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8. Foot and Ankle MCQs

Practice Set 123 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 2441

Topic: 8. Foot and Ankle

A 22-year-old snowboarder presents with lateral ankle pain mimicking a severe ankle sprain following a hard landing. Point tenderness is maximized just inferior and anterior to the lateral malleolus. CT confirms a displaced fracture of the lateral process of the talus. If left untreated, this injury most commonly leads to post-traumatic arthritis in which joint?

. Subtalar joint
. Tibiotalar joint
. Talonavicular joint
. Calcaneocuboid joint
. Distal tibiofibular joint

Correct Answer & Explanation

. Subtalar joint

Explanation

A "snowboarder's fracture" is a fracture of the lateral process of the talus. This anatomical structure articulates with the fibula superiorly and the calcaneus inferiorly (forming part of the posterior facet of the subtalar joint). Displaced, unrecognized fractures frequently lead to subtalar osteoarthritis and chronic lateral ankle pain.

Question 2442

Topic: 8. Foot and Ankle

A 33-year-old male sustains a midfoot crush injury in a high-speed motorcycle crash. Imaging reveals a combined Chopart and Lisfranc dislocation. Following closed reduction, a temporary spanning external fixator is placed. Which sequence of bones anatomically defines the medial column of the foot that must eventually be restored to proper length for normal foot biomechanics?

. Talus, navicular, medial cuneiform, and first metatarsal
. Calcaneus, cuboid, and fourth and fifth metatarsals
. Talus, cuboid, and third metatarsal
. Calcaneus, navicular, and lateral cuneiform
. Talus, calcaneus, and navicular

Correct Answer & Explanation

. Talus, navicular, medial cuneiform, and first metatarsal

Explanation

The foot is divided longitudinally into columns. The medial column consists of the talus, navicular, medial cuneiform, and first metatarsal. Restoring the length and alignment of the medial column is vital for re-establishing the longitudinal arch and normal gait biomechanics.

Question 2443

Topic: 8. Foot and Ankle

Which radiographic parameter is the most reliable indicator of syndesmotic widening on a mortise radiograph of the ankle?

. Tibiofibular overlap less than 10 mm
. Tibiofibular clear space greater than 5 mm
. Medial clear space greater than 2 mm
. Talocrural angle greater than 83 degrees
. Talar tilt greater than 5 degrees

Correct Answer & Explanation

. Tibiofibular clear space greater than 5 mm

Explanation

The tibiofibular clear space (measured 1 cm proximal to the plafond) should be less than 5 mm on both the AP and mortise views. It is considered the most reliable radiographic parameter for assessing syndesmotic integrity because, unlike tibiofibular overlap, it is relatively independent of ankle rotation. A clear space > 5 mm indicates widening of the syndesmosis.

Question 2444

Topic: 8. Foot and Ankle

The artery of the tarsal canal provides the dominant blood supply to the body of the talus. This vessel is a direct branch of which of the following arteries?

. Dorsalis pedis artery
. Anterior tibial artery
. Posterior tibial artery
. Peroneal artery
. Lateral plantar artery

Correct Answer & Explanation

. Posterior tibial artery

Explanation

The artery of the tarsal canal is a branch of the posterior tibial artery. It typically arises 1-2 cm proximal to the bifurcation into the medial and lateral plantar arteries. It supplies the medial two-thirds of the talar body and gives off the deltoid artery. The artery of the tarsal sinus (which anastomoses with the artery of the tarsal canal) is formed by branches from the dorsalis pedis and perforating peroneal arteries.

Question 2445

Topic: 8. Foot and Ankle

A 35-year-old male presents with a stiff, painful foot one year after undergoing ORIF for a displaced talar neck fracture. Radiographs reveal a varus malunion of the talar neck. Which of the following biomechanical consequences is the primary cause of his restricted foot motion?

