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8. Foot and Ankle MCQs

Practice Set 285 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 5681

Topic: 8. Foot and Ankle

The true Lisfranc ligament is a critical stabilizer of the midfoot. Which of the following describes its exact anatomical attachments?

. Plantar aspect of the medial cuneiform to the base of the second metatarsal
. Dorsal aspect of the medial cuneiform to the base of the first metatarsal
. Plantar aspect of the middle cuneiform to the base of the second metatarsal
. Interosseous extension from the lateral cuneiform to the third metatarsal base
. Plantar aspect of the navicular to the base of the second metatarsal

Correct Answer & Explanation

. Plantar aspect of the medial cuneiform to the base of the second metatarsal

Explanation

The true Lisfranc ligament is a strong interosseous ligament that connects the lateral surface of the medial cuneiform to the medial aspect of the base of the second metatarsal. It is the strongest and most important stabilizing structure of the tarsometatarsal joint complex. There is notably no direct ligamentous connection between the bases of the first and second metatarsals.

Question 5682

Topic: 8. Foot and Ankle

According to the Brodsky classification of diabetic Charcot neuroarthropathy, a Type 1 injury primarily involves which of the following anatomic joint complexes?

. Tarsometatarsal and naviculocuneiform joints
. Subtalar, talonavicular, and calcaneocuboid joints
. Tibiotalar joint
. Interphalangeal joints
. Metatarsophalangeal joints

Correct Answer & Explanation

. Tarsometatarsal and naviculocuneiform joints

Explanation

The Brodsky classification categorizes Charcot neuroarthropathy of the foot based on anatomic location. Type 1 involves the midfoot (tarsometatarsal and naviculocuneiform joints) and is the most common presentation (60%). Type 2 involves the hindfoot (subtalar, talonavicular, or calcaneocuboid joints). Type 3A involves the tibiotalar joint, and Type 3B involves the calcaneus (tuberosity fracture).

Question 5683

Topic: Midfoot & Hindfoot

A 25-year-old athlete sustains a purely ligamentous Lisfranc injury. Nonoperative management is unsuccessful, and surgical intervention is planned. Based on high-quality prospective literature comparing open reduction internal fixation (ORIF) to primary arthrodesis for purely ligamentous Lisfranc injuries, which of the following is true regarding primary arthrodesis?

. It yields clinically inferior functional outcome scores compared to ORIF.
. It results in a higher rate of hardware-related complications requiring removal.
. It is associated with a significantly lower rate of secondary surgical procedures.
. It preserves greater midfoot sagittal plane motion than ORIF.
. It is contraindicated in young, highly active patients.

Correct Answer & Explanation

. It yields clinically inferior functional outcome scores compared to ORIF.

Explanation

Prospective randomized trials (such as Ly and Coetzee, JBJS 2006) comparing ORIF to primary arthrodesis for primarily ligamentous Lisfranc injuries have shown that primary arthrodesis results in better or comparable short- and long-term functional outcomes and significantly lowers the rate of secondary surgeries (such as hardware removal or salvage fusion for post-traumatic arthritis).

Question 5684

Topic: 8. Foot and Ankle

The primary stabilizing ligament of the Lisfranc joint complex is crucial for maintaining the integrity of the midfoot. This ligament connects which two osseous structures?

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

Correct Answer & Explanation

. First metatarsal to the base of the second metatarsal

Explanation

The Lisfranc ligament is an intra-articular ligament that originates on the lateral aspect of the medial cuneiform and inserts onto the medial aspect of the base of the second metatarsal. There is no direct ligamentous connection between the bases of the first and second metatarsals, making the Lisfranc ligament essential for stability.

Question 5685

Topic: 8. Foot and Ankle
A 55-year-old poorly controlled diabetic patient presents with a swollen, warm, and erythematous left foot with a bounding pulse. Plain radiographs reveal severe osseous fragmentation, periarticular debris, and joint subluxation at the midfoot. According to the Eichenholtz classification for Charcot neuroarthropathy, what stage does this represent?
. Stage 0
. Stage I
. Stage II
. Stage III
. Stage IV

Correct Answer & Explanation

. Stage I

Explanation

Eichenholtz Stage I is the Development/Fragmentation phase, characterized clinically by acute swelling and erythema, and radiographically by bony fragmentation, joint subluxation/dislocation, and debris. Stage 0 shows soft tissue swelling with normal radiographs. Stage II is Coalescence (absorption of debris, early fusion). Stage III is Consolidation (remodeling).

