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8. Foot and Ankle MCQs

Practice Set 230 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 4581

Topic: Forefoot

A 45-year-old female presents with a painful bunion. Weight-bearing radiographs reveal a Hallux Valgus Angle (HVA) of 45 degrees, an Intermetatarsal Angle (IMA) of 18 degrees, and clinical hypermobility of the first tarsometatarsal (TMT) joint. Which of the following surgical procedures is most biomechanically appropriate to correct her deformity?

. Distal chevron osteotomy
. Scarf osteotomy
. Proximal crescentic osteotomy with distal soft tissue realignment
. First TMT joint arthrodesis (Lapidus procedure) with distal soft tissue realignment
. First metatarsophalangeal (MTP) joint arthrodesis

Correct Answer & Explanation

. First TMT joint arthrodesis (Lapidus procedure) with distal soft tissue realignment

Explanation

A severe hallux valgus deformity (IMA >15 degrees, HVA >40 degrees) in the presence of first TMT joint hypermobility is classically treated with a Lapidus procedure (first TMT arthrodesis). This provides powerful correction of the intermetatarsal angle and stabilizes the medial column, preventing recurrence that is common if hypermobility is ignored.

Question 4582

Topic: 8. Foot and Ankle
A 40-year-old roofer falls from a ladder, sustaining a Sanders type III calcaneus fracture. An open reduction and internal fixation via an extensile lateral approach is planned. To minimize the risk of the most common postoperative wound complication associated with this approach, how should the surgical flap be managed?
. Developing the flap in a subperiosteal plane to create a full-thickness "no-touch" flap
. Using a combination of sharp dissection and electrocautery directly on the periosteum
. Dividing the flap at the level of the deep fascia to preserve superficial nerves
. Making the vertical limb of the incision directly over the Achilles tendon to avoid the sural nerve
. Delaying surgery until exactly 4 weeks post-injury to allow maximal swelling reduction

Correct Answer & Explanation

. Developing the flap in a subperiosteal plane to create a full-thickness "no-touch" flap

Explanation

The extensile lateral approach to the calcaneus carries a significant risk of wound edge necrosis and infection. To minimize this, a full-thickness subperiosteal flap must be developed. Retractors (such as K-wires inserted into the talus) should be used to hold the flap (the 'no-touch' technique), preserving the delicate vascular supply from the lateral calcaneal artery.

Question 4583

Topic: 8. Foot and Ankle

A 25-year-old professional athlete sustains a purely ligamentous Lisfranc injury with 3 mm of displacement between the medial cuneiform and second metatarsal base. Based on recent prospective studies evaluating primarily ligamentous Lisfranc injuries, primary arthrodesis compared to open reduction and internal fixation (ORIF) is associated with which of the following?

. Higher rates of hardware removal
. Decreased rates of return to pre-injury level of sport
. Lower rates of secondary surgeries and less functional deterioration over time
. Increased incidence of nonunion requiring revision
. Superior outcomes for concurrent 4th and 5th TMT joint involvement

Correct Answer & Explanation

. Lower rates of secondary surgeries and less functional deterioration over time

Explanation

Prospective studies (such as Coetzee and Ly) comparing ORIF to primary arthrodesis for purely ligamentous Lisfranc injuries have demonstrated that primary arthrodesis leads to comparable or superior functional outcomes in the short term, but significantly less functional deterioration over time, and lower rates of secondary surgeries (due to lack of hardware irritation/removal or post-traumatic arthritis). The 4th and 5th TMT joints should almost never be primarily fused, as they are essential for mobile foot adaptation.

Question 4584

Topic: Midfoot & Hindfoot

A 58-year-old male with poorly controlled type II diabetes presents with a swollen, erythematous, and warm right foot. He denies any trauma. Radiographs reveal periarticular fragmentation, subluxation of the tarsometatarsal joints, and osseous debris. According to the Eichenholtz classification, what stage does this represent, and what is the standard initial treatment?

. Stage 0; immediate open reduction and internal fixation
. Stage 1 (Developmental); total contact casting and non-weight bearing
. Stage 2 (Coalescence); custom orthoses and weight bearing as tolerated
. Stage 3 (Reconstruction); primary arthrodesis
. Stage 1 (Developmental); intravenous antibiotics and irrigation and debridement

Correct Answer & Explanation

. Stage 1 (Developmental); total contact casting and non-weight bearing

Explanation

This clinical and radiographic picture characterizes Eichenholtz Stage 1 (Developmental/Fragmentation) Charcot arthropathy. It is marked by joint edema, warmth, periarticular fragmentation, debris, and subluxation/dislocation. The standard of care in the acute active phase is immobilization (Total Contact Cast) and strict non-weight bearing to prevent further deformity until the active phase transitions to coalescence (Stage 2).