. Increased dorsiflexion of the first ray
. Locking of the transverse tarsal joint resulting from decreased subtalar eversion
. Hypermobility of the talonavicular joint
. Subluxation of the posterior tibial tendon
. Loss of tension in the plantar aponeurosis

Correct Answer & Explanation

. Locking of the transverse tarsal joint resulting from decreased subtalar eversion

Explanation

Varus malunion is the most common complication following talar neck fractures. A varus malunion decreases the ability of the subtalar joint to evert. Because the axes of the talonavicular and calcaneocuboid joints must become parallel (which occurs during hindfoot eversion) to unlock the transverse tarsal (Chopart) joint and allow midfoot flexibility, a loss of subtalar eversion effectively 'locks' the transverse tarsal joint. This results in a rigid, stiff foot and a supinated forefoot that cannot compensate during gait.

Question 2446

Topic: Midfoot & Hindfoot

A 24-year-old professional football player sustains a purely ligamentous Lisfranc injury. Based on prospective randomized data (e.g., Ly and Coetzee), which of the following statements comparing primary arthrodesis to open reduction internal fixation (ORIF) is true?

. ORIF results in a significantly higher return to pre-injury level of sport compared to primary arthrodesis.
. Primary arthrodesis yields better mid-term functional outcomes and lower rates of secondary surgery.
. Primary arthrodesis is associated with a higher rate of deep infection.
. ORIF provides greater preservation of midfoot motion, leading to significantly higher AOFAS scores.
. There is no difference in outcomes, but ORIF requires a shorter period of immobilization.

Correct Answer & Explanation

. Primary arthrodesis yields better mid-term functional outcomes and lower rates of secondary surgery.

Explanation

For purely ligamentous Lisfranc injuries, primary arthrodesis of the first, second, and third tarsometatarsal joints has been shown to provide better functional outcomes and lower rates of hardware removal and secondary salvage procedures (due to post-traumatic arthritis) compared to ORIF. Ly and Coetzee's landmark prospective randomized study demonstrated superiority of primary arthrodesis over ORIF in purely ligamentous injuries.

Question 2447

Topic: 8. Foot and Ankle

Recent meta-analyses (such as Willits et al.) comparing early functional rehabilitation (non-operative) to surgical repair for acute Achilles tendon ruptures have demonstrated which of the following?

. Surgical repair has a significantly higher re-rupture rate.
. Non-operative treatment has a higher rate of sural nerve injury.
. With early functional rehabilitation, non-operative and operative treatments have similar re-rupture rates, but surgery has higher overall complication rates.
. Surgical repair yields significantly greater plantarflexion strength at 2 years.
. Non-operative treatment requires an immobilization period of at least 12 weeks.

Correct Answer & Explanation

. With early functional rehabilitation, non-operative and operative treatments have similar re-rupture rates, but surgery has higher overall complication rates.

Explanation

Recent high-level evidence, including randomized controlled trials and meta-analyses, has shown that when an early functional rehabilitation protocol (early weight-bearing and ROM in a boot) is utilized, the re-rupture rates between operative and non-operative management of acute Achilles tendon ruptures are statistically similar. However, surgical repair is associated with a higher risk of complications, such as infection, wound healing issues, and sural nerve injury.

Question 2448

Topic: 8. Foot and Ankle

When utilizing the extensile lateral approach for open reduction and internal fixation of a displaced intra-articular calcaneus fracture, creating a full-thickness subperiosteal flap is critical to avoid wound necrosis. Which artery serves as the primary vascular supply to this flap?

. Anterior lateral malleolar artery
. Dorsalis pedis artery
. Lateral calcaneal artery
. Medial plantar artery
. Perforating peroneal artery

Correct Answer & Explanation

. Lateral calcaneal artery

Explanation

The lateral calcaneal artery, a branch of the peroneal artery, provides the main angiosome for the lateral skin of the hindfoot. During an extensile lateral approach to the calcaneus, a full-thickness 'no-touch' subperiosteal flap must be elevated off the lateral wall of the calcaneus to preserve this vascular supply and minimize the risk of wound slough and necrosis.

