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8. Foot and Ankle MCQs

Practice Set 151 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 3001

Topic: 8. Foot and Ankle

The "screw-home mechanism" of the knee joint is a critical passive locking mechanism that occurs during the terminal degrees of knee extension. Which of the following best describes the motion of the tibia relative to the femur during this mechanism in an open kinematic chain (e.g., leg extension exercise)?

. Internal rotation
. Anterior translation
. External rotation
. Posterior translation
. Valgus rotation

Correct Answer & Explanation

. External rotation

Explanation

The screw-home mechanism is a non-voluntary rotation that occurs during the terminal phase of knee extension, contributing to knee stability in full extension. In an open kinematic chain (e.g., when the foot is free to move, as in a leg extension exercise), the tibia externally rotates approximately 10-15 degrees on the femur during the final 15-20 degrees of extension. In a closed kinematic chain (e.g., standing up), the femur internally rotates on the tibia. This "locking" action uses the tension in the cruciate ligaments and the shape of the femoral condyles to create a stable, energy-efficient position for standing.

Question 3002

Topic: 8. Foot and Ankle
Following an Achilles tendon repair, the tendon undergoes distinct phases of healing. At approximately which postoperative time frame is the repairing tendon typically at its mechanically weakest point, characterized by active remodeling and predominantly type III collagen?
. 1 to 3 days
. 7 to 10 days
. 3 to 4 weeks
. 6 to 8 weeks
. 12 to 16 weeks

Correct Answer & Explanation

. 7 to 10 days

Explanation

A healing tendon is typically weakest around 7 to 14 days post-injury during the transition from the inflammatory to the early proliferative phase. At this time, collagen degradation outpaces the synthesis of new, disorganized type III collagen.

Question 3003

Topic: 8. Foot and Ankle

A 55-year-old diabetic patient presents with a swollen, erythematous, and painless foot. Radiographs show periarticular debris and fragmentation of the midfoot. What is the most appropriate initial management?

. Intravenous antibiotics
. Total contact casting
. Surgical arthrodesis of the midfoot
. Ankle-foot orthosis
. Below-knee amputation

Correct Answer & Explanation

. Total contact casting

Explanation

In the acute inflammatory phase of Charcot arthropathy (Eichenholtz stage I), immediate immobilization and offloading are critical to prevent further structural collapse. A Total Contact Cast (TCC) is the gold standard initial treatment.

Question 3004

Topic: Midfoot & Hindfoot

A 55-year-old diabetic patient presents with a swollen, erythematous, and warm foot. There are no systemic signs of infection and no skin ulcerations. Radiographs show periarticular debris, fragmentation, and subluxation at the tarsometatarsal joints. What is the most appropriate initial management?

. Intravenous antibiotics and surgical debridement
. Open reduction and internal fixation of the midfoot
. Total contact casting and non-weight bearing
. Primary arthrodesis of the affected joints
. Below-knee amputation

Correct Answer & Explanation

. Total contact casting and non-weight bearing

Explanation

The patient has acute Eichenholtz Stage 1 (developmental/fragmentation phase) Charcot arthropathy. The gold standard for initial treatment is immobilization and offloading using a total contact cast to halt progressive deformity.

Question 3005

Topic: 8. Foot and Ankle

During a surgical debridement for insertional Achilles tendinopathy and excision of a prominent Haglund's deformity, it is necessary to detach a portion of the Achilles tendon. What is the generally accepted maximum percentage of the tendon insertion that can be detached before a formal tendon augmentation (e.g., FHL transfer) is strictly required?

. 10%
. 25%
. 50%
. 75%
. 90%

Correct Answer & Explanation

. 50%

Explanation

Biomechanical and clinical studies demonstrate that up to 50% of the Achilles tendon insertion can be detached and resected without critically compromising its strength. Resections exceeding 50% generally mandate reconstruction, often utilizing a flexor hallucis longus (FHL) transfer.

Question 3006

Topic: 8. Foot and Ankle

A 55-year-old diabetic male presents with a swollen, erythematous, and warm left foot. Radiographs reveal fragmentation and subluxation of the tarsometatarsal joints. His pedal pulses are bounding. What is the most appropriate initial management?

. Immediate open reduction and internal fixation
. Total contact casting and strict non-weight-bearing
. Intravenous antibiotics and surgical debridement
. Below-knee amputation
. Primary arthrodesis of the midfoot joints

Correct Answer & Explanation

. Total contact casting and strict non-weight-bearing

Explanation

This patient is in the acute inflammatory (Eichenholtz stage I) phase of Charcot neuroarthropathy. The gold standard for initial management is strict immobilization and offloading, typically achieved with a total contact cast, to halt progression and prevent further deformity.