Question 4585

Topic: Forefoot

A 22-year-old running back sustains an acute hyperextension injury to his great toe. MRI demonstrates a complete tear of the plantar plate with proximal retraction of the sesamoids. Which of the following is an absolute indication for operative repair in this type of injury?

. Associated dorsal capsular sprain
. Diastasis of a bipartite sesamoid of 1 mm
. Proximal migration of the sesamoids with a frankly unstable first MTP joint
. Inability to push off at 2 days post-injury
. Extension block of 5 degrees compared to the contralateral side

Correct Answer & Explanation

. Proximal migration of the sesamoids with a frankly unstable first MTP joint

Explanation

Turf toe is a sprain/tear of the first MTP plantar plate complex. Operative indications for turf toe include: a large intra-articular sesamoid fracture, retraction of the sesamoids >3 mm, traumatic bunion deformity, a purely unstable joint (gross instability), or failure of conservative management. Proximal migration of the sesamoids with gross first MTP instability indicates a complete (Grade 3) rupture requiring surgical repair.

Question 4586

Topic: 8. Foot and Ankle

A 20-year-old collegiate basketball player complains of lateral foot pain for 3 months. Radiographs demonstrate a radiolucent line with cortical hypertrophy distal to the fourth-fifth intermetatarsal articulation in the fifth metatarsal. What is the most appropriate management to ensure the fastest return to play with the lowest risk of nonunion?

. Non-weight bearing in a short leg cast for 6 weeks
. Weight bearing as tolerated in a stiff-soled shoe
. Intramedullary screw fixation
. Excision of the fifth metatarsal base
. Plate and screw fixation

Correct Answer & Explanation

. Intramedullary screw fixation

Explanation

The clinical scenario and radiographic findings describe a Zone 3 proximal diaphyseal stress fracture of the fifth metatarsal. Because these fractures occur in a vascular watershed area and have a high risk of delayed union or nonunion (especially with cortical hypertrophy indicating chronicity), the gold standard treatment in an elite athlete to allow for rapid return to play is intramedullary screw fixation.

Question 4587

Topic: 8. Foot and Ankle

During an open reduction and internal fixation of a bimalleolar equivalent ankle fracture, the surgeon performs an intraoperative Cotton test to evaluate the syndesmosis. Which fluoroscopic measurement objectively indicates syndesmotic instability requiring operative fixation?

. Tibiofibular clear space > 5 mm on the AP view
. Medial clear space > 4 mm on the mortise view with lateral translation of the fibula
. Tibiofibular overlap > 1 mm on the mortise view
. Talar tilt of 2 degrees compared to the uninjured side
. Anterior translation of the talus > 3 mm on a lateral stress view

Correct Answer & Explanation

. Medial clear space > 4 mm on the mortise view with lateral translation of the fibula

Explanation

The Cotton test involves applying a lateral force to the fibula using a bone hook. Widening of the medial clear space > 4 mm (or asymmetry compared to the superior clear space) on a mortise view indicates deep deltoid and syndesmotic disruption. Normal tibiofibular clear space is < 6 mm on both AP and mortise views, and normal overlap is > 1 mm on the mortise view.

Question 4588

Topic: 8. Foot and Ankle
A 42-year-old recreational runner presents with 6 months of posterior ankle pain. Physical exam reveals a palpable, tender nodule 4 cm proximal to the calcaneal insertion of the Achilles tendon. MRI shows fusiform thickening and mucoid degeneration involving >50% of the tendon substance. Conservative treatment has failed. During surgical debridement of the tendinosis, if more than 50% of the tendon is debrided, what is the most appropriate adjunctive procedure to preserve plantarflexion strength?
. Flexor digitorum longus (FDL) tendon transfer
. Flexor hallucis longus (FHL) tendon transfer
. Peroneus brevis tendon transfer
. Tibialis anterior tendon transfer
. Primary end-to-end repair using non-absorbable suture alone

Correct Answer & Explanation

. Flexor hallucis longus (FHL) tendon transfer

Explanation

For severe non-insertional Achilles tendinopathy where more than 50% of the tendon is compromised and requires debridement, primary repair alone is biomechanically insufficient. Augmentation is indicated. The flexor hallucis longus (FHL) tendon transfer is the procedure of choice due to its strong plantarflexion force, line of pull (in phase with the Achilles), and anatomic proximity.

