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8. Foot and Ankle MCQs

Practice Set 226 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 4501

Topic: 8. Foot and Ankle

A 55-year-old female with long-standing poorly controlled type 2 diabetes mellitus presents with a swollen, warm, and erythematous left foot and ankle. She recently started a walking program. Radiographs demonstrate early periarticular fragmentation at the tarsometatarsal joints. Which of the following best describes the underlying neurovascular pathogenesis of this condition?

. Autonomic neuropathy causing decreased sympathetic tone, leading to increased blood flow and active bone resorption.
. Loss of protective sensation leading to unrecognized repetitive microtrauma.
. Peripheral arterial disease leading to focal ischemia and bone collapse.
. Upregulation of RANKL from localized soft tissue infection.
. Impaired venous return leading to venous stasis and periosteal reaction.

Correct Answer & Explanation

. Autonomic neuropathy causing decreased sympathetic tone, leading to increased blood flow and active bone resorption.

Explanation

Charcot arthropathy has two main proposed theories: neurotraumatic and neurovascular. The neurovascular theory posits that autonomic neuropathy causes a loss of sympathetic vascular tone. This leads to increased peripheral blood flow with arteriovenous shunting, hyperemia, and subsequent increased osteoclastic bone resorption, predisposing the bone to fracture and collapse.

Question 4502

Topic: 8. Foot and Ankle

When performing a calcaneal exostectomy and Achilles tendon debridement for insertional Achilles tendinopathy, what percentage of the Achilles tendon insertion can typically be detached before structural augmentation or reattachment with bone anchors is biomechanically required?

. 20%
. 50%
. 75%
. 90%
. 100%

Correct Answer & Explanation

. 50%

Explanation

Biomechanical studies and clinical experience have shown that up to 50% of the Achilles tendon insertion can be detached during a retrocalcaneal exostectomy without significant loss of pull-out strength or requirement for suture anchor repair. If greater than 50% is detached, reattachment with bone anchors is recommended to prevent avulsion.

Question 4503

Topic: 8. Foot and Ankle

A 24-year-old professional football player sustains a hyperplantarflexion injury to his right foot. He has plantar ecchymosis and pain with pronation and abduction of the midfoot. Weight-bearing radiographs show a 2 mm diastasis between the base of the first and second metatarsals. What is the most appropriate definitive management?

. Cast immobilization for 6 weeks, non-weight-bearing
. Closed reduction and percutaneous pinning
. Open reduction and internal fixation or primary arthrodesis
. Rigid walking boot for 4 weeks with progressive weight-bearing
. Corticosteroid injection and immediate return to play

Correct Answer & Explanation

. Open reduction and internal fixation or primary arthrodesis

Explanation

Plantar ecchymosis is highly suggestive of a Lisfranc injury. Weight-bearing radiographs showing >2 mm diastasis between the 1st and 2nd metatarsal bases indicate instability. The standard of care for a displaced or unstable Lisfranc injury in a young, active patient or athlete is operative intervention, typically open reduction and internal fixation (ORIF) or primary arthrodesis, to restore the anatomic alignment and stability of the midfoot.

Question 4504

Topic: 8. Foot and Ankle

A 60-year-old male presents with dorsal foot pain and stiffness of the great toe. On examination, he has a palpable dorsal osteophyte at the first metatarsophalangeal (MTP) joint and pain primarily with dorsiflexion. Radiographs reveal joint space narrowing with a large dorsal osteophyte but preserved plantar joint space. According to the Coughlin and Shurnas classification, this is Grade 2. What is the most appropriate initial surgical management if conservative measures fail?

. Cheilectomy
. First MTP arthrodesis
. Keller resection arthroplasty
. First MTP total joint replacement
. Proximal phalanx osteotomy (Moberg) alone

Correct Answer & Explanation

. Cheilectomy

Explanation

For Coughlin and Shurnas Grade 1 and 2 hallux rigidus (mild to moderate joint space narrowing, dorsal osteophyte, pain with dorsiflexion but preserved plantar joint space), a cheilectomy (removal of the dorsal osteophyte and the dorsal third of the metatarsal head) is the recommended initial surgical procedure. Arthrodesis is typically reserved for Grade 3 or 4 disease.

