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8. Foot and Ankle MCQs

Practice Set 221 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 4401

Topic: 8. Foot and Ankle

A 13-year-old boy presents with recurrent left ankle sprains and a painful rigid flatfoot. On examination, he has significantly decreased subtalar motion and peroneal spasticity.

A lateral radiograph of the foot reveals an elongated anterior process of the calcaneus (the 'anteater' sign). What is the most likely diagnosis?

. Talocalcaneal coalition
. Calcaneonavicular coalition
. Accessory navicular syndrome
. Cuboid syndrome
. Naviculocuneiform coalition

Correct Answer & Explanation

. Calcaneonavicular coalition

Explanation

The clinical presentation of a rigid, painful flatfoot with peroneal spasticity and recurrent sprains in an adolescent is classic for a tarsal coalition. The 'anteater nose' sign on a lateral radiograph is highly specific for a calcaneonavicular coalition. This condition is best visualized on a 45-degree internal oblique radiograph of the foot. Talocalcaneal coalitions often present slightly later (ages 12-16) and are associated with the 'C-sign' on lateral radiographs.

Question 4402

Topic: 8. Foot and Ankle

A 12-year-old boy presents with a history of recurrent ankle sprains and a painful, rigid flatfoot. On examination, subtalar motion is severely restricted, and there is palpable spasm of the peroneal muscles. Oblique radiographs of the foot demonstrate an 'anteater nose' sign. Which of the following is the most likely diagnosis?

. Talocalcaneal coalition
. Calcaneonavicular coalition
. Accessory navicular syndrome
. Congenital vertical talus
. Talonavicular coalition

Correct Answer & Explanation

. Calcaneonavicular coalition

Explanation

The clinical presentation of a rigid flatfoot, restricted subtalar motion, and peroneal spasticity in an adolescent is classic for a tarsal coalition. The 'anteater nose' sign seen on a 45-degree internal oblique radiograph of the foot is pathognomonic for a calcaneonavicular coalition. It represents an elongated anterior process of the calcaneus approaching the navicular. A talocalcaneal coalition typically presents with a 'C-sign' on a lateral radiograph.

Question 4403

Topic: 8. Foot and Ankle

A 14-year-old boy presents with chronic, vague lateral foot pain and a history of multiple ankle sprains. On physical examination, he has a rigid pes planovalgus deformity with absent subtalar motion. A lateral radiograph of the foot demonstrates an elongated anterior process of the calcaneus projecting toward the navicular. To properly characterize this anatomy prior to surgical intervention, what is the best diagnostic imaging modality?

. Weight-bearing anteroposterior and lateral ankle radiographs
. Magnetic Resonance Imaging (MRI) without contrast
. Computed Tomography (CT) scan of the foot and ankle
. Three-phase bone scintigraphy
. Dynamic ultrasound of the peroneal tendons

Correct Answer & Explanation

. Computed Tomography (CT) scan of the foot and ankle

Explanation

The clinical presentation of rigid flatfoot, absent subtalar motion, and an elongated anterior process of the calcaneus ('anteater sign') strongly suggests a calcaneonavicular tarsal coalition. A CT scan is the gold standard imaging modality to fully evaluate the size and extent of the coalition, assess for degenerative changes in adjacent joints, and rule out concurrent talocalcaneal coalitions prior to planning a surgical resection.

Question 4404

Topic: 8. Foot and Ankle

A 13-year-old boy presents with a 6-month history of frequent ankle sprains, difficulty running, and lateral foot pain. On physical examination, he has a rigid flatfoot with marked restriction of subtalar motion, and the peroneal tendons appear spastic. A lateral radiograph of the foot reveals a distinct "C-sign". Which of the following is the most likely primary diagnosis, and what is the best initial advanced imaging modality to clearly delineate the extent of the pathology for preoperative planning?

. Calcaneonavicular coalition; MRI
. Talocalcaneal coalition; CT scan
. Calcaneonavicular coalition; CT scan
. Talocalcaneal coalition; Ultrasound
. Naviculocuneiform coalition; MRI

Correct Answer & Explanation

. Talocalcaneal coalition; CT scan

Explanation

The clinical presentation of a rigid flatfoot, limited subtalar motion, and peroneal spasticity in an adolescent is highly suggestive of a tarsal coalition. The "C-sign" on a lateral radiograph is a classic finding for a talocalcaneal (subtalar) coalition, representing the continuous bony outline of the medial talar dome and the sustentaculum tali. Calcaneonavicular coalitions are typically identified by the "anteater nose" sign on an oblique view. A CT scan is the gold standard imaging modality to definitively define the location, extent, and osseous bridging of the coalition for accurate surgical planning.

