Menu

8. Foot and Ankle MCQs

Practice Set 48 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 941

Topic: 8. Foot and Ankle

Regarding the classification and epidemiology of subtalar dislocations, which of the following statements is most accurate?

. Lateral subtalar dislocations are more common than medial dislocations.
. Medial subtalar dislocations are typically higher energy injuries with a higher rate of open reduction.
. Anterior and posterior dislocations collectively account for approximately 10-15% of all subtalar dislocations.
. Medial dislocations have a higher success rate for closed reduction compared to lateral dislocations.
. The direction of a subtalar dislocation is named by the direction the talus displaces relative to the foot.

Correct Answer & Explanation

. The direction of a subtalar dislocation is named by the direction the talus displaces relative to the foot.

Explanation

Correct Answer: DThe case states: 'Medial Dislocations: Account for approximately 80 to 85 percent of all subtalar dislocations. They are typically lower energy than lateral dislocations and have a higher success rate for closed reduction.' This directly supports option D and refutes options A and B. Lateral dislocations account for 15 to 20 percent of cases and are often higher-energy with a higher rate of irreducibility. Anterior and posterior dislocations are 'exceedingly rare, representing less than 1 percent of cases,' refuting option C. Finally, the 'Clinical Pearls and Pitfalls' section notes: 'Pearl Understanding the Nomenclature: Subtalar dislocations are named by the direction the foot travels, not the talus,' refuting option E.

Question 942

Topic: 8. Foot and Ankle

A 22-year-old athlete sustains a high-energy knee dislocation. Following closed reduction, the foot remains warm and pink, but pedal pulses are faint. The Ankle-Brachial Index (ABI) is measured at 0.85. What is the most appropriate next step in the management of this patient?

. Immediate vascular surgery consultation for bypass graphing
. CT angiography of the lower extremity
. Discharge with an urgent outpatient MRI
. Observation with serial clinical examinations every 4 hours
. Emergent application of a spanning external fixator

Correct Answer & Explanation

. CT angiography of the lower extremity

Explanation

An Ankle-Brachial Index (ABI) less than 0.9 in the setting of a knee dislocation is highly suggestive of a clinically significant vascular injury. A CT angiogram is the standard of care to definitively identify the location and extent of popliteal artery compromise before deciding on surgical intervention.

Question 943

Topic: 8. Foot and Ankle
A 45-year-old male is scheduled to undergo open reduction and internal fixation for a displaced Sanders Type III calcaneus fracture via an extensile lateral approach. Which of the following is the most common and significant complication uniquely associated with this surgical approach?
. Sural nerve permanent transection
. Deep vein thrombosis of the popliteal vein
. Subtalar joint arthrofibrosis
. Wound edge necrosis and flap dehiscence
. Posterior tibial nerve palsy

Correct Answer & Explanation

. Wound edge necrosis and flap dehiscence

Explanation

The extensile lateral approach for calcaneus fractures carries a notoriously high risk of wound healing complications, including edge necrosis, dehiscence, and deep infection. Meticulous soft tissue handling and adhering to a "no-touch" technique with K-wires for retraction are critical to minimize this risk.

Question 944

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 of the following structures is at the highest risk of iatrogenic injury during the full-thickness flap elevation?

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

Correct Answer & Explanation

. Sural nerve

Explanation

The sural nerve is at significant risk during the extensile lateral approach to the calcaneus, particularly at the proximal and distal limbs of the L-shaped incision. Meticulous full-thickness, subperiosteal flap elevation is critical to protect it and the vascular supply.

Question 945

Topic: 8. Foot and Ankle

A 22-year-old football player presents with midfoot pain after an axial load on a plantarflexed foot. Weight-bearing radiographs demonstrate a 3 mm diastasis between the base of the first and second metatarsals. What is the most appropriate definitive management?

. Non-weight bearing in a short leg cast for 6 weeks
. Closed reduction and percutaneous pinning
. Open reduction and internal fixation (ORIF) or primary arthrodesis
. Custom orthotics and immediate weight-bearing
. Corticosteroid injection and physical therapy

Correct Answer & Explanation

. Open reduction and internal fixation (ORIF) or primary arthrodesis

Explanation

Displaced Lisfranc injuries (typically greater than 2 mm diastasis) require anatomic restoration for optimal outcomes. Operative management with ORIF or primary arthrodesis (especially for purely ligamentous injuries) is the standard of care.

