column of the foot.

What is the classic mechanism of injury for this "nutcracker" fracture?

. Forced plantarflexion and inversion
. Axial loading in a dorsiflexed position
. Forced abduction of the forefoot with compression of the lateral column
. Avulsion by the peroneus brevis tendon
. Direct dorsal crush

Correct Answer & Explanation

. Forced abduction of the forefoot with compression of the lateral column

Explanation

A "nutcracker" fracture of the cuboid occurs when the forefoot is forcefully abducted. This mechanism compresses the cuboid between the anterior calcaneus and the base of the 4th and 5th metatarsals, crushing the bone and leading to lateral column shortening. Treatment often requires restoration of lateral column length with an external fixator or bridge plating and bone grafting.

Question 2107

Topic: 8. Foot and Ankle

A 27-year-old female presents with ankle pain after an external rotation injury. Ankle radiographs show a widened medial clear space and disruption of the distal tibiofibular syndesmosis, but no lateral malleolus fracture is visible. What is the most critical next step in radiographic evaluation?

. Contralateral ankle radiographs
. MRI of the ankle to evaluate the deltoid ligament
. Full-length tibia/fibula radiographs to evaluate the proximal fibula
. CT scan of the ankle to rule out a posterior malleolus fracture
. Weight-bearing ankle radiographs

Correct Answer & Explanation

. Full-length tibia/fibula radiographs to evaluate the proximal fibula

Explanation

The presentation describes a syndesmotic injury with medial clear space widening (deltoid ligament rupture), strongly suggesting a pronation-external rotation injury mechanism. When these ankle findings are present without a distal fibula fracture, a Maisonneuve fracture (proximal third fibular shaft fracture) must be suspected. Full-length tibia/fibula radiographs are essential to diagnose this injury.

Question 2108

Topic: 8. Foot and Ankle

When placing a syndesmotic screw for a confirmed distal tibiofibular syndesmosis injury, which of the following describes the most widely accepted mechanical principles for fixation?

. The screw must be a lag screw to compress the syndesmosis tightly
. The screw should engage 3 or 4 cortices and be placed 2 to 3 cm proximal to the joint line
. The foot must be held in maximum plantarflexion during screw insertion
. Two screws must always be used regardless of patient weight
. Bioabsorbable screws are contraindicated due to high osteolysis rates

Correct Answer & Explanation

. The screw should engage 3 or 4 cortices and be placed 2 to 3 cm proximal to the joint line

Explanation

The most widely accepted technique for syndesmotic screw fixation involves placing one or two screws 2 to 3 cm proximal and parallel to the ankle joint line. They can engage either 3 or 4 cortices (both fibula cortices and one or two tibial cortices). The screw is a position screw, not a lag screw, as over-compression can restrict normal fibular motion and lead to ankle stiffness. The ankle is typically held in neutral dorsiflexion, though recent evidence questions the strict necessity of this.

Question 2109

Topic: 8. Foot and Ankle

In the setting of a trimalleolar ankle fracture, recent literature emphasizes the importance of fixing the posterior malleolus. Which of the following is considered the primary biomechanical rationale for anatomical open reduction and internal fixation of the posterior malleolus, even for smaller fragments?

. To restore the articular congruity of the talocrural joint
. To repair the avulsed anterior inferior tibiofibular ligament
. To restore the competence of the posterior inferior tibiofibular ligament and stabilize the syndesmosis
. To prevent anterior subluxation of the talus
. To provide a buttress against varus talar tilt

Correct Answer & Explanation

. To restore the competence of the posterior inferior tibiofibular ligament and stabilize the syndesmosis

Explanation

Historically, posterior malleolus fractures were fixed only if they involved >25-33% of the articular surface. However, recent biomechanical and clinical studies have shown that the posterior malleolus is the primary insertion site of the posterior inferior tibiofibular ligament (PITFL). Fixing the posterior malleolus restores the tension of the PITFL, which is crucial for the rotational stability of the syndesmosis. This is often biomechanically superior to placing a syndesmotic screw alone.

Question 2110

Topic: 8. Foot and Ankle

A 55-year-old female presents to the emergency department after a slip and fall on ice. Her ankle is visibly deformed with the foot displaced laterally. The skin over the medial malleolus is severely blanched and tightly tented, but intact. What is the most urgent and appropriate next step?

. Immediate transfer to the operating room for open reduction and internal fixation
. Administration of intravenous antibiotics and tetanus prophylaxis
. Immediate closed reduction of the ankle deformity in the emergency department
. Obtaining orthogonal radiographs to characterize the fracture pattern prior to manipulation
. Application of a sterile dressing and splint in the current position of deformity

Correct Answer & Explanation

. Immediate closed reduction of the ankle deformity in the emergency department

Explanation

Severe tenting and blanching of the skin over a bony prominence (like the medial malleolus in a lateral fracture-dislocation of the ankle) is a surgical/orthopedic emergency. It indicates impending skin necrosis. The deformity must be immediately reduced via closed manipulation in the ED to relieve pressure on the skin, even before obtaining formal radiographs if the delay would be significant. Once reduced and splinted, radiographs can be obtained.

