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8. Foot and Ankle MCQs

Practice Set 105 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 2081

Topic: Midfoot & Hindfoot
A 24-year-old snowboarder sustains a hyperdorsiflexion injury to his ankle. Radiographs show a talar neck fracture with subluxation of the subtalar joint, but the tibiotalar joint remains congruous. According to the Hawkins classification, what type is this fracture, and what is the approximate rate of avascular necrosis (AVN)?
. Type I, 0-10%
. Type II, 20-50%
. Type III, 80-100%
. Type IV, 100%
. Type II, 80-100%

Correct Answer & Explanation

. Type II, 20-50%

Explanation

According to the Hawkins classification of talar neck fractures: Type I is nondisplaced (AVN 0-10%). Type II has subtalar subluxation or dislocation with an intact tibiotalar joint (AVN ~20-50%). Type III has both subtalar and tibiotalar dislocation (AVN ~80-100%). Type IV (Canale modification) includes talonavicular subluxation/dislocation.

Question 2082

Topic: 8. Foot and Ankle

A 28-year-old male construction worker falls from a ladder and sustains an intra-articular calcaneus fracture. Radiographs show a decreased Bohler's angle and an increased angle of Gissane. He is scheduled for open reduction and internal fixation. Which of the following surgical approaches provides the most comprehensive exposure of the subtalar joint and the lateral wall of the calcaneus?

. Medial approach
. Sinus tarsi approach
. Extensile lateral approach
. Posterior Achilles-splitting approach
. Plantar approach

Correct Answer & Explanation

. Medial approach

Explanation

The extensile lateral approach is the standard, traditional surgical approach for complex, displaced intra-articular calcaneus fractures. It provides excellent, comprehensive exposure of the entire lateral wall of the calcaneus, the posterior facet of the subtalar joint, and the calcaneocuboid joint, allowing for precise reduction and plate fixation. While the sinus tarsi approach is less invasive and gaining popularity, it provides more limited exposure compared to the extensile lateral approach.

Question 2083

Topic: 8. Foot and Ankle
A 25-year-old male sustains a Hawkins type III talar neck fracture following a fall from height. Which of the following accurately describes the pathoanatomy and associated risk of avascular necrosis (AVN) for this fracture pattern?
. Nondisplaced fracture; 0-10% AVN risk
. Displaced fracture with subtalar dislocation; 20-50% AVN risk
. Displaced fracture with subtalar and tibiotalar dislocation; >80% AVN risk
. Displaced fracture with talonavicular dislocation; 100% AVN risk
. Extruded talus; 50% AVN risk

Correct Answer & Explanation

. Displaced fracture with subtalar and tibiotalar dislocation; >80% AVN risk

Explanation

A Hawkins type III talar neck fracture involves displacement with dislocation of both the subtalar and tibiotalar joints. This severely disrupts the blood supply (artery of the tarsal canal, deltoid branches), leading to an AVN risk that frequently approaches 80-100%.

Question 2084

Topic: 8. Foot and Ankle
A 38-year-old man underwent a transtibial amputation for chronic posttraumatic foot and ankle pain and chronic calcaneal osteomyelitis. Postoperative radiographs are seen in Figures 41a and 41b. What is the proposed purpose of the surgical modification seen in the radiographs?
. Reduces shrinkage of the residual limb
. Creates a more stable platform for load transfer
. Reduces wound healing complications by avoiding the soft-tissue dissection necessary to transect the fibula at a level proximal to the tibia
. Connecting bone strut provides an attachment point for more effective myodesis
. Allows a more proximal resection level to decrease tension on the wound

Correct Answer & Explanation

. Creates a more stable platform for load transfer

Explanation

The Ertl modification of a below-knee amputation has been proposed to create a more stable “platform” to aid in transferring the load of weight bearing between the residual limb and the prosthetic socket. It is felt that a stable platform allows total contact loading over an enlarged stable surface area. Early studies have suggested that this modification may enhance the patient’s perceived functional outcome.