Question 4405

Topic: 8. Foot and Ankle

A 13-year-old boy presents with a history of recurrent ankle sprains and an increasingly rigid, painful right flatfoot. Peroneal spasm is noted on physical examination. A lateral radiograph of the foot demonstrates a continuous osseous bridge connecting the talar dome to the sustentaculum tali (the 'C-sign'). What is the initial treatment of choice for this condition?

. Surgical resection of the coalition with interposition of a fat pad
. Subtalar arthrodesis
. Short leg cast immobilization for 4 to 6 weeks
. Custom orthotics with a medial heel wedge
. Corticosteroid injection into the subtalar joint

Correct Answer & Explanation

. Short leg cast immobilization for 4 to 6 weeks

Explanation

The presence of a 'C-sign' on the lateral radiograph strongly suggests a talocalcaneal (subtalar) coalition. The patient exhibits the classic presentation of a rigid, peroneal spastic flatfoot. Despite the anatomical abnormality, the initial treatment for symptomatic tarsal coalition is always nonoperative, aimed at breaking the pain cycle and reducing inflammation. A period of immobilization in a short leg walking cast or a rigid CAM boot for 4 to 6 weeks is the standard first-line therapy before considering surgical resection.

Question 4406

Topic: 8. Foot and Ankle

A 14-year-old boy presents with a 6-month history of frequent right ankle sprains and lateral foot pain. Examination reveals a rigid flatfoot with restricted subtalar motion. Radiographs show a prominent 'C sign' on the lateral view. A CT scan confirms a talocalcaneal coalition involving 65% of the posterior facet with early degenerative changes. He has failed a 6-month trial of casting and orthotics. What is the most appropriate surgical treatment?

. Resection of the coalition with extensor digitorum brevis interposition
. Medial displacement calcaneal osteotomy
. Subtalar arthrodesis
. Triple arthrodesis
. Calcaneal lengthening osteotomy

Correct Answer & Explanation

. Subtalar arthrodesis

Explanation

The 'C sign' is a radiographic marker of a talocalcaneal coalition. While simple resection (with or without interposition) is effective for small coalitions without arthritis, a subtalar arthrodesis is the treatment of choice for a talocalcaneal coalition that involves >50% of the posterior facet, is associated with degenerative changes, or occurs in an older adolescent. Triple arthrodesis is reserved for more extensive hindfoot arthritis or multiple coalitions.

Question 4407

Topic: 8. Foot and Ankle

A 13-year-old boy presents with recurrent ankle sprains and rigid, painful flatfeet. Radiographs reveal a prominent "C-sign" on the lateral view of the ankle. What is the most likely diagnosis?

. Calcaneonavicular coalition
. Talocalcaneal coalition
. Accessory navicular
. Vertical talus
. Flexible pes planovalgus

Correct Answer & Explanation

. Talocalcaneal coalition

Explanation

The "C-sign" on a lateral radiograph is formed by the continuous outline of the medial talar dome and the sustentaculum tali. It is a classic radiographic indicator of a talocalcaneal coalition.

Question 4408

Topic: Ankle Trauma & Sports
A 14-year-old adolescent boy sustains an ankle injury. Radiographs and a CT scan reveal a Salter-Harris III fracture of the anterolateral aspect of the distal tibial epiphysis, displaced by 3 mm. Which ligament is primarily responsible for the avulsion of this fracture fragment?
. Anterior talofibular ligament (ATFL)
. Calcaneofibular ligament (CFL)
. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Deltoid ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

A juvenile Tillaux fracture is a Salter-Harris III fracture of the anterolateral distal tibial epiphysis. It is caused by an avulsion force from the anterior inferior tibiofibular ligament (AITFL) resulting from an external rotation mechanism.

Question 4409

Topic: 8. Foot and Ankle

A 12-year-old boy presents with frequent ankle sprains and rigid, painful flatfeet. On examination, he has markedly decreased subtalar motion and peroneal spasticity. Radiographs demonstrate a "C sign" on the lateral view. This radiographic finding indicates a coalition primarily in which location?