Question 2449

Topic: Forefoot

A 28-year-old wide receiver sustains a hyperextension injury to his first metatarsophalangeal (MTP) joint, resulting in a severe turf toe. Which of the following is considered an absolute indication for surgical intervention?

. Grade 1 injury with localized plantar tenderness
. Grade 2 injury with a partial tear of the plantar plate
. Proximal retraction of the sesamoids by greater than 3 mm compared to the contralateral side
. A hallux valgus angle of 12 degrees
. Mild attenuation of the medial collateral ligament of the MTP joint

Correct Answer & Explanation

. Proximal retraction of the sesamoids by greater than 3 mm compared to the contralateral side

Explanation

Turf toe is a sprain of the first MTP joint plantar plate complex. Grade 3 injuries involve complete tears of the plantar plate. Indications for operative management of turf toe include: large intra-articular loose bodies/fractures, traumatic hallux valgus deformity, gross clinical instability, and proximal migration of the sesamoids > 3 mm (indicating a complete tear of the plantar plate and flexor hallucis brevis from the base of the proximal phalanx).

Question 2450

Topic: Ankle Trauma & Sports

In the management of an unstable ankle fracture, the posterior malleolus is often evaluated for fixation. Biomechanical studies have shown that direct osteosynthesis of the posterior malleolus provides greater syndesmotic stability than isolated trans-syndesmotic screws because it directly restores the tension of which ligament?

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

Correct Answer & Explanation

. Posterior inferior tibiofibular ligament (PITFL)

Explanation

The posterior inferior tibiofibular ligament (PITFL) attaches to the posterior malleolus. The PITFL provides approximately 40-50% of the stability of the syndesmosis. Anatomically reducing and fixing a posterior malleolus fracture directly restores the PITFL's stabilizing function, providing superior biomechanical strength to the syndesmosis compared to trans-syndesmotic screw fixation alone.

Question 2451

Topic: 8. Foot and Ankle

A 14-year-old girl presents with a unilateral cavovarus foot deformity. A Coleman block test is performed by placing her heel and lateral border of the foot on a 1-inch block, allowing the first metatarsal to drop off the edge. During the test, her hindfoot varus completely corrects to neutral. This finding indicates which of the following?

. The hindfoot varus is rigid and requires a lateral closing wedge calcaneal osteotomy.
. The deformity is flexible and driven by a plantarflexed first ray.
. The patient requires a triple arthrodesis.
. The Achilles tendon is over-lengthened, necessitating a transfer.
. The anterior tibial tendon is driving the deformity.

Correct Answer & Explanation

. The deformity is flexible and driven by a plantarflexed first ray.

Explanation

The Coleman block test evaluates the flexibility of hindfoot varus in a cavovarus foot. By allowing the plantarflexed first ray to hang off the block, it eliminates the forefoot's contribution to the hindfoot posture. If the hindfoot varus corrects to neutral, the deformity is flexible and primarily driven by the plantarflexed first ray. In this scenario, correction should focus on the forefoot, such as a dorsiflexion osteotomy of the first metatarsal (often accompanied by soft tissue releases).

Question 2452

Topic: 8. Foot and Ankle

A 13-year-old boy presents with frequent ankle sprains and rigid, painful flatfeet. Radiographs demonstrate a 'C-sign', and a CT scan confirms a talocalcaneal coalition involving approximately 60% of the posterior facet with evidence of degenerative changes. Non-operative management has failed. What is the most appropriate surgical treatment?

. Resection of the coalition with interposition of an extensor digitorum brevis flap
. Subtalar arthrodesis
. Calcaneocuboid distraction arthrodesis
. Medial displacement calcaneal osteotomy alone
. Talonavicular arthrodesis

Correct Answer & Explanation

. Subtalar arthrodesis

Explanation

Tarsal coalitions typically present as rigid flatfeet. The 'C-sign' on a lateral radiograph is indicative of a talocalcaneal coalition. Surgical resection of the coalition is typically indicated if the coalition involves less than 50% of the subtalar joint surface and there is no degenerative arthritis. If the coalition involves >50% of the joint or if degenerative arthritic changes are present, a subtalar arthrodesis (or triple arthrodesis if adjacent joints are involved) is the recommended treatment.

