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8. Foot and Ankle MCQs

Practice Set 310 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 6181

Topic: 8. Foot and Ankle

A 65-year-old female with long-standing RA reports increasing difficulty with balance and frequent falls. On examination, you note severe, rigid hindfoot valgus and midfoot collapse. Which of the following gait characteristics is MOST likely contributing to her instability?

. Increased ankle dorsiflexion
. Excessive pronation during initial contact
. Loss of the normal 'tripod' effect of the foot and diminished push-off power
. Shortened swing phase duration
. Increased step length

Correct Answer & Explanation

. Loss of the normal 'tripod' effect of the foot and diminished push-off power

Explanation

Severe rigid hindfoot valgus and midfoot collapse lead to a significant loss of the normal 'tripod' effect of the foot (calcaneus, first metatarsal head, fifth metatarsal head) which is essential for stable weight-bearing. This, combined with painful and dysfunctional MTP joints, diminishes the push-off power during gait. The combination severely compromises balance and propulsive force, directly contributing to instability and frequent falls. The foot essentially becomes a 'rocker bottom' leading to poor ground reaction forces and altered lever arm mechanics.

Question 6182

Topic: 8. Foot and Ankle

When palpating the plantar aspect of the metatarsal heads in a rheumatoid foot, a 'boggy' or 'spongy' feel, particularly with tenderness, is characteristic of:

. Plantar fat pad atrophy
. Metatarsal stress fracture
. Active synovitis of the MTP joint capsule
. Chronic callus formation
. A tight plantar fascia

Correct Answer & Explanation

. Active synovitis of the MTP joint capsule

Explanation

A 'boggy' or 'spongy' feel with tenderness on palpation of the MTP joint capsule, especially from the plantar aspect, is a classic clinical sign of active synovitis. This sensation comes from the inflamed, thickened synovial lining within the joint. Plantar fat pad atrophy leads to a bony, hard feel. Stress fracture causes localized bony tenderness. Callus is hard skin. A tight plantar fascia causes heel pain and restricts dorsiflexion.

Question 6183

Topic: 8. Foot and Ankle

Which deformity in the rheumatoid foot is often associated with a compensatory contracture of the Achilles tendon?

. Hallux rigidus
. Hammer toes
. Pes cavus
. Pes planovalgus
. Bunionette deformity

Correct Answer & Explanation

. Pes planovalgus

Explanation

A progressive pes planovalgus deformity, where the arch collapses and the hindfoot everts, often leads to a compensatory contracture of the Achilles tendon (equinus deformity). As the foot flattens and pronates, the Achilles tendon can shorten or become tight, further contributing to the deformity and limiting ankle dorsiflexion. This is a significant factor in the progression of the flatfoot and is a target for surgical correction (e.g., Achilles lengthening or gastrocnemius recession).

Question 6184

Topic: 8. Foot and Ankle

A patient with long-standing rheumatoid arthritis reports inability to extend their toes and difficulty clearing the ground during the swing phase of gait. On examination, you observe fixed MTP joint hyperextension and PIP/DIP flexion in the lesser toes. This constellation of findings is MOST indicative of:

. Hallux valgus interphalangeus
. Flexible hammer toes
. Severe, rigid claw toe deformities with MTP joint subluxation
. Plantar fasciitis
. Tarsal tunnel syndrome

Correct Answer & Explanation

. Severe, rigid claw toe deformities with MTP joint subluxation

Explanation

Fixed MTP joint hyperextension combined with PIP and DIP flexion in the lesser toes describes severe, rigid claw toe deformities. These deformities are often associated with MTP joint subluxation or dislocation in RA. The MTP hyperextension and inability to extend the toes (due to fixed flexion at the PIP/DIP) lead to the 'cock-up' deformity, making it difficult to clear the ground during the swing phase, causing tripping and rubbing against shoe tops.

Question 6185

Topic: 8. Foot and Ankle

When assessing the forefoot for instability in a rheumatoid patient, which test specifically evaluates the integrity of the plantar plate of the second MTP joint?

. Mulder's click test
. Lachman test of the MTP joint
. Drawer test of the MTP joint
. Kleiger's test
. Forefoot adduction test

Correct Answer & Explanation

. Drawer test of the MTP joint

Explanation

A 'drawer test' of the MTP joint (similar to the Lachman test for the knee) specifically assesses the integrity of the plantar plate. By stabilizing the metatarsal and attempting to translate the proximal phalanx dorsally, one can elicit a positive drawer sign if the plantar plate is ruptured or significantly attenuated, indicating MTP joint instability. Mulder's click test is for Morton's neuroma, and Kleiger's test is for syndesmotic ankle injuries.

Question 6186

Topic: 8. Foot and Ankle

Which of the following is the MOST common site for rheumatoid nodule formation in the foot?