Question 946

Topic: 8. Foot and Ankle

A 28-year-old male sustains an anterior knee dislocation during a tackle. The knee is reduced in the ER. His distal pulses are palpable, and the Ankle-Brachial Index (ABI) is 0.85. What is the most appropriate next step?

. Discharge with outpatient orthopedic follow-up
. Immediate surgical exploration of the popliteal artery
. CT angiography of the lower extremity
. Observation with serial clinical exams
. Apply a long leg cast and recheck in 1 week

Correct Answer & Explanation

. CT angiography of the lower extremity

Explanation

An ABI of less than 0.90 in the setting of a knee dislocation is highly suspicious for a vascular injury, even if pulses are palpable. A CT angiogram is indicated to evaluate the popliteal artery.

Question 947

Topic: 8. Foot and Ankle

A 26-year-old male sustains a pronation-external rotation (PER) ankle fracture. Intraoperative stress testing reveals syndesmotic widening. When placing a syndesmotic screw, in what position should the ankle be held, and why?

. Maximal plantarflexion, to ensure the narrowest part of the talus is in the mortise
. Neutral dorsiflexion, to accommodate the widest portion of the talar dome and prevent over-constriction
. Maximum inversion, to tighten the lateral ligaments
. Maximum eversion, to reduce the medial clear space
. Position does not matter as long as the clamp is tight

Correct Answer & Explanation

. Neutral dorsiflexion, to accommodate the widest portion of the talar dome and prevent over-constriction

Explanation

The talar dome is wider anteriorly. Placing the ankle in neutral or slight dorsiflexion during syndesmotic screw fixation ensures the widest part of the talus is within the mortise, minimizing the risk of over-constriction and loss of dorsiflexion.

Question 948

Topic: 8. Foot and Ankle

A 24-year-old male presents with a grossly deformed right knee after a football tackle. After emergent closed reduction in the trauma bay, his pedal pulses are palpable, but the Ankle-Brachial Index (ABI) is measured at 0.8. What is the most appropriate next step in management?

. Discharge with an immobilizer and outpatient MRI
. Immediate exploration of the popliteal artery by a vascular surgeon
. CT angiography of the lower extremity
. Observation and repeat ABI in 4 hours
. Application of a spanning external fixator

Correct Answer & Explanation

. CT angiography of the lower extremity

Explanation

An ABI less than 0.9 in the setting of a knee dislocation is highly suspicious for a vascular injury, specifically to the popliteal artery. CT angiography is the gold standard next step to accurately evaluate for intimal tears or arterial occlusion.

Question 949

Topic: 8. Foot and Ankle

A 21-year-old collegiate soccer player injures his midfoot while planting his cleated foot and twisting. Physical examination reveals plantar ecchymosis. Weight-bearing radiographs show 3 mm of widening between the medial cuneiform and the base of the second metatarsal. Which ligament is primarily injured in this scenario?

. Plantar calcaneonavicular ligament
. Dorsal tarsometatarsal ligament
. Interosseous ligament between the medial cuneiform and second metatarsal base
. Plantar fascia
. Cervical ligament

Correct Answer & Explanation

. Interosseous ligament between the medial cuneiform and second metatarsal base

Explanation

The Lisfranc ligament is an interosseous ligament that connects the medial cuneiform to the base of the second metatarsal. Plantar ecchymosis and diastasis greater than 2 mm at this interval are pathognomonic for a Lisfranc injury.

Question 950

Topic: 8. Foot and Ankle

A 38-year-old male undergoes open reduction and internal fixation of a displaced intra-articular calcaneus fracture via an extensile lateral approach. Postoperatively, he complains of numbness and tingling along the lateral aspect of his foot. Which nerve was most likely injured or compressed during the surgical exposure?

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

Correct Answer & Explanation

. Sural nerve

Explanation

The sural nerve runs along the lateral aspect of the hindfoot and is at high risk of iatrogenic injury during the extensile lateral approach to the calcaneus. Retraction or direct transection can cause sensory deficits along the lateral border of the foot.

Question 951

Topic: 8. Foot and Ankle
A 28-year-old male sustains a Hawkins Type III fracture of the talar neck. Which of the following provides the predominant blood supply to the talar body, placing it at highest risk for avascular necrosis when disrupted?
. Artery of the tarsal canal
. Artery of the tarsal sinus
. Deltoid artery branches
. Dorsalis pedis artery
. 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. Disruption of this primary supply, along with the dorsal vessels and deltoid branches, significantly increases the risk of avascular necrosis in displaced talar neck fractures.

