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8. Foot and Ankle MCQs

Practice Set 6 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 101

Topic: 8. Foot and Ankle
A 32-year-old runner suffers a spontaneous Achilles tendon rupture after a recent course of ciprofloxacin. What is the cellular mechanism by which fluoroquinolones increase the risk of tendon rupture?
. Decreased matrix metalloproteinase (MMP) expression
. Inhibition of tenocyte proliferation and upregulation of MMPs
. Hyperproliferation of type III collagen
. Direct inhibition of vitamin C-dependent hydroxylation
. Induction of massive macrophage infiltration

Correct Answer & Explanation

. Inhibition of tenocyte proliferation and upregulation of MMPs

Explanation

Fluoroquinolones cause direct toxicity to tenocytes, leading to decreased cell proliferation and increased expression of matrix metalloproteinases (MMPs). This degrades the extracellular matrix, compromising tendon strength.

Question 102

Topic: 8. Foot and Ankle

A professional football player sustains an external rotation injury to his right ankle. The squeeze test is highly positive. Which syndesmotic ligament is typically the first to tear in this injury pattern?

. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Interosseous ligament
. Transverse tibiofibular ligament
. Deltoid ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

In a syndesmotic (high) ankle sprain, the external rotation force sequentially damages the stabilizing structures. The anterior inferior tibiofibular ligament (AITFL) is typically the first structure to fail, followed by the interosseous membrane and then the PITFL.

Question 103

Topic: 8. Foot and Ankle

An 18-year-old soccer player sustains an inversion ankle injury. Clinical examination shows a positive squeeze test and positive external rotation stress test. Which of the following syndesmotic ligaments is typically the first to tear in a high ankle sprain?

. Posterior inferior tibiofibular ligament (PITFL)
. Interosseous ligament
. Anterior inferior tibiofibular ligament (AITFL)
. Deltoid ligament
. Transverse tibiofibular ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

In syndesmotic (high ankle) sprains, external rotation forces typically cause progressive injury from anterior to posterior. The anterior inferior tibiofibular ligament (AITFL) is the first and most commonly injured structure.

Question 104

Topic: 8. Foot and Ankle

A 21-year-old dancer suffers an acute inversion ankle sprain while "en pointe" (maximally plantarflexed). Which ligament serves as the primary restraint to inversion in this foot position and is most likely to be injured?

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

Correct Answer & Explanation

. Anterior talofibular ligament

Explanation

The anterior talofibular ligament (ATFL) is the primary restraint to inversion when the ankle is plantarflexed. The calcaneofibular ligament (CFL) becomes the primary restraint to inversion when the ankle is dorsiflexed.

Question 105

Topic: 8. Foot and Ankle

The spring ligament (plantar calcaneonavicular ligament) primarily supports the head of the talus. Which of the following tendons provides dynamic support directly inferior to this ligament?

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

Correct Answer & Explanation

. Tibialis posterior

Explanation

The tibialis posterior tendon courses directly inferior and medial to the spring ligament. It provides crucial dynamic support to the medial longitudinal arch and the talar head.

Question 106

Topic: 8. Foot and Ankle

Which ligament acts as the primary restraint to anterior translation of the talus within the ankle mortise when the foot is positioned in plantar flexion?

. Calcaneofibular ligament
. Posterior talofibular ligament
. Anterior talofibular ligament
. Deltoid ligament
. Cervical ligament

Correct Answer & Explanation

. Calcaneofibular ligament

Explanation

The anterior talofibular ligament (ATFL) is tightest in plantar flexion, making it the primary restraint to anterior translation of the talus. Due to this biomechanical role, it is the most commonly injured ligament in lateral ankle sprains.

Question 107

Topic: 8. Foot and Ankle

The Achilles tendon is most susceptible to rupture in its distinct hypovascular "watershed" zone. This region is typically located what distance proximal to its insertion on the calcaneal tuberosity?

. 0 to 2 cm
. 2 to 6 cm
. 6 to 10 cm
. 10 to 14 cm
. At the musculotendinous junction

Correct Answer & Explanation

. 2 to 6 cm

Explanation

The Achilles tendon has a relative hypovascular watershed zone located approximately 2 to 6 cm proximal to its calcaneal insertion. Due to diminished blood supply, this specific region is the most common site for degenerative tendinosis and acute ruptures.

