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8. Foot and Ankle MCQs

Practice Set 34 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 661

Topic: 8. Foot and Ankle

A 20-year-old presents with a progressive, painful cavovarus foot deformity. Radiographs show a high arch, claw toes, and increased calcaneal pitch. Which radiographic measurement is typically increased in a cavus foot, indicating hindfoot deformity?

. Meary's angle
. Talonavicular coverage angle
. Calcaneal pitch angle
. Lateral talo-first metatarsal angle
. Angle of Gissane

Correct Answer & Explanation

. Calcaneal pitch angle

Explanation

Correct Answer: CThe calcaneal pitch angle (also known as the angle of inclination of the calcaneus or the calcaneal inclination angle) is formed by the intersection of a line tangent to the inferior border of the calcaneus and the floor or a line parallel to the weight-bearing surface. In a cavus foot, the calcaneus is typically more vertically oriented, resulting in anincreasedcalcaneal pitch angle, contributing to the high arch. Meary's angle (lateral talo-first metatarsal angle) is often increased (dorsal apex angulation) due to forefoot equinus or plantarflexed first ray. The talonavicular coverage angle assesses forefoot abduction/adduction, and the Angle of Gissane (critical angle of Gissane) relates to calcaneal fractures, not primarily cavus foot morphology.

Question 662

Topic: 8. Foot and Ankle

Which of the following muscle imbalances is most commonly implicated in the development and progression of a cavus foot deformity, particularly in neuromuscular conditions?

. Weakness of tibialis anterior relative to peroneus longus.
. Overactivity of tibialis posterior relative to tibialis anterior.
. Weakness of intrinsic foot muscles leading to claw toe deformity.
. Overactivity of peroneus brevis relative to tibialis anterior.
. Spasticity of the gastrocnemius-soleus complex.

Correct Answer & Explanation

. Weakness of tibialis anterior relative to peroneus longus.

Explanation

Correct Answer: AThe classic muscle imbalance contributing to a cavus foot is an imbalance between the tibialis anterior and peroneus longus. Weakness of the tibialis anterior (which dorsiflexes the ankle and first metatarsal) combined with overactivity or normal strength of the peroneus longus (which plantarflexes the first metatarsal) leads to a plantarflexed first ray. This plantarflexed first ray drives the forefoot equinus and subsequent compensatory hindfoot varus to achieve a plantigrade foot. While intrinsic muscle weakness contributes to claw toes, and other muscle imbalances may exist, the tibialis anterior/peroneus longus imbalance is a primary driver of the arch deformity.

Question 663

Topic: 8. Foot and Ankle

When examining a child with a suspected progressive cavus foot, what is the most critical component of the initial evaluation to determine etiology?

. Detailed family history and neurological examination.
. Assessment of shoe wear patterns.
. Review of activity level and participation in sports.
. Biomechanical gait analysis.
. Foot pressure mapping studies.

Correct Answer & Explanation

. Detailed family history and neurological examination.

Explanation

Correct Answer: AA progressive cavus foot, especially in a child, is highly suggestive of an underlying neurological condition (e.g., Charcot-Marie-Tooth disease, Friedreich's ataxia, spinal dysraphism). Therefore, a detailed family history for similar conditions and a thorough neurological examination are paramount to identify the underlying etiology. The neurological exam should include evaluation of muscle strength, sensation, reflexes, and coordination. Shoe wear, activity levels, gait analysis, and pressure mapping are valuable for characterizing the deformity and its biomechanical impact but are secondary to identifying the primary cause.

Question 664

Topic: 8. Foot and Ankle

A patient presents with a rigid cavus foot and chronic lateral ankle instability. You determine the hindfoot varus is rigid and irreducible. Which surgical procedure is most appropriate for correcting the hindfoot deformity in this scenario?

. Dorsal closing wedge osteotomy of the first metatarsal.
. Plantar fascia release and flexor to extensor transfer for claw toes.
. Dwyer osteotomy (lateral closing wedge calcaneal osteotomy).
. Posterior tibial tendon transfer.
. Subtalar arthrodesis.

Correct Answer & Explanation

. Dwyer osteotomy (lateral closing wedge calcaneal osteotomy).

Explanation

Correct Answer: CFor a rigid hindfoot varus, a calcaneal osteotomy is often required. The Dwyer osteotomy (lateral closing wedge osteotomy of the calcaneus) is a well-established procedure to correct a rigid hindfoot varus by removing a wedge of bone from the lateral aspect of the calcaneus, effectively rotating the tuberosity into valgus. Subtalar arthrodesis might be considered for severe, symptomatic, arthritic, or recalcitrant deformities, but an osteotomy preserves joint motion if possible. The other options address forefoot or soft tissue components, not primarily rigid hindfoot varus.

