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8. Foot and Ankle MCQs

Practice Set 33 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 641

Topic: 8. Foot and Ankle

A 35-year-old male sustains a high-energy rotational injury to his ankle, resulting in a Maisonneuve fracture. What is the key to appropriate diagnosis and management of this injury?

. Evaluation and fixation of the medial malleolus.
. Assessment for a calcaneal fracture.
. Careful palpation and imaging of the proximal fibula and assessment of syndesmotic integrity.
. Immediate non-weight bearing cast immobilization.
. Referral to a vascular surgeon for angiography.

Correct Answer & Explanation

. Careful palpation and imaging of the proximal fibula and assessment of syndesmotic integrity.

Explanation

Correct Answer: CA Maisonneuve fracture is a specific type of ankle injury characterized by a fracture of the proximal fibula, rupture of the syndesmosis (anterior inferior tibiofibular ligament, posterior inferior tibiofibular ligament, interosseous membrane), and often a deltoid ligament rupture or medial malleolus fracture. The key to diagnosis is recognizing the proximal fibula fracture in the context of an ankle injury, which often appears innocuous on standard ankle views. The critical aspect for management is assessing and restoring syndesmotic integrity, as disruption of the syndesmosis leads to ankle instability. Fixation of the medial malleolus is only done if it is fractured and significantly displaced. Calcaneal fractures are not directly associated. Vascular injury is rare unless there's a significant open injury or dislocation. Non-weight bearing cast immobilization alone is insufficient if the syndesmosis is unstable, which it typically is.

Question 642

Topic: 8. Foot and Ankle

A 40-year-old male sustains a Lisfranc injury after a fall with his foot plantarflexed and axially loaded. Which of the following is the most reliable radiographic sign of a Lisfranc injury?

. Fracture of the base of the fifth metatarsal.
. Avulsion fracture of the navicular.
. Diastasis between the base of the first and second metatarsals on weight-bearing AP radiographs.
. Talonavicular subluxation.
. Fracture of the cuboid.

Correct Answer & Explanation

. Diastasis between the base of the first and second metatarsals on weight-bearing AP radiographs.

Explanation

Correct Answer: CThe Lisfranc ligament connects the medial cuneiform to the base of the second metatarsal. Diastasis (widening) between the base of the first and second metatarsals on weight-bearing AP radiographs is the most reliable radiographic sign of a Lisfranc injury, indicating disruption of the Lisfranc ligament complex and instability of the midfoot. A fleck sign (small avulsion fracture off the base of the second metatarsal or medial cuneiform) is also highly indicative. Fractures of the 5th metatarsal base or navicular/cuboid can occur but are not primary indicators of a Lisfranc injury. Talonavicular subluxation indicates a different midfoot or hindfoot pathology.

Question 643

Topic: 8. Foot and Ankle

A 22-year-old football player sustains a high-energy knee injury with gross instability in multiple planes. Physical exam suggests a multi-ligamentous knee injury, likely a knee dislocation. Dorsalis pedis and posterior tibial pulses are present and strong. What is the most important immediate diagnostic study?

. MRI of the knee.
. X-rays of the knee (AP and Lateral).
. CT scan of the knee.
. Ankle-brachial index (ABI) measurement.
. Arteriography.

Correct Answer & Explanation

. Ankle-brachial index (ABI) measurement.

Explanation

Correct Answer: DKnee dislocations have a high rate of associated popliteal artery injury (up to 40%). Even with palpable pulses, intimal tears can lead to delayed thrombosis and limb loss. Therefore, a vascular assessment is critical. Ankle-brachial index (ABI) is a rapid and reliable screening tool. An ABI <0.9 is highly suspicious for vascular injury and warrants further imaging like CT angiography or conventional arteriography. While X-rays confirm dislocation and rule out fracture, and MRI details ligamentous injuries, these are not the most immediate concern for limb viability. Arteriography is usually reserved for a compromised ABI or strong clinical suspicion after ABI.

Question 644

Topic: 8. Foot and Ankle

A 55-year-old obese male presents with acute onset of severe left foot pain after tripping. Initial X-rays show widening between the first and second metatarsal bases and a 'fleck sign' (small avulsion from the medial cuneiform). He cannot bear weight. What is the most appropriate management?