. Calcaneonavicular
. Talocalcaneal
. Talonavicular
. Calcaneocuboid
. Naviculocuneiform

Correct Answer & Explanation

. Talocalcaneal

Explanation

The "C sign" on a lateral ankle radiograph represents a continuous bony outline of the medial talar dome and sustentaculum tali. This finding is highly indicative of a talocalcaneal (subtalar) coalition.

Question 4410

Topic: 8. Foot and Ankle

A 13-year-old boy presents with a history of recurrent ankle sprains and foot pain. Examination reveals a rigid flatfoot and peroneal spasticity. Radiographs show an "anteater nose" sign. What is the most likely diagnosis?

. Talocalcaneal coalition
. Calcaneonavicular coalition
. Talonavicular coalition
. Accessory navicular syndrome
. Idiopathic peroneal tendon subluxation

Correct Answer & Explanation

. Calcaneonavicular coalition

Explanation

The "anteater nose" sign on an oblique radiograph of the foot is pathognomonic for a calcaneonavicular coalition. By contrast, talocalcaneal coalitions often display a "C-sign" on the lateral radiograph.

Question 4411

Topic: 8. Foot and Ankle
Following an acute Achilles tendon rupture treated nonoperatively, the tendon undergoes a predictable sequence of healing phases. During the remodeling phase (beginning approximately 6 weeks post-injury), which of the following cellular and biochemical changes predominantly occurs?
. Peak concentration of inflammatory macrophages and neutrophils
. Maximum synthesis of Type III collagen to form a disorganized provisional matrix
. Transition of Type III collagen to Type I collagen with increased cross-linking
. Peak angiogenesis driven by vascular endothelial growth factor (VEGF)
. Rapid proliferation of epitenon-derived fibroblasts replacing intrinsic tenocytes

Correct Answer & Explanation

. Transition of Type III collagen to Type I collagen with increased cross-linking

Explanation

Tendon healing occurs in three overlapping phases: inflammatory, proliferative/repair, and remodeling. During the proliferative phase, Type III collagen is synthesized rapidly to form a provisional, disorganized matrix. In the remodeling phase, cellularity and matrix synthesis decrease, and the weaker Type III collagen is gradually replaced by stronger, highly cross-linked Type I collagen, which aligns along the axis of mechanical stress to maximize tensile strength.

Question 4412

Topic: 8. Foot and Ankle
A 24-year-old elite sprinter sustains an acute Achilles tendon rupture and undergoes open surgical repair. During the remodeling phase of tendon healing, which of the following biochemical and structural changes predominantly occurs to maximize the tensile strength of the repair?
. Replacement of Type I collagen with Type III collagen
. Replacement of Type III collagen with Type I collagen
. Increased concentration of water and non-sulfated glycosaminoglycans
. Peak proliferation of inflammatory macrophages and neutrophils
. Decreased covalent cross-linking of newly synthesized collagen fibrils

Correct Answer & Explanation

. Replacement of Type III collagen with Type I collagen

Explanation

Tendon healing proceeds through inflammatory, proliferative, and remodeling phases. During the proliferative phase, fibroblasts rapidly produce disorganized Type III collagen, which is mechanically weak. In the remodeling phase (starting around 6 weeks and lasting for months), this Type III collagen is gradually degraded and replaced by stronger, highly organized Type I collagen parallel to the axis of tension. Concurrently, covalent cross-linking between collagen molecules increases, significantly enhancing the tendon's tensile strength.

Question 4413

Topic: Midfoot & Hindfoot
A 25-year-old snowboarder sustains a hyperdorsiflexion injury to his right ankle. Radiographs reveal a displaced fracture of the talar neck with subluxation of the subtalar joint. The tibiotalar and talonavicular joints remain congruent. According to the Hawkins classification, what is the approximate expected rate of avascular necrosis (AVN) of the talar body?
. 0-10%
. 20-50%
. 70-90%
. 100%
. 5-15%

Correct Answer & Explanation

. 20-50%

Explanation

This injury describes a Hawkins Type II talar neck fracture, which is characterized by a talar neck fracture with subluxation or dislocation of the subtalar joint, while the ankle joint remains normally aligned. The historical rate of avascular necrosis (AVN) for a Type II fracture is approximately 20% to 50%. In contrast, Type I (nondisplaced) fractures have an AVN rate of 0-10%, Type III (subtalar and tibiotalar dislocation) have an AVN rate of 70-90%, and Type IV (involving talonavicular dislocation as well) approach a 100% AVN rate.