Question 665

Topic: 8. Foot and Ankle

During a physical examination of a cavus foot, you observe significant clawing of the lesser toes. This deformity is primarily caused by:

. Overactivity of the lumbricals and interossei muscles.
. Weakness of the extensor digitorum longus.
. Imbalance between strong extrinsic flexors and weak intrinsic foot muscles.
. Tightness of the Achilles tendon.
. Fixed equinus deformity of the ankle joint.

Correct Answer & Explanation

. Imbalance between strong extrinsic flexors and weak intrinsic foot muscles.

Explanation

Correct Answer: CClaw toe deformities (hyperextension of the MTP joint, flexion of the PIP and DIP joints) in a cavus foot primarily result from an imbalance where the strong extrinsic flexor muscles (flexor digitorum longus and brevis) overpower the weak intrinsic foot muscles (lumbricals and interossei). The intrinsic muscles are responsible for stabilizing the MTP joints in a neutral position and assisting in toe extension. Their weakness allows the extrinsic flexors to pull the toes into the characteristic clawed position.

Question 666

Topic: 8. Foot and Ankle

Which of the following is considered a key differentiating factor between a 'flexible' and 'rigid' cavus foot during clinical examination?

. The presence of callosities under the metatarsal heads.
. The ability to passively correct the forefoot and hindfoot deformities.
. The degree of plantar fasciitis symptoms.
. The history of recurrent ankle sprains.
. The patient's age at presentation.

Correct Answer & Explanation

. The ability to passively correct the forefoot and hindfoot deformities.

Explanation

Correct Answer: BThe ability to passively correct the forefoot and hindfoot deformities is the fundamental differentiator between a flexible and rigid cavus foot. A flexible deformity can be manually corrected to a plantigrade position, indicating that soft tissue releases or tendon transfers may suffice, or that the deformity is driven by a flexible primary deformity (e.g., plantarflexed first ray). A rigid deformity resists passive correction, often necessitating osteotomies or arthrodesis to achieve correction. Callosities, ankle sprains, and plantar fasciitis are common symptoms but do not directly define flexibility or rigidity. Age can be a factor in progression but not a direct measure of rigidity.

Question 667

Topic: 8. Foot and Ankle

A 7-year-old child presents with a progressive, unilateral cavus foot. This finding should immediately raise suspicion for which of the following etiologies?

. Idiopathic cavus foot.
. Charcot-Marie-Tooth disease.
. Spinal cord lesion or dysraphism.
. Hereditary motor and sensory neuropathy type 1.
. Friedreich's ataxia.

Correct Answer & Explanation

. Spinal cord lesion or dysraphism.

Explanation

Correct Answer: CWhile most neurological causes of cavus foot (like CMT and Friedreich's ataxia) are typically bilateral and often symmetric, a unilateral or markedly asymmetric progressive cavus foot strongly suggests an underlying acquired neurological cause, such as a spinal cord tumor, tethered cord syndrome, poliomyelitis, or other localized neurological pathology. It warrants urgent neurological imaging (e.g., MRI of the spine) to rule out compressive or developmental lesions. Idiopathic cavus feet are usually bilateral, and hereditary neuropathies like CMT are systemic and bilateral.

Question 668

Topic: 8. Foot and Ankle

In a cavus foot patient with a flexible plantarflexed first ray, what is the biomechanical consequence of attempting to bring the foot flat on the ground during gait?

. Increased pronation of the subtalar joint.
. Compensatory dorsiflexion of the ankle joint.
. Forefoot abduction and hallux valgus development.
. Hindfoot varus and supination of the midtarsal joint.
. Increased load on the lateral column of the foot.

Correct Answer & Explanation

. Hindfoot varus and supination of the midtarsal joint.

Explanation

Correct Answer: DA plantarflexed first ray means the first metatarsal head is lower than the other metatarsal heads. To bring the entire forefoot to the ground, the hindfoot must excessively supinate or invert, resulting in a compensatory hindfoot varus. This creates the characteristic cavovarus deformity. The midtarsal joint also supinates. This mechanism explains why correcting the plantarflexed first ray can resolve the hindfoot varus in flexible cases.

Question 669

Topic: 8. Foot and Ankle

A 24-year-old football player sustains a hyperplantarflexion injury to his midfoot. Radiographs demonstrate a 'fleck sign' in the first intermetatarsal space. The torn ligament responsible for this finding originates from and attaches to which of the following structures?

. Lateral cuneiform to the base of the second metatarsal
. Medial cuneiform to the base of the first metatarsal
. Medial cuneiform to the base of the second metatarsal
. Middle cuneiform to the base of the second metatarsal
. Cuboid to the base of the fourth metatarsal

Correct Answer & Explanation

. Medial cuneiform to the base of the second metatarsal

Explanation

The Lisfranc ligament is a critical stabilizer of the midfoot. It originates from the lateral aspect of the medial cuneiform and attaches to the medial base of the second metatarsal.

