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8. Foot and Ankle MCQs

Practice Set 205 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 4081

Topic: Midfoot & Hindfoot

A 28-year-old male sustains a Hawkins type III fracture of the talar neck after falling from a height. Which of the following accurately describes the joint subluxations or dislocations seen in this specific classification?

. Nondisplaced talar neck fracture
. Dislocation of the subtalar joint only
. Dislocation of both the subtalar and tibiotalar joints
. Dislocation of the subtalar, tibiotalar, and talonavicular joints
. Isolated talonavicular joint dislocation

Correct Answer & Explanation

. Nondisplaced talar neck fracture

Explanation

Hawkins Type III talar neck fractures involve displacement of the fracture with dislocation of both the subtalar joint and the tibiotalar (ankle) joint. This pattern carries a very high risk (often near 100% without prompt reduction) of avascular necrosis.

Question 4082

Topic: 8. Foot and Ankle

A 35-year-old female complains of midfoot pain after misstepping off a curb. She has plantar ecchymosis and pain with pronation and abduction of the forefoot. Non-weight-bearing radiographs appear normal. What is the most appropriate next step in evaluation?

. MRI of the midfoot
. CT scan of the foot
. Weight-bearing radiographs of the bilateral feet
. Diagnostic ultrasound
. Discharge with a stiff-soled shoe

Correct Answer & Explanation

. MRI of the midfoot

Explanation

Plantar ecchymosis is highly suggestive of a Lisfranc injury. When non-weight-bearing films are normal, weight-bearing bilateral radiographs are the most appropriate next step to evaluate for dynamic instability or subtle widening.

Question 4083

Topic: 8. Foot and Ankle

A 40-year-old male undergoes open reduction and internal fixation of a displaced intra-articular calcaneus fracture via an extensile lateral approach. Which complication is most frequently associated with this specific surgical approach?

. Medial plantar nerve injury
. Sural nerve injury and wound edge necrosis
. Deep peroneal nerve entrapment
. Tibialis anterior tendon rupture
. Flexor hallucis longus tethering

Correct Answer & Explanation

. Medial plantar nerve injury

Explanation

The extensile lateral approach to the calcaneus carries a notorious risk of wound healing complications (necrosis of the flap apex) and injury to the sural nerve. Meticulous "no-touch" handling of the full-thickness subperiosteal flap is required.

Question 4084

Topic: 8. Foot and Ankle

A 26-year-old male sustains a pronation-external rotation (PER) ankle fracture. Intraoperatively, after fixing the fibula and medial malleolus, the Cotton test is positive. Which structure must be injured to allow this syndesmotic instability?

. Anterior talofibular ligament only
. Calcaneofibular ligament
. Interosseous membrane and at least one syndesmotic ligament
. Deltoid ligament alone
. Spring ligament

Correct Answer & Explanation

. Anterior talofibular ligament only

Explanation

A positive Cotton test (widening of the syndesmosis with lateral traction on the fibula) indicates syndesmotic instability. This requires disruption of the interosseous membrane/ligament along with the anterior and/or posterior inferior tibiofibular ligament.

Question 4085

Topic: Midfoot & Hindfoot

A 24-year-old professional athlete sustains a purely ligamentous Lisfranc injury. What is the currently recommended treatment approach to minimize long-term arthrosis and maximize functional outcome?

. Cast immobilization for 8 weeks and non-weight bearing
. Open reduction and internal fixation with transarticular screws
. Dorsal bridge plating without joint violation
. Closed reduction and percutaneous K-wire pinning
. Primary arthrodesis of the first, second, and third tarsometatarsal joints

Correct Answer & Explanation

. Cast immobilization for 8 weeks and non-weight bearing

Explanation

Recent high-level literature supports primary arthrodesis over open reduction and internal fixation for purely ligamentous Lisfranc injuries. Arthrodesis has been associated with lower rates of hardware failure, fewer subsequent surgeries, and superior mid-term functional outcomes.

Question 4086

Topic: 8. Foot and Ankle

A 22-year-old collegiate football player sustains a knee dislocation. Upon reduction in the ED, his distal pulses are palpable but his ankle-brachial index (ABI) is calculated to be 0.8. What is the most appropriate next step in his management?

. Serial physical examinations and ABI measurements every 2 hours
. Immediate surgical exploration of the popliteal artery
. CT angiography of the lower extremity
. Application of a spanning external fixator
. Venous duplex ultrasonography

Correct Answer & Explanation

. Serial physical examinations and ABI measurements every 2 hours

Explanation

In a patient with a documented knee dislocation, an ABI of less than 0.9 indicates a high suspicion for a clinically significant popliteal artery injury. This warrants further definitive imaging with CT angiography to determine if vascular intervention is required.

Question 4087

Topic: Midfoot & Hindfoot

A 29-year-old male sustains a displaced fracture of the talar neck with subluxation of the subtalar joint and a dislocated tibiotalar joint. What is the expected historical rate of avascular necrosis (AVN) of the talar body for this Hawkins type III injury?