Question 2085

Topic: 8. Foot and Ankle
A 47-year-old man ruptured his left patellar tendon and twisted his right ankle in a fall. Initial radiographs of the ankle are unremarkable. One week following repair of the left patellar tendon, he reports increased pain with weight bearing in his right ankle. A follow-up radiograph is shown in Figure 38. Management of the ankle injury should consist of
. functional rehabilitation with range of motion and strengthening.
. reduction and screw fixation of the syndesmosis.
. closed reduction and a long leg cast.
. repair of the talofibular ligaments.
. fibular osteotomy and plate fixation.

Correct Answer & Explanation

. reduction and screw fixation of the syndesmosis.

Explanation

The radiograph reveals disruption of the syndesmosis with lateral displacement of the talus and widening of the medial ankle clear space. There is clear instability of the syndesmosis, and surgical stabilization is needed, either by direct repair of the ligaments or more commonly with surgical stabilization of the fibula to the tibia with screws.

Question 2086

Topic: 8. Foot and Ankle
A 23-year-old man has pain and a callus beneath the second metatarsal head. Initial management should consist of
. corn pads impregnated with salicylic acid.
. paring of the callus and an offloading orthosis.
. metatarsal dorsiflexion osteotomy.
. metatarsal head excision.
. plantar condylectomy.

Correct Answer & Explanation

. paring of the callus and an offloading orthosis.

Explanation

The initial treatment of metatarsalgia with or without the presence of an intractable keratosis should be conservative. Simple paring of the callus with elevation of the metatarsals may suffice. A prefabricated “off-the-shelf” orthosis or felt pad can be used before investing in a custom orthosis.

Question 2087

Topic: Midfoot & Hindfoot
A 40-year-old man with amyloidosis injured his left knee while walking. Figure 17a shows an AP radiograph that was obtained 2 weeks after the injury. The radiograph shown in Figure 17b was obtained after the patient wore a hinged knee brace for 3 months. A clinical photograph is shown in Figure 17c. What is the most likely diagnosis?
. Pyarthrosis
. Pigmented villonodular synovitis
. Synovial osteochondromatosis
. Charcot arthropathy
. Spontaneous osteonecrosis

Correct Answer & Explanation

. Charcot arthropathy

Explanation

The patient has a Charcot arthropathy of the knee, which is associated with amyloidosis. The rapid joint destruction shown in the radiographs is most consistent with that diagnosis.

Question 2088

Topic: 8. Foot and Ankle
A 35-year-old woman who is training for a triathlon has had a 2-month history of heel pain with weight bearing and is unable to run. History reveals that she is amenorrheic. Examination reveals that she is thin and has pain over the heel that is exacerbated with medial and lateral compression. Range of motion and motor and sensory function are normal. Radiographs are normal. What is the most likely diagnosis?
. Plantar fasciitis
. Seronegative inflammatory arthritis
. Stress fracture of the calcaneus
. Tarsal tunnel syndrome
. Peripheral neuropathy

Correct Answer & Explanation

. Stress fracture of the calcaneus

Explanation

The most likely diagnosis is a stress fracture of the calcaneus and is supported by the history of running, female gender, and amenorrhea. Reproducing pain with medial and lateral compression of the heel also supports the diagnosis. A bone scan or MRI would most likely confirm the diagnosis. Plantar fasciitis would result in pain on the bottom of the heel with point tenderness. The lack of other areas of involvement or other symptoms does not support a seronegative inflammatory arthritis. Tarsal tunnel syndrome and peripheral neuropathy are unlikely because of the normal neurologic examination.

Question 2089

Topic: 8. Foot and Ankle

A 30-year-old male sustains a twisting injury to his right ankle. In the emergency department, plain radiographs show a severely displaced fracture-dislocation. Attempts at closed reduction under conscious sedation are repeatedly unsuccessful due to a mechanical block. A Bosworth fracture-dislocation is suspected. What is the anatomic block to reduction in this injury?

