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8. Foot and Ankle MCQs

Practice Set 286 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 5701

Topic: 8. Foot and Ankle
A 32-year-old male presents with a Hawkins type III talar neck fracture following a motor vehicle collision. Which of the following best describes the specific vascular disruption that places him at an 80-100% risk for avascular necrosis?
. Disruption of the artery of the tarsal canal only
. Disruption of the deltoid branches and artery of the tarsal sinus
. Disruption of the artery of the tarsal canal, artery of the tarsal sinus, and deltoid branches
. Disruption of the dorsalis pedis artery only
. Disruption of the medial plantar artery

Correct Answer & Explanation

. Disruption of the artery of the tarsal canal, artery of the tarsal sinus, and deltoid branches

Explanation

Hawkins III fractures involve dislocation of both the subtalar and tibiotalar joints, disrupting all three main blood supplies to the talar body. These include the artery of the tarsal canal, the artery of the tarsal sinus, and the deltoid branches.

Question 5702

Topic: 8. Foot and Ankle

In the surgical treatment of a displaced intra-articular calcaneus fracture, the 'constant fragment' remains anatomically aligned with the talus. Which structure provides the primary ligamentous attachment holding this fragment in place?

. Anterior talofibular ligament
. Calcaneofibular ligament
. Bifurcate ligament
. Interosseous talocalcaneal ligament
. Achilles tendon

Correct Answer & Explanation

. Anterior talofibular ligament

Explanation

The sustentaculum tali is considered the 'constant fragment' because it remains firmly attached to the talus via the strong interosseous talocalcaneal and deltoid ligaments. It serves as the medial foundation for calcaneal reconstruction.

Question 5703

Topic: 8. Foot and Ankle

A 35-year-old construction worker falls from a ladder and sustains a displaced intra-articular calcaneus fracture. The surgeon elects to perform an open reduction and internal fixation via an extensile lateral approach. Which of the following is the most common complication specifically associated with this surgical approach?

. Sural nerve transection
. Superficial peroneal nerve entrapment
. Wound edge necrosis and dehiscence
. Posterior tibial artery pseudoaneurysm
. Flexor hallucis longus tethering

Correct Answer & Explanation

. Sural nerve transection

Explanation

The extensile lateral approach to the calcaneus involves creating a large full-thickness fasciocutaneous flap. Due to the tenuous vascular supply at the corner of the flap, wound edge necrosis and dehiscence are the most frequent and significant complications of this approach.

Question 5704

Topic: 8. Foot and Ankle

A 22-year-old collegiate football player presents with severe midfoot pain after a plant-and-twist injury. Weight-bearing radiographs reveal a 3 mm widening between the base of the first and second metatarsals. The primary ligament disrupted in this injury normally connects which two anatomic structures?

. Medial cuneiform to the base of the first metatarsal
. Medial cuneiform to the base of the second metatarsal
. Middle cuneiform to the base of the second metatarsal
. Lateral cuneiform to the base of the third metatarsal
. Navicular to the base of the first metatarsal

Correct Answer & Explanation

. Medial cuneiform to the base of the first metatarsal

Explanation

The Lisfranc ligament is an 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 midfoot arch.

Question 5705

Topic: Ankle Trauma & Sports

A 35-year-old male sustains a pronation-external rotation (Weber C) ankle fracture.

Intraoperatively, after rigid internal fixation of the fibula, the surgeon performs a 'Cotton test' by applying a lateral pull on the fibula using a bone hook. What ligamentous structure is primarily being assessed for integrity?

. Anterior talofibular ligament
. Calcaneofibular ligament
. Syndesmotic ligament complex
. Deltoid ligament
. Spring ligament

Correct Answer & Explanation

. Anterior talofibular ligament

Explanation

The Cotton test (lateral stress test) is used intraoperatively to assess the integrity of the distal tibiofibular syndesmosis. After fixing the lateral malleolus, a lateral force is applied to the fibula. Widening of the tibiofibular clear space on fluoroscopy indicates syndesmotic instability, which requires stabilization (e.g., syndesmotic screws or suture button construct).