. Plantar arch
. Medial malleolus
. Dorsum of the foot, especially over bony prominences and extensor tendons
. Lateral aspect of the calcaneus
. Heel pad

Correct Answer & Explanation

. Dorsum of the foot, especially over bony prominences and extensor tendons

Explanation

Rheumatoid nodules are most commonly found over bony prominences and areas subjected to pressure or friction. In the foot, this frequently includes the dorsum of the foot, particularly over the metatarsal heads or extensor tendons, and sometimes the Achilles tendon or olecranon. While they can occur elsewhere, these are the typical sites due to the combination of inflammation and mechanical stress.

Question 6187

Topic: 8. Foot and Ankle

A 35-year-old female with newly diagnosed rheumatoid arthritis presents with pain and swelling limited to her forefoot MTP joints. Which of the following is the LEAST likely finding on her initial physical examination?

. Slightly widened forefoot with early splaying
. Tenderness and warmth over the 2nd and 3rd MTP joints
. Early hallux valgus with a compressible bunion
. Severe, rigid hindfoot valgus with talonavicular collapse
. Positive 'squeeze test' across the MTP joints

Correct Answer & Explanation

. Severe, rigid hindfoot valgus with talonavicular collapse

Explanation

In newly diagnosed or early rheumatoid arthritis, it is LEAST likely to find severe, rigid hindfoot valgus with talonavicular collapse. These are typically features of long-standing, advanced rheumatoid disease where chronic inflammation has led to significant joint destruction, subluxation, and bony remodeling of the midfoot and hindfoot. Early RA usually presents with synovitis and subtle deformities in the forefoot, as indicated by the other options.

Question 6188

Topic: 8. Foot and Ankle

When performing a thorough physical examination for cavus foot, what finding would indicate a 'positive Peek-A-Boo' sign?

. The posterior heel pad is visible from the front of the patient.
. The medial malleolus is prominent and easily palpable.
. The first metatarsal head remains plantarflexed even with ankle dorsiflexion.
. The tibialis anterior tendon is visible and taut during gait.
. The plantar fascia is noticeably tightened and palpable.

Correct Answer & Explanation

. The posterior heel pad is visible from the front of the patient.

Explanation

The 'Peek-A-Boo' sign is a clinical indicator of hindfoot varus. When observing the patient from the front (anteriorly), if the medial portion of the heel (specifically, the heel pad) is visible, it suggests that the calcaneus is in varus, rotating the heel inward and allowing its medial aspect to 'peek out' from behind the ankle. This sign indicates a significant hindfoot varus component to the cavus deformity.

Question 6189

Topic: 8. Foot and Ankle

What is the primary goal of surgical management for a rigid, symptomatic cavus foot with severe hindfoot varus and forefoot equinus?

. To achieve complete pain relief and restore normal shoe wear.
. To correct the deformity to a plantigrade, functional foot, even if some motion is sacrificed.
. To preserve all joint motion, regardless of the severity of deformity.
. To perform only soft tissue releases to avoid joint fusion.
. To reduce the calcaneal pitch angle to less than 10 degrees.

Correct Answer & Explanation

. To correct the deformity to a plantigrade, functional foot, even if some motion is sacrificed.

Explanation

The primary goal of surgical management for severe, rigid cavus feet is to create a plantigrade, functional foot that is pain-free and can fit into shoes. This often involves a combination of soft tissue releases, osteotomies, and sometimes arthrodesis. While preserving motion is desirable, in rigid deformities, some joint motion may need to be sacrificed (e.g., via fusion) to achieve a stable, corrected, and functional foot. Complete pain relief and normal shoe wear are important outcomes, but the 'plantigrade, functional foot' encompasses the overarching surgical aim.

Question 6190

Topic: 8. Foot and Ankle

Which of the following conditions is LEAST likely to be associated with the development of a cavus foot deformity?

. Friedreich's ataxia.
. Spina bifida occulta.
. Cerebral palsy.
. Poliomyelitis.
. Marfan syndrome.

Correct Answer & Explanation

. Marfan syndrome.

Explanation

Marfan syndrome is a connective tissue disorder characterized by skeletal, ocular, and cardiovascular abnormalities. While foot deformities can occur (e.g., pes planus, hallux valgus), cavus foot is not a typical or primary association. Friedreich's ataxia, spina bifida occulta (especially with tethered cord), cerebral palsy (particularly spastic types), and poliomyelitis are all well-recognized neurological conditions that can lead to muscle imbalance and subsequent cavus foot deformity.

Question 6191

Topic: 8. Foot and Ankle

When evaluating a cavus foot, palpation of which structure on the plantar aspect of the foot is most likely to elicit pain due to an associated contracture or inflammation?

. Flexor hallucis longus tendon.
. Navicular tuberosity.
. Plantar fascia.
. Cuboid.
. Peroneus brevis tendon.

Correct Answer & Explanation

. Plantar fascia.