Question 5686

Topic: Midfoot & Hindfoot
A 55-year-old poorly controlled diabetic patient presents with a swollen, warm, and erythematous left foot. Peripheral pulses are bounding. Radiographs show periarticular debris, subluxation of the tarsometatarsal joints, and active fragmentation of the bone without signs of coalescence. According to the Eichenholtz classification, what is the current stage of this patient's Charcot arthropathy and what is the primary treatment?
. Stage 0; Surgical arthrodesis
. Stage I; Total contact casting and strict non-weight bearing
. Stage II; Total contact casting and weight bearing as tolerated
. Stage III; Custom accommodative orthotic footwear
. Stage I; Intravenous antibiotics and surgical debridement

Correct Answer & Explanation

. Stage I; Total contact casting and strict non-weight bearing

Explanation

This patient is in Eichenholtz Stage I (Developmental/Fragmentation) of Charcot arthropathy, characterized clinically by the 'hot, swollen' foot and radiographically by bony fragmentation, joint dislocation, and debris. The standard of care during this active phase is strict offloading and immobilization, most effectively achieved with a total contact cast (TCC) to prevent further deformity until the active inflammatory process subsides.

Question 5687

Topic: 8. Foot and Ankle

A 22-year-old football player sustains a hyperplantarflexion injury to his midfoot. Radiographs show a small avulsion fracture fragment in the intercuneiform space (the 'fleck sign'). This bony fragment represents an avulsion of the Lisfranc ligament from its attachment on which of the following structures?

. Medial cuneiform
. Middle cuneiform
. Base of the second metatarsal
. Base of the first metatarsal
. Cuboid

Correct Answer & Explanation

. Medial cuneiform

Explanation

The Lisfranc ligament is an intraosseous ligament that runs from the lateral aspect of the medial cuneiform to the medial aspect of the base of the second metatarsal. The 'fleck sign' pathognomonic for a Lisfranc injury represents a bony avulsion of this ligament from the base of the second metatarsal.

Question 5688

Topic: Midfoot & Hindfoot

The spring ligament complex is a critical static stabilizer of the medial longitudinal arch of the foot. Which of its distinct anatomic fascicles is the strongest and provides the most significant structural support to the talar head?

. Plantar calcaneocuboid ligament
. Inferoplantar calcaneonavicular ligament
. Superomedial calcaneonavicular ligament
. Medioplantar calcaneonavicular ligament
. Dorsal talonavicular ligament

Correct Answer & Explanation

. Plantar calcaneocuboid ligament

Explanation

The spring ligament (plantar calcaneonavicular ligament) complex has three main distinct components: superomedial, inferoplantar, and medioplantar. The superomedial calcaneonavicular ligament is the thickest, widest, and most important fascicle. It provides the primary hammock-like support beneath the talar head and is commonly attenuated or ruptured in adult acquired flatfoot deformity (posterior tibial tendon dysfunction).

Question 5689

Topic: 8. Foot and Ankle
A 32-year-old male sustains a high-energy motor vehicle accident resulting in a displaced fracture of the talar neck with associated dislocation of the subtalar, ankle, and talonavicular joints. According to the Hawkins classification, what is the risk of developing avascular necrosis (AVN) of the talar body in this specific injury pattern?
. Less than 10%
. 20 to 50%
. 50 to 75%
. Greater than 90%
. AVN is anatomically impossible in this pattern

Correct Answer & Explanation

. Greater than 90%

Explanation

This injury is a Hawkins Type III talar neck fracture (fracture with dislocation of the subtalar, tibiotalar/ankle, and talonavicular joints). Because all three primary sources of blood supply to the talar body (artery of the tarsal canal, branches from the dorsalis pedis, and branches from the peroneal artery via the sinus tarsi) are disrupted, the risk of avascular necrosis (AVN) of the talar body is extremely high, nearly always exceeding 90% in large series.