. Immobilization in a walking boot for 6 weeks.
. Closed reduction and casting for 8 weeks.
. Urgent open reduction and internal fixation (ORIF).
. Physical therapy and NSAIDs.
. Non-weight bearing for 2 weeks followed by progressive weight bearing.

Correct Answer & Explanation

. Urgent open reduction and internal fixation (ORIF).

Explanation

Correct Answer: CThe presentation (widening between 1st/2nd metatarsal bases, fleck sign, inability to bear weight) is highly consistent with a Lisfranc (tarsometatarsal) joint injury. Displaced or unstable Lisfranc injuries require urgent surgical stabilization with ORIF (or primary arthrodesis in some cases) to restore anatomic alignment. Non-operative management or delayed treatment of unstable injuries leads to poor outcomes, including painful arthritis, arch collapse, and chronic pain. Immediate weight bearing or simple immobilization in a boot is insufficient for displaced/unstable injuries.

Question 645

Topic: 8. Foot and Ankle

A 38-year-old male sustains a high-energy talus neck fracture (Hawkins Type II). What is the primary concern for long-term complication in this fracture type?

. Nonunion of the fracture.
. Post-traumatic arthritis of the subtalar joint.
. Avascular necrosis (AVN) of the talar body.
. Malunion leading to ankle instability.
. Delayed union.

Correct Answer & Explanation

. Avascular necrosis (AVN) of the talar body.

Explanation

Correct Answer: CHawkins Type II talus neck fractures involve a displaced talus neck fracture with subtalar dislocation but an intact ankle joint. The blood supply to the talar body is tenuous and primarily enters through the talar neck. Displacement of the neck fracture and subtalar dislocation significantly disrupts this blood supply, placing the talar body at high risk (20-50%) for avascular necrosis (AVN). While nonunion and post-traumatic arthritis are also potential complications, AVN of the talar body is a hallmark and often devastating complication specifically associated with displaced talus neck fractures, increasing with higher Hawkins types. Post-traumatic arthritis is common regardless of AVN due to articular damage.

Question 646

Topic: Midfoot & Hindfoot

A 7-year-old child undergoes limb salvage surgery for Ewing's Sarcoma of the distal femur, which included resection of the growth plate. What is a primary long-term concern related to growth in this patient?

. Increased risk of deep vein thrombosis
. Development of significant limb length discrepancy
. Accelerated growth of the contralateral limb
. Premature fusion of all growth plates
. Development of Charcot arthropathy

Correct Answer & Explanation

. Development of significant limb length discrepancy

Explanation

Correct Answer: BIn growing children undergoing limb salvage surgery, particularly around long bones like the distal femur where a significant portion of the growth plate is removed or damaged (e.g., by radiation), the most significant long-term concern is the development of a substantial limb length discrepancy. This occurs because the treated limb's growth is arrested or severely impaired, while the contralateral limb continues to grow normally. This requires careful planning, often using expandable prostheses or subsequent lengthening procedures, to manage the discrepancy as the child grows.Incorrect Options:A. Increased risk of deep vein thrombosis:DVT is an acute or subacute surgical complication, not a primary long-term growth-related concern.C. Accelerated growth of the contralateral limb:While the contralateral limb continues to grow, it does not accelerate its growth; rather, the treated limb's growth is stunted, creating the discrepancy.D. Premature fusion of all growth plates:Radiation or surgery typically affects only the treated growth plate(s), not all growth plates in the body.E. Development of Charcot arthropathy:Charcot arthropathy is a neuropathic joint condition, typically seen in patients with severe peripheral neuropathy (e.g., from diabetes or certain chemotherapy agents), and is not a direct consequence of limb salvage surgery for Ewing's Sarcoma.

Question 647

Topic: 8. Foot and Ankle
A 28-year-old male sustains a severe hyperdorsiflexion injury to his foot, resulting in a Hawkins III talar neck fracture. Disruption of which of the following combinations of blood supplies accounts for the nearly 100% rate of avascular necrosis seen with this injury?
. Artery of the tarsal canal, artery of the sinus tarsi, and superior talar neck branches
. Medial plantar artery, lateral plantar artery, and dorsalis pedis artery
. Anterior tibial artery, peroneal artery, and posterior tibial artery
. Deep peroneal nerve artery, sural artery, and saphenous artery
. Calcaneal branches, metatarsal arteries, and medial tarsal artery

Correct Answer & Explanation

. Artery of the tarsal canal, artery of the sinus tarsi, and superior talar neck branches

Explanation

A Hawkins III fracture involves dislocation of both the subtalar and tibiotalar joints, disrupting all three major blood supplies to the talar body. These include the artery of the tarsal canal, the artery of the sinus tarsi, and the superior neck branches.