Question 952

Topic: 8. Foot and Ankle
In a highly comminuted, displaced intra-articular calcaneus fracture (Sanders Type III), which anatomical fragment consistently remains aligned with the talus and serves as the foundation for surgical reconstruction?
. Anteromedial (sustentacular) fragment
. Posterolateral (tuberosity) fragment
. Anterolateral fragment
. Central posterior facet fragment
. Anterior process fragment

Correct Answer & Explanation

. Anteromedial (sustentacular) fragment

Explanation

The anteromedial fragment, containing the sustentaculum tali, is considered the 'constant' fragment in intra-articular calcaneus fractures. It maintains its anatomic relationship with the talus due to robust attachments from the talocalcaneal (interosseous) and deltoid ligaments.

Question 953

Topic: 8. Foot and Ankle

A 22-year-old collegiate football player sustains a purely ligamentous Lisfranc injury with lateral subluxation of the 2nd and 3rd metatarsals. According to recent literature, what is the most appropriate definitive surgical management to optimize functional outcome and reduce reoperation rates?

. Closed reduction and cast immobilization for 8 weeks
. Open reduction and internal fixation utilizing transarticular screws
. Primary arthrodesis of the first, second, and third tarsometatarsal joints
. Dorsal bridge plating without joint preparation
. Primary arthrodesis encompassing all five tarsometatarsal joints

Correct Answer & Explanation

. Primary arthrodesis of the first, second, and third tarsometatarsal joints

Explanation

Purely ligamentous Lisfranc injuries have high rates of hardware failure, loss of reduction, and post-traumatic arthritis when treated with traditional ORIF. Primary arthrodesis of the medial three rays provides superior long-term functional outcomes and significantly lower reoperation rates in these patients.

Question 954

Topic: 8. Foot and Ankle

A 35-year-old female presents to the trauma bay with a grossly unstable knee following a severe hyperextension injury. The limb is well-perfused, but an Ankle-Brachial Index (ABI) is measured at 0.8. What is the most appropriate next step in management?

. Immediate surgical exploration of the popliteal fossa
. Computed tomography angiography (CTA) of the lower extremity
. Close clinical observation with repeat ABI in 4 hours
. Duplex ultrasonography of the popliteal artery
. Application of a spanning external fixator before any further vascular workup

Correct Answer & Explanation

. Computed tomography angiography (CTA) of the lower extremity

Explanation

An ABI less than 0.9 following a knee dislocation indicates a high likelihood of arterial intimal injury or impending occlusion, mandating emergent CT angiography. Immediate surgical exploration is reserved for 'hard signs' of ischemia, such as absent pulses, expanding hematoma, or active pulsatile bleeding.

Question 955

Topic: 8. Foot and Ankle

During a percutaneous repair of an acute Achilles tendon rupture, the surgeon must be particularly cautious to avoid iatrogenic injury to the sural nerve. At what approximate distance proximal to the calcaneal insertion does the sural nerve cross the lateral border of the Achilles tendon?

. 2 to 4 cm
. 5 to 7 cm
. 9 to 12 cm
. 15 to 18 cm
. 20 to 22 cm

Correct Answer & Explanation

. 9 to 12 cm

Explanation

The sural nerve is at significant risk during percutaneous Achilles repairs. It consistently crosses from the midline of the calf to the lateral border of the Achilles tendon at a distance of approximately 9.8 to 12 cm proximal to the calcaneal insertion.

Question 956

Topic: 8. Foot and Ankle

A 37-year-old male has a confirmed L5/S1 paracentral disc prolapse causing left S1 radiculopathy. Using the provided dermatome and reflex/motor innervation charts, which combination of clinical findings is most consistent with a left S1 radiculopathy?

. A. Numbness over the anterior thigh, weakness in knee extension, and a diminished patellar reflex.
. B. Numbness over the lateral calf and dorsum of the foot, weakness in ankle dorsiflexion, and a diminished tibialis anterior reflex.
. C. Numbness over the posterior calf, heel, and lateral border of the foot, weakness in ankle plantarflexion, and a diminished Achilles reflex.
. D. Numbness over the medial calf and foot, weakness in hip adduction, and normal reflexes.
. E. Numbness over the perineum, bilateral leg weakness, and absent lower extremity reflexes.

