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8. Foot and Ankle MCQs

Practice Set 126 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 2501

Topic: 8. Foot and Ankle

During an extensile lateral approach for open reduction internal fixation of a calcaneus fracture, full-thickness subperiosteal flaps are raised. Which structure is at greatest risk of iatrogenic injury when developing the superior-vertical limb of the incision?

. Sural nerve
. Deep peroneal nerve
. Superficial peroneal nerve
. Poster tibial artery
. Peroneus brevis tendon

Correct Answer & Explanation

. Sural nerve

Explanation

The sural nerve is at the greatest risk of injury during the extensile lateral approach to the calcaneus. It courses closely to both the vertical (superior) limb and the horizontal (inferior) limb of the incision. Injury can result in painful neuromas or lateral foot numbness. Retracting the full-thickness flap with 'no-touch' techniques utilizing K-wires in the talus/fibula minimizes this risk.

Question 2502

Topic: 8. Foot and Ankle

A 24-year-old snowboarder presents with lateral ankle pain after a hard landing. Radiographs show a fracture of the lateral process of the talus. CT imaging confirms it involves the subtalar joint and is displaced 3 mm with a 1.5 cm primary fragment. What is the most appropriate management?

. Immobilization in a short leg cast, non-weight-bearing for 6 weeks
. Excision of the fracture fragment
. Open reduction and internal fixation (ORIF) with small screws
. Primary subtalar arthrodesis
. Closed reduction and percutaneous pinning

Correct Answer & Explanation

. Open reduction and internal fixation (ORIF) with small screws

Explanation

Lateral process of the talus fractures ('snowboarder's fractures') with >2 mm of displacement or significant joint involvement (>1 cm fragment) are typically treated with ORIF to restore subtalar congruity and prevent post-traumatic arthritis. Comminuted, unfixable fragments may be treated with primary excision, but large displaced fragments warrant internal fixation.

Question 2503

Topic: 8. Foot and Ankle

A 14-year-old boy presents with a rigid flatfoot and recurrent lateral ankle sprains. Radiographs reveal a continuous 'C-sign' on the lateral view. What is the most likely diagnosis, and which anatomical structure is most commonly used for interposition following resection?

. Calcaneonavicular coalition; Extensor digitorum brevis (EDB) muscle belly
. Talocalcaneal coalition; Flexor hallucis longus (FHL) tendon or fat graft
. Talocalcaneal coalition; Extensor digitorum brevis (EDB) muscle belly
. Calcaneonavicular coalition; Flexor hallucis longus (FHL) tendon
. Calcaneonavicular coalition; Bone wax

Correct Answer & Explanation

. Talocalcaneal coalition; Extensor digitorum brevis (EDB) muscle belly

Explanation

The continuous 'C-sign' on a lateral foot radiograph is highly specific for a talocalcaneal coalition (typically involving the middle facet). Operative resection is indicated for symptomatic cases failing conservative care. Interposition with a fat graft or the flexor hallucis longus (FHL) tendon is commonly performed to prevent recurrence. The extensor digitorum brevis (EDB) is typically used as an interposition graft for calcaneonavicular coalitions, which are best seen on the 45-degree oblique view.

Question 2504

Topic: 8. Foot and Ankle

A 28-year-old man with Charcot-Marie-Tooth disease presents with a progressive, symptomatic bilateral cavovarus foot deformity. A Coleman block test is performed. The hindfoot corrects to a neutral alignment when the plantarflexed first metatarsal is allowed to hang off the medial edge of the block. What does this indicate, and what hindfoot-specific bony procedure is indicated?

. Forefoot-driven varus; dorsiflexion osteotomy of the 1st metatarsal without calcaneal osteotomy
. Rigid hindfoot varus; lateralizing calcaneal osteotomy
. Rigid forefoot valgus; plantar fasciotomy alone
. Flexible hindfoot varus; medializing calcaneal osteotomy
. Rigid hindfoot varus; subtalar arthrodesis

Correct Answer & Explanation

. Forefoot-driven varus; dorsiflexion osteotomy of the 1st metatarsal without calcaneal osteotomy

Explanation

The Coleman block test differentiates between a forefoot-driven (flexible) hindfoot varus and a rigid hindfoot varus. If the hindfoot corrects to neutral when the plantarflexed first ray drops off the block, the varus is forefoot-driven (the rigidly plantarflexed 1st ray is forcing the hindfoot into varus). In this scenario, the hindfoot is flexible, and addressing the forefoot (e.g., dorsiflexion osteotomy of the 1st metatarsal) is sufficient without the need for a structural calcaneal osteotomy.