Question 2111

Topic: 8. Foot and Ankle

A 45-year-old female sustains a rotational ankle fracture. Computed tomography demonstrates a posterior malleolus fragment. Based on recent biomechanical and clinical literature, what is considered the most critical indication for surgical fixation of the posterior malleolus?

. Fragment size greater than 25% of the articular surface
. Fragment size greater than 33% of the articular surface
. Restoration of the posterior inferior tibiofibular ligament (PITFL) tension to stabilize the syndesmosis
. Prevention of anterior talar translation during weight-bearing
. The concurrent presence of a medial malleolus fracture requiring fixation

Correct Answer & Explanation

. Fragment size greater than 25% of the articular surface

Explanation

Historically, posterior malleolus fixation was dictated by fragment size (e.g., >25% or >33% of the articular surface). However, recent biomechanical studies emphasize that the primary indication for fixing the posterior malleolus is to restore syndesmotic stability by reattaching the PITFL. Anatomical reduction of the posterior malleolus effectively stabilizes the syndesmosis, often obviating the need for trans-syndesmotic screws.

Question 2112

Topic: 8. Foot and Ankle
A 28-year-old male sustains a high-energy motor vehicle collision, resulting in a Hawkins Type III fracture of the talar neck. What is the approximate rate of avascular necrosis (AVN) of the talar body associated with this specific injury pattern?
. 0-10%
. 10-20%
. 30-50%
. 50-60%
. 70-100%

Correct Answer & Explanation

. 70-100%

Explanation

The Hawkins classification for talar neck fractures predicts the risk of avascular necrosis (AVN). Type I (nondisplaced) has a 0-10% risk. Type II (subtalar subluxation/dislocation) has a 20-50% risk. Type III (dislocation of both subtalar and tibiotalar joints) disrupts the three major sources of blood supply (artery of the tarsal canal, artery of the sinus tarsi, and deltoid branches), leading to a 70-100% risk of AVN. Type IV includes talonavicular subluxation/dislocation with a similarly high or higher risk.

Question 2113

Topic: 8. Foot and Ankle

A 24-year-old snowboarder presents with lateral ankle pain after a hard landing. Initial plain radiographs are unremarkable, but a subsequent CT scan reveals a displaced fracture of the lateral process of the talus.

Which of the following physical examination findings is most specific for this injury compared to a standard ankle sprain?

. Tenderness directly over the anterior talofibular ligament (ATFL)
. Tenderness 1 cm inferior and anterior to the tip of the lateral malleolus
. Positive anterior drawer test
. Tenderness over the calcaneocuboid joint
. Tenderness posterior to the medial malleolus

Correct Answer & Explanation

. Tenderness directly over the anterior talofibular ligament (ATFL)

Explanation

A fracture of the lateral process of the talus, often called a 'snowboarder's fracture', is frequently misdiagnosed as an ATFL sprain. Point tenderness is typically located slightly inferior and anterior to the tip of the lateral malleolus, corresponding precisely to the anatomical location of the lateral process of the talus, differentiating it from the ATFL which is slightly more anterior.

Question 2114

Topic: Ankle Trauma & Sports
A 14-year-old boy falls while skateboarding and sustains a Salter-Harris III fracture of the anterolateral aspect of the distal tibia. Which specific ligament is responsible for the avulsion force creating this fracture fragment?
. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Anterior talofibular ligament (ATFL)
. Calcaneofibular ligament (CFL)
. Deep deltoid ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

The Tillaux fracture is an avulsion of the anterolateral epiphysis of the distal tibia. It occurs in adolescents due to the asymmetrical closure of the distal tibial physis (which closes central, then medial, then lateral). An external rotation force places tension on the anterior inferior tibiofibular ligament (AITFL), which avulses the still-open anterolateral epiphysis.

Question 2115

Topic: 8. Foot and Ankle

A 30-year-old male presents with severe midfoot swelling and pain following a motorcycle accident. Radiographs reveal a dislocation involving the talonavicular and calcaneocuboid articulations. What is the standard eponym used to describe this specific joint complex?

. Lisfranc joint
. Chopart joint
. Subtalar joint
. Transverse tarsal joint
. Both Chopart joint and Transverse tarsal joint

Correct Answer & Explanation

. Lisfranc joint

Explanation

The articulation separating the hindfoot (talus and calcaneus) from the midfoot (navicular and cuboid) is anatomically referred to as the transverse tarsal joint. Eponymously, it is known as the Chopart joint. The Lisfranc joint refers to the tarsometatarsal articulations.

Question 2116

Topic: 8. Foot and Ankle

A 33-year-old equestrian falls, and her foot is forcefully abducted while caught in the stirrup. She sustains a highly comminuted 'nutcracker' fracture of the cuboid. This specific fracture pattern occurs secondary to severe compression between which two bones?