Question 3007

Topic: Midfoot & Hindfoot

A 55-year-old diabetic male presents with a swollen, warm, and erythematous left foot. Radiographs reveal fragmentation of the tarsometatarsal joints, subchondral cysts, and periarticular debris. He is diagnosed with acute Charcot arthropathy (Eichenholtz Stage 1). What is the gold standard initial treatment?

. Urgent surgical arthrodesis of the midfoot
. Total contact casting and non-weight bearing
. Intravenous antibiotics for presumed osteomyelitis
. Custom orthotic shoe wear
. Corticosteroid injection into the affected joints

Correct Answer & Explanation

. Total contact casting and non-weight bearing

Explanation

The gold standard initial management for acute phase (Eichenholtz Stage 1) Charcot arthropathy is strict immobilization and offloading using a total contact cast. Surgical intervention during the acute, inflammatory phase is associated with high failure and complication rates.

Question 3008

Topic: 8. Foot and Ankle

In the surgical harvest of the Flexor Hallucis Longus (FHL) tendon for an Achilles tendon reconstruction, the dissection often proceeds to the 'Master Knot of Henry' in the midfoot to gain extra length. At this anatomical landmark, what is the relationship of the FHL tendon to the Flexor Digitorum Longus (FDL) tendon?

. FHL crosses plantar (superficial) to the FDL
. FHL crosses dorsal (deep) to the FDL
. FHL runs strictly medial and parallel to the FDL without crossing
. FHL runs strictly lateral and parallel to the FDL without crossing
. FHL merges completely with the FDL to form a common tendon

Correct Answer & Explanation

. FHL crosses dorsal (deep) to the FDL

Explanation

The Master Knot of Henry is a decussation point located in the plantar midfoot just posterior to the navicular tuberosity. At this location, the Flexor Hallucis Longus (FHL) tendon crosses dorsal (deep) to the Flexor Digitorum Longus (FDL) tendon as it courses from lateral (fibula origin) to medial (great toe insertion). Understanding this relationship is crucial when harvesting the FHL to maximize length without injuring the medial plantar nerve, which lies adjacent.

Question 3009

Topic: 8. Foot and Ankle

The Lisfranc ligament complex is critical for midfoot stability. Which of the following accurately describes the attachments of the primary (strongest) component of the Lisfranc ligament?

. Dorsal surface of the medial cuneiform to the dorsal base of the 2nd metatarsal
. Plantar-lateral aspect of the medial cuneiform to the plantar-medial base of the 2nd metatarsal
. Plantar aspect of the middle cuneiform to the base of the 2nd metatarsal
. Plantar aspect of the lateral cuneiform to the base of the 3rd metatarsal
. Medial cuneiform to the base of the 1st metatarsal

Correct Answer & Explanation

. Plantar-lateral aspect of the medial cuneiform to the plantar-medial base of the 2nd metatarsal

Explanation

The Lisfranc ligament complex consists of dorsal, interosseous, and plantar ligaments. The plantar (and interosseous) components are the thickest and strongest. The classic 'Lisfranc ligament' refers specifically to the strong interosseous/plantar band connecting the plantar-lateral aspect of the medial cuneiform to the plantar-medial aspect of the base of the second metatarsal. Notably, there is no intermetatarsal ligament connecting the bases of the 1st and 2nd metatarsals, making this articulation entirely dependent on the Lisfranc ligament.

Question 3010

Topic: 8. Foot and Ankle

The spring ligament (plantar calcaneonavicular ligament) is a primary static stabilizer of the medial longitudinal arch of the foot. It spans from the sustentaculum tali to the navicular. Which of the following tendons provides the most significant dynamic support to this ligament and the medial arch?

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

Correct Answer & Explanation

. Tibialis posterior

Explanation

The tibialis posterior tendon is the primary dynamic stabilizer of the medial longitudinal arch. Its dysfunction (Posterior Tibial Tendon Dysfunction) leads to increased stress and subsequent failure of the static stabilizers, particularly the spring ligament, resulting in adult acquired flatfoot deformity.

Question 3011

Topic: 8. Foot and Ankle

A 55-year-old male with long-standing, poorly controlled type 2 diabetes presents with a swollen, erythematous, and warm right foot without open ulceration. Radiographs demonstrate periarticular fragmentation, subluxation, and debris at the tarsometatarsal joints. According to the Eichenholtz classification, what stage of Charcot arthropathy does this represent, and what is the standard initial treatment?