Question 2505

Topic: 8. Foot and Ankle
An extensile lateral approach is planned for a displaced intra-articular calcaneus fracture (Sanders Type III). Which of the following technical considerations is most critical to minimize the risk of wound-healing complications and flap necrosis?
. Subcutaneous dissection prior to periosteal elevation to identify and mobilize the sural nerve
. Raising a full-thickness fasciocutaneous/periosteal flap and retracting it using 'no-touch' technique with K-wires placed into the talus
. Using self-retaining retractors to maintain constant, even tension on the apex of the flap
. Placing the horizontal limb of the incision distal to the glabrous skin junction
. Elevating the peroneal tendons from their sheath and retracting them plantarward out of the flap

Correct Answer & Explanation

. Raising a full-thickness fasciocutaneous/periosteal flap and retracting it using 'no-touch' technique with K-wires placed into the talus

Explanation

Wound complications are common (up to 25%) with the extensile lateral approach to the calcaneus. A full-thickness subperiosteal flap must be raised in a single plane (without undermining the subcutaneous tissue) to preserve the delicate blood supply from the lateral calcaneal artery. The 'no-touch' retraction technique using K-wires placed into the talus, cuboid, and fibula avoids the focal pressure necrosis caused by self-retaining or hand-held retractors.

Question 2506

Topic: Midfoot & Hindfoot
A 55-year-old woman presents with a flexible flatfoot deformity, marked weakness with manual muscle testing of inversion in plantarflexion, and inability to perform a single-limb heel rise test. The deformity is fully correctable passively. According to the Johnson and Strom classification, what stage of posterior tibial tendon dysfunction (PTTD) does this represent, and what is the standard surgical treatment if conservative measures fail?
. Stage I; Tenosynovectomy of the PTT
. Stage II; FDL transfer to the navicular combined with a medial displacement calcaneal osteotomy
. Stage III; Subtalar or Triple arthrodesis
. Stage IV; Tibiotalocalcaneal arthrodesis
. Stage II; Isolated primary repair of the PTT

Correct Answer & Explanation

. Stage II; FDL transfer to the navicular combined with a medial displacement calcaneal osteotomy

Explanation

Stage II PTTD is characterized by a flexible flatfoot deformity, inability to perform a single-limb heel rise, and PTT weakness/dysfunction. Treatment typically involves a soft tissue procedure (FDL transfer to reconstruct the PTT) combined with a bony procedure to correct the deformity and protect the transfer (e.g., medial displacement calcaneal osteotomy, lateral column lengthening). Stage I involves pain and tenosynovitis without deformity. Stage III is a rigid deformity requiring arthrodesis.

Question 2507

Topic: 8. Foot and Ankle

A 30-year-old male sustains a severe crush injury to his foot. Clinical signs raise high suspicion for an acute compartment syndrome. How many distinct fascial compartments are classically described in the foot, and which surgical approach is standardly recommended to release them?

. Four compartments; two dorsal incisions
. Seven compartments; two dorsal and one medial incision
. Nine compartments; two dorsal and one medial incision
. Nine compartments; three dorsal incisions
. Five compartments; one dorsal and one plantar incision

Correct Answer & Explanation

. Nine compartments; two dorsal and one medial incision

Explanation

There are classically 9 distinct fascial compartments in the foot: medial, lateral, superficial, calcaneal, four interosseous, and adductor. The standard surgical release utilizes a dual dorsal approach (incisions slightly medial to the 2nd metatarsal and lateral to the 4th metatarsal) combined with a medial approach (along the inferior border of the first metatarsal) to adequately access and release all 9 compartments.

Question 2508

Topic: Forefoot

A 45-year-old female presents for surgical correction of symptomatic hallux valgus. Radiographs demonstrate a Hallux Valgus Angle (HVA) of 32 degrees, an Intermetatarsal Angle (IMA) of 13 degrees, and a Distal Metatarsal Articular Angle (DMAA) of 20 degrees. The first MTP joint is congruous. Which of the following procedures is best suited to address this specific combination of radiographic findings?

. Standard Chevron osteotomy
. Proximal crescentic osteotomy with distal soft tissue release
. Ludloff osteotomy
. Lapidus procedure
. Biplanar (Reverdin) or distal medial closing wedge osteotomy

Correct Answer & Explanation

. Biplanar (Reverdin) or distal medial closing wedge osteotomy

Explanation

The patient has an abnormally high DMAA (>10-15 degrees is considered abnormal). If the DMAA is high and the joint is congruous, a standard proximal or diaphyseal osteotomy alone will tilt the articular surface further into valgus, leading to incongruity and rapid recurrence. A distal biplanar osteotomy (like a Reverdin) or a modified chevron that includes a medial closing wedge is required to correct the articular orientation (DMAA).