Question 648

Topic: 8. Foot and Ankle

A 45-year-old roofer falls 15 feet, sustaining a displaced, intra-articular calcaneus fracture. The surgeon elects to perform open reduction and internal fixation via an extensile lateral approach. Which nerve is most at risk during the surgical incision and flap elevation?

. Sural nerve
. Superficial peroneal nerve
. Deep peroneal nerve
. Saphenous nerve
. Tibial nerve

Correct Answer & Explanation

. Sural nerve

Explanation

The extensile lateral approach to the calcaneus involves creating a full-thickness flap. The sural nerve courses posterior to the lateral malleolus and along the lateral aspect of the foot, placing it at high risk during the vertical and horizontal limbs of the incision.

Question 649

Topic: Midfoot & Hindfoot
A 30-year-old snowboarder sustains a Hawkins Type III talar neck fracture. Which of the following best describes the specific anatomic dislocations associated with this injury?
. Subtalar joint dislocation only
. Subtalar and tibiotalar joint dislocations
. Subtalar, tibiotalar, and talonavicular joint dislocations
. Tibiotalar joint dislocation only
. Talonavicular joint dislocation only

Correct Answer & Explanation

. Subtalar, tibiotalar, and talonavicular joint dislocations

Explanation

A Hawkins Type III talar neck fracture involves displacement of the talar body with dislocation of the subtalar, tibiotalar, and talonavicular joints. This injury carries a very high risk of avascular necrosis approaching 100%.

Question 650

Topic: 8. Foot and Ankle

A 42-year-old male sustains a displaced intra-articular calcaneus fracture and undergoes ORIF via an extensile lateral approach. Which of the following is the most significant risk associated with this specific surgical approach?

. Sural nerve transection
. Deep vein thrombosis
. Wound edge necrosis and deep infection
. Tibial nerve neuropraxia
. Nonunion of the subtalar joint

Correct Answer & Explanation

. Wound edge necrosis and deep infection

Explanation

The extensile lateral approach to the calcaneus involves creating a full-thickness fasciocutaneous flap dependent on the lateral calcaneal artery. The most feared complication is wound edge necrosis leading to deep infection.

Question 651

Topic: 8. Foot and Ankle
A 28-year-old male sustains a Hawkins type III talar neck fracture. Disruption of which of the following arteries is most responsible for the high rate of talar body avascular necrosis in this injury pattern?
. Dorsalis pedis artery
. Artery of the tarsal canal
. Artery of the tarsal sinus
. Deltoid branch of the posterior tibial artery
. Lateral tarsal 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 dominant blood supply to the talar body. It is typically completely disrupted in displaced talar neck fractures, leading to avascular necrosis.

Question 652

Topic: 8. Foot and Ankle

A 55-year-old male presents with a 3-month history of progressive right buttock pain radiating down the posterior thigh and lateral calf to the dorsum of the foot. He reports numbness in the web space between the first and second toes. On examination, he has weakness with ankle dorsiflexion and great toe extension. Which lumbar nerve root is most likely affected?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L5

Explanation

Correct Answer: CThis clinical presentation is classic for L5 radiculopathy. Key features include:Pain distribution:Buttock, posterior thigh, lateral calf, dorsum of the foot.Sensory deficit:Numbness in the web space between the first and second toes (L5 dermatome).Motor weakness:Ankle dorsiflexion (tibialis anterior, L4-L5), great toe extension (extensor hallucis longus, L5).In contrast:L3 radiculopathy:Pain in the anterior thigh, weakness in hip flexion and knee extension.L4 radiculopathy:Pain in the anterior thigh, medial calf, weakness in knee extension, diminished patellar reflex.S1 radiculopathy:Pain in the posterior thigh, calf, plantar foot, weakness in ankle plantarflexion, diminished Achilles reflex.

Question 653

Topic: 8. Foot and Ankle

A 28-year-old collegiate soccer player sustains an acute eversion injury to his right ankle during a game. He reports immediate pain and swelling on the medial side of his ankle. Which of the following ligaments is most likely to be injured?

