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8. Foot and Ankle MCQs

Practice Set 195 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 3881

Topic: Midfoot & Hindfoot

A 50-year-old diabetic male undergoes total contact casting for Eichenholtz Stage I Charcot arthropathy of the midfoot. Which of the following radiographic findings marks the transition to Eichenholtz Stage II (Coalescence)?

. Subchondral osteopenia and severe soft tissue swelling without fracture
. Joint subluxation and active bony fragmentation
. Absorption of fine intra-articular debris and fusion of large fragments
. Complete bony remodeling and resolution of sclerosis
. Rapid destruction of the metatarsophalangeal joints

Correct Answer & Explanation

. Subchondral osteopenia and severe soft tissue swelling without fracture

Explanation

Eichenholtz Stage I (Development) involves active fragmentation and joint dislocation. Stage II (Coalescence) is marked radiographically by the absorption of fine debris, early bony fusion, and marginal sclerosis. Stage III is consolidation and remodeling.

Question 3882

Topic: 8. Foot and Ankle

A 65-year-old poorly controlled diabetic sustains an unstable bimalleolar ankle fracture. Operative fixation is planned. Compared to a non-diabetic patient, what is the most appropriate modification to the surgical technique and postoperative protocol?

. Standard fixation with 6 weeks non-weight-bearing
. Use of a single syndesmotic screw and 8 weeks non-weight-bearing
. Augmented fixation with multiple syndesmotic screws and 12 weeks non-weight-bearing
. Primary tibiotalar arthrodesis
. Casting only due to high infection risk

Correct Answer & Explanation

. Standard fixation with 6 weeks non-weight-bearing

Explanation

Diabetic patients with ankle fractures have significantly higher complication rates, including loss of fixation and Charcot arthropathy. Augmented fixation (e.g., multiple syndesmotic screws, locking plates) and prolonged non-weight-bearing (typically 10-12 weeks) are recommended to minimize hardware failure.

Question 3883

Topic: 8. Foot and Ankle

A 55-year-old patient with long-standing diabetes presents with a unilateral warm, erythematous, and swollen foot and ankle. There are no open wounds. Radiographs show soft tissue swelling without bony abnormalities. Which of the following physical examination findings is most useful to differentiate acute Charcot arthropathy from cellulitis?

. Presence of a bounding dorsalis pedis pulse
. Resolution of erythema with leg elevation
. Increased pain with passive ankle dorsiflexion
. Decreased vibratory sensation
. Presence of a positive Babinski sign

Correct Answer & Explanation

. Presence of a bounding dorsalis pedis pulse

Explanation

In acute Eichenholtz stage 1 Charcot arthropathy, the limb is erythematous and warm due to autonomic neuropathy and arteriovenous shunting. Elevating the affected limb for 5 to 10 minutes typically results in the resolution of erythema, distinguishing it from cellulitis.

Question 3884

Topic: 8. Foot and Ankle

The most common anatomic location for the development of Charcot neuroarthropathy in the diabetic foot is:

. Tibiotalar joint
. Subtalar joint
. Tarsometatarsal (Lisfranc) joint
. Metatarsophalangeal joints
. Calcaneocuboid joint

Correct Answer & Explanation

. Tibiotalar joint

Explanation

The tarsometatarsal (Lisfranc) joint complex is the most common site of Charcot neuroarthropathy. Collapse at this level typically leads to a characteristic rocker-bottom foot deformity and increased risk of midfoot plantar ulceration.

Question 3885

Topic: 8. Foot and Ankle

A 35-year-old woman sustains a trimalleolar ankle fracture. The posterior malleolus fracture involves 30% of the articular surface. Which of the following is the primary biomechanical advantage of open reduction and internal fixation of the posterior malleolus compared to placing a trans-syndesmotic screw?