Question 4505

Topic: 8. Foot and Ankle

A 28-year-old male sustains an external rotation injury to his ankle. Radiographs show no fracture. An MRI reveals a complete tear of the anterior inferior tibiofibular ligament (AITFL) and interosseous membrane, with an intact posterior inferior tibiofibular ligament (PITFL). Intraoperative stress testing confirms syndesmotic instability. During fixation with suture button devices, what is the correct anatomical trajectory for drilling from the fibula to the tibia?

. 30 degrees anteriorly relative to the coronal plane
. 30 degrees posteriorly relative to the coronal plane
. Parallel to the coronal plane
. 15 degrees inferiorly relative to the axial plane
. 45 degrees superiorly relative to the axial plane

Correct Answer & Explanation

. 30 degrees anteriorly relative to the coronal plane

Explanation

The fibula sits slightly posterior to the tibia at the level of the syndesmosis. When drilling from the fibula to the tibia for syndesmotic screw or suture button fixation, the drill should be directed approximately 30 degrees anteriorly relative to the coronal plane to ensure it passes through the center of the tibia and avoids eccentric placement.

Question 4506

Topic: 8. Foot and Ankle
A 32-year-old male falls from a height and sustains a Hawkins Type III talar neck fracture. Which of the following vascular structures provides the primary blood supply to the talar body and is at greatest risk of disruption in this injury pattern?
. Artery of the tarsal canal
. Artery of the tarsal sinus
. Deltoid branches of the posterior tibial artery
. Dorsalis pedis artery branches
. Peroneal artery perforators

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. In a Hawkins Type III fracture (talar neck fracture with subluxation or dislocation of both the subtalar and tibiotalar joints), this blood supply, along with the artery of the tarsal sinus and the deltoid branches, is significantly disrupted, leading to a high rate of avascular necrosis (AVN).

Question 4507

Topic: 8. Foot and Ankle
A 55-year-old female presents with progressive flattening of her left foot, medial-sided pain, and difficulty performing a single-leg heel rise. Examination reveals a flexible flatfoot deformity with forefoot abduction (too-many-toes sign). Which of the following procedures is typically included in the surgical reconstruction for this stage of posterior tibial tendon dysfunction?
. Triple arthrodesis
. Talonavicular arthrodesis
. Flexor digitorum longus (FDL) transfer with medial displacement calcaneal osteotomy
. First tarsometatarsal joint arthrodesis (Lapidus) alone
. Gastrocnemius recession alone

Correct Answer & Explanation

. Flexor digitorum longus (FDL) transfer with medial displacement calcaneal osteotomy

Explanation

The patient has Stage II adult acquired flatfoot deformity (flexible deformity with inability to perform a single-leg heel rise). The gold standard surgical treatment for Stage II disease typically involves a soft tissue reconstruction, such as transferring the FDL to the navicular to replace the dysfunctional posterior tibial tendon, combined with a bony procedure to correct the biomechanical axis, most commonly a medial displacement calcaneal osteotomy (MDCO). Rigid deformities (Stage III) would require a triple arthrodesis.

Question 4508

Topic: 8. Foot and Ankle

A 45-year-old runner complains of burning pain and tingling radiating into the plantar aspect of his foot, exacerbated by running and prolonged standing. Examination shows a positive Tinel's sign posterior to the medial malleolus. Which of the following structures is located most anteriorly within the tarsal tunnel?

. Posterior tibial artery
. Tibial nerve
. Flexor hallucis longus tendon
. Posterior tibial tendon
. Flexor digitorum longus tendon

Correct Answer & Explanation

. Posterior tibial tendon

Explanation

The structures in the tarsal tunnel from anterior to posterior (or medial to lateral) are easily remembered by the mnemonic 'Tom, Dick, And Very Nervous Harry': Tibialis posterior tendon, flexor Digitorum longus tendon, posterior tibial Artery, posterior tibial Vein, tibial Nerve, and flexor Hallucis longus tendon. Therefore, the posterior tibial tendon is the most anterior structure.