Question 5706

Topic: 8. Foot and Ankle

A 30-year-old male football player sustains a hyperplantarflexion injury to his midfoot. Radiographs demonstrate widening of the space between the medial cuneiform and the second metatarsal base.

This finding signifies a disruption of the Lisfranc ligament. The Lisfranc ligament anatomically connects which two osseous structures?

. Medial cuneiform and base of the 1st metatarsal
. Medial cuneiform and base of the 2nd metatarsal
. Middle cuneiform and base of the 2nd metatarsal
. Lateral cuneiform and base of the 3rd metatarsal
. Cuboid and base of the 4th metatarsal

Correct Answer & Explanation

. Medial cuneiform and base of the 1st metatarsal

Explanation

The Lisfranc ligament is a crucial, strong interosseous ligament that connects the lateral aspect of the medial cuneiform to the medial aspect of the base of the second metatarsal. There is no ligamentous connection between the bases of the first and second metatarsals, making this area vulnerable to disruption.

Question 5707

Topic: 8. Foot and Ankle
A 32-year-old male is involved in a severe motor vehicle accident and sustains a displaced fracture of the talar neck with subtalar and tibiotalar dislocation (Hawkins type III). Which of the following vessels provides the predominant blood supply to the talar body and is at greatest risk in this injury?
. Artery of the tarsal canal
. Artery of the tarsal sinus
. Deltoid branch of the posterior tibial artery
. Dorsalis pedis artery
. Perforating peroneal artery

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 talar neck fractures carry a high risk of osteonecrosis due to the disruption of this retrograde blood supply.

Question 5708

Topic: 8. Foot and Ankle

A 30-year-old football player sustains an axial load to a plantarflexed foot. Weight-bearing radiographs show widening between the first and second metatarsals, and a small bony avulsion is noted in the intercuneiform space (the "fleck sign"). The Lisfranc ligament, responsible for this sign, connects which two anatomical structures?

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

Correct Answer & Explanation

. Medial cuneiform to the base of the second metatarsal

Explanation

The Lisfranc ligament is a strong interosseous ligament that attaches the lateral aspect of the medial cuneiform to the medial aspect of the base of the second metatarsal. The "fleck sign" represents a bony avulsion of this ligament and is pathognomonic for a Lisfranc injury.

Question 5709

Topic: 8. Foot and Ankle
A 45-year-old male sustains a displaced intra-articular calcaneus fracture (Sanders type III). Surgical fixation via an extensile lateral approach is planned. Which of the following patient factors is the most significant independent predictor for postoperative wound necrosis and deep infection?
. Hypertension
. Body Mass Index (BMI) of 28
. Active tobacco smoking
. History of deep vein thrombosis
. Age greater than 40 years

Correct Answer & Explanation

. Active tobacco smoking

Explanation

Active smoking is the most significant risk factor for wound edge necrosis, dehiscence, and deep infection following the extensile lateral approach to the calcaneus. The risk of wound complications is significantly magnified due to nicotine-induced microvascular vasoconstriction.

Question 5710

Topic: Midfoot & Hindfoot
A 28-year-old male is involved in a high-speed MVA and sustains a closed fracture of the talar neck. Imaging shows a displaced fracture of the talar neck with subluxation of the subtalar joint, while the tibiotalar and talonavicular joints remain congruent. What is the Hawkins classification for this injury?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type II

Explanation

The Hawkins classification is used for talar neck fractures. Type I: Non-displaced. Type II: Displaced with subtalar subluxation or dislocation. Type III: Displaced with subtalar and tibiotalar dislocation. Type IV: Displaced with subtalar, tibiotalar, and talonavicular dislocation. The scenario describes a Type II fracture, which carries an avascular necrosis risk of approximately 20-50%.

Question 5711

Topic: 8. Foot and Ankle

A 40-year-old male misses a step and presents with midfoot pain and swelling. X-rays show a small bony avulsion in the first intermetatarsal space ('Fleck sign'). Weight-bearing films demonstrate widening of the space between the 1st and 2nd metatarsal bases. What ligament is primarily injured?