. Interposition of the posterior tibial tendon
. Entrapment of the proximal fibular fragment behind the posterior lateral tubercle of the tibia
. Incarceration of the flexor hallucis longus (FHL) tendon within the syndesmosis
. Entrapment of the anterior tibial tendon in the tibiotalar joint
. An osteochondral fragment from the talar dome blocking the mortise

Correct Answer & Explanation

. Interposition of the posterior tibial tendon

Explanation

A Bosworth fracture-dislocation is an irreducible ankle fracture characterized by posterior dislocation of the proximal fibular fragment behind the posterior lateral tubercle of the distal tibia. The intact interosseous membrane acts as a tether, making closed reduction impossible. Open reduction is required to physically lever the fibula out from behind the tibia.

Question 2090

Topic: Ankle Trauma & Sports
A 22-year-old female presents with an ankle injury after a fall during a soccer match. Radiographs demonstrate a short oblique fracture of the lateral malleolus starting at the level of the syndesmosis and extending proximally and posteriorly. Additionally, the medial clear space is widened to 6 mm on the gravity stress view. According to the Lauge-Hansen classification, what stage of injury does this represent?
. Supination-External Rotation Stage II
. Pronation-External Rotation Stage III
. Supination-External Rotation Stage IV
. Pronation-Abduction Stage III
. Supination-Adduction Stage II

Correct Answer & Explanation

. Supination-External Rotation Stage IV

Explanation

The fracture pattern described is a Supination-External Rotation (SER) injury. The sequence of injury in SER is: Stage I (AITFL rupture), Stage II (short oblique/spiral fracture of the distal fibula), Stage III (PITFL rupture or posterior malleolus fracture), and Stage IV (deltoid ligament rupture or medial malleolus transverse fracture). Widening of the medial clear space indicates a disrupted deltoid ligament, moving this to an SER Stage IV injury.

Question 2091

Topic: Midfoot & Hindfoot
A 25-year-old male is involved in a high-speed motor vehicle collision and sustains a talar neck fracture. Radiographs and a subsequent CT scan confirm a completely displaced talar neck fracture with dislocation of both the subtalar and tibiotalar joints. The talonavicular joint remains reduced. According to the Hawkins classification, what type of fracture is this, and what is the approximate historical rate of avascular necrosis (AVN) associated with it?
. Hawkins Type I; AVN rate < 10%
. Hawkins Type II; AVN rate 20-50%
. Hawkins Type III; AVN rate 80-100%
. Hawkins Type IV; AVN rate 10-20%
. Hawkins Type III; AVN rate 20-50%

Correct Answer & Explanation

. Hawkins Type III; AVN rate 80-100%

Explanation

Hawkins classification for talar neck fractures: Type I is non-displaced (AVN < 10%). Type II is displaced with subtalar dislocation (AVN 20-50%). Type III is displaced with subtalar and tibiotalar dislocation (AVN 80-100% historically). Type IV includes talonavicular dislocation. Therefore, this is a Hawkins Type III with a historical AVN risk of nearly 100%.

Question 2092

Topic: 8. Foot and Ankle

An orthopedic surgeon is utilizing an extensile lateral approach for open reduction and internal fixation of a displaced intra-articular calcaneus fracture.

To minimize the risk of apex wound necrosis, the full-thickness flap must be elevated in a 'no-touch' subperiosteal plane. Which of the following vascular structures provides the primary blood supply to the apex of this flap?

. Sural artery
. Lateral calcaneal artery
. Medial calcaneal artery
. Anterior tibial artery
. Dorsalis pedis artery

Correct Answer & Explanation

. Sural artery

Explanation

The primary blood supply to the corner (apex) of the extensile lateral flap used for calcaneus fractures is the lateral calcaneal artery, which is a terminal branch of the peroneal artery. Careful, full-thickness subperiosteal elevation and 'no-touch' retraction techniques with K-wires in the talus are utilized to protect this vascular supply and prevent disastrous wound sloughing.