Question 4509

Topic: 8. Foot and Ankle

A 42-year-old obese male undergoes an endoscopic plantar fascia release for recalcitrant plantar fasciitis after 18 months of failed conservative management. The surgeon completely transects the plantar fascia. Which of the following is the most likely biomechanical complication of completely releasing the plantar fascia?

. Unopposed action of the Achilles tendon leading to equinus contracture
. Loss of the windlass mechanism resulting in a dynamic flatfoot and lateral column overload
. Subluxation of the peroneal tendons
. Entrapment of the first branch of the lateral plantar nerve (Baxter's nerve)
. Progressive clawing of the lesser toes

Correct Answer & Explanation

. Loss of the windlass mechanism resulting in a dynamic flatfoot and lateral column overload

Explanation

The plantar fascia is a critical structure for maintaining the longitudinal arch of the foot through the windlass mechanism. Complete transection of the plantar fascia can lead to a loss of this mechanism, resulting in a decrease in arch height (acquired flatfoot), increased strain on the midfoot ligaments, and lateral column pain or overload (cuboid syndrome or stress fractures). A partial (medial one-third to one-half) release is generally recommended.

Question 4510

Topic: 8. Foot and Ankle

A 35-year-old recreational basketball player sustains an acute Achilles tendon rupture. He opts for non-operative management with a functional rehabilitation protocol. Compared to traditional cast immobilization, functional rehabilitation for non-operative management of Achilles tendon ruptures has been shown to result in:

. A significantly higher re-rupture rate
. An increased rate of deep vein thrombosis
. Equivalent re-rupture rates with improved functional outcomes and earlier return to work
. A higher risk of sural nerve injury
. Decreased ultimate tendon length and excessive plantarflexion strength

Correct Answer & Explanation

. Equivalent re-rupture rates with improved functional outcomes and earlier return to work

Explanation

Recent high-quality studies have demonstrated that non-operative management of acute Achilles tendon ruptures utilizing an early functional rehabilitation protocol (early weight-bearing in a functional brace and early range of motion) yields re-rupture rates equivalent to operative management, while avoiding surgical complications. Compared to traditional prolonged static cast immobilization, functional rehab offers better functional outcomes, less muscle atrophy, and an earlier return to work.

Question 4511

Topic: 8. Foot and Ankle
A 25-year-old male is brought to the emergency department after a high-speed motorcycle accident. Radiographs and CT scans of the foot and ankle reveal a displaced fracture of the talar neck. The subtalar joint is dislocated, but the tibiotalar and talonavicular joints remain concentrically reduced. Based on the most appropriate classification system for this injury, what is the estimated risk of developing avascular necrosis (AVN) of the talar body?
. 0% to 10%
. 20% to 50%
. 70% to 90%
. 90% to 100%
. Risk of AVN is dependent solely on the time to reduction rather than the fracture pattern.

Correct Answer & Explanation

. 20% to 50%

Explanation

This injury represents a Hawkins Type II talar neck fracture. The Hawkins classification dictates that Type I is a nondisplaced fracture (AVN risk 0-15%); Type II involves a displaced talar neck fracture with subtalar subluxation or dislocation (AVN risk 20-50%); Type III involves dislocation of both the subtalar and tibiotalar joints (AVN risk 50-100%, typically cited around 80%); and Type IV includes subluxation or dislocation of the talonavicular joint in addition to the subtalar and tibiotalar joints (AVN risk approaching 100%). Therefore, a Type II fracture carries a 20% to 50% risk of AVN.