Question 4589

Topic: 8. Foot and Ankle
A 30-year-old male sustains a high-energy motor vehicle collision resulting in a closed injury to his foot and ankle. Radiographs reveal a displaced fracture of the talar neck with subluxation of the subtalar joint, while the tibiotalar joint remains completely congruent. According to the Hawkins classification, what is the injury type and the approximate associated risk of avascular necrosis (AVN) of the talar body?
. Hawkins Type I; 0% to 10% risk of AVN
. Hawkins Type II; 20% to 50% risk of AVN
. Hawkins Type III; 80% to 100% risk of AVN
. Hawkins Type IV; 100% risk of AVN
. Hawkins Type II; greater than 80% risk of AVN

Correct Answer & Explanation

. Hawkins Type II; 20% to 50% risk of AVN

Explanation

This is a Hawkins Type II fracture, defined as a vertical fracture of the talar neck with subluxation or dislocation of the subtalar joint, but with an intact ankle (tibiotalar) joint. The risk of avascular necrosis (AVN) for a Type II injury is historically cited as 20% to 50%. Hawkins Type I is non-displaced (0-10% AVN risk), Type III involves both subtalar and tibiotalar dislocation (high AVN risk, >80%), and Type IV adds talonavicular subluxation/dislocation.

Question 4590

Topic: Midfoot & Hindfoot

A 55-year-old female presents with progressive, painful flatfoot deformity. Examination reveals a flexible hindfoot valgus and an inability to perform a single-limb heel rise. When viewing the foot from behind, 'too many toes' are visible. Radiographs demonstrate an uncoverage of the talar head of 45%. Which of the following surgical strategies is most appropriate for addressing this specific stage of adult acquired flatfoot deformity?

. Flexor digitorum longus (FDL) transfer to the navicular and spring ligament repair alone
. Medial displacement calcaneal osteotomy and FDL transfer
. Lateral column lengthening, medial displacement calcaneal osteotomy, and FDL transfer
. Isolated subtalar arthrodesis
. Triple arthrodesis

Correct Answer & Explanation

. Lateral column lengthening, medial displacement calcaneal osteotomy, and FDL transfer

Explanation

This patient has Stage IIb adult-acquired flatfoot deformity (posterior tibial tendon dysfunction). Stage IIb is differentiated from Stage IIa by the presence of significant forefoot abduction (typically >30% talonavicular uncoverage). While Stage IIa can be treated with a medial displacement calcaneal osteotomy (MDCO) and FDL transfer, Stage IIb requires the addition of a lateral column lengthening (e.g., Evans osteotomy) to adequately correct the transverse plane deformity (forefoot abduction).

Question 4591

Topic: 8. Foot and Ankle

A 24-year-old male with a history of Charcot-Marie-Tooth disease presents with a bilateral symptomatic cavovarus foot deformity. During the Coleman block test, the patient's lateral foot and heel are placed on a 1-inch wooden block while the first metatarsal is allowed to hang freely in plantarflexion. During this test, the hindfoot varus completely corrects to neutral. What does this clinical finding indicate regarding the primary driver of the deformity?

. The deformity is driven by a fixed contracture of the subtalar joint
. The deformity is driven by isolated spasticity of the tibialis posterior tendon
. The deformity is secondary to an isolated Achilles tendon contracture
. The deformity is a flexible, forefoot-driven hindfoot varus secondary to a plantarflexed first ray
. The deformity is a rigid, hindfoot-driven varus requiring a triple arthrodesis

Correct Answer & Explanation

. The deformity is a flexible, forefoot-driven hindfoot varus secondary to a plantarflexed first ray

Explanation

The Coleman block test is essential in evaluating a cavovarus foot. If allowing the first ray to plantarflex off the block corrects the hindfoot varus, it demonstrates that the hindfoot varus is flexible and primarily driven by the rigid, plantarflexed first ray hitting the ground early and forcing the hindfoot into varus. Surgical correction in this case must address the forefoot (e.g., dorsiflexion osteotomy of the 1st metatarsal) alongside any necessary soft tissue balancing.

Question 4592

Topic: 8. Foot and Ankle

A 22-year-old collegiate football player sustains a hyperplantarflexion injury to his midfoot. Weight-bearing radiographs show a 3 mm diastasis between the base of the first and second metatarsals. CT scan confirms a pure ligamentous Lisfranc injury with no associated osseous fractures. To optimize functional outcomes and minimize the risk of hardware failure or post-traumatic arthritis, which of the following is the most evidence-based surgical treatment?