Question 2453

Topic: Midfoot & Hindfoot

A 55-year-old female presents with stage IIb posterior tibial tendon dysfunction (PTTD), characterized by a flexible flatfoot deformity and greater than 40% uncovering of the talonavicular joint on the AP radiograph. What is the standard of care surgical reconstruction for this specific stage?

. Isolated flexor digitorum longus (FDL) transfer to the navicular
. Triple arthrodesis
. FDL transfer, medial displacement calcaneal osteotomy, and a lateral column lengthening procedure
. Subtalar arthroereisis
. Talonavicular fusion alone

Correct Answer & Explanation

. FDL transfer, medial displacement calcaneal osteotomy, and a lateral column lengthening procedure

Explanation

Stage II PTTD is a flexible deformity. Stage IIa has minimal forefoot abduction, while Stage IIb has significant forefoot abduction (typically >30-40% talonavicular uncovering). To correct the severe forefoot abduction in Stage IIb, a lateral column lengthening (such as an Evans calcaneal osteotomy or calcaneocuboid distraction arthrodesis) is required in addition to an FDL transfer and often a medial displacement calcaneal osteotomy (MDCO) to correct the hindfoot valgus.

Question 2454

Topic: 8. Foot and Ankle

A 58-year-old patient with poorly controlled diabetes mellitus presents with a warm, swollen, erythematous right foot. There are no open wounds or ulcers. Radiographs demonstrate periarticular bony fragmentation and subluxation at the tarsometatarsal joints. Laboratory studies show a normal ESR, normal CRP, and WBC count of 7.0. What is the most appropriate initial management?

. Emergent surgical debridement and intravenous antibiotics
. Open reduction and internal fixation of the midfoot
. Total contact casting and strict non-weight-bearing
. Prescription of custom orthotics and weight-bearing as tolerated
. Amputation at the midcalf level

Correct Answer & Explanation

. Total contact casting and strict non-weight-bearing

Explanation

This patient has an acute Charcot arthropathy (Eichenholtz Stage I - Fragmentation phase). The presentation mimics infection (red, hot, swollen foot), but the lack of an ulcer and normal inflammatory markers support a diagnosis of Charcot neuroarthropathy rather than osteomyelitis. The gold standard initial treatment in the acute fragmentation phase is immobilization with a total contact cast (TCC) and strict non-weight-bearing to prevent further deformity until the active inflammatory phase resolves.

Question 2455

Topic: Forefoot

A 40-year-old female presents with a painful bunion. Clinical examination reveals hypermobility of the first tarsometatarsal (TMT) joint. Weight-bearing radiographs demonstrate a hallux valgus angle of 45 degrees and an intermetatarsal angle of 18 degrees. Which of the following surgical procedures is most appropriate to address her deformity?

. Distal chevron osteotomy
. Akin osteotomy alone
. Lapidus procedure (first TMT arthrodesis)
. Keller resection arthroplasty
. First metatarsophalangeal (MTP) joint arthrodesis

Correct Answer & Explanation

. Lapidus procedure (first TMT arthrodesis)

Explanation

This patient has a severe hallux valgus deformity (IMA > 15 degrees, HVA > 40 degrees) associated with clinical hypermobility of the first TMT joint. The Lapidus procedure involves arthrodesis of the first TMT joint. It provides powerful correction for large intermetatarsal angles and inherently addresses the hypermobility of the first ray, making it the procedure of choice in this scenario.