Question 5690

Topic: Midfoot & Hindfoot
A 25-year-old male sustains a Hawkins type III talar neck fracture following an aviation accident. Which of the following accurately describes the displacement and the associated risk of avascular necrosis (AVN) for this specific injury pattern?
. Undisplaced fracture; 0-10% AVN risk
. Subtalar subluxation/dislocation; 20-50% AVN risk
. Subtalar dislocation; 70-90% AVN risk
. Subtalar, tibiotalar, and talonavicular dislocation; close to 100% AVN risk
. Subtalar and tibiotalar dislocation; close to 100% AVN risk

Correct Answer & Explanation

. Subtalar and tibiotalar dislocation; close to 100% AVN risk

Explanation

Hawkins classification for talar neck fractures determines the risk of AVN. Type I: Undisplaced (0-15% AVN risk). Type II: Associated with subtalar subluxation/dislocation (20-50% AVN risk). Type III: Subtalar and tibiotalar dislocation (approaching 90-100% AVN risk). Type IV (Canale addition): Subtalar, tibiotalar, and talonavicular dislocation (~100% AVN risk).

Question 5691

Topic: 8. Foot and Ankle

A 40-year-old obese male presents to the Emergency Room after sustaining a low-velocity knee dislocation while playing basketball. The knee is currently reduced, and physical examination reveals a symmetric, palpable dorsalis pedis pulse. An ankle-brachial index (ABI) is performed, yielding a value of 0.85. What is the most appropriate next step in management?

. Discharge with a knee immobilizer
. Serial clinical examinations only
. Immediate surgical exploration of the popliteal artery
. Duplex ultrasonography
. CT angiogram of the lower extremity

Correct Answer & Explanation

. Discharge with a knee immobilizer

Explanation

In the setting of a knee dislocation, an ABI < 0.9 is highly suspicious for a significant arterial injury (specifically the popliteal artery). Even with palpable pulses, this finding is an absolute indication for an advanced vascular imaging study, most commonly a CT angiogram, to rule out intimal tears or occult vascular compromise.

Question 5692

Topic: 8. Foot and Ankle

A 42-year-old male requires open reduction and internal fixation of a highly displaced intra-articular calcaneus fracture via an extensile lateral approach. Which of the following neurological structures is most at risk during the creation of the full-thickness subperiosteal flap?

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

Correct Answer & Explanation

. Superficial peroneal nerve

Explanation

The extensile lateral approach to the calcaneus involves an L-shaped incision, requiring the careful creation of a full-thickness subperiosteal flap. The sural nerve crosses the lateral aspect of the hindfoot and is the primary structure at risk when making the vertical and horizontal limbs of the incision and elevating the soft tissue flap.

Question 5693

Topic: 8. Foot and Ankle

A 24-year-old football player presents with midfoot pain after an axial load force was applied to his plantar-flexed foot. Weight-bearing radiographs demonstrate a 3 mm diastasis between the base of the first and second metatarsals. What is the primary stabilizing structure disrupted in this classic Lisfranc injury?

. Dorsal Lisfranc ligament
. Plantar ligament between the first and second metatarsal bases
. Spring ligament
. Plantar interosseous ligament between the medial cuneiform and second metatarsal base
. Dorsal ligament between the navicular and medial cuneiform

Correct Answer & Explanation

. Dorsal Lisfranc ligament

Explanation

The Lisfranc ligament is an essential interosseous ligament that connects the lateral aspect of the medial cuneiform to the medial base of the second metatarsal. It is the critical stabilizer of the midfoot complex. There is no direct transverse ligamentous connection between the bases of the first and second metatarsals.

Question 5694

Topic: 8. Foot and Ankle

A 28-year-old male sustains an ankle fracture with a concomitant syndesmotic disruption. During operative fixation, a syndesmotic screw is planned. Which radiographic parameter on a perfect mortise view is considered the most reliable metric to intraoperatively assess the anatomic integrity of the syndesmosis?

. Tibiofibular clear space < 6 mm
. Tibiofibular overlap > 1 mm
. Talar tilt angle < 2 degrees
. Medial clear space > 4 mm
. Bohler's angle > 20 degrees

Correct Answer & Explanation

. Tibiofibular clear space < 6 mm

Explanation

On an AP or mortise radiograph, the tibiofibular clear space is measured 1 cm proximal to the plafond. A distance of < 6 mm is considered normal and is the most reliable radiographic parameter for evaluating syndesmotic integrity, as it does not vary significantly with foot rotation, unlike the tibiofibular overlap.