Question 2093

Topic: 8. Foot and Ankle

A 24-year-old athlete reports midfoot pain after an axial load on a plantarflexed foot. Weight-bearing radiographs of the foot appear largely normal, but a close inspection reveals a small bony fragment in the first intermetatarsal space, known as the 'fleck sign.' This sign represents an avulsion from which of the following structures?

. Lateral aspect of the medial cuneiform
. Base of the second metatarsal
. Base of the first metatarsal
. Medial aspect of the intermediate cuneiform
. Navicular tuberosity

Correct Answer & Explanation

. Lateral aspect of the medial cuneiform

Explanation

The 'fleck sign' is pathognomonic for a Lisfranc injury. It represents an avulsion fracture at the attachment site of the Lisfranc ligament. The Lisfranc ligament runs from the lateral aspect of the medial cuneiform to the medial base of the second metatarsal. The avulsion typically occurs at the base of the second metatarsal.

Question 2094

Topic: Ankle Trauma & Sports
A 28-year-old male presents with isolated medial ankle pain and swelling after an inversion and rotational injury. Radiographs show a transverse fracture of the medial malleolus and widening of the tibiofibular clear space. A full-length tibia-fibula radiograph reveals a fracture of the proximal third of the fibula. What is the most likely Lauge-Hansen mechanism for this specific injury pattern (Maisonneuve fracture)?
. Pronation-External Rotation
. Supination-External Rotation
. Pronation-Abduction
. Supination-Adduction
. Pronation-Dorsiflexion

Correct Answer & Explanation

. Pronation-External Rotation

Explanation

A Maisonneuve fracture is classically described as a Pronation-External Rotation (PER) stage III or IV injury. The medial injury (deltoid rupture or medial malleolar fracture) occurs first (Stage I), followed by rupture of the anterior tibiofibular ligament and interosseous membrane (Stage II), and then the fibula fractures at the proximal third as the force exits (Stage III).

Question 2095

Topic: 8. Foot and Ankle

An 82-year-old female with severe osteoporosis, dementia, and compromised soft tissues presents with a highly unstable bimalleolar ankle fracture. Given her inability to comply with non-weight-bearing restrictions, the surgeon elects to perform a primary tibiotalocalcaneal (TTC) nailing. Which of the following is the most significant advantage of this approach in this specific patient compared to traditional ORIF?

. Preservation of subtalar range of motion
. Decreased risk of soft tissue wound complications
. Lower incidence of hardware prominence requiring removal
. Superior anatomical reduction of the ankle mortise
. Prevention of future Charcot neuroarthropathy

Correct Answer & Explanation

. Preservation of subtalar range of motion

Explanation

In frail, elderly patients with significant comorbidities (dementia, poor skin, osteoporosis) who cannot adhere to non-weight-bearing restrictions, primary TTC nailing is an excellent salvage option for ankle fractures. The most significant advantage is the minimal soft tissue dissection required (inserted via a limited plantar approach), which drastically reduces the high rates of wound breakdown and infection associated with traditional ORIF in this population. It allows immediate weight-bearing, though it sacrifices the tibiotalar and subtalar joints.

Question 2096

Topic: 8. Foot and Ankle

During open reduction and internal fixation of a Weber B ankle fracture, the surgeon must intraoperatively assess the integrity of the syndesmosis. Under live fluoroscopy, which of the following stress tests is the most reliable and sensitive for demonstrating latent syndesmotic instability?

. Dorsiflexion and eversion stress
. External rotation stress test
. Internal rotation stress test
. Plantarflexion and inversion stress
. Axial loading

Correct Answer & Explanation

. Dorsiflexion and eversion stress

Explanation

The external rotation stress test, often performed using a 'hook test' (pulling the fibula laterally with a bone hook) or by manually externally rotating the foot while stabilizing the tibia, is the most reliable intraoperative method to assess the syndesmosis under fluoroscopy. Widening of the medial clear space or the tibiofibular clear space indicates syndesmotic instability requiring fixation.