Question 4512

Topic: Midfoot & Hindfoot
A 55-year-old female presents with a progressive, painful flatfoot deformity of her right foot that has failed 6 months of conservative management with custom orthotics. Clinical examination demonstrates a flexible hindfoot valgus and an inability to perform a single-limb heel rise. Radiographs demonstrate advanced collapse of the medial longitudinal arch with 45% uncoverage of the talonavicular joint on the weight-bearing AP view. Which of the following surgical strategies is most appropriate?
. Flexor digitorum longus (FDL) transfer to the navicular and a medial displacement calcaneal osteotomy (MDCO) only
. Gastrocnemius recession and a lateral column lengthening only
. Flexor digitorum longus (FDL) transfer, medial displacement calcaneal osteotomy (MDCO), and lateral column lengthening
. Triple arthrodesis (subtalar, talonavicular, and calcaneocuboid)
. Talonavicular arthrodesis with a split anterior tibialis tendon transfer (SPLATT)

Correct Answer & Explanation

. Flexor digitorum longus (FDL) transfer, medial displacement calcaneal osteotomy (MDCO), and lateral column lengthening

Explanation

This patient has Stage IIb Adult Acquired Flatfoot Deformity (posterior tibial tendon dysfunction). Stage II is characterized by a flexible deformity. Stage IIa has minimal forefoot abduction, typically managed with FDL transfer and MDCO. Stage IIb is defined by significant forefoot abduction (>30% talonavicular uncoverage). To adequately address the multiplanar deformity in Stage IIb, a lateral column lengthening (e.g., Evans osteotomy) must be added to the FDL transfer and MDCO to correct the transverse plane deformity (forefoot abduction). A triple arthrodesis is reserved for Stage III (rigid) deformities.

Question 4513

Topic: 8. Foot and Ankle

A 22-year-old collegiate football player sustains an axial loading injury to a plantarflexed foot. Weight-bearing radiographs reveal a 3.5 mm diastasis between the medial and middle cuneiforms, with no obvious fractures visualized. An MRI confirms a complete, purely ligamentous rupture of the Lisfranc ligament complex. According to recent high-level evidence, which of the following treatments provides the best long-term functional outcome and lowest rate of hardware removal?

. Non-weight-bearing cast immobilization for 8 weeks
. Closed reduction and percutaneous pinning of the medial and middle columns
. Open reduction and internal fixation (ORIF) with transarticular screws across the 1st, 2nd, and 3rd tarsometatarsal joints
. Primary arthrodesis of the 1st, 2nd, and 3rd tarsometatarsal joints
. Suture-button fixation of the 1st and 2nd metatarsal bases

Correct Answer & Explanation

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

Explanation

A purely ligamentous Lisfranc injury is inherently unstable and prone to collapse or post-traumatic arthritis if treated with ORIF alone. Landmark studies (such as those by Ly and Coetzee) have demonstrated that primary arthrodesis of the medial columns (1st, 2nd, and 3rd TMT joints) for purely ligamentous Lisfranc injuries yields superior functional outcomes, a faster return to baseline activities, and avoids the need for planned hardware removal compared to ORIF.

Question 4514

Topic: Forefoot

A 48-year-old female presents for surgical management of a painful hallux valgus deformity. Clinical examination reveals profound hypermobility of the first tarsometatarsal (TMT) joint in the sagittal plane. Weight-bearing radiographs show a Hallux Valgus Angle (HVA) of 42 degrees and an Intermetatarsal Angle (IMA) of 18 degrees. Which of the following procedures is most strongly indicated?

. Distal chevron osteotomy with a modified McBride procedure
. Scarf (midshaft) osteotomy of the first metatarsal
. Proximal opening wedge osteotomy of the first metatarsal
. First tarsometatarsal joint arthrodesis (Lapidus procedure)
. First metatarsophalangeal (MTP) joint arthrodesis

Correct Answer & Explanation

. First tarsometatarsal joint arthrodesis (Lapidus procedure)

Explanation

The patient has a severe hallux valgus deformity (HVA >40 degrees, IMA >15 degrees) combined with first TMT joint hypermobility. The Lapidus procedure (first TMT arthrodesis) is the procedure of choice in the setting of first ray hypermobility or significant midfoot instability, as it corrects the primary site of instability and allows for excellent correction of a large IMA. Distal or diaphyseal osteotomies would likely fail or recur due to the unaddressed hypermobility at the TMT joint.