. Anterior talofibular ligament (ATFL)
. Calcaneofibular ligament (CFL)
. Posterior talofibular ligament (PTFL)
. Deltoid ligament complex
. Anterior inferior tibiofibular ligament (AITFL)

Correct Answer & Explanation

. Deltoid ligament complex

Explanation

Correct Answer: DAn eversion ankle injury (where the foot rolls outward) places stress on the medial side of the ankle. The deltoid ligament complex is a strong, fan-shaped ligament on the medial aspect of the ankle that primarily resists eversion forces. Therefore, it is the most likely ligament to be injured in an eversion sprain. The ATFL, CFL, and PTFL are components of the lateral collateral ligament complex and are injured in inversion sprains. The AITFL is part of the syndesmosis and is injured in high ankle sprains, typically involving external rotation of the talus.

Question 654

Topic: 8. Foot and Ankle

A 32-year-old competitive runner presents with chronic pain along the medial aspect of her left foot, exacerbated by activity. Examination reveals tenderness just distal to the medial malleolus, reproducible pain with resisted plantarflexion and inversion, and a pes planus foot posture. What is the most likely diagnosis?

. Plantar fasciitis
. Achilles tendinopathy
. Tarsal tunnel syndrome
. Posterior tibial tendon dysfunction (PTTD)
. Navicular stress fracture

Correct Answer & Explanation

. Posterior tibial tendon dysfunction (PTTD)

Explanation

Correct Answer: DThe symptoms of chronic medial foot pain exacerbated by activity, tenderness distal to the medial malleolus, pain with resisted plantarflexion and inversion, and an associated pes planus deformity are highly suggestive of Posterior Tibial Tendon Dysfunction (PTTD). PTTD is a progressive condition that can lead to adult-acquired flatfoot. Plantar fasciitis causes heel pain. Achilles tendinopathy causes pain in the posterior ankle/heel. Tarsal tunnel syndrome involves nerve compression, often with burning/tingling. A navicular stress fracture would typically present with localized dorsal midfoot pain and often swelling.

Question 655

Topic: 8. Foot and Ankle

A 24-year-old athlete sustains a hyperplantarflexion injury to the midfoot. Radiographs show a widened space between the bases of the 1st and 2nd metatarsals. The Lisfranc ligament connects which two osseous structures?

. Medial cuneiform and base of the 1st metatarsal
. Medial cuneiform and base of the 2nd metatarsal
. Middle cuneiform and base of the 2nd metatarsal
. Lateral cuneiform and base of the 3rd metatarsal
. Cuboid and base of the 4th metatarsal

Correct Answer & Explanation

. Medial cuneiform and base of the 2nd metatarsal

Explanation

The Lisfranc ligament is a stout interosseous ligament spanning from the lateral aspect of the medial cuneiform to the medial base of the second metatarsal. It is critical for the stability of the tarsometatarsal joint complex.

Question 656

Topic: Midfoot & Hindfoot

A 58-year-old male with long-standing diabetes mellitus presents with a swollen, warm, and erythematous right foot. He denies trauma and is afebrile. Radiographs show fragmentation of the navicular and cuneiforms, with subluxation of the tarsometatarsal joints, but no open ulcers are present. Which of the following is the most appropriate initial management?

. Urgent surgical debridement and culture
. Intravenous antibiotics
. Total contact casting
. Open reduction and rigid internal fixation of the midfoot
. Below-knee amputation

Correct Answer & Explanation

. Total contact casting

Explanation

This patient has an acute Eichenholtz stage I Charcot arthropathy, characterized by fragmentation and subluxation. The mainstay of initial treatment for acute Charcot without an open ulcer or deep infection is strict immobilization and offloading, typically using a total contact cast.

Question 657

Topic: 8. Foot and Ankle

A 55-year-old female presents with midfoot pain and inability to bear weight after stepping off a curb awkwardly. Radiographs show subtle widening between the first and second cuneiforms. What is the most sensitive imaging modality to confirm a Lisfranc injury and guide management?

. Standard weight-bearing plain radiographs.
. Stress radiographs of the midfoot.
. MRI of the foot.
. CT scan of the foot.
. Bone scan.

Correct Answer & Explanation

. CT scan of the foot.