. Closed reduction and percutaneous pinning with removal at 6 weeks
. Open reduction and internal fixation (ORIF) with transarticular solid screws
. Primary arthrodesis of the first, second, and third tarsometatarsal joints
. Dorsal bridge plating spanning the entire midfoot
. Non-operative management in a non-weight-bearing cast for 8 weeks

Correct Answer & Explanation

. Primary arthrodesis of the first, second, and third tarsometatarsal joints

Explanation

Multiple studies, including the landmark prospective randomized trial by Ly and Coetzee, have demonstrated that primary arthrodesis of the medial column (first, second, and third tarsometatarsal joints) provides superior functional outcomes and lower reoperation rates compared to ORIF in cases of purely ligamentous Lisfranc injuries. ORIF has a higher rate of hardware failure, loss of reduction, and subsequent post-traumatic arthritis in purely ligamentous variants.

Question 4593

Topic: Forefoot

A 45-year-old female presents with a painful bunion. Clinical examination demonstrates significant hypermobility of the first tarsometatarsal (TMT) joint in the sagittal plane. Weight-bearing radiographs reveal a hallux valgus angle (HVA) of 42 degrees and an intermetatarsal angle (IMA) of 16 degrees. Which of the following surgical options is most appropriate?

. Distal chevron osteotomy
. Proximal crescentic osteotomy
. First tarsometatarsal (TMT) joint arthrodesis (Lapidus procedure)
. First metatarsophalangeal (MTP) joint arthrodesis
. Isolated medial eminence excision (Silver procedure)

Correct Answer & Explanation

. First tarsometatarsal (TMT) joint arthrodesis (Lapidus procedure)

Explanation

The Lapidus procedure (first TMT arthrodesis) is indicated for patients with moderate to severe hallux valgus (IMA > 13 degrees) who have concurrent hypermobility of the first ray. It provides excellent correction of the intermetatarsal angle and stabilizes the medial column, preventing recurrence that is often seen if only a distal or proximal osteotomy is utilized in the presence of TMT hypermobility.

Question 4594

Topic: 8. Foot and Ankle

During open reduction and internal fixation of a pronation-external rotation (PER) ankle fracture, a syndesmotic diastasis is confirmed using the intraoperative hook test. When placing a trans-syndesmotic positional screw, which of the following represents the most accurate anatomic and biomechanical principle?

. The ankle must be held in maximal dorsiflexion during screw placement to prevent postoperative stiffness
. The screw should be directed parallel to the joint line, angled approximately 20 to 30 degrees from posterolateral to anteromedial
. The screw must engage exactly three cortices to allow for physiologic syndesmotic micro-motion
. Suture button constructs have a significantly higher rate of hardware failure and removal than rigid screws
. The screw should be placed 5 cm above the ankle joint line to maximize biomechanical stability

Correct Answer & Explanation

. The screw should be directed parallel to the joint line, angled approximately 20 to 30 degrees from posterolateral to anteromedial

Explanation

Because the fibula is positioned posterior to the tibia at the level of the syndesmosis, the optimal trajectory for a trans-syndesmotic screw is 20 to 30 degrees from posterolateral to anteromedial to anatomically capture the tibia. Research (e.g., Tornetta et al.) has shown that the position of the ankle (dorsiflexion vs. plantarflexion) during screw placement does not significantly affect the final mortise width or postoperative range of motion. Typically, screws are placed 2-3 cm above the joint line.

Question 4595

Topic: 8. Foot and Ankle

A 35-year-old male presents with an isolated, complete, and irreversible common peroneal nerve palsy following a traumatic knee dislocation 2 years ago. He has a flexible hindfoot and a passively correctable equinus contracture. Which tendon transfer is considered the gold standard to restore active dorsiflexion and prevent foot drop in this patient?

. Flexor hallucis longus transferred to the anterior midfoot
. Tibialis posterior transferred through the interosseous membrane to the lateral or middle cuneiform
. Peroneus longus transferred to the tibialis anterior
. Flexor digitorum longus transferred to the navicular
. Achilles tendon split transfer to the anterior tibial crest

Correct Answer & Explanation

. Tibialis posterior transferred through the interosseous membrane to the lateral or middle cuneiform

Explanation

The tibialis posterior tendon is the classic and most reliable transfer for an isolated common peroneal nerve palsy (foot drop). It is usually detached from its insertion, routed through the interosseous membrane, and secured to the dorsum of the foot (often the lateral or middle cuneiform) to restore active dorsiflexion. A concomitant Achilles lengthening is often required if an equinus contracture is present, but the primary motor substitution is the posterior tibial tendon.

Question 4596

Topic: 8. Foot and Ankle

A 55-year-old female presents with stage IIB posterior tibial tendon dysfunction. During her surgical reconstruction, a lateral column lengthening is performed in addition to a medializing calcaneal osteotomy and flexor digitorum longus (FDL) transfer. What is the primary biomechanical purpose of the lateral column lengthening in this setting?