. Stage 0; treated with broad-spectrum intravenous antibiotics
. Stage 1; treated with a total contact cast and non-weight bearing
. Stage 2; treated with an ankle-foot orthosis (AFO) and weight bearing as tolerated
. Stage 3; treated with primary arthrodesis of the midfoot
. Stage 1; treated with immediate surgical debridement and external fixation

Correct Answer & Explanation

. Stage 1; treated with a total contact cast and non-weight bearing

Explanation

Eichenholtz Stage 1 is the developmental/fragmentation phase, characterized clinically by a red, hot, swollen foot and radiographically by bony fragmentation, joint dislocation, and debris. The cornerstone of treatment in Stage 1 Charcot arthropathy is immobilization and offloading, typically using a total contact cast (TCC) to prevent further deformity until the acute inflammatory phase resolves (Stage 2: coalescence).

Question 3012

Topic: 8. Foot and Ankle

A 55-year-old patient with poorly controlled diabetes mellitus presents with a red, hot, swollen right foot. Radiographs demonstrate periarticular debris, fragmentation of the tarsal bones, and early joint subluxation. According to the Eichenholtz classification of Charcot arthropathy, what stage does this represent?

. Stage 0 (prodromal)
. Stage 1 (developmental/fragmentation)
. Stage 2 (coalescence)
. Stage 3 (reconstruction/consolidation)
. Stage 4 (ankylosis)

Correct Answer & Explanation

. Stage 1 (developmental/fragmentation)

Explanation

Eichenholtz Stage 1 (developmental/fragmentation stage) is characterized clinically by a red, hot, swollen foot and radiographically by bone fragmentation, periarticular debris, and joint subluxation/dislocation. Stage 2 (coalescence) shows absorption of fine debris and early fusion. Stage 3 (consolidation) shows remodeling and rounding of bone ends.

Question 3013

Topic: 8. Foot and Ankle

A 25-year-old rugby player sustains a purely ligamentous Lisfranc injury with 3 mm of diastasis between the medial and middle cuneiforms and bases of the 1st and 2nd metatarsals. Based on recent prospective randomized controlled trials, how does primary arthrodesis compare to open reduction and internal fixation (ORIF) for this specific injury pattern?

. ORIF provides superior functional outcomes at 2 years.
. Primary arthrodesis has a higher rate of hardware-related complications.
. Primary arthrodesis results in fewer unplanned secondary surgeries.
. ORIF is associated with a lower rate of post-traumatic osteoarthritis.
. There is no difference in the rate of secondary surgeries between the two groups.

Correct Answer & Explanation

. Primary arthrodesis results in fewer unplanned secondary surgeries.

Explanation

For purely ligamentous Lisfranc injuries, studies (such as the landmark trial by Ly and Coetzee) have demonstrated that primary arthrodesis of the medial columns leads to better short- to medium-term functional outcomes and significantly fewer unplanned secondary surgeries compared to ORIF. ORIF is associated with a high rate of hardware removal and subsequent progressive post-traumatic arthritis requiring salvage arthrodesis.

Question 3014

Topic: 8. Foot and Ankle

A 30-year-old construction worker drops a heavy steel beam on the midfoot. Non-weight-bearing radiographs are initially read as normal, but weight-bearing films demonstrate a 3 mm diastasis between the base of the first and second metatarsals. An MRI confirms a complete rupture of the Lisfranc ligament. Which of the following correctly describes the anatomical attachments of the primary Lisfranc ligament?

. Plantar aspect of the medial cuneiform to the plantar aspect of the base of the second metatarsal
. Dorsal aspect of the medial cuneiform to the dorsal base of the second metatarsal
. Plantar aspect of the middle cuneiform to the base of the third metatarsal
. Medial cuneiform to the base of the first metatarsal
. Navicular to the medial cuneiform

Correct Answer & Explanation

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

Explanation

The Lisfranc ligament is an essential stabilizing structure of the midfoot. It is an interosseous ligament that runs obliquely from the plantar-lateral aspect of the medial cuneiform to the plantar-medial aspect of the base of the second metatarsal. There is no direct transverse ligamentous connection between the bases of the first and second metatarsals, making the Lisfranc ligament the critical restraint to lateral displacement of the lesser metatarsals.

Question 3015

Topic: 8. Foot and Ankle

A 35-year-old male sustains an acute, closed Achilles tendon rupture while playing basketball. He elects to undergo a percutaneous repair technique. During the placement of sutures into the proximal tendon stump, which of the following structures is at the highest risk of iatrogenic injury?

. Tibial nerve
. Saphenous nerve
. Sural nerve
. Posterior tibial artery
. Flexor hallucis longus tendon

Correct Answer & Explanation

. Sural nerve

Explanation

The sural nerve courses distally down the posterior aspect of the calf. Approximately 10 cm proximal to the calcaneal insertion, it crosses from the midline to the lateral border of the Achilles tendon. During percutaneous or minimally invasive repair of the Achilles tendon, blind passage of sutures in the proximal stump (especially laterally) puts the sural nerve at high risk for entrapment or transection. To minimize this, careful blunt dissection or ultrasound guidance is often utilized laterally.