Question 4414

Topic: 8. Foot and Ankle
A 40-year-old construction worker sustains a displaced intra-articular calcaneus fracture (Sanders Type III). He is scheduled for open reduction and internal fixation utilizing a standard extensile lateral approach. Which of the following neurological structures is at greatest risk of iatrogenic injury during the creation and full-thickness elevation of this surgical flap?
. Sural nerve
. Tibial nerve
. Deep peroneal nerve
. Superficial peroneal nerve
. Medial plantar nerve

Correct Answer & Explanation

. Sural nerve

Explanation

The extensile lateral approach to the calcaneus involves creating an L-shaped full-thickness fasciocutaneous flap to expose the lateral wall and subtalar joint. The sural nerve courses along the posterolateral aspect of the calf and lateral hindfoot. It is at significant risk of injuryโ€”either through direct transection during the incision or via traction neuritis during flap retraction. Retracting the flap using 'no-touch' techniques with K-wires placed into the talus and fibula helps minimize soft tissue and nerve damage.

Question 4415

Topic: 8. Foot and Ankle

A 40-year-old woman undergoes open reduction and internal fixation for an unstable pronation-external rotation ankle fracture. Intraoperatively, the external rotation stress test demonstrates widening of the medial clear space and the distal tibiofibular articulation. Syndesmotic fixation is planned. Which of the following statements is true regarding syndesmotic reduction and fixation?

. The ankle must be placed in maximal plantarflexion during screw placement to prevent overtightening.
. Direct visualization of the anterior inferior tibiofibular ligament (AITFL) footprint improves reduction accuracy compared to fluoroscopy alone.
. Tricortical screw fixation is biomechanically superior to quadricortical fixation.
. Rigid metallic syndesmotic screws must be routinely removed before weight-bearing to prevent catastrophic hardware breakage.
. Dynamic suture-button constructs have a significantly higher rate of malreduction than traditional screw fixation.

Correct Answer & Explanation

. Direct visualization of the anterior inferior tibiofibular ligament (AITFL) footprint improves reduction accuracy compared to fluoroscopy alone.

Explanation

Malreduction of the syndesmosis is a frequent and detrimental complication, occurring in up to 50% of cases when relying on 2D fluoroscopy alone. Direct open visualization of the syndesmosis (specifically the anterior tibiofibular articulation) or the use of intraoperative 3D imaging significantly improves the accuracy of reduction. The classic teaching of maximal dorsiflexion has been largely debunked. Suture-buttons have similar or lower malreduction rates compared to screws, and routine screw removal is no longer considered universally mandatory.

Question 4416

Topic: Midfoot & Hindfoot

A 22-year-old collegiate football player sustains a high-energy foot injury. Advanced imaging reveals a purely ligamentous Lisfranc injury with complete disruption of the Lisfranc ligament complex and dorsal subluxation of the 1st, 2nd, and 3rd tarsometatarsal (TMT) joints. Based on recent prospective evidence, which of the following is the most appropriate primary surgical management?

. Closed reduction and percutaneous pinning of the TMT joints
. Primary arthrodesis of the medial column (1st, 2nd, and 3rd TMT joints)
. Open reduction and internal fixation utilizing transarticular screws
. Open reduction and internal fixation using dorsal bridge plating
. Strict non-weight-bearing cast immobilization for 8 weeks

Correct Answer & Explanation

. Primary arthrodesis of the medial column (1st, 2nd, and 3rd TMT joints)

Explanation

For purely ligamentous Lisfranc injuries, multiple prospective randomized studies (e.g., Ly and Coetzee) have demonstrated that primary arthrodesis of the involved medial column TMT joints yields significantly better functional outcomes, decreased pain scores, and a much lower rate of revision surgeries compared to open reduction and internal fixation (ORIF). ORIF remains a standard option for bony Lisfranc fracture-dislocations.

Question 4417

Topic: 8. Foot and Ankle

A 35-year-old man falls from a roof and sustains a severely comminuted, joint-depressed intra-articular calcaneus fracture (Sanders Type IV). Due to his heavy smoking history and poorly controlled diabetes, a shared decision is made to proceed with nonoperative management. What is the most common long-term clinical consequence of managing this displaced intra-articular fracture nonoperatively?