. To correct fixed forefoot supination
. To restore the medial longitudinal arch by directly plantarflexing the first ray
. To directly repair and tension the spring ligament complex
. To correct forefoot abduction through the transverse tarsal joint
. To prevent progression to secondary ankle valgus

Correct Answer & Explanation

. To correct forefoot abduction through the transverse tarsal joint

Explanation

Lateral column lengthening (such as an Evans osteotomy) is primarily used in Stage IIB adult-acquired flatfoot deformity to correct forefoot abduction, which occurs due to uncoupling of the transverse tarsal joint (talonavicular joint uncoverage). While it indirectly restores the medial arch, its primary and direct effect is correcting the abduction deformity.

Question 4597

Topic: 8. Foot and Ankle

A 32-year-old male undergoes anterior ankle arthroscopy for an osteochondral lesion of the talus. During the establishment of the anterolateral portal, a nerve is inadvertently injured. Which of the following functional deficits is most likely to result from this specific injury?

. Loss of sensation over the dorsal first web space
. Loss of sensation over the lateral border of the foot
. Loss of sensation over the dorsum of the foot excluding the first web space
. Weakness in active ankle dorsiflexion
. Weakness in great toe extension

Correct Answer & Explanation

. Loss of sensation over the dorsum of the foot excluding the first web space

Explanation

The anterolateral portal places the superficial peroneal nerve at risk. Injury to this nerve leads to sensory loss or paresthesias over the dorsum of the foot, sparing the first web space (which is innervated by the deep peroneal nerve). The anteromedial portal places the saphenous nerve at risk.

Question 4598

Topic: 8. Foot and Ankle

A 58-year-old patient with poorly controlled type 2 diabetes presents with a swollen, erythematous, and warm right foot without any open ulcers. Radiographs show periarticular osteopenia and early subluxation of the tarsometatarsal joints. Which of the following MRI findings best differentiates acute Charcot arthropathy from osteomyelitis in this patient?

. Bone marrow edema restricted to the cuboid and cuneiforms
. Diffuse soft tissue edema without fluid collections
. Enhancement of the bone marrow on T1 post-contrast images
. Diffuse bone marrow edema involving the entire calcaneus
. Subchondral bone marrow edema strictly confined to periarticular regions

Correct Answer & Explanation

. Subchondral bone marrow edema strictly confined to periarticular regions

Explanation

In acute Charcot arthropathy, MRI typically reveals bone marrow edema that is periarticular and subchondral, involving multiple adjacent bones around a joint (e.g., the midfoot). Conversely, osteomyelitis usually arises contiguous to a soft tissue ulcer, presenting with diffuse marrow edema that is not strictly periarticular, often associated with cortical destruction, sinus tracts, or abscesses.

Question 4599

Topic: 8. Foot and Ankle

A 40-year-old male undergoes open reduction and internal fixation of a displaced intra-articular calcaneus fracture via an extensile lateral approach. At his 6-week follow-up, he is noted to have significant clawing of the lesser toes. What is the most likely cause of this complication?

. Injury to the superficial peroneal nerve
. Undiagnosed compartment syndrome of the foot
. Over-lengthening of the Achilles tendon
. Entrapment of the flexor hallucis longus tendon
. Iatrogenic sural nerve neuroma

Correct Answer & Explanation

. Undiagnosed compartment syndrome of the foot

Explanation

Clawing of the lesser toes after a calcaneus fracture is the hallmark late sequela of an unrecognized foot compartment syndrome. Ischemia and subsequent fibrotic contracture of the intrinsic muscles of the foot (specifically the interossei and lumbricals, as well as quadratus plantae) lead to an imbalance, causing the claw toe deformity.

Question 4600

Topic: 8. Foot and Ankle
A 28-year-old motorcyclist sustains a Hawkins type III talar neck fracture. Which of the following arteries provides the majority of the blood supply to the talar body, placing it at the highest risk for avascular necrosis (AVN) in this injury pattern?
. Artery of the tarsal sinus
. Dorsalis pedis artery
. Artery of the tarsal canal
. Deltoid branches of the posterior tibial artery
. Peroneal 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 majority of the blood supply to the talar body. In a Hawkins type III fracture (displaced talar neck fracture with subluxation/dislocation of both the subtalar and ankle joints), the blood supply from the artery of the tarsal canal, artery of the tarsal sinus, and the capsular vessels is severely disrupted, leading to an AVN risk nearing 100%.

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