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8. Foot and Ankle MCQs

Practice Set 176 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 3501

Topic: 8. Foot and Ankle

An orthopedic surgeon is performing a lateral approach to the hindfoot for an intra-articular calcaneal fracture fixation. Which nerve is most at risk during the standard lateral extensile approach?

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

Correct Answer & Explanation

. Sural nerve

Explanation

The sural nerve courses posterior to the lateral malleolus and provides sensation to the lateral aspect of the foot, making it highly susceptible to injury during a lateral extensile approach to the calcaneus.

Question 3502

Topic: 8. Foot and Ankle

The "watershed" area of the Achilles tendon, which is prone to rupture and represents an area of relative hypovascularity, is typically located:

. At the musculotendinous junction
. 2 to 6 cm proximal to the calcaneal insertion
. At the calcaneal insertion
. 10 to 12 cm proximal to the calcaneal insertion
. At the level of the soleus aponeurosis

Correct Answer & Explanation

. 2 to 6 cm proximal to the calcaneal insertion

Explanation

The watershed zone of the Achilles tendon is an area of relative hypovascularity located roughly 2 to 6 cm proximal to its insertion on the calcaneus, making it the most common site for degenerative tears and ruptures.

Question 3503

Topic: 8. Foot and Ankle

During a plantar approach to the foot for a plantar fibromatosis excision, the surgeon identifies the "Master Knot of Henry". Which two tendons intersect at this anatomic landmark?

. Flexor hallucis longus and Flexor digitorum longus
. Tibialis anterior and Tibialis posterior
. Flexor hallucis longus and Tibialis posterior
. Flexor digitorum longus and Tibialis posterior
. Peroneus longus and Peroneus brevis

Correct Answer & Explanation

. Flexor hallucis longus and Flexor digitorum longus

Explanation

The Master Knot of Henry is located in the medial plantar aspect of the midfoot. At this location, the flexor hallucis longus (FHL) tendon crosses dorsal to the flexor digitorum longus (FDL) tendon.

Question 3504

Topic: 8. Foot and Ankle

In evaluating the deltoid ligament of the ankle, the superficial portion crosses two joints. Which of the following is a component of the deep deltoid ligament, the primary medial stabilizer of the ankle?

. Tibiocalcaneal ligament
. Tibionavicular ligament
. Superficial posterior tibiotalar ligament
. Deep anterior tibiotalar ligament
. Plantar calcaneonavicular (spring) ligament

Correct Answer & Explanation

. Deep anterior tibiotalar ligament

Explanation

The deep deltoid ligament consists primarily of the deep anterior and deep posterior tibiotalar ligaments, providing the most significant restraint against lateral talar shift.

Question 3505

Topic: 8. Foot and Ankle

During a lateral approach to the calcaneus for open reduction internal fixation of a fracture, the sural nerve must be protected. What is its sensory distribution?

. Medial aspect of the heel
. Lateral aspect of the hindfoot and midfoot
. Plantar surface of the toes
. Dorsal web space between the first and second toes
. Medial border of the forefoot

Correct Answer & Explanation

. Lateral aspect of the hindfoot and midfoot

Explanation

The sural nerve provides sensory innervation to the posterolateral lower leg and the lateral aspect of the foot and heel.

Question 3506

Topic: 8. Foot and Ankle

A surgeon performs an extensile lateral approach to the calcaneus for open reduction and internal fixation of a joint-depressed fracture. The sural nerve is at high risk of iatrogenic injury during the flap elevation. The sural nerve receives its contributing fibers from which of the following nerve pairs?

. Medial plantar and lateral plantar nerves
. Tibial and common peroneal nerves
. Saphenous and tibial nerves
. Superficial peroneal and deep peroneal nerves
. Saphenous and common peroneal nerves

Correct Answer & Explanation

. Tibial and common peroneal nerves

Explanation

The sural nerve provides sensation to the posterolateral distal leg and lateral foot. It is formed by the union of the medial sural cutaneous nerve (a branch of the tibial nerve) and the sural communicating branch of the lateral sural cutaneous nerve (from the common peroneal nerve).

Question 3507

Topic: 8. Foot and Ankle

During a lateral extensile approach for a displaced intra-articular calcaneus fracture, full-thickness flaps are elevated. Which structure is at highest risk of iatrogenic injury during the creation of the inferior and posterior limb corner?

. Deep peroneal nerve
. Sural nerve
. Posterior tibial artery
. Superficial peroneal nerve
. Saphenous nerve

Correct Answer & Explanation

. Sural nerve

Explanation

The sural nerve courses along the lateral aspect of the foot and ankle, posterior to the lateral malleolus. It is highly susceptible to injury when creating the corner of the 'L' flap in a lateral extensile approach to the calcaneus.

Question 3508

Topic: 8. Foot and Ankle

The major blood supply to the body of the talus is derived primarily from which of the following vessels?