. Sural nerve entrapment
. Subtalar post-traumatic arthritis
. Tibiotalar post-traumatic arthritis
. Avascular necrosis of the calcaneal tuberosity
. Chronic Achilles tendon rupture

Correct Answer & Explanation

. Subtalar post-traumatic arthritis

Explanation

The most common and significant long-term complication of a displaced intra-articular calcaneus fracture, particularly when managed nonoperatively, is the development of post-traumatic subtalar arthritis. This results from the residual incongruity of the posterior facet of the subtalar joint and altered hindfoot biomechanics (loss of calcaneal height, increased width, and varus malalignment). Patients frequently present with chronic lateral hindfoot pain and stiffness, eventually requiring a subtalar arthrodesis.

Question 4418

Topic: 8. Foot and Ankle

A 22-year-old collegiate football player sustains a hyperplantarflexion injury to his midfoot. Radiographs demonstrate widening of the interval between the bases of the first and second metatarsals. Weight-bearing views confirm a 4-mm diastasis. MRI reveals complete disruption of the Lisfranc ligament complex without associated fractures. What is the most appropriate definitive surgical management?

. Closed reduction and percutaneous pinning
. Open reduction and internal fixation with transarticular screws
. Primary arthrodesis of the first, second, and third tarsometatarsal joints
. Application of a circular external fixator
. Dorsal spanning plate fixation of the midfoot

Correct Answer & Explanation

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

Explanation

For purely ligamentous Lisfranc injuries in young, active patients, strong clinical evidence (including prospective randomized trials) demonstrates that primary arthrodesis of the medial column (1st, 2nd, and 3rd TMT joints) results in superior functional outcomes, a lower rate of hardware-related complications, and a significantly lower need for revision surgery compared to open reduction and internal fixation (ORIF). ORIF is generally preferred for cases with significant bony involvement.

Question 4419

Topic: 8. Foot and Ankle
A 34-year-old man sustains a Hawkins Type III fracture of the talar neck following a severe motor vehicle collision. In this specific injury pattern, which of the following blood vessels typically represents the ONLY remaining source of perfusion to the talar body?
. Artery of the tarsal canal
. Artery of the tarsal sinus
. Deltoid branch of the posterior tibial artery
. Branches of the dorsalis pedis artery
. Perforating branches of the peroneal artery

Correct Answer & Explanation

. Deltoid branch of the posterior tibial artery

Explanation

A Hawkins Type III fracture involves a fracture of the talar neck with dislocation of both the subtalar and tibiotalar joints. The blood supply to the talus is extremely precarious. The artery of the tarsal canal and the artery of the tarsal sinus are disrupted by the subtalar dislocation. The dorsalis pedis branches supplying the dorsal neck are disrupted by the fracture itself. The deltoid branch of the posterior tibial artery, which enters the medial aspect of the talar body, is often the only remaining intact blood supply. Preservation of the deltoid ligament during surgical approaches is therefore critical.

Question 4420

Topic: 8. Foot and Ankle

A 22-year-old collegiate football player sustains a hyperplantarflexion injury to his midfoot. Weight-bearing radiographs demonstrate a 3 mm diastasis between the base of the first and second metatarsals. Operative stabilization is planned. The primary stabilizing ligament of this articulation (the Lisfranc ligament) is correctly described by which of the following anatomic paths?

. Originates on the lateral aspect of the medial cuneiform and inserts on the medial aspect of the base of the second metatarsal
. Originates on the intermediate cuneiform and inserts on the medial aspect of the first metatarsal
. Originates on the medial cuneiform and inserts on the lateral aspect of the base of the first metatarsal
. Originates on the lateral cuneiform and inserts on the lateral aspect of the second metatarsal
. Originates on the navicular and inserts on the base of the second metatarsal

Correct Answer & Explanation

. Originates on the lateral aspect of the medial cuneiform and inserts on the medial aspect of the base of the second metatarsal

Explanation

The Lisfranc ligament is a robust interosseous ligament that provides vital stability to the midfoot. It runs obliquely from the lateral aspect of the medial cuneiform to the medial aspect of the base of the second metatarsal. There is no transverse ligament directly connecting the bases of the first and second metatarsals, making this ligament critical.

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