. Calcaneus and the bases of the 4th/5th metatarsals
. Talus and the navicular
. Navicular and the lateral cuneiform
. Calcaneus and the lateral cuneiform
. Talus and the bases of the 4th/5th metatarsals

Correct Answer & Explanation

. Calcaneus and the bases of the 4th/5th metatarsals

Explanation

A 'nutcracker' fracture of the cuboid is a crush/compression injury. It typically occurs during forced abduction of the forefoot, which violently compresses the cuboid between the anterior process of the calcaneus proximally and the bases of the 4th and 5th metatarsals distally. This leads to shortening of the lateral column of the foot.

Question 2117

Topic: 8. Foot and Ankle

A 62-year-old male with long-standing, poorly controlled diabetes and profound peripheral neuropathy sustains a bimalleolar ankle fracture. Which of the following modifications to standard surgical fixation and postoperative care is recommended to minimize the risk of hardware failure and Charcot arthropathy?

. Use of bioabsorbable interference screws to avoid late hardware removal
. Enhanced fixation (e.g., multiple syndesmotic screws, locked plating, trans-articular pins) and prolonged non-weight-bearing
. Immediate weight-bearing in a total contact cast to stimulate bone healing
. Isolated closed reduction and casting due to extreme infection risk
. Primary arthrodesis of the tibiotalar joint in all cases

Correct Answer & Explanation

. Use of bioabsorbable interference screws to avoid late hardware removal

Explanation

Diabetic patients with severe neuropathy are at exceptionally high risk for hardware failure, nonunion, wound complications, and subsequent Charcot neuroarthropathy. Standard fixation is often insufficient. Surgeons should employ enhanced, rigid fixation constructs (often doubling the normal hardware) and enforce a significantly prolonged non-weight-bearing period (often 2 to 3 times longer than a non-diabetic patient) to ensure stable union.

Question 2118

Topic: 8. Foot and Ankle

When performing an extensile lateral approach for the open reduction and internal fixation of a displaced intra-articular calcaneus fracture, the incision is made in an 'L' shape. Which nerve is at greatest risk of transection if the horizontal limb of the incision is carried too far anteriorly or placed too dorsally?

. Saphenous nerve
. Deep peroneal nerve
. Superficial peroneal nerve
. Sural nerve
. Medial plantar nerve

Correct Answer & Explanation

. Saphenous nerve

Explanation

The sural nerve travels posterior to the lateral malleolus and courses along the lateral aspect of the hindfoot and midfoot. It is at direct risk during the extensile lateral approach to the calcaneus. The vertical limb must be placed precisely between the Achilles and fibula, and the horizontal limb must remain low (at the junction of the plantar and lateral skin) to protect the sural nerve.

Question 2119

Topic: 8. Foot and Ankle

A 29-year-old male sustains a supination-external rotation ankle injury. Non-weight-bearing radiographs demonstrate an isolated, minimally displaced trans-syndesmotic fracture of the distal fibula (Weber B). The medial clear space measures 3 mm.

What is the most appropriate next step to assess the integrity of the deep deltoid ligament and rule out a bimalleolar equivalent injury?

. Magnetic Resonance Imaging (MRI) of the ankle
. Computed Tomography (CT) scan of the ankle without contrast
. Gravity stress radiograph
. Weight-bearing anteroposterior radiograph
. Either Gravity stress radiograph or Weight-bearing anteroposterior radiograph

Correct Answer & Explanation

. Magnetic Resonance Imaging (MRI) of the ankle

Explanation

To accurately assess for deep deltoid ligament disruption in an apparent isolated lateral malleolus fracture (Weber B), dynamic assessment is required. Both gravity stress views and weight-bearing radiographs are validated methods. If the medial clear space widens to greater than 4-5 mm (or >1 mm compared to the superior clear space), it indicates deep deltoid incompetence, classifying it as a bimalleolar equivalent fracture requiring operative intervention.

Question 2120

Topic: 8. Foot and Ankle

A 68-year-old female with osteoporosis misjudges a curb step and feels a sudden 'pop' in her posterior heel. Radiographs reveal a large 'beak' type avulsion fracture of the superior calcaneal tuberosity, displaced proximally by 4 cm.

On examination, the skin overlying the posterior heel is visibly blanched and tense. What is the most appropriate management?

. Application of a short leg cast in maximal equinus (plantarflexion) for 6 weeks
. Urgent operative intervention for open reduction and internal fixation
. Strict elevation and ice, with delayed fixation planned for 10-14 days after swelling subsides
. Surgical excision of the bony fragment and direct repair of the Achilles tendon to the calcaneus using anchors
. Closed reduction under sedation and percutaneous pinning

Correct Answer & Explanation

. Application of a short leg cast in maximal equinus (plantarflexion) for 6 weeks

Explanation

A displaced avulsion fracture of the calcaneal tuberosity that causes blanching (ischemia) of the thin overlying posterior heel skin represents a true orthopedic surgical emergency. The direct pressure from the displaced bony fragment will rapidly lead to full-thickness skin necrosis if not urgently reduced and definitively stabilized. Delaying for swelling to subside is contraindicated here.

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