Question 670

Topic: Forefoot

A 45-year-old female presents with a painful bunion deformity. Weight-bearing radiographs reveal a hallux valgus angle (HVA) of 28 degrees and an intermetatarsal angle (IMA) of 12 degrees. There is no hypermobility of the first tarsometatarsal joint. Which of the following is the most appropriate surgical indication for a distal chevron osteotomy?

. IMA > 20 degrees
. Hypermobile first tarsometatarsal joint
. Mild to moderate hallux valgus with IMA < 13 degrees
. Severe hallux valgus with severe first MTP osteoarthritis
. Previous failed Lapidus procedure

Correct Answer & Explanation

. Mild to moderate hallux valgus with IMA < 13 degrees

Explanation

A distal chevron osteotomy is indicated for mild to moderate hallux valgus deformities, typically with an intermetatarsal angle (IMA) of less than 13 degrees. Severe deformities or hypermobility require proximal osteotomies or a Lapidus procedure.

Question 671

Topic: 8. Foot and Ankle

A 32-year-old male sustains a Hawkins Type II talar neck fracture. He is at significant risk for avascular necrosis (AVN) of the talar body. What is the primary blood supply to the talar body that is disrupted in this injury?

. Dorsalis pedis artery
. Artery of the tarsal sinus
. Artery of the tarsal canal
. Peroneal artery
. Deltoid branch of the posterior tibial artery

Correct Answer & Explanation

. Artery of the tarsal canal

Explanation

The artery of the tarsal canal, a branch of the posterior tibial artery, is the predominant blood supply to the talar body. Disruption of this supply in talar neck fractures significantly increases the risk of AVN.

Question 672

Topic: 8. Foot and Ankle
A 30-year-old male is brought to the trauma bay after a high-speed motorcycle collision. He has a grossly unstable knee with multi-ligamentous injury (KD-III). After reduction, his distal pulses are palpable, but his Ankle-Brachial Index (ABI) is 0.8. What is the most appropriate next step in management?
. Immediate surgical exploration of the popliteal artery
. Duplex ultrasonography of the lower extremity
. CT Angiography of the lower extremity
. Observation and repeat ABI in 4 hours
. MR Angiography of the lower extremity

Correct Answer & Explanation

. CT Angiography of the lower extremity

Explanation

In a patient with a knee dislocation, an ABI less than 0.9 or asymmetric pulses strongly warrants further vascular imaging. CT angiography is the gold standard next step to rapidly evaluate for a popliteal artery injury.

Question 673

Topic: 8. Foot and Ankle

A 55-year-old male sustains an acute Achilles tendon rupture while playing tennis. He is treated non-operatively in a functional rehabilitation brace. Most Achilles tendon ruptures occur in a hypovascular 'watershed' zone. Where is this zone anatomically located?

. Directly at the calcaneal insertion
. 2 to 6 cm proximal to the calcaneal insertion
. 10 cm proximal to the calcaneal insertion
. At the musculotendinous junction
. Exclusively within the paratenon

Correct Answer & Explanation

. 2 to 6 cm proximal to the calcaneal insertion

Explanation

The watershed zone of the Achilles tendon is an area of poor vascularity that makes it highly susceptible to rupture. It is consistently located 2 to 6 cm proximal to the tendon's insertion on the calcaneus.

Question 674

Topic: Midfoot & Hindfoot

A 60-year-old overweight female complains of medial foot pain and a collapsed arch. On examination, she has a flexible pes planus deformity and cannot perform a single-leg heel rise. Which of the following is the standard surgical treatment for this Stage II posterior tibial tendon dysfunction (PTTD)?

. Triple arthrodesis
. Talonavicular arthrodesis
. Subtalar arthrodesis
. Flexor digitorum longus (FDL) transfer and medializing calcaneal osteotomy
. Tibialis anterior tendon transfer

Correct Answer & Explanation

. Flexor digitorum longus (FDL) transfer and medializing calcaneal osteotomy

Explanation

Stage II PTTD is characterized by a flexible flatfoot deformity. The standard surgical treatment involves an extra-articular correction, typically utilizing an FDL tendon transfer combined with a medializing calcaneal osteotomy.

Question 675

Topic: Midfoot & Hindfoot

A 55-year-old poorly controlled diabetic male presents with a painless, erythematous, and significantly swollen left foot. He is afebrile with bounding pedal pulses. Radiographs show soft tissue swelling, periarticular debris, and early subluxation of the tarsometatarsal joints. What is the most appropriate initial management?