Question 108

Topic: 8. Foot and Ankle

A 28-year-old male is brought to the trauma bay after a severe knee hyperextension injury. The knee is grossly unstable in multiple planes. Ankle-brachial index (ABI) is measured at 0.85. What is the most appropriate next step in management?

. Immediate surgical exploration
. CT angiography of the lower extremity
. Application of a hinged knee brace
. Duplex ultrasonography
. Serial ABI measurements every 4 hours

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. CT angiography is the standard of care to accurately localize and define the arterial injury before surgical intervention.

Question 109

Topic: 8. Foot and Ankle

A patient is evaluated in the emergency department after a high-velocity knee dislocation. After reduction, distal pulses are palpable but the ankle-brachial index (ABI) is measured at 0.85. According to current guidelines, what is the most appropriate next step in management?

. Immediate operative exploration of the popliteal artery
. Observation and serial physical examinations every 4 hours
. Discharge with a hinged knee brace locked in extension
. CT angiography of the lower extremity
. Application of a bridging external fixator

Correct Answer & Explanation

. CT angiography of the lower extremity

Explanation

In the setting of a knee dislocation, an Ankle-Brachial Index (ABI) of less than 0.9 is highly predictive of a clinically significant vascular injury and is a strict indication to proceed with CT angiography or standard angiography.

Question 110

Topic: 8. Foot and Ankle

A 28-year-old male presents to the emergency department following a high-energy multiligament knee injury. The knee is reduced, but the Ankle-Brachial Index (ABI) is measured at 0.85. There are no hard signs of vascular injury. What is the most appropriate next step in management?

. Immediate surgical exploration of the popliteal artery
. CT angiography of the lower extremity
. Close observation and repeat ABI in 4 hours
. MR angiography of the lower extremity
. Duplex ultrasound in the outpatient setting

Correct Answer & Explanation

. CT angiography of the lower extremity

Explanation

In the setting of a knee dislocation, an ABI less than 0.9 or asymmetric pulses (without hard signs of ischemia) warrants advanced imaging, most commonly CT angiography, to rule out a popliteal artery injury.

Question 111

Topic: 8. Foot and Ankle
A 28-year-old male sustains a KD-III multi-ligament knee injury. Following closed reduction, the limb is well-perfused, but the Ankle-Brachial Index (ABI) is measured at 0.8. What is the most appropriate next step in management?
. Observation and repeat ABI in 4 hours
. CT angiography of the lower extremity
. Immediate surgical exploration of the popliteal artery
. Application of a hinged knee brace and discharge
. Duplex ultrasound of the lower extremity

Correct Answer & Explanation

. CT angiography of the lower extremity

Explanation

An ABI less than 0.9 in a knee dislocation with a well-perfused limb warrants a CT angiogram to rule out a clinically significant intimal tear or vascular injury. Immediate surgical exploration is reserved for hard signs of vascular compromise.

Question 112

Topic: 8. Foot and Ankle

A 30-year-old male sustains a high-energy knee dislocation. Following reduction, his limb is neurovascularly intact with an Ankle-Brachial Index (ABI) of 1.1. What is the most appropriate vascular management?

. Immediate vascular surgery consultation
. Routine CT angiography
. Serial neurovascular checks for 24-48 hours
. Discharge with outpatient follow-up
. MR angiography

Correct Answer & Explanation

. Serial neurovascular checks for 24-48 hours

Explanation

In the setting of a reduced knee dislocation with normal pulses and an ABI > 0.9, the risk of a flow-limiting vascular injury is extremely low. Standard of care is admission for serial neurovascular observation for 24 to 48 hours.

Question 113

Topic: 8. Foot and Ankle

A 38-year-old man develops acute right-sided leg pain radiating down the posterior thigh and calf to the lateral border of his foot. He has a diminished Achilles tendon reflex and weakness in ankle plantar flexion. Which nerve root is most likely compressed?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. S1

Explanation

Compression of the S1 nerve root classically presents with pain radiating to the lateral foot, weakness in ankle plantar flexion, and a diminished or absent Achilles reflex.

Question 114

Topic: 8. Foot and Ankle

When pelvic retroversion is exhausted in a patient with severe positive sagittal malalignment, what is the next typical compensatory mechanism involving the lower extremities?

. Hip extension and knee extension
. Hip flexion and knee extension
. Hip extension and knee flexion
. Hip flexion and knee flexion
. Ankle dorsiflexion and hip extension

Correct Answer & Explanation

. Hip extension and knee flexion

Explanation

When the pelvis can no longer retrovert to compensate for an anterior sagittal shift, the patient will typically resort to hip extension and knee flexion. This crouching stance helps physically shift the center of gravity posteriorly over the feet.