Question 2509

Topic: Midfoot & Hindfoot
A 28-year-old male sustains a Hawkins Type III fracture of the talar neck. What does this fracture pattern involve, and what is the approximate historical rate of avascular necrosis (AVN) of the talar body associated with it?
. Fracture of the talar neck with subtalar subluxation; AVN rate is 20-50%
. Fracture of the talar neck with subtalar and tibiotalar dislocation; AVN rate is 80-100%
. Fracture of the talar neck with talonavicular dislocation; AVN rate is 10-15%
. Fracture of the talar head with talonavicular dislocation; AVN rate is 50%
. Fracture of the talar neck with extrusion of the talar body; AVN rate is 100%

Correct Answer & Explanation

. Fracture of the talar neck with subtalar and tibiotalar dislocation; AVN rate is 80-100%

Explanation

Hawkins Type III is a vertical fracture of the talar neck with dislocation of both the subtalar and tibiotalar (ankle) joints. Because the major blood supply to the talar body is severely disrupted, the rate of AVN is historically reported as nearly 80-100%.

Question 2510

Topic: 8. Foot and Ankle

A 25-year-old equestrian presents with midfoot pain after her foot was caught in the stirrup. Weight-bearing radiographs show a 3 mm diastasis between the base of the 1st and 2nd metatarsals. An MRI confirms a complete tear of the Lisfranc ligament without any associated fractures. Which of the following is the most appropriate definitive management for this purely ligamentous Lisfranc injury?

. Non-weight-bearing cast for 8 weeks
. Primary arthrodesis of the 1st, 2nd, and 3rd tarsometatarsal joints
. Open reduction and rigid screw fixation of the 1st, 2nd, and 3rd tarsometatarsal joints
. Closed reduction and percutaneous pinning of the midfoot
. Corticosteroid injection and a stiff-soled shoe

Correct Answer & Explanation

. Primary arthrodesis of the 1st, 2nd, and 3rd tarsometatarsal joints

Explanation

High-level evidence (Ly and Coetzee, JBJS 2006) supports primary arthrodesis for purely ligamentous Lisfranc injuries, as it yields superior functional outcomes and lower reoperation rates compared to ORIF. Ligamentous injuries heal poorly and often lead to late midfoot collapse or post-traumatic arthritis when treated with ORIF alone.

Question 2511

Topic: 8. Foot and Ankle

In the surgical management of a rigid cavovarus foot deformity secondary to Charcot-Marie-Tooth disease, a Dwyer osteotomy is frequently utilized. Which of the following accurately describes this procedure?

. A medial closing-wedge osteotomy of the calcaneus to correct hindfoot valgus
. A lateral closing-wedge osteotomy of the calcaneus to correct hindfoot varus
. A medial displacement osteotomy of the calcaneal tuberosity without wedge resection
. A lateral opening-wedge osteotomy of the cuboid to correct forefoot adduction
. A dorsal closing-wedge osteotomy of the first metatarsal to elevate the medial column

Correct Answer & Explanation

. A lateral closing-wedge osteotomy of the calcaneus to correct hindfoot varus

Explanation

The Dwyer osteotomy is a lateral closing-wedge osteotomy of the calcaneus. It is used to correct the rigid hindfoot varus deformity commonly seen in cavovarus feet. Removing a laterally based wedge allows the calcaneal tuberosity to translate and angulate into valgus.

Question 2512

Topic: Midfoot & Hindfoot

A 45-year-old marathon runner complains of chronic, severe heel pain that has failed 6 months of conservative management for plantar fasciitis. Pain is maximal at the medial calcaneal tuberosity and radiates distally. At surgery, release of the first branch of the lateral plantar nerve (Baxter's nerve) is planned. Between which two muscles is this nerve typically entrapped?

. Abductor hallucis and quadratus plantae
. Flexor digitorum brevis and abductor digiti minimi
. Abductor hallucis and flexor digitorum brevis
. Quadratus plantae and flexor digitorum longus
. Tibialis posterior and flexor hallucis longus

Correct Answer & Explanation

. Flexor digitorum brevis and abductor digiti minimi

Explanation

Baxter's nerve (the first branch of the lateral plantar nerve) provides motor innervation to the abductor digiti minimi. It typically becomes entrapped as it passes under the deep fascia of the abductor hallucis and travels between the deep surface of the abductor hallucis muscle and the medial surface of the quadratus plantae muscle.