Correct Answer & Explanation

. C. Numbness over the posterior calf, heel, and lateral border of the foot, weakness in ankle plantarflexion, and a diminished Achilles reflex.

Explanation

Correct Answer: CThe case explicitly states that for an S1 distribution, one would expect pain, paraesthesia, and numbness in the posterior calf, heel, and lateral border of the foot. The S1 nerve root is responsible for ankle plantarflexion (gastrocnemius/soleus) and the Achilles reflex. Therefore, numbness in this dermatomal pattern, weakness in plantarflexion, and a diminished Achilles reflex are the classic findings for an S1 radiculopathy. Options A, B, D, and E describe findings consistent with L3/L4, L5, L4/L5 (saphenous nerve distribution), and Cauda Equina Syndrome, respectively, which are not consistent with an isolated S1 radiculopathy.

Question 957

Topic: 8. Foot and Ankle
A 28-year-old male presents to the emergency department after a high-speed motorcycle collision with an obvious KD-III multiligament knee injury. Distal pulses are palpable but slightly diminished. An ankle-brachial index (ABI) is measured at 0.82. What is the next most appropriate step in management?
. Immediate surgical exploration of the popliteal artery
. Observation and repeat ABI in 4 hours
. CT angiography of the lower extremity
. Application of a knee-spanning external fixator before vascular studies
. Duplex ultrasound of the lower extremity venous system

Correct Answer & Explanation

. CT angiography of the lower extremity

Explanation

An ABI less than 0.90 in the setting of a knee dislocation is highly suspicious for a vascular injury. CT angiography is the diagnostic modality of choice to accurately identify and localize popliteal artery damage prior to surgical intervention.

Question 958

Topic: 8. Foot and Ankle

A 40-year-old male is brought to the trauma bay after a high-speed motorcycle collision. He has an obvious knee dislocation that is reduced in the ED. Post-reduction, his Ankle-Brachial Index (ABI) is 0.85, but pedal pulses are palpable. What is the most appropriate next step in management?

. Admit for serial vascular checks every 4 hours
. Perform a CT angiogram of the lower extremity
. Immediate surgical exploration of the popliteal artery
. Application of a bridging external fixator
. Perform a duplex ultrasound in the emergency department

Correct Answer & Explanation

. Perform a CT angiogram of the lower extremity

Explanation

An ABI < 0.9 after a knee dislocation is highly suspicious for a popliteal artery intimal tear or occlusion, even if pulses are palpable. A CT angiogram is urgently indicated to precisely evaluate the vascular integrity before proceeding with further management.

Question 959

Topic: 8. Foot and Ankle

A 28-year-old male sustains a knee dislocation during a high-speed motorcycle accident. It is reduced in the trauma bay. His pedal pulses are palpable, but the ankle-brachial index (ABI) is measured at 0.85. What is the most appropriate next step?

. Discharge with an immobilizer and close orthopedic follow-up
. Observation and repeat ABI in 24 hours
. Perform a CT angiogram of the lower extremity
. Immediate operative exploration by vascular surgery
. Duplex ultrasonography of the popliteal vein

Correct Answer & Explanation

. Perform a CT angiogram of the lower extremity

Explanation

After a knee dislocation, an ABI less than 0.90 is highly suspicious for a vascular injury (specifically to the popliteal artery), even if pulses are palpable. The next appropriate step is a CT angiogram to definitively evaluate the arterial integrity.

Question 960

Topic: 8. Foot and Ankle

A 30-year-old male presents to the trauma bay following a motorcycle collision. Examination reveals a grossly deformed right knee which is subsequently reduced. Palpable dorsalis pedis and posterior tibial pulses are present post-reduction. What is the most appropriate next step in management regarding his vascular status?

. Observation and serial clinical examinations
. Measure ankle-brachial indices (ABI)
. Immediate CT angiography (CTA)
. Immediate conventional catheter angiography
. Emergent surgical exploration of the popliteal artery

Correct Answer & Explanation

. Measure ankle-brachial indices (ABI)

Explanation

Following a knee dislocation, even with palpable pulses post-reduction, ABIs must be measured to rule out occult intimal injury to the popliteal artery. If the ABI is <0.9 or pulses are asymmetric, a CTA is indicated.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page