Question 4515

Topic: 8. Foot and Ankle

Total ankle arthroplasty (TAA) is increasingly utilized for end-stage ankle osteoarthritis. However, stringent patient selection is critical for prosthesis survival. Which of the following is considered an absolute contraindication for primary total ankle arthroplasty?

. Patient age of 52 years
. Severe adjacent subtalar joint osteoarthritis
. Prior history of an ipsilateral ankle fracture treated with ORIF 10 years ago
. Charcot neuroarthropathy with loss of protective sensation
. Contralateral ankle arthrodesis

Correct Answer & Explanation

. Charcot neuroarthropathy with loss of protective sensation

Explanation

Charcot neuroarthropathy, active infection, absent leg sensation/neurologic compromise, and severe avascular necrosis of the talus (loss of >50% of the talar body) are widely recognized as absolute contraindications for total ankle arthroplasty due to unacceptably high rates of catastrophic failure, loosening, and infection. Subtalar arthritis is actually a relative indication for TAA over arthrodesis to preserve remaining hindfoot motion, and a contralateral ankle arthrodesis often sways surgeons to perform a TAA to prevent bilateral stiffening.

Question 4516

Topic: 8. Foot and Ankle

A 28-year-old professional skier reports chronic posterolateral ankle pain and a 'snapping' sensation over the lateral malleolus when turning forcefully. Examination reveals subluxation of the peroneal tendons over the distal fibula with active dorsiflexion and eversion. MRI demonstrates a torn superior peroneal retinaculum (SPR) and a convex posterior fibular border. Operative intervention is planned. In addition to primary repair or reconstruction of the SPR, which surgical step is most critical to prevent recurrence?

. Peroneus brevis to peroneus longus tenodesis
. Fibular groove deepening
. Lateral column lengthening
. Evans tenodesis
. Release of the inferior peroneal retinaculum

Correct Answer & Explanation

. Fibular groove deepening

Explanation

The patient has chronic peroneal tendon subluxation, primarily stabilized by the superior peroneal retinaculum (SPR). An anatomic variant such as a flat or convex retromalleolar fibular groove strongly predisposes to this condition and its recurrence. Therefore, fibular groove deepening is critical alongside SPR repair to ensure a stable anatomic trough for the tendons, significantly lowering the risk of recurrent subluxation.

Question 4517

Topic: 8. Foot and Ankle

A 62-year-old male with poorly controlled type II diabetes and peripheral neuropathy presents with a globally swollen, erythematous, and warm right foot for the past 3 weeks. He denies any trauma or skin ulcerations. His oral temperature is 37.1 °C, WBC is 8.5 x 10^9/L, and CRP is mildly elevated. Radiographs show soft tissue swelling and early fragmentation of the navicular with subtle periarticular debris, but no focal osteopenia. If the limb is elevated for 10 minutes, the erythema significantly diminishes. What is the most appropriate initial management?

. Empiric intravenous vancomycin and piperacillin-tazobactam
. Immediate operative debridement and bone biopsy
. Total contact casting and strict non-weight-bearing
. Open reduction and internal fixation of the midfoot
. Prescription of custom accommodating footwear and full weight-bearing

Correct Answer & Explanation

. Total contact casting and strict non-weight-bearing

Explanation

This patient is presenting with acute Charcot neuroarthropathy (Eichenholtz Stage 0 or I), characterized by a red, hot, swollen foot in a neuropathic patient. The absence of an ulcer makes osteomyelitis highly unlikely. The 'elevation test' (dependent rubor that resolves with elevation) strongly supports an inflammatory/autonomic etiology (Charcot) rather than infection. The gold standard initial treatment for acute Charcot arthropathy is strict offloading and immobilization using a total contact cast (TCC) to arrest the acute inflammatory phase and prevent further bony collapse.