. Urgent irrigation and debridement
. Intravenous antibiotics and observation
. Open reduction and internal fixation of the midfoot
. Application of a total contact cast and non-weight bearing
. Primary below-knee amputation

Correct Answer & Explanation

. Application of a total contact cast and non-weight bearing

Explanation

The patient is presenting with acute Eichenholtz Stage I (fragmentation) Charcot arthropathy. The gold standard initial treatment to prevent progressive deformity is offloading and immobilization using a total contact cast.

Question 676

Topic: 8. Foot and Ankle

During closed reduction of a subtle Lisfranc injury in a 30-year-old male, the surgeon notes widening between the medial and middle cuneiforms. The Lisfranc ligament provides crucial stability to the midfoot. What are the true anatomical attachments of the Lisfranc ligament?

. Medial cuneiform to the base of the first metatarsal
. Medial cuneiform to the base of the second metatarsal
. Middle cuneiform to the base of the second metatarsal
. Lateral cuneiform to the base of the third metatarsal
. Navicular to the base of the second metatarsal

Correct Answer & Explanation

. Medial cuneiform to the base of the second metatarsal

Explanation

The Lisfranc ligament is an intra-articular ligament that originates on the lateral aspect of the medial cuneiform and inserts on the medial base of the second metatarsal. It is a vital stabilizer because there is no direct ligamentous connection between the first and second metatarsal bases.

Question 677

Topic: 8. Foot and Ankle

A 42-year-old male presents with a palpable gap in his posterior ankle following a sudden acceleration while playing tennis. He is diagnosed with an acute Achilles tendon rupture. The tear occurred in the 'watershed' area of the tendon. How far proximal to the calcaneal insertion is this zone typically located?

. 0 to 1 cm
. 2 to 6 cm
. 7 to 10 cm
. 11 to 14 cm
. At the musculotendinous junction

Correct Answer & Explanation

. 2 to 6 cm

Explanation

The watershed area of the Achilles tendon is the region of poorest vascularity, located approximately 2 to 6 cm proximal to its insertion on the calcaneus. This relative ischemia makes it the most common site for spontaneous ruptures.

Question 678

Topic: Forefoot

A 62-year-old female presents with severe pain and stiffness at the base of her great toe. Radiographs demonstrate end-stage hallux rigidus (Coughlin Grade 4). She elects to undergo a first metatarsophalangeal (MTP) joint arthrodesis. What is the optimal position for fusing the first MTP joint?

. 0 degrees of extension, 0 degrees of valgus
. 5 degrees of dorsiflexion, 5 degrees of varus
. 10-15 degrees of dorsiflexion, 10-15 degrees of valgus
. 25 degrees of dorsiflexion, 5 degrees of valgus
. 10 degrees of plantarflexion, 10 degrees of valgus

Correct Answer & Explanation

. 10-15 degrees of dorsiflexion, 10-15 degrees of valgus

Explanation

The optimal position for first MTP arthrodesis is 10-15 degrees of valgus, 10-15 degrees of dorsiflexion (relative to the floor), and neutral rotation. This allows for normal push-off during the gait cycle and accommodates most shoewear.

Question 679

Topic: 8. Foot and Ankle
A 30-year-old male sustains a high-energy knee dislocation (KD-III). The knee is reduced in the emergency department. His foot is warm, but pedal pulses are asymmetrical. An Ankle-Brachial Index (ABI) is measured. At what ABI threshold is a CT angiogram (CTA) strictly indicated to rule out a popliteal artery injury?
. Less than 1.1
. Less than 1.0
. Less than 0.9
. Less than 0.7
. Less than 0.5

Correct Answer & Explanation

. Less than 0.9

Explanation

Following a knee dislocation, an ABI of less than 0.9 is highly sensitive for an occult popliteal artery injury. Any patient with an ABI < 0.9, asymmetrical pulses, or signs of limb ischemia warrants urgent advanced vascular imaging (CTA) or vascular surgery consultation.

Question 680

Topic: 8. Foot and Ankle

A 24-year-old female sustains a severe midfoot twisting injury. Radiographs show a widened space between the bases of the 1st and 2nd metatarsals with no obvious avulsion fractures. MRI confirms a complete tear of the Lisfranc ligament. What is the most appropriate surgical treatment?

. Closed reduction and percutaneous pinning
. Open reduction and internal fixation with transarticular screws
. Primary arthrodesis of the first, second, and third tarsometatarsal joints
. Excision of the medial cuneiform
. Casting in equinus for 8 weeks

Correct Answer & Explanation

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

Explanation

Purely ligamentous Lisfranc injuries have a higher rate of poor outcomes and post-traumatic arthritis with open reduction and internal fixation compared to bony avulsion variants. Primary arthrodesis of the medial column is preferred to improve functional outcomes.

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