. Artery of the tarsal canal
. Artery of the sinus tarsi
. Dorsalis pedis artery
. Perforating peroneal artery
. Anterior tibial 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 dominant blood supply to the body of the talus. It forms an anastomotic sling with the artery of the sinus tarsi.

Question 3509

Topic: Midfoot & Hindfoot

During a medial approach to the midfoot, the surgeon encounters the "Master Knot of Henry". This anatomic structure is formed by the crossing of which two tendons?

. Flexor hallucis longus and flexor digitorum longus
. Tibialis posterior and flexor digitorum longus
. Tibialis anterior and posterior tibial tendon
. Peroneus longus and flexor hallucis longus
. Tibialis posterior and flexor hallucis longus

Correct Answer & Explanation

. Flexor hallucis longus and flexor digitorum longus

Explanation

The "Master Knot of Henry" is located in the plantar midfoot near the navicular. It is the site where the flexor hallucis longus tendon crosses dorsal (superior) to the flexor digitorum longus tendon.

Question 3510

Topic: 8. Foot and Ankle

In an extensile lateral approach for an intra-articular calcaneus fracture, a full-thickness flap is created. Which of the following structures must be intentionally kept within the flap to prevent necrosis and wound complications?

. Deep peroneal nerve and dorsalis pedis artery
. Sural nerve and lesser saphenous vein
. Medial plantar nerve and posterior tibial artery
. Saphenous nerve and great saphenous vein
. Lateral plantar nerve and peroneal artery

Correct Answer & Explanation

. Sural nerve and lesser saphenous vein

Explanation

The extensile lateral approach to the calcaneus utilizes a full-thickness "no-touch" flap. The sural nerve and lesser saphenous vein must be included within the retracted superior flap to preserve flap vascularity and avoid nerve injury.

Question 3511

Topic: 8. Foot and Ankle

During a lateral extensile approach to the calcaneus for an intra-articular fracture, the sural nerve is at risk of injury. What is the normal anatomic course of the sural nerve at the level of the lateral malleolus?

. Anterior to the lateral malleolus and superficial to the superior extensor retinaculum
. Posterior to the lateral malleolus and deep to the peroneal tendons
. Posterior to the lateral malleolus and superficial to the peroneal tendons
. Anterior to the lateral malleolus and deep to the inferior extensor retinaculum
. Directly over the tip of the lateral malleolus

Correct Answer & Explanation

. Posterior to the lateral malleolus and superficial to the peroneal tendons

Explanation

The sural nerve passes posterior to the lateral malleolus and runs superficial to the peroneal tendons and their retinaculum. It must be carefully elevated with the full-thickness flap.

Question 3512

Topic: 8. Foot and Ankle

Which ligament is considered the primary static restraint to anterior translation of the talus relative to the tibia in a plantarflexed ankle?

. Calcaneofibular ligament
. Anterior talofibular ligament
. Posterior talofibular ligament
. Deltoid ligament
. Anterior inferior tibiofibular ligament

Correct Answer & Explanation

. Anterior talofibular ligament

Explanation

The anterior talofibular ligament (ATFL) is the weakest of the lateral ankle ligaments and acts as the primary restraint to anterior translation of the talus on the tibia. It is the most commonly torn ligament in an ankle inversion sprain.

Question 3513

Topic: 8. Foot and Ankle

A 28-year-old male is brought to the emergency department after a motorcycle collision with a grossly deformed left knee. Radiographs confirm a knee dislocation. After closed reduction, his pedal pulses are asymmetric. The ankle-brachial index (ABI) on the affected side is 0.75. What is the next most appropriate step in management?

. Immediate application of a hinged knee brace
. CT angiography of the lower extremity
. Observation and repeat ABI in 4 hours
. Immediate surgical exploration of the popliteal artery
. Duplex ultrasonography in 24 hours

Correct Answer & Explanation

. CT angiography of the lower extremity

Explanation

In the setting of a knee dislocation, an ABI less than 0.90 or asymmetric pulses warrant advanced vascular imaging, most commonly CT angiography, to evaluate for a popliteal artery injury. Hard signs of vascular injury (e.g., active bleeding, absent pulses) would mandate immediate surgical exploration without delaying for imaging.

Question 3514

Topic: 8. Foot and Ankle
A 26-year-old male sustains a high-energy multiligamentous knee injury resulting in a knee dislocation (KD-III). After successful closed reduction in the trauma bay, his ankle-brachial index (ABI) is measured at 0.8. The foot is warm and pink. What is the most appropriate next step in management?
. Observation with serial neurovascular checks every 2 hours
. Immediate operative exploration of the popliteal artery without imaging
. CT angiography (CTA) of the affected lower extremity
. Application of a spanning external fixator
. Immediate prophylactic four-compartment fasciotomies

Correct Answer & Explanation

. CT angiography (CTA) of the affected lower extremity

Explanation

An ABI less than 0.9 in the setting of a knee dislocation is highly suspicious for an occult vascular injury, such as a popliteal artery intimal tear. CT angiography is the gold standard next step to accurately localize and characterize the vascular lesion.