Question 5695

Topic: Midfoot & Hindfoot
A 28-year-old male sustains a displaced talar neck fracture with subluxation of the subtalar joint, while the tibiotalar and talonavicular joints remain congruous. According to the Hawkins classification, what is the type and approximate historical risk of avascular necrosis (AVN)?
. Hawkins I, 0-10%
. Hawkins II, 80-100%
. Hawkins III, 80-100%
. Hawkins IV, 100%
. Hawkins II, 20-50%

Correct Answer & Explanation

. Hawkins II, 20-50%

Explanation

Hawkins type II is defined as a talar neck fracture with subluxation or dislocation of the subtalar joint, while the tibiotalar and talonavicular joints remain intact. The risk of AVN is historically reported as 20-50%. Hawkins I: undisplaced (0-10%). Hawkins III: subtalar and tibiotalar dislocation (approaching 100%).

Question 5696

Topic: 8. Foot and Ankle

A 24-year-old athlete sustains a hyperplantarflexion injury to the midfoot. Radiographs demonstrate subtle widening between the 1st and 2nd metatarsal bases and a "fleck sign."

The "fleck sign" typically represents an avulsion of the Lisfranc ligament from which structure?

. Base of the 1st metatarsal
. Medial cuneiform
. Base of the 2nd metatarsal
. Middle cuneiform
. Navicular

Correct Answer & Explanation

. Base of the 1st metatarsal

Explanation

The Lisfranc ligament connects the medial cuneiform to the base of the second metatarsal. The "fleck sign" represents a bony avulsion of this ligament, most commonly from its attachment on the base of the second metatarsal, indicating significant midfoot instability.

Question 5697

Topic: 8. Foot and Ankle

Which ligament is considered the strongest and most critical for maintaining the structural stability of the Lisfranc complex?

. Dorsal tarsometatarsal ligament
. Plantar tarsometatarsal ligament
. Interosseous ligament between the medial cuneiform and second metatarsal base
. Spring ligament
. Bifurcate ligament

Correct Answer & Explanation

. Dorsal tarsometatarsal ligament

Explanation

The interosseous ligament, commonly known as the Lisfranc ligament, connects the medial cuneiform to the base of the second metatarsal. It is the thickest and strongest ligament stabilizing the complex, whereas the dorsal ligaments are the weakest.

Question 5698

Topic: 8. Foot and Ankle

When utilizing an extensile lateral approach for a displaced intra-articular calcaneus fracture, the surgical flap relies primarily on which of the following vessels for its blood supply?

. Medial plantar artery
. Lateral plantar artery
. Lateral calcaneal artery
. Sural artery
. Dorsalis pedis artery

Correct Answer & Explanation

. Medial plantar artery

Explanation

The full-thickness fasciocutaneous flap in the extensile lateral approach to the calcaneus is primarily supplied by the lateral calcaneal artery, a branch of the peroneal artery. Careful "no-touch" retraction is vital to protect this vessel and the sural nerve.

Question 5699

Topic: 8. Foot and Ankle

A 25-year-old male sustains a traumatic knee dislocation. Following closed reduction, the patient has palpable pedal pulses but an Ankle-Brachial Index (ABI) of 0.8. What is the most appropriate next step in management?

. Discharge with close outpatient follow-up
. Immediate open vascular exploration in the operating room
. CT angiography of the lower extremity
. Magnetic resonance angiography (MRA)
. Serial clinical examinations every 4 hours

Correct Answer & Explanation

. Discharge with close outpatient follow-up

Explanation

In a patient with a knee dislocation, an ABI less than 0.9 or asymmetric pulses indicates a high index of suspicion for popliteal artery intimal injury. CT angiography is the standard non-invasive imaging modality required to definitively evaluate the vascular tree.

Question 5700

Topic: 8. Foot and Ankle

In a patient with a suspected syndesmotic injury following an ankle fracture, intraoperative fluoroscopy is used to perform a "Cotton test." Which maneuver accurately describes this test?

. External rotation of the foot with the tibia stabilized
. Lateral traction applied to the fibula using a bone hook
. Anterior translation of the talus within the mortise
. Dorsiflexion of the ankle combined with medial pressure on the fibula
. Plantarflexion and forced inversion of the hindfoot

Correct Answer & Explanation

. External rotation of the foot with the tibia stabilized

Explanation

The Cotton test is performed intraoperatively by applying lateral traction to the fibula with a bone hook or clamp under fluoroscopy. Asymmetric widening of the tibiofibular clear space confirms syndesmotic instability requiring fixation.

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