. It prevents anterior talar subluxation
. It provides superior restoration of syndesmotic stability
. It eliminates the need for lateral malleolus fixation
. It accelerates the healing of the medial malleolus
. It decreases the risk of deep vein thrombosis

Correct Answer & Explanation

. It prevents anterior talar subluxation

Explanation

Anatomical fixation of the posterior malleolus effectively restores the posterior inferior tibiofibular ligament (PITFL) footprint. This provides superior biomechanical stability to the syndesmosis compared to isolated trans-syndesmotic screw fixation.

Question 3886

Topic: 8. Foot and Ankle

A 60-year-old diabetic patient presents with a chronic, recurrent plantar neuropathic ulcer under the first metatarsal head despite the use of total contact casting and accommodative footwear. Ankle dorsiflexion is limited to 5 degrees past neutral with the knee extended, but improves to 15 degrees with the knee flexed. What is the most appropriate surgical intervention to promote healing and prevent recurrence?

. First metatarsophalangeal joint arthrodesis
. Gastrocnemius recession
. Achilles tendon lengthening
. Tibialis anterior tendon transfer
. First metatarsal osteotomy

Correct Answer & Explanation

. First metatarsophalangeal joint arthrodesis

Explanation

The patient has a positive Silfverskiold test, indicating isolated gastrocnemius tightness. A gastrocnemius recession reduces forefoot plantar pressures, promoting the healing of recalcitrant plantar forefoot ulcers in patients with equinus contracture.

Question 3887

Topic: 8. Foot and Ankle

According to the Lauge-Hansen classification, what is the initial ligamentous injury in a supination-external rotation (SER) type ankle fracture?

. Posterior inferior tibiofibular ligament
. Anterior inferior tibiofibular ligament
. Calcaneofibular ligament
. Deep deltoid ligament
. Interosseous membrane

Correct Answer & Explanation

. Posterior inferior tibiofibular ligament

Explanation

In an SER injury, the sequence of failure begins with the anterior inferior tibiofibular ligament (AITFL) (Stage I). This is followed by a short oblique fracture of the lateral malleolus (Stage II), the PITFL (Stage III), and finally the medial malleolus or deltoid ligament (Stage IV).

Question 3888

Topic: Midfoot & Hindfoot

A 58-year-old patient with poorly controlled type 2 diabetes presents with an ulcerated, swollen midfoot. The clinician is concerned about osteomyelitis versus acute Charcot arthropathy. Which of the following MRI findings is most specific for diagnosing osteomyelitis over Charcot arthropathy?

. Bone marrow edema on T2-weighted images
. Subchondral cysts and joint effusion
. Replacement of normal marrow fat on T1-weighted images with a contiguous soft tissue ulcer
. Periarticular enhancement with gadolinium
. Bone fragmentation and debris

Correct Answer & Explanation

. Bone marrow edema on T2-weighted images

Explanation

While bone marrow edema is present in both conditions, the replacement of normal T1 marrow fat with contiguous soft tissue ulceration or a sinus tract is highly specific for osteomyelitis. Charcot arthropathy typically shows periarticular marrow edema without direct extension from a cutaneous ulcer.

Question 3889

Topic: 8. Foot and Ankle

A 60-year-old diabetic patient presents with a swollen, erythematous foot without an open ulcer. Radiographs show periarticular fragmentation and subluxation at the tarsometatarsal joint. Skin temperature is elevated compared to the contralateral side. What is the most appropriate initial management?

. Intravenous antibiotics
. Total contact casting
. Arthrodesis of the midfoot
. Incision and drainage
. Exostectomy

Correct Answer & Explanation

. Intravenous antibiotics

Explanation

The patient is presenting with acute Eichenholtz stage I Charcot neuroarthropathy. The initial treatment of choice is immediate immobilization with a total contact cast and non-weight bearing until the acute inflammatory phase resolves.

Question 3890

Topic: Ankle Trauma & Sports

A 45-year-old man sustains an ankle injury. Radiographs show an isolated lateral malleolus fracture at the level of the syndesmosis. A gravity stress view shows 6 mm of medial clear space widening. What Lauge-Hansen classification does this injury represent?