Question 3515

Topic: 8. Foot and Ankle

A 24-year-old male is evaluated in the emergency department following a high-speed motorcycle accident. He has a grossly unstable knee with suspected multi-ligamentous injury. His ankle-brachial index (ABI) is 0.85. What is the most appropriate next step in management?

. Immediate surgical exploration of the popliteal artery
. CT angiography of the lower extremity
. Observation with serial neurovascular checks every 2 hours
. Application of a hinged knee brace and outpatient follow-up
. MRI of the knee

Correct Answer & Explanation

. CT angiography of the lower extremity

Explanation

An ABI less than 0.9 in the setting of a suspected knee dislocation requires further vascular evaluation, typically with a CT angiogram, to rule out a popliteal artery injury.

Question 3516

Topic: 8. Foot and Ankle

A 29-year-old male sustains an acute knee dislocation that is reduced in the emergency department. Pulses are palpable but somewhat asymmetric. The ankle-brachial index (ABI) is measured at 0.85. What is the most appropriate next step in management?

. Immediate surgical exploration of the popliteal fossa
. CT angiography of the lower extremity
. Serial clinical vascular examinations every 4 hours
. Discharge with a knee immobilizer and outpatient follow-up
. Duplex ultrasound at 1 week

Correct Answer & Explanation

. CT angiography of the lower extremity

Explanation

An Ankle-Brachial Index (ABI) less than 0.90 following a knee dislocation is highly sensitive for an underlying arterial injury. This finding mandates immediate advanced vascular imaging, such as CT angiography, to rule out a surgical vascular lesion.

Question 3517

Topic: 8. Foot and Ankle

A 29-year-old downhill skier catches an edge, forcibly dorsiflexing her ankle while the peroneals are contracted. She reports lateral ankle pain and a snapping sensation. Disruption of which structure is the primary cause of her pathology?

. Anterior talofibular ligament
. Calcaneofibular ligament
. Superior peroneal retinaculum
. Inferior peroneal retinaculum
. Lateral root of the extensor retinaculum

Correct Answer & Explanation

. Superior peroneal retinaculum

Explanation

Forced dorsiflexion with eversion against contracted peroneal muscles can rupture the superior peroneal retinaculum. This leads to recurrent peroneal tendon subluxation or dislocation.

Question 3518

Topic: 8. Foot and Ankle

A 21-year-old football lineman sustains an axial load to a plantarflexed foot. Radiographs demonstrate a 3mm diastasis between the base of the first and second metatarsals. What is the most appropriate treatment for this athlete?

. Immobilization in a short leg cast for 6 weeks
. Closed reduction and percutaneous pinning
. Open reduction and internal fixation or primary arthrodesis
. Custom orthotics and immediate weight-bearing
. Corticosteroid injection and bracing

Correct Answer & Explanation

. Open reduction and internal fixation or primary arthrodesis

Explanation

A diastasis of greater than 2 mm between the first and second metatarsal bases indicates a mechanically unstable Lisfranc injury. Operative management (ORIF or primary arthrodesis) is required to restore and maintain the midfoot arch.

Question 3519

Topic: 8. Foot and Ankle

A 19-year-old basketball player 'rolls' his ankle. MRI reveals an osteochondral lesion on the posteromedial aspect of the talar dome. What is the most common mechanism for this specific lesion?

. Inversion and dorsiflexion
. Inversion and plantarflexion
. Eversion and dorsiflexion
. Eversion and plantarflexion
. Direct axial load in neutral

Correct Answer & Explanation

. Inversion and plantarflexion

Explanation

Posteromedial osteochondral lesions of the talus typically occur due to an inversion and plantarflexion mechanism. These lesions are usually deeper and less likely to displace compared to anterolateral lesions, which occur with inversion and dorsiflexion.

Question 3520

Topic: 8. Foot and Ankle

A 22-year-old collegiate football player sustains a twisting ankle injury. Which physical examination finding has the highest specificity for diagnosing a syndesmotic (high ankle) sprain?

. Positive anterior drawer test
. Maximal tenderness over the anterior talofibular ligament
. Pain over the distal tibiofibular joint with external rotation of the foot in dorsiflexion
. Medial malleolar tenderness
. Positive Thompson test

Correct Answer & Explanation

. Pain over the distal tibiofibular joint with external rotation of the foot in dorsiflexion

Explanation

The external rotation stress test, performed by externally rotating the foot with the ankle in dorsiflexion, stresses the syndesmosis. It is considered one of the most specific physical examination maneuvers for diagnosing a syndesmotic injury.

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