Explanation

Correct Answer: DLisfranc injuries (tarsometatarsal joint complex disruption) can be subtle on standard plain radiographs, especially non-displaced or purely ligamentous injuries. While weight-bearing and stress radiographs are crucial for initial assessment, a CT scan is considered the most sensitive imaging modality to definitively diagnose and characterize Lisfranc injuries. It provides detailed bony anatomy, identifies small avulsion fractures, and measures subtle diastasis not visible on plain films. This information is critical for surgical planning. MRI is excellent for soft tissue injuries (ligaments) but often follows a CT scan for bony detail. A bone scan is not an acute management tool.

Question 658

Topic: 8. Foot and Ankle

A 35-year-old football player presents with midfoot pain after an axial load to a plantarflexed foot. Weight-bearing radiographs show a "fleck sign" between the base of the 1st and 2nd metatarsals. Which structure is avulsed?

. Spring ligament
. Plantar fascia
. Interosseous ligament between the medial cuneiform and 2nd metatarsal base
. Dorsal tarsometatarsal ligament
. Calcaneocuboid ligament

Correct Answer & Explanation

. Interosseous ligament between the medial cuneiform and 2nd metatarsal base

Explanation

The Lisfranc ligament is a strong interosseous ligament connecting the medial cuneiform to the base of the second metatarsal. The "fleck sign" represents a bony avulsion of this ligament, pathognomonic for a Lisfranc injury.

Question 659

Topic: 8. Foot and Ankle

A 14-year-old male presents with bilateral cavovarus feet. On examination, you note significant plantarflexion of the first metatarsal and hindfoot varus that corrects when a 1cm block is placed under the lateral aspect of the foot, elevating the fifth metatarsal head. What is the most appropriate interpretation of this Coleman Block Test result?

. The hindfoot varus is primarily rigid and requires a calcaneal osteotomy.
. The hindfoot varus is flexible and secondary to a plantarflexed first ray.
. The hindfoot varus is due to a primary subtalar joint pathology.
. The patient has a fixed forefoot valgus deformity.
. This finding suggests an intrinsic muscle weakness, likely Charcot-Marie-Tooth disease type 1.

Correct Answer & Explanation

. The hindfoot varus is flexible and secondary to a plantarflexed first ray.

Explanation

Correct Answer: BThe Coleman Block Test assesses the flexibility of the hindfoot varus component of a cavus foot. By placing a 1cm block under the lateral border of the foot (from the calcaneus to the fifth metatarsal head), the test effectively dorsiflexes and pronates the forefoot, neutralizing the effect of a plantarflexed first ray. If the hindfoot varus corrects to neutral or valgus with the block, it indicates that the hindfoot varus is flexible and compensatory for a plantarflexed first ray. This means the primary deformity is in the forefoot (plantarflexed first ray), and addressing this will correct the hindfoot. If the hindfoot varus remains uncorrected, it signifies a rigid hindfoot deformity, likely requiring a calcaneal osteotomy (e.g., Dwyer or lateralizing calcaneal osteotomy).

Question 660

Topic: 8. Foot and Ankle

Regarding the neurological examination in a patient with a suspected cavus foot, which of the following findings is most strongly associated with Charcot-Marie-Tooth (CMT) disease?

. Isolated weakness of the tibialis posterior muscle.
. Upper motor neuron signs, such as spasticity and hyperreflexia.
. Absent deep tendon reflexes, particularly in the ankles, along with distal sensory loss and muscle wasting.
. Asymmetric weakness and atrophy, predominantly affecting the quadriceps.
. Acute onset of unilateral foot drop with intact sensation.

Correct Answer & Explanation

. Absent deep tendon reflexes, particularly in the ankles, along with distal sensory loss and muscle wasting.

Explanation

Correct Answer: CCharcot-Marie-Tooth (CMT) disease, particularly CMT1 (demyelinating form), is the most common hereditary neuropathy and a frequent cause of cavus foot. Classic neurological findings include slowly progressive, bilateral, and symmetric distal muscle weakness and atrophy (peroneal muscle atrophy leading to 'stork leg' appearance), sensory loss (often stocking-glove distribution), and absent or diminished deep tendon reflexes, particularly at the ankles. Upper motor neuron signs are characteristic of other neurological conditions (e.g., spinal cord lesions), while isolated or acute unilateral findings are less typical of CMT.

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