Question 2097

Topic: 8. Foot and Ankle

A 21-year-old snowboarder presents with chronic lateral ankle pain 6 weeks after a hard landing. He was initially diagnosed with an 'ankle sprain' at an urgent care. He has localized tenderness just inferior to the tip of the lateral malleolus. An occult fracture is suspected. What specific anatomical structure is most likely fractured in this 'snowboarder's fracture'?

. Anterior process of the calcaneus
. Lateral process of the talus
. Posterior process of the talus
. Base of the fifth metatarsal
. Cuboid

Correct Answer & Explanation

. Anterior process of the calcaneus

Explanation

A 'snowboarder's fracture' refers to a fracture of the lateral process of the talus. It typically occurs due to axial loading, dorsiflexion, and inversion/eversion while snowboarding. Because it mimics a severe lateral ankle sprain, it is frequently missed on standard AP and lateral ankle radiographs. CT scan is often required for definitive diagnosis and to assess displacement, which dictates operative vs. non-operative management.

Question 2098

Topic: 8. Foot and Ankle

A 35-year-old male falls from a height of 10 feet, landing on a plantarflexed foot. Radiographs reveal a comminuted compression fracture of the cuboid with notable shortening of the lateral column of the foot (the 'nutcracker' fracture). What is the primary surgical objective when treating this injury?

. Primary arthrodesis of the calcaneocuboid joint
. Excision of the comminuted cuboid fragments and soft tissue interposition
. Medial column lengthening to match the lateral side
. Restoration of lateral column length via ORIF, often requiring bone grafting
. Immediate subtalar arthrodesis

Correct Answer & Explanation

. Primary arthrodesis of the calcaneocuboid joint

Explanation

A 'nutcracker' fracture of the cuboid occurs when severe abduction force combined with axial load crushes the cuboid between the calcaneus and the 4th/5th metatarsals. The primary surgical goal is the restoration and maintenance of lateral column length. This is typically achieved with external fixation or distractor application followed by ORIF, frequently necessitating structural bone graft to fill the void.

Question 2099

Topic: 8. Foot and Ankle

A 35-year-old male sustains a severe ankle injury following an axial load on a neutral foot. Radiographs show vertical migration of the talus driving apart the tibia and fibula, severely disrupting the syndesmosis without significant medial or lateral malleolar fractures. This specific high-energy injury pattern is colloquially known as:

. Bosworth fracture
. Chaput-Tillaux injury
. Logsplitter injury
. Chopart dislocation
. Pilon variant

Correct Answer & Explanation

. Bosworth fracture

Explanation

The 'logsplitter' injury is a severe variant of a syndesmotic injury caused by a high-energy axial load that drives the talus superiorly into the distal tibiofibular joint, splitting it apart much like an axe splitting a log. It involves profound disruption of the syndesmosis, interosseous membrane, and often requires robust surgical stabilization of the mortise.

Question 2100

Topic: 8. Foot and Ankle

According to the Lauge-Hansen classification, an ankle fracture characterized by a transverse fracture of the medial malleolus, rupture of the syndesmosis, and a comminuted or short oblique 'bending' fracture of the fibula above the level of the joint line is produced by which mechanism?

. Supination-External Rotation
. Pronation-External Rotation
. Supination-Adduction
. Pronation-Abduction
. Supination-Plantarflexion

Correct Answer & Explanation

. Supination-External Rotation

Explanation

The Pronation-Abduction (PA) mechanism occurs when the foot is pronated (taut medial structures) and an abduction force is applied. Sequence: Stage 1) Transverse fracture of medial malleolus or deltoid rupture. Stage 2) Rupture of AITFL/PITFL (syndesmosis). Stage 3) Short oblique or comminuted (bending) fracture of the fibula at or above the level of the syndesmosis, often with a butterfly fragment on the lateral side due to compression.

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