Question 2456

Topic: Forefoot

A 66-year-old male presents with severe pain in his great toe with walking. Examination reveals only 5 degrees of dorsiflexion and pain at all ranges of motion. Radiographs show a complete loss of the first MTP joint space, severe flattening of the metatarsal head, and large dorsal and lateral osteophytes (Coughlin and Shurnas Grade 4 Hallux Rigidus). Which of the following is the most definitive and reliable surgical option?

. Dorsal cheilectomy
. First MTP joint arthrodesis
. Moberg osteotomy
. Extensor hallucis longus lengthening
. Resection of the sesamoids

Correct Answer & Explanation

. First MTP joint arthrodesis

Explanation

For advanced (Grade 3 or 4) hallux rigidus where there is near complete loss of the joint space and pain throughout the entire range of motion (Grade 4), a dorsal cheilectomy will fail because the articular cartilage is already destroyed. First MTP joint arthrodesis is the gold standard and most reliable surgical option for pain relief and functional improvement in severe hallux rigidus.

Question 2457

Topic: 8. Foot and Ankle

When performing a medial approach to release the compartments of the foot for acute compartment syndrome, the surgeon makes an incision along the medial border of the foot. Which muscle must be mobilized and retracted superiorly to gain access to the central and deep (calcaneal) compartments?

. Flexor digitorum brevis
. Abductor hallucis
. Quadratus plantae
. Adductor hallucis
. Flexor hallucis longus

Correct Answer & Explanation

. Abductor hallucis

Explanation

The foot has 9 discrete compartments. A common approach for complete fasciotomy utilizes two dorsal incisions and one medial incision. Through the medial incision (made along the inferior border of the first metatarsal to the medial calcaneus), the abductor hallucis muscle and its investing fascia are identified and retracted superiorly (dorsally). This allows the surgeon to access and release the central, interosseous, and deep calcaneal compartments.

Question 2458

Topic: 8. Foot and Ankle

A 24-year-old snowboarder presents with lateral ankle pain after a hard landing. Radiographs are negative for a lateral malleolus fracture, but a CT scan reveals a displaced fracture of the lateral process of the talus. What is the typical mechanism of injury for this specific fracture pattern?

. Plantarflexion and inversion
. Dorsiflexion, axial loading, and eversion
. Supination and external rotation
. Pronation and abduction
. Plantarflexion and external rotation

Correct Answer & Explanation

. Dorsiflexion, axial loading, and eversion

Explanation

Fractures of the lateral process of the talus (Snowboarder's fracture) typically occur due to dorsiflexion and axial loading combined with inversion or eversion, most commonly eversion. They are often misdiagnosed as severe ankle sprains. Large or displaced fragments (>2 mm) typically require ORIF or excision.

Question 2459

Topic: 8. Foot and Ankle

To minimize wound complications when utilizing an extensile lateral approach for a calcaneus fracture, the surgical flap must be elevated as a full-thickness subperiosteal flap. Which of the following arteries is the primary vascular supply to this flap?

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

Correct Answer & Explanation

. Lateral calcaneal artery

Explanation

The extensile lateral approach creates a large L-shaped flap. To prevent tip necrosis and wound breakdown, it must be elevated as a 'no-touch' full-thickness subperiosteal flap. The primary blood supply to this flap is the lateral calcaneal artery, which is a terminal branch of the peroneal artery.

Question 2460

Topic: 8. Foot and Ankle

A 21-year-old track athlete is diagnosed with a delayed union of a navicular stress fracture. Which of the following anatomic factors primarily contributes to the high risk of nonunion in this specific bone?

. High tensile forces from the posterior tibial tendon
. An avascular zone in the central third of the bone
. Interposition of the spring ligament
. Excessive compressive forces from the talus
. Lack of periosteal coverage on the dorsal surface

Correct Answer & Explanation

. An avascular zone in the central third of the bone

Explanation

The tarsal navicular has a watershed (avascular) zone in its central third. The blood supply enters dorsally and plantarly, leaving the central third relatively avascular. This anatomic feature predisposes central third navicular stress fractures to a higher rate of delayed union and nonunion.

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