. Less than 10%
. 15% to 25%
. 30% to 40%
. 70% to 100%
. 100% in all cases despite prompt reduction

Correct Answer & Explanation

. Less than 10%

Explanation

A Hawkins type III talar neck fracture involves displacement of the talar neck with dislocation of both the subtalar and tibiotalar joints, severely disrupting the blood supply. The risk of avascular necrosis (AVN) is historically reported to be between 70% and 100%.

Question 4088

Topic: 8. Foot and Ankle

A 28-year-old female falls from a height and sustains a Hawkins type III talar neck fracture. Which of the following best describes the vascular disruption and the associated risk of avascular necrosis (AVN)?

. Disruption of the artery of the tarsal canal only; AVN risk ~20%
. Disruption of the deltoid branch only; AVN risk ~50%
. Disruption of all three major blood supplies; AVN risk nearly 100%
. Disruption of the anterior tibial and dorsalis pedis only; AVN risk ~10%
. Disruption of the artery of the tarsal sinus only; AVN risk ~75%

Correct Answer & Explanation

. Disruption of the artery of the tarsal canal only; AVN risk ~20%

Explanation

A Hawkins type III fracture involves the talar neck with dislocation of the talar body from both the subtalar and tibiotalar joints. This typically disrupts all three major blood supplies (tarsal canal, tarsal sinus, and deltoid branches), leading to a nearly 100% risk of AVN.

Question 4089

Topic: 8. Foot and Ankle

A 45-year-old construction worker sustains a highly comminuted, displaced intra-articular calcaneus fracture (Sanders type IV). He is a heavy smoker and has poorly controlled diabetes. What is the most appropriate primary surgical treatment option to minimize complications?

. Extensile lateral approach with open reduction and internal fixation
. Primary subtalar arthrodesis
. Closed reduction and percutaneous pinning
. Total ankle arthroplasty
. Nonoperative management with early range of motion

Correct Answer & Explanation

. Extensile lateral approach with open reduction and internal fixation

Explanation

In Sanders type IV fractures (highly comminuted) in patients with severe soft tissue risk factors like heavy smoking and diabetes, primary subtalar arthrodesis is often indicated. This approach manages the severe articular damage while minimizing the high wound complication rates associated with extensile lateral approaches.

Question 4090

Topic: 8. Foot and Ankle

A 22-year-old athlete sustains a hyperplantarflexion injury to his midfoot. Non-weight-bearing radiographs appear normal. He has severe pain with weight-bearing and noticeable plantar ecchymosis. What is the most appropriate next step in the diagnostic workup?

. MRI of the ankle
. CT scan of the foot without contrast
. Weight-bearing radiographs of the foot
. Diagnostic ultrasound of the midfoot
. Bone scan

Correct Answer & Explanation

. MRI of the ankle

Explanation

Plantar ecchymosis is highly pathognomonic for a Lisfranc injury. When non-weight-bearing films are normal but clinical suspicion remains high, weight-bearing radiographs of the foot are required to demonstrate dynamic instability and diastasis.

Question 4091

Topic: Midfoot & Hindfoot

A 24-year-old female sustains a purely ligamentous Lisfranc injury with dynamic instability. What is the most appropriate definitive surgical management based on prospective randomized trials?

. Closed reduction and percutaneous pinning
. Primary arthrodesis of the medial tarsometatarsal joints
. Open reduction and internal fixation (ORIF) with transarticular screws
. Nonoperative management in a non-weight-bearing cast
. Dorsal bridge plating without joint debridement

Correct Answer & Explanation

. Closed reduction and percutaneous pinning

Explanation

Prospective randomized studies demonstrate that primary arthrodesis for purely ligamentous Lisfranc injuries results in superior functional outcomes and lower reoperation rates compared to ORIF. ORIF is generally preferred when treating bony Lisfranc fracture-dislocations.

Question 4092

Topic: 8. Foot and Ankle

During an extensile lateral approach for a displaced intra-articular calcaneus fracture, what anatomical structure is at highest risk of iatrogenic injury when developing the full-thickness soft tissue flap?

. Sural nerve
. Superficial peroneal nerve
. Posterior tibial artery
. Deep peroneal nerve
. Medial plantar nerve

Correct Answer & Explanation

. Sural nerve

Explanation

The sural nerve crosses the lateral border of the foot and is at significant risk during the extensile lateral approach to the calcaneus. A "no-touch" technique developing a full-thickness subperiosteal flap is critical to protect the nerve and the tenuous vascular supply of the skin.

Question 4093

Topic: 8. Foot and Ankle

During ORIF of a bimalleolar equivalent ankle fracture, the syndesmosis is stabilized with two positional screws. A postoperative CT scan reveals the fibula is malreduced within the incisura fibularis. What is the most common direction of this syndesmotic malreduction?

. Anterior and medial
. Anterior and lateral
. Posterior and lateral
. Posterior and medial
. Directly proximal

Correct Answer & Explanation

. Anterior and medial

Explanation

During reduction and clamping of the syndesmosis, the fibula is most commonly malreduced in an anterior and medial direction (often internally rotated) within the incisura. Open direct visualization can significantly reduce this malreduction rate.