Question 3016

Topic: 8. Foot and Ankle

A 24-year-old football player sustains a hyperplantarflexion injury to his midfoot. Weight-bearing radiographs reveal a subtle widening between the first and second metatarsal bases, and a "fleck sign" is present. The Lisfranc ligament, which is critical for midfoot stability and is avulsed in this scenario, 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 cuboid
. Navicular to the medial cuneiform

Correct Answer & Explanation

. Medial cuneiform to the base of the second 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. There is no direct ligamentous connection between the bases of the first and second metatarsals.

Question 3017

Topic: Midfoot & Hindfoot
A 55-year-old poorly controlled diabetic patient presents with a swollen, warm, erythematous foot without an open ulcer or history of trauma. Radiographs show subluxation of the tarsometatarsal joints, osteopenia, and periarticular debris. According to the Eichenholtz classification, this stage of Charcot arthropathy is characterized primarily by which of the following?
. Coalescence with absorption of fine bone debris
. Consolidation with remodeling of bone ends
. Development of an infected neuropathic ulcer
. Active bone fragmentation, joint dislocation, and debris formation
. Complete osseous ankylosis of the midfoot

Correct Answer & Explanation

. Active bone fragmentation, joint dislocation, and debris formation

Explanation

The Eichenholtz classification of Charcot arthropathy has three main stages: Stage I (Development/Fragmentation) is marked by active bone fragmentation, subluxation/dislocation, joint effusion, and debris formation. Stage II (Coalescence) is marked by absorption of fine debris and early fusion. Stage III (Consolidation/Reconstruction) is marked by remodeling, rounding of bone ends, and stable fusion/ankylosis.

Question 3018

Topic: Midfoot & Hindfoot
A 40-year-old male presents with a long-standing, rigid, and painful flatfoot deformity. Examination reveals an inability to perform a single-leg heel rise and rigid hindfoot valgus. Radiographs show advanced osteoarthritis of the subtalar, talonavicular, and calcaneocuboid joints. What is the gold standard surgical intervention?
. Medial displacement calcaneal osteotomy
. Flexor digitorum longus (FDL) tendon transfer to the navicular
. Isolated subtalar arthrodesis
. Triple arthrodesis
. Pantalar arthrodesis

Correct Answer & Explanation

. Triple arthrodesis

Explanation

The patient has a Stage III adult acquired flatfoot deformity (rigid flatfoot with degenerative changes). The gold standard treatment for a rigid deformity with arthritis involving the subtalar, talonavicular, and calcaneocuboid joints is a triple arthrodesis. Tendon transfers and osteotomies are reserved for flexible, earlier-stage deformities (Stage II).

Question 3019

Topic: 8. Foot and Ankle

A 24-year-old male sustains a midfoot injury. Radiographs show widening of the space between the base of the 1st and 2nd metatarsals. The primary restraint to lateral displacement of the second metatarsal base is the Lisfranc ligament. What is the precise anatomical attachment of the Lisfranc ligament?

. Base of 1st metatarsal to base of 2nd metatarsal
. Medial cuneiform to base of 2nd metatarsal
. Intermediate cuneiform to base of 2nd metatarsal
. Medial cuneiform to base of 1st metatarsal
. Navicular to base of 2nd metatarsal

Correct Answer & Explanation

. Medial cuneiform to base of 2nd 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. There is no direct transverse intermetatarsal ligament between the bases of the first and second metatarsals.

Question 3020

Topic: Midfoot & Hindfoot
A 32-year-old male falls from a height and sustains a Hawkins Type III fracture of the talar neck. Which of the following best describes the anatomical disruptions defining a Hawkins III fracture?
. Nondisplaced fracture of the talar neck
. Displaced fracture of the talar neck with subluxation of the subtalar joint
. Displaced fracture of the talar neck with dislocation of both the subtalar and tibiotalar joints
. Displaced fracture of the talar neck with dislocation of the subtalar, tibiotalar, and talonavicular joints
. Comminuted fracture of the talar body with extrusion

Correct Answer & Explanation

. Displaced fracture of the talar neck with dislocation of both the subtalar and tibiotalar joints

Explanation

The Hawkins classification describes talar neck fractures: Type I is nondisplaced; Type II involves subtalar subluxation/dislocation; Type III involves dislocation of the subtalar and tibiotalar joints. Type IV (added by Canale and Kelly) includes talonavicular dislocation. Type III injuries have a very high rate of avascular necrosis.

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