. Plantar ligament connecting the 1st cuneiform to the 1st metatarsal
. Dorsal ligament connecting the 2nd cuneiform to the 2nd metatarsal
. Interosseous ligament connecting the medial cuneiform to the base of the 2nd metatarsal
. Interosseous ligament connecting the lateral cuneiform to the base of the 3rd metatarsal
. Plantar ligament connecting the navicular to the medial cuneiform

Correct Answer & Explanation

. Plantar ligament connecting the 1st cuneiform to the 1st metatarsal

Explanation

The Lisfranc ligament is a strong interosseous ligament that runs obliquely from the lateral aspect of the medial cuneiform to the medial aspect of the base of the second metatarsal. It is the critical stabilizer of the midfoot arch. A 'fleck sign' represents a bony avulsion of this ligament and is pathognomonic for a Lisfranc injury.

Question 5712

Topic: 8. Foot and Ankle
A 40-year-old roofer falls from a ladder and sustains a severely displaced intra-articular calcaneus fracture (Sanders Type III). He is scheduled to undergo open reduction and internal fixation via an extensile lateral approach. Which complication is most frequently and classically associated with this specific surgical approach?
. Sural nerve neuroma
. Wound edge necrosis and dehiscence
. Tibial nerve entrapment
. Flexor hallucis longus (FHL) tendon laceration
. Avascular necrosis of the tuberosity

Correct Answer & Explanation

. Wound edge necrosis and dehiscence

Explanation

The extensile lateral approach to the calcaneus is notorious for severe soft tissue complications, specifically wound edge necrosis, dehiscence, and deep infection, occurring in 10-25% of cases. The flap relies heavily on the lateral calcaneal artery. Proper timing (waiting for the 'wrinkle sign'), careful subperiosteal elevation creating a full-thickness 'no-touch' flap, and minimal retraction are critical to mitigate this risk.

Question 5713

Topic: 8. Foot and Ankle

A 28-year-old sustains an ultra-low velocity knee dislocation during a sporting event. Following prompt closed reduction, the dorsalis pedis and posterior tibial pulses are palpable and symmetrical. The Ankle-Brachial Index (ABI) is calculated to be 0.85. What is the most appropriate next step in management?

. Serial clinical vascular examinations every 2 hours for 24 hours
. Immediate discharge with close outpatient orthopedic follow-up
. Immediate operative exploration of the popliteal artery
. CT angiography of the lower extremity
. Duplex ultrasound of the superficial femoral artery

Correct Answer & Explanation

. Serial clinical vascular examinations every 2 hours for 24 hours

Explanation

In the setting of a knee dislocation, an ABI < 0.9 is highly indicative of a vascular injury, even if pulses are palpable. The appropriate next step is advanced imaging with CT angiography (CTA) to rule out an intimal flap or popliteal artery injury. If the ABI is > 0.9, serial examinations are appropriate.

Question 5714

Topic: 8. Foot and Ankle

According to the findings of the Lower Extremity Assessment Project (LEAP) study, which of the following factors was found to be the most reliable predictor of poor functional outcome at 2 years following a severe, limb-threatening lower extremity injury?

. The initial decision to pursue limb salvage rather than amputation
. An initial Mangled Extremity Severity Score (MESS) greater than 7
. The presence of an insensate plantar surface at initial presentation
. Lack of adequate soft-tissue coverage within 7 days
. Patient characteristics such as lower educational level, lack of private insurance, and poor social support

Correct Answer & Explanation

. The initial decision to pursue limb salvage rather than amputation

Explanation

The LEAP study demonstrated that functional outcomes between limb salvage and amputation were statistically similar at 2 years. The strongest predictors of poor functional outcomes were not injury characteristics (like an insensate foot or MESS score), but rather patient demographic and socioeconomic factors, including lack of private insurance, lower educational level, poor social support, and smoking.

Question 5715

Topic: 8. Foot and Ankle

A 35-year-old roofer falls and lands directly on his heels, sustaining a severely displaced intra-articular calcaneus fracture. On the lateral foot radiograph, Bohler's angle is measured at 5 degrees. What is the normal anatomic range for Bohler's angle?