Question 115

Topic: 8. Foot and Ankle

A 68-year-old female undergoes a T10 to pelvis fusion. Postoperatively, she develops a 'flatback deformity'. Which of the following consequences is most likely a direct result of this specific iatrogenic deformity?

. Cervical hyperlordosis
. Knee extension contracture
. Anterior shift of the center of gravity and increased paraspinal muscle fatigue
. Decreased pelvic retroversion
. Ankle plantarflexion compensation

Correct Answer & Explanation

. Anterior shift of the center of gravity and increased paraspinal muscle fatigue

Explanation

Flatback syndrome results from a loss of normal lumbar lordosis, causing an anterior shift in the center of gravity (positive SVA). Patients experience severe paraspinal muscle fatigue and pain as they constantly recruit these muscles to maintain an upright posture.

Question 116

Topic: 8. Foot and Ankle

A 45-year-old man presents with right leg pain radiating to the lateral aspect of his foot. Physical examination reveals a diminished ankle jerk reflex and 3/5 weakness in ankle plantar flexion. Sensation is decreased over the lateral border of the foot. Which nerve root is most likely affected?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. S1

Explanation

The S1 nerve root controls ankle plantar flexion, provides sensation to the lateral aspect of the foot, and mediates the Achilles reflex. This is most commonly compressed by a posterolateral L5-S1 disc herniation.

Question 117

Topic: 8. Foot and Ankle

The type of disk herniation shown (Slide) at the L5-S1 level is most likely to cause:

. Quadriceps weakness and numbness of the medial thigh
. Diminished sensation to the anteromedial calf
. Weakness of the tibialis anterior
. Weakness of the gastrocsoleus complex
. Extensor hallucis longus weakness

Correct Answer & Explanation

. Weakness of the gastrocsoleus complex

Explanation

This slide shows a posterolateral disk herniation on the right. Posterolateral disk herniations cause compression of the traversing S1 nerve root at this level. Sensation affected is the posterior calf and lateral border of the foot, while motor innervation is to the gastroc soleus complex. With far lateral disk herniations, the exiting nerve root is compressed and symptoms may be seen referred to the level above.

Question 118

Topic: 8. Foot and Ankle

A patient with radicular pain is experiencing skin numbness on the medial aspect of his leg and great toe. Which of the following nerve roots is effected:

. L2
. L3
. L4
. L5
. S1

Correct Answer & Explanation

. L4

Explanation

When examining patients, it is important to remember the sensory dermatomes. The medial aspect of the leg, foot, and great toe are supplied by the L4 lumbosacral nerve root. The tibial crest separates the L4 and L5 dermatomes on the leg. L4 Medial aspect of leg, foot, and great toe L5 Lateral aspect of the leg and toes 2 through 4 S1 Lateral aspect of the fifth toe

Question 119

Topic: 8. Foot and Ankle

Testing of the L5 lumbosacral nerve root in a patient who has radicular back pain can be accomplished through which of the following reflexes or tests:

. Patellar tendon reflex
. Achilles tendon reflex
. Tibialis posterior reflex
. Superficial anal reflex
. Beevor sign

Correct Answer & Explanation

. Tibialis posterior reflex

Explanation

Although there is not a well-defined reflex arc for the L5 lumbosacral nerve root, the tibialis posterior reflex can be elicited. The tibialis posterior reflex is mediated through the L5 lumbosacral nerve root. Reflexes and associated nerve roots include: Patellar tendon --- L4 Achilles tendon --- S1 Superficial anal reflex --- S2, S3, S4 Beevor sign refers to asymmetry of the segmental innervation of the rectus abdominus muscles and when performing a situp, there is unilateral segmental nerve root loss.

Question 120

Topic: 8. Foot and Ankle

A patient with radicular pain is experiencing skin numbness on the lateral aspect of the leg and the dorsum of the foot between the second and fourth toes. Which of the following nerve roots is being compressed:

. L1
. L2
. L3
. L4
. L5

Correct Answer & Explanation

. L5

Explanation

The L5 dermatome covers the skin on the lateral leg and dorsum of the foot from the lateral border of the great toe to the medial border of the little toe. L4 Medial aspect of leg, foot, and great toe L5 Lateral aspect of the leg and toes 2 through 4 S1 Lateral aspect of the fifth toe

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