Question 4518

Topic: 8. Foot and Ankle

During open reduction and internal fixation of a pronation-external rotation (PER) ankle fracture, you suspect an associated syndesmotic injury. The medial clear space was widened preoperatively. After rigid fixation of the fibula, you perform an intraoperative 'hook test' which demonstrates 4 mm of lateral translation of the fibula. You decide to fix the syndesmosis. Which of the following modalities has the highest sensitivity for detecting postoperative syndesmotic malreduction?

. Standard intraoperative anterior-posterior (AP) and mortise fluoroscopy
. Measurement of the tibiofibular clear space on plain radiographs
. Measurement of the tibiofibular overlap on plain radiographs
. Bilateral computed tomography (CT) or intraoperative 3D fluoroscopy
. Clinical assessment of ankle dorsiflexion range of motion post-fixation

Correct Answer & Explanation

. Bilateral computed tomography (CT) or intraoperative 3D fluoroscopy

Explanation

Standard plain radiographs and 2D intraoperative fluoroscopy are notoriously inaccurate for assessing syndesmotic reduction, missing malreductions in up to 20-30% of cases. Bilateral axial CT imaging (or intraoperative 3D fluoroscopy) is the gold standard and has the highest sensitivity and specificity for evaluating the reduction of the distal tibiofibular syndesmosis, as it allows direct visualization of the fibula within the incisura fibularis.

Question 4519

Topic: 8. Foot and Ankle

A 42-year-old healthy male suffers an acute, complete mid-substance rupture of his Achilles tendon while playing tennis. He opts for non-operative management. Based on recent prospective randomized controlled trials (e.g., Willits et al.), which rehabilitation protocol has been shown to result in re-rupture rates comparable to surgical repair?

. Strict non-weight-bearing in an equinus cast for 8 weeks followed by neutral bracing
. Early functional rehabilitation in a removable brace with early protected weight-bearing
. Immediate full weight-bearing in a flat shoe with no immobilization
. Non-weight-bearing cast in equinus for 4 weeks, followed by casting in neutral for 4 weeks
. Prolonged immobilization in an external fixator to maintain tendon length

Correct Answer & Explanation

. Early functional rehabilitation in a removable brace with early protected weight-bearing

Explanation

High-level evidence, particularly the landmark study by Willits et al., has demonstrated that acute Achilles tendon ruptures treated non-operatively with an early functional rehabilitation protocol (removable brace allowing early protected weight-bearing and early range of motion) yield functional outcomes and re-rupture rates that are statistically comparable to those of operative repair. Prolonged rigid casting (options 0 and 3) leads to tendon elongation, profound calf atrophy, and higher re-rupture rates compared to functional rehab.

Question 4520

Topic: Forefoot

A 45-year-old female presents with a progressive medial deviation of her great toe 1 year after a distal chevron osteotomy with a lateral soft tissue release for hallux valgus. She complains of pain and difficulty with shoe wear. Examination reveals a flexible hallux varus deformity. Radiographs show a congruent first metatarsophalangeal (MTP) joint with a negative intermetatarsal angle and no evidence of MTP joint arthritis. What is the most appropriate surgical management?

. First MTP joint arthrodesis
. Extensor hallucis longus (EHL) transfer beneath the transverse metatarsal ligament
. Medial capsulorrhaphy with adductor hallucis advancement
. First tarsometatarsal (TMT) joint arthrodesis
. Closing wedge osteotomy of the proximal phalanx

Correct Answer & Explanation

. Extensor hallucis longus (EHL) transfer beneath the transverse metatarsal ligament

Explanation

This patient has an iatrogenic flexible hallux varus deformity following an overcorrected bunion surgery. For a flexible deformity without degenerative changes, soft tissue reconstruction is indicated. The classic and most reliable procedure is the transfer of the extensor hallucis longus (EHL) (either split or whole) beneath the transverse intermetatarsal ligament into the base of the proximal phalanx, often combined with an MTP joint release. First MTP arthrodesis is reserved for a stiff, arthritic hallux varus or failed soft tissue reconstructions.

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