Question 2513

Topic: 8. Foot and Ankle

The high rate of delayed union and nonunion in Jones fractures (Zone 2 of the proximal fifth metatarsal) is primarily attributed to its unique vascular supply. Which of the following describes the vascular pattern that creates this watershed area?

. The metaphyseal arteries alone supply the entire proximal fifth metatarsal, with no diaphyseal contribution.
. A single nutrient artery supplies the bone from proximal to distal, ending at the diaphysis.
. An intraosseous anastomosis exists between the metaphyseal and diaphyseal arteries, but flow is highly variable.
. A watershed area exists at Zone 2 because it lies between the retrograde flow from the diaphyseal nutrient artery and antegrade flow from metaphyseal arteries.
. The peroneus brevis tendon directly avulses the sole blood supply at the insertion site.

Correct Answer & Explanation

. A watershed area exists at Zone 2 because it lies between the retrograde flow from the diaphyseal nutrient artery and antegrade flow from metaphyseal arteries.

Explanation

The proximal fifth metatarsal has a distinct vascular anatomy. The tuberosity and metaphysis (Zone 1) are well-supplied by metaphyseal arteries. The diaphysis is supplied by a nutrient artery that enters the medial cortex and sends a retrograde branch proximally. Zone 2 (the metaphyseal-diaphyseal junction) represents a vascular 'watershed' area between these two distinct blood supplies, rendering it prone to poor healing.

Question 2514

Topic: 8. Foot and Ankle

A 24-year-old female presents with a snapping sensation over the lateral aspect of her ankle during dorsiflexion and eversion. Examination reveals subluxation of the peroneal tendons over the lateral malleolus. During surgical repair, an osseous procedure is deemed necessary to deepen a flat retromalleolar groove. What is the most appropriate osseous procedure to achieve this while preserving the gliding mechanism?

. A closing-wedge osteotomy of the lateral malleolus
. Excision of the os peroneum
. Drilling and packing of the subchondral bone with cancellous allograft
. Elevation of a cortical osteoperiosteal flap from the posterior fibula, cancellous excavation, and tamping the flap back into place
. Transfer of the lateral half of the Achilles tendon to the fibula

Correct Answer & Explanation

. Elevation of a cortical osteoperiosteal flap from the posterior fibula, cancellous excavation, and tamping the flap back into place

Explanation

Deepening the retromalleolar groove can be achieved by elevating a cortical 'trapdoor' or osteoperiosteal flap from the posterior aspect of the distal fibula, excavating the underlying cancellous bone, and tamping the cortical flap back down. This preserves the smooth fibrocartilaginous gliding surface for the tendons while effectively deepening the groove to prevent subluxation.

Question 2515

Topic: 8. Foot and Ankle

A 60-year-old male with end-stage post-traumatic ankle osteoarthritis is undergoing an isolated ankle arthrodesis. To optimize gait kinematics and limit adjacent joint degeneration, what is the ideal position for fusing the tibiotalar joint?

. Neutral dorsiflexion, 5 degrees of varus, and 10 degrees of external rotation
. 5 degrees of dorsiflexion, 5 degrees of valgus, and internal rotation equal to the contralateral side
. Neutral dorsiflexion, 5 degrees of valgus, and external rotation equal to the contralateral side
. 5 degrees of plantarflexion, neutral coronal alignment, and 5 degrees of external rotation
. Neutral dorsiflexion, neutral coronal alignment, and internal rotation equal to the contralateral side

Correct Answer & Explanation

. Neutral dorsiflexion, 5 degrees of valgus, and external rotation equal to the contralateral side

Explanation

The optimal position for ankle arthrodesis is neutral dorsiflexion (0 degrees), 0 to 5 degrees of hindfoot valgus, and external rotation equal to the contralateral side (typically 5 to 10 degrees). Plantarflexion causes a recurvatum thrust at the knee, dorsiflexion causes a peg-leg gait, and varus leads to rigid locking of the transverse tarsal joints and overload of the lateral border of the foot.

Question 2516

Topic: 8. Foot and Ankle

A 24-year-old snowboarder presents with lateral ankle pain after a hard landing. Radiographs show a small bony fragment inferior to the lateral malleolus. CT confirms a highly comminuted fracture of the lateral process of the talus involving the subtalar joint. Which of the following is the most appropriate management for a severely displaced, comminuted lateral process fracture that cannot be adequately reconstructed?