. Supination-adduction
. Supination-external rotation
. Pronation-abduction
. Pronation-external rotation
. Pronation-adduction

Correct Answer & Explanation

. Supination-adduction

Explanation

An SER-IV injury involves a fracture of the fibula at the syndesmosis with disruption of the deltoid ligament or medial malleolus. The disruption of the medial structures is indicated by medial clear space widening on a stress view.

Question 3891

Topic: 8. Foot and Ankle

In a patient with long-standing diabetes mellitus and a plantar forefoot ulcer that has failed to heal despite total contact casting, what surgical intervention is most likely to promote healing and prevent recurrence?

. Metatarsal head resection
. Gastrocnemius recession or Achilles tendon lengthening
. First metatarsophalangeal joint arthrodesis
. Ankle arthrodesis
. Triple arthrodesis

Correct Answer & Explanation

. Metatarsal head resection

Explanation

Equinus contracture increases forefoot plantar pressures, which is a major contributor to recurrent forefoot ulcers. Lengthening the Achilles tendon or performing a gastrocnemius recession reduces these pressures and significantly aids in ulcer healing.

Question 3892

Topic: 8. Foot and Ankle

A 55-year-old poorly controlled diabetic patient undergoes open reduction and internal fixation of a bimalleolar ankle fracture. What modification to the standard postoperative protocol is most strongly recommended for this patient?

. Early weight-bearing at 2 weeks
. Removal of hardware at 6 weeks
. Prolonged non-weight-bearing for 8 to 12 weeks
. Routine use of an external fixator
. Immediate active range of motion without immobilization

Correct Answer & Explanation

. Early weight-bearing at 2 weeks

Explanation

Diabetic patients with ankle fractures have a significantly higher risk of complications, including Charcot arthropathy and loss of fixation. Prolonged immobilization and at least a doubled non-weight-bearing period (8 to 12 weeks) are standard recommendations.

Question 3893

Topic: 8. Foot and Ankle

A patient sustains a pronation-external rotation (PER) ankle injury. According to the Lauge-Hansen classification, what is the first structure injured in this sequential failure pattern?

. Anterior inferior tibiofibular ligament (AITFL)
. Deltoid ligament or medial malleolus
. Fibula shaft
. Posterior inferior tibiofibular ligament (PITFL)
. Lateral collateral ligaments

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

In a pronation-external rotation injury, the sequence of failure begins medially with the deltoid ligament or medial malleolus (Stage I). This is followed by the AITFL (Stage II), a high fibula fracture (Stage III), and finally the PITFL or posterior malleolus (Stage IV).

Question 3894

Topic: 8. Foot and Ankle

What is the pathomechanical consequence of a 1-mm lateral shift of the talus within the ankle mortise following a malreduced ankle fracture?

. 10% decrease in tibiotalar contact area
. 25% decrease in tibiotalar contact area
. 42% decrease in tibiotalar contact area
. 60% decrease in tibiotalar contact area
. No significant change in contact area

Correct Answer & Explanation

. 10% decrease in tibiotalar contact area

Explanation

Classic biomechanical studies by Ramsey and Hamilton demonstrated that a 1-mm lateral displacement of the talus reduces the tibiotalar contact area by 42%. This severely increases joint contact pressures and accelerates post-traumatic arthritis.

Question 3895

Topic: 8. Foot and Ankle

In the treatment of acute Charcot neuroarthropathy (Eichenholtz stage I), when is the transition from a total contact cast to a Charcot Restraint Orthotic Walker (CROW) or custom therapeutic footwear most appropriate?

. When radiographic consolidation of fractures is seen
. After exactly 4 weeks of casting
. When skin temperatures equalize to within 1-2 degrees Celsius of the contralateral foot
. When the patient is able to bear weight without pain
. Following prophylactic exostectomy

Correct Answer & Explanation

. When radiographic consolidation of fractures is seen

Explanation

The clinical resolution of the acute inflammatory phase of Charcot arthropathy is best indicated by the equalization of skin temperatures (within 1-2°C) and reduction in edema compared to the unaffected foot. Radiographic consolidation occurs much later in Stage III.