Question 4094

Topic: 8. Foot and Ankle

In a Sanders Type II calcaneus fracture, what anatomical structure is primarily evaluated on the coronal CT scan to determine the classification?

. Anterior process of the calcaneus
. Calcaneocuboid joint
. Posterior facet of the subtalar joint
. Sustentaculum tali
. Lateral wall of the calcaneus

Correct Answer & Explanation

. Anterior process of the calcaneus

Explanation

The Sanders classification is based on the number and location of fracture lines through the posterior facet of the subtalar joint on coronal CT images. Type II consists of a two-part fracture of the posterior facet.

Question 4095

Topic: Ankle Trauma & Sports

During open reduction and internal fixation of a severe Pilon fracture, the Chaput fragment is identified. Which ligament attaches to this fragment?

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

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

The Chaput fragment is the anterolateral fragment of the distal tibia. The anterior inferior tibiofibular ligament (AITFL) attaches the Chaput fragment to the Wagstaffe fragment of the fibula.

Question 4096

Topic: Ankle Trauma & Sports

A 30-year-old male has an unstable ankle syndesmosis after fixation of a Weber C fibula fracture. Which of the following is true regarding suture button fixation compared to rigid syndesmotic screws?

. Suture buttons require routine removal at 3 months
. Suture buttons provide rigid fixation preventing all physiologic fibular motion
. Suture buttons allow earlier weight-bearing and reduce the need for hardware removal
. Suture buttons have a significantly higher rate of syndesmotic malreduction
. Suture buttons are only indicated in purely ligamentous injuries without fracture

Correct Answer & Explanation

. Suture buttons require routine removal at 3 months

Explanation

Suture button constructs provide dynamic stabilization, allowing physiologic motion while maintaining reduction. They generally allow earlier weight-bearing and eliminate the need for routine hardware removal compared to syndesmotic screws.

Question 4097

Topic: 8. Foot and Ankle

A surgeon utilizes an extensile lateral approach for open reduction and internal fixation of a joint-depressed calcaneus fracture. During the elevation of the full-thickness flap, which of the following nerves is at greatest risk of injury near the proximal vertical limb of the incision?

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

Correct Answer & Explanation

. Superficial peroneal nerve

Explanation

The sural nerve is at significant risk during the extensile lateral approach to the calcaneus, particularly where it crosses the superior aspect of the proximal vertical limb of the incision. Careful, subperiosteal flap elevation is required to protect it.

Question 4098

Topic: 8. Foot and Ankle

A 24-year-old collegiate football player sustains a purely ligamentous Lisfranc injury. An MRI confirms complete disruption of the Lisfranc ligament complex with multi-directional instability, but no fractures are noted. Based on recent literature, what is the best operative treatment for optimizing long-term function?

. Closed reduction and percutaneous pinning
. ORIF with transarticular screws
. Primary arthrodesis of the 1st, 2nd, and 3rd tarsometatarsal joints
. Flexible fixation using suture-button devices across all metatarsals
. Non-weight bearing short leg cast for 8 weeks

Correct Answer & Explanation

. Closed reduction and percutaneous pinning

Explanation

For purely ligamentous Lisfranc injuries, primary arthrodesis of the first, second, and third tarsometatarsal joints has been shown to yield better functional outcomes and lower reoperation rates compared to traditional ORIF.

Question 4099

Topic: 8. Foot and Ankle

Following open reduction and internal fixation of a bimalleolar ankle fracture with syndesmotic instability, the surgeon obtains intraoperative fluoroscopy to assess the syndesmotic reduction. Which of the following parameters is the most reliable radiographic indicator of a normally reduced syndesmosis on a mortise view?

. Medial clear space greater than 4 mm
. Tibiofibular overlap less than 1 mm
. Talar tilt of exactly 5 degrees
. Tibiofibular clear space less than 5 mm
. Shenton's line disruption at the ankle mortise

Correct Answer & Explanation

. Medial clear space greater than 4 mm

Explanation

The tibiofibular clear space is the most reliable plain radiographic parameter for evaluating syndesmotic integrity. It is measured 1 cm proximal to the joint line, and a clear space of less than 5 mm on both AP and mortise views indicates a normal relationship.

Question 4100

Topic: Midfoot & Hindfoot

A 29-year-old snowboarder is diagnosed with a Hawkins type III fracture of the talar neck. What specific pattern of displacement defines a Hawkins type III injury?

. A nondisplaced talar neck fracture
. A talar neck fracture with subtalar subluxation or dislocation
. A talar neck fracture with simultaneous subtalar and tibiotalar dislocation
. A talar neck fracture with subtalar, tibiotalar, and talonavicular dislocation
. A fracture of the talar head with articular surface depression

Correct Answer & Explanation

. A nondisplaced talar neck fracture

Explanation

In the Hawkins classification for talar neck fractures, Type III is defined as a displaced talar neck fracture with dislocation of both the subtalar and tibiotalar joints. This injury carries a very high risk of avascular necrosis (AVN) of the talar body.

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