. Immobilization in a short leg cast for 6 weeks
. Closed reduction and percutaneous pinning
. Open reduction and internal fixation with a mini-fragment plate
. Excision of the fracture fragments
. Primary subtalar arthrodesis

Correct Answer & Explanation

. Excision of the fracture fragments

Explanation

Fractures of the lateral process of the talus (Snowboarder's fractures) often involve the subtalar joint. While large, non-comminuted fragments (>1 cm) are best treated with open reduction and internal fixation (ORIF), severely comminuted and displaced fragments that cannot be anatomically reconstructed should be excised to prevent post-traumatic subtalar arthritis and impingement.

Question 2517

Topic: 8. Foot and Ankle

A 15-year-old boy presents with progressive bilateral foot deformities. On examination, he has a high medial arch, plantarflexed first ray, and hindfoot varus. A Coleman block test is performed, and the hindfoot varus corrects to neutral. Which of the following tendon transfers is most appropriate to address the muscular imbalance driving this specific flexible hindfoot and rigid forefoot deformity?

. Peroneus brevis to peroneus longus
. Peroneus longus to peroneus brevis
. Posterior tibial tendon to dorsum of the foot
. Flexor digitorum longus to the navicular
. Anterior tibial tendon to the lateral cuneiform

Correct Answer & Explanation

. Peroneus longus to peroneus brevis

Explanation

The Coleman block test correcting the hindfoot varus indicates a forefoot-driven deformity (due to a rigid plantarflexed first ray). In Charcot-Marie-Tooth (CMT) disease, the peroneus longus is typically overactive relative to the weak anterior tibialis, driving the first ray down. Transferring the peroneus longus to the peroneus brevis removes the deforming plantarflexion force on the first ray and augments hindfoot eversion.

Question 2518

Topic: Midfoot & Hindfoot

In Stage II adult acquired flatfoot deformity (posterior tibial tendon dysfunction), the spring ligament is frequently attenuated or torn. Which of the following is the most important static stabilizer of the talonavicular joint and the strongest component of the spring ligament complex?

. Superomedial calcaneonavicular ligament
. Inferior calcaneonavicular ligament
. Medioplantar oblique calcaneonavicular ligament
. Bifurcate ligament
. Dorsal talonavicular ligament

Correct Answer & Explanation

. Superomedial calcaneonavicular ligament

Explanation

The spring ligament complex consists of three main components. The superomedial calcaneonavicular ligament is the strongest and most critical static restraint to plantar and medial subluxation of the talar head in flatfoot deformity.

Question 2519

Topic: 8. Foot and Ankle

A 45-year-old diabetic male undergoes a Chopart (midtarsal) amputation for necrotizing fasciitis of the forefoot. Which of the following deformities is most likely to develop postoperatively if prophylactic tendon balancing is not performed?

. Equinovalgus
. Equinovarus
. Calcaneocavus
. Planovalgus
. Dorsiflexion-eversion

Correct Answer & Explanation

. Equinovarus

Explanation

A Chopart amputation removes the distal insertions of the primary dorsiflexors (anterior tibialis, EHL, EDL) and evertors (peroneus longus and brevis). This leaves the strong plantarflexors (Achilles) and invertors (posterior tibialis) unopposed, reliably leading to a severe equinovarus deformity unless appropriate tendon transfers (e.g., anterior tibialis to the talar neck) and Achilles lengthening are performed.

Question 2520

Topic: 8. Foot and Ankle

A 42-year-old recreational athlete sustains an acute Achilles tendon rupture. The treating physician is deciding between non-operative and operative management using ultrasound guidance. Which of the following findings is widely accepted as an indication to favor surgical repair over non-operative treatment?

. Rupture occurring 2-6 cm proximal to the calcaneal insertion
. Tendon gap greater than 1 cm in neutral ankle dorsiflexion
. Tendon gap greater than 5 mm in 20 degrees of plantarflexion
. Presence of an organizing hematoma at the rupture site
. Intact plantaris tendon

Correct Answer & Explanation

. Tendon gap greater than 5 mm in 20 degrees of plantarflexion

Explanation

Non-operative management of acute Achilles tendon ruptures yields excellent results provided the tendon ends can appose in equinus. An ultrasound demonstrating a gap > 5 mm with the ankle resting in 20 degrees of plantarflexion suggests insufficient apposition for functional healing, making it a strong relative indication for surgical repair.

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