Question 3896

Topic: 8. Foot and Ankle

A 50-year-old diabetic woman with peripheral neuropathy undergoes ORIF for an unstable ankle fracture. To enhance construct stability and reduce the high risk of catastrophic failure, which of the following techniques is most appropriate?

. Use of biodegradable screws
. Single-cortex syndesmotic fixation
. Application of a spanning external fixator without internal hardware
. Use of multiple syndesmotic screws and multiple quadricortical fibular screws
. Immediate postoperative weight-bearing in a boot

Correct Answer & Explanation

. Use of biodegradable screws

Explanation

In diabetic patients with ankle fractures, augmented fixation techniques are strongly recommended to prevent hardware failure in osteopenic bone. This includes multiple trans-syndesmotic screws (even without obvious syndesmosis injury), locking plates, and quadricortical pro-tibia screws.

Question 3897

Topic: 8. Foot and Ankle

What is the most appropriate indication for repairing the deltoid ligament during open reduction and internal fixation of a supination-external rotation stage IV ankle fracture?

. Routine repair in all cases to prevent late valgus collapse
. If the ligament is avulsed from its calcaneal insertion
. When the deltoid ligament blocks anatomic reduction of the talus into the mortise
. Whenever a syndesmotic screw is placed
. In all diabetic patients

Correct Answer & Explanation

. Routine repair in all cases to prevent late valgus collapse

Explanation

Routine repair of the deltoid ligament in ankle fractures is not indicated and does not improve outcomes. It is indicated almost exclusively when the medial clear space fails to reduce, suggesting the deltoid ligament is inverted and entrapped, blocking talar reduction.

Question 3898

Topic: 8. Foot and Ankle

A 55-year-old patient with long-standing, poorly controlled diabetes presents with a red, hot, swollen left foot. The patient denies any trauma. Pedal pulses are bounding. Inflammatory markers are within normal limits. Radiographs show soft tissue swelling but no fractures or joint subluxation. What is the most appropriate next step in management?

. Intravenous antibiotics
. Magnetic resonance imaging
. Total contact casting
. Incision and debridement
. Intra-articular corticosteroid injection

Correct Answer & Explanation

. Intravenous antibiotics

Explanation

This clinical presentation is classic for Eichenholtz Stage 0 (prodromal) Charcot neuroarthropathy. The mainstay of treatment is immediate immobilization and offloading, typically with a total contact cast, to prevent progression to fragmentation and severe deformity.

Question 3899

Topic: 8. Foot and Ankle

When treating a trimalleolar ankle fracture, which of the following is the most widely accepted absolute indication for operative fixation of the posterior malleolus?

. Any fragment involving > 10% of the articular surface
. Persistent posterior subluxation of the talus with the ankle in neutral
. Concomitant syndesmotic injury
. Complete deltoid ligament rupture
. A fibular fracture occurring above the syndesmosis

Correct Answer & Explanation

. Any fragment involving > 10% of the articular surface

Explanation

Persistent posterior subluxation of the talus indicates gross tibiotalar instability and is an absolute indication for posterior malleolar fixation. Fragment size criteria vary, though >25% of the articular surface is commonly considered a relative indication.

Question 3900

Topic: 8. Foot and Ankle

A 32-year-old man presents to the emergency department after a skiing fall. He complains of severe medial ankle pain and proximal lateral leg pain. Ankle radiographs show an isolated widening of the medial clear space. Knee radiographs reveal a proximal third fibula fracture. According to the Lauge-Hansen classification, what is the mechanism of this injury?

. Supination-Adduction
. Supination-External Rotation
. Pronation-Abduction
. Pronation-External Rotation
. Vertical Compression

Correct Answer & Explanation

. Supination-Adduction

Explanation

This describes a Maisonneuve fracture, which involves a proximal fibular fracture with syndesmotic disruption and medial ankle injury. This pattern typically results from a Pronation-External Rotation (PER) mechanism.

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