. 0 to 10 degrees
. 10 to 20 degrees
. 20 to 40 degrees
. 40 to 60 degrees
. -10 to 0 degrees

Correct Answer & Explanation

. 0 to 10 degrees

Explanation

Bohler's angle is formed by the intersection of a line drawn from the highest point of the anterior process to the highest point of the posterior facet, and a line drawn from the highest point of the posterior facet to the superior edge of the calcaneal tuberosity. The normal range is 20 to 40 degrees. A decrease in this angle indicates collapse of the posterior facet.

Question 5716

Topic: 8. Foot and Ankle

A collegiate football player sustains an axial load and twisting injury to a plantarflexed foot. Weight-bearing radiographs reveal a 3 mm diastasis between the base of the first and second metatarsals. What is the primary ligamentous stabilizer of this joint complex?

. Dorsal Lisfranc ligament
. Interosseous Lisfranc ligament
. Plantar Lisfranc ligament
. Spring ligament
. Bifurcate ligament

Correct Answer & Explanation

. Dorsal Lisfranc ligament

Explanation

The Lisfranc ligament complex stabilizes the midfoot. The interosseous Lisfranc ligament, connecting the medial cuneiform to the base of the second metatarsal, is the largest, thickest, and primary stabilizer of the Lisfranc joint. The plantar ligament is the second strongest, while the dorsal ligament is the weakest.

Question 5717

Topic: Ankle Trauma & Sports

A 35-year-old male sustains an ankle fracture. Radiographs show a vertical medial malleolus fracture and a transverse lateral malleolus fracture below the level of the syndesmosis. According to the Lauge-Hansen classification, which of the following is the mechanism of injury?

. Supination-External Rotation
. Pronation-External Rotation
. Supination-Adduction
. Pronation-Abduction
. Pronation-Adduction

Correct Answer & Explanation

. Supination-External Rotation

Explanation

The Supination-Adduction (SAD) injury pattern classically presents with a transverse fracture of the fibula below the level of the syndesmosis (Stage 1) and a vertical shear fracture of the medial malleolus (Stage 2).

Question 5718

Topic: Midfoot & Hindfoot
A 29-year-old male falls from a height and sustains a talar neck fracture with subluxation of the subtalar joint but a congruous tibiotalar and talonavicular joint. According to the Hawkins classification, what is the risk of avascular necrosis (AVN)?
. 0-10%
. 20-50%
. 70-100%
. 100%
. AVN does not occur in this pattern

Correct Answer & Explanation

. 20-50%

Explanation

This is a Hawkins Type II fracture (talar neck fracture with subtalar dislocation). The risk of AVN for Type I is 0-10%, Type II is 20-50%, Type III (subtalar and tibiotalar dislocation) is 50-100%, and Type IV (Type III plus talonavicular dislocation) is near 100%.

Question 5719

Topic: 8. Foot and Ankle

A 30-year-old athlete complains of midfoot pain after a twisting injury. Non-weight-bearing radiographs appear normal. A 'fleck sign' is noted on careful inspection. What is the most appropriate next imaging step?

. MRI of the midfoot
. CT scan of the foot
. Weight-bearing radiographs of the foot
. Ultrasound of the Lisfranc ligament
. Bone scan

Correct Answer & Explanation

. MRI of the midfoot

Explanation

In suspected Lisfranc injuries with normal non-weight-bearing radiographs, weight-bearing radiographs (anteroposterior and lateral) are the critical next step to evaluate for dynamic instability. A 'fleck sign' represents an avulsion of the Lisfranc ligament from the base of the second metatarsal.

Question 5720

Topic: 8. Foot and Ankle

A 26-year-old football player sustains a multi-ligamentous knee injury that spontaneously reduced. Distal pulses are palpable. What is the most appropriate next step to evaluate for vascular injury?

. Immediate surgical exploration of the popliteal artery
. Ankle-Brachial Index (ABI); if >0.9, observe
. Venous duplex ultrasound
. Angiography in all cases regardless of exam
. Ankle-Brachial Index (ABI); if <0.9, CT angiography

Correct Answer & Explanation

. Immediate surgical exploration of the popliteal artery

Explanation

In knee dislocations, initial assessment should include an ABI. If the ABI is >0.9, serial examinations are generally sufficient. If the ABI is <0.9 or if there are asymmetric pulses, CT angiography (CTA) is mandated.

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