Explanation

The plantar fascia is a thick fibrous band on the sole of the foot that maintains the arch. In a cavus foot, the arch is excessively high, leading to chronic tension and contracture of the plantar fascia. This increased tension often results in plantar fasciitis, a common source of pain in these patients, typically felt at its origin on the medial calcaneal tuberosity. While other structures may be painful, the plantar fascia is most directly and commonly implicated in cavus foot pain due to architectural stress.

Question 6192

Topic: 8. Foot and Ankle

A 10-year-old child presents with a progressive cavus foot. Parents report the child frequently trips and has difficulty participating in sports. On physical exam, there is noticeable atrophy of the intrinsic foot muscles and weakness of ankle dorsiflexors. Deep tendon reflexes are diminished at the ankles. These findings are most consistent with which type of cavus foot?

. Idiopathic cavus foot.
. Congenital vertical talus.
. Neuromuscular cavus foot (e.g., Charcot-Marie-Tooth).
. Post-traumatic cavus foot.
. Compensatory cavus foot secondary to ankle equinus.

Correct Answer & Explanation

. Neuromuscular cavus foot (e.g., Charcot-Marie-Tooth).

Explanation

The constellation of progressive cavus foot, intrinsic foot muscle atrophy, weakness of ankle dorsiflexors, and diminished deep tendon reflexes strongly points towards a neuromuscular etiology, with Charcot-Marie-Tooth (CMT) disease being the most common. Idiopathic cavus foot typically lacks distinct neurological deficits. Congenital vertical talus is a severe flatfoot deformity. Post-traumatic cavus foot has a clear history of trauma. Compensatory cavus foot implies a primary equinus, but the neurological signs are the key here.

Question 6193

Topic: 8. Foot and Ankle

The primary goal of a dorsiflexion osteotomy of the first metatarsal in the surgical correction of a cavus foot is to:

. Increase the stability of the subtalar joint.
. Correct a fixed hindfoot varus deformity.
. Reduce the prominence of the medial malleolus.
. Address a plantarflexed first ray deformity.
. Improve ankle dorsiflexion range of motion.

Correct Answer & Explanation

. Address a plantarflexed first ray deformity.

Explanation

A dorsiflexion osteotomy of the first metatarsal (e.g., a closing wedge osteotomy at the base of the first metatarsal) is performed to correct a fixed plantarflexion deformity of the first ray. By dorsiflexing the first metatarsal, this procedure helps to level the forefoot, which in turn can reduce the compensatory hindfoot varus and create a more plantigrade foot. It does not directly impact subtalar stability, hindfoot varus (unless it's compensatory), or ankle dorsiflexion.

Question 6194

Topic: 8. Foot and Ankle

Which of the following soft tissue procedures is often combined with bony corrections in a cavus foot to address severe claw toe deformities?

. Achilles tendon lengthening.
. Peroneus brevis transfer.
. Extensor digitorum longus lengthening.
. Flexor-to-extensor transfer of the lesser toes.
. Tibialis posterior tendon transfer.

Correct Answer & Explanation

. Flexor-to-extensor transfer of the lesser toes.

Explanation

Claw toe deformities in cavus feet are typically caused by an imbalance between strong extrinsic flexors and weak intrinsic muscles. A flexor-to-extensor transfer (e.g., Girdlestone-Taylor procedure) involves rerouting the flexor digitorum longus tendon from the plantar to the dorsal aspect of the proximal phalanx, converting it into an extensor. This helps to correct the hyperextension at the MTP joint and the flexion at the PIP joint, improving toe alignment and function.

Question 6195

Topic: 8. Foot and Ankle

During gait analysis of a cavus foot patient, what characteristic finding is commonly observed during the stance phase?

. Prolonged pronation of the subtalar joint.
. Early heel-off and forefoot rocker.
. Increased pressure under the lateral border of the foot and metatarsal heads.
. Excessive ankle dorsiflexion.
. Wide-based, shuffling gait with reduced step length.

Correct Answer & Explanation

. Increased pressure under the lateral border of the foot and metatarsal heads.

Explanation

In a cavus foot, the high arch and hindfoot varus typically lead to altered weight-bearing. There is often increased pressure concentrated under the lateral border of the foot and under the metatarsal heads (particularly the first and fifth). This is due to the lack of midfoot contact with the ground and the varus alignment. This can lead to callosities in these areas. Prolonged pronation is characteristic of flatfoot, not cavus foot.

Question 6196

Topic: 8. Foot and Ankle

A 45-year-old male with long-standing bilateral cavus feet complains of chronic pain and stiffness in his ankles and subtalar joints. Radiographs show significant degenerative changes in both joints. Conservative management has failed. Which of the following surgical options is most appropriate for a painful, rigid, end-stage cavus foot with arthritis?

. Multiple soft tissue releases.
. Isolated first metatarsal osteotomy.
. Triple arthrodesis.
. Achilles tendon lengthening.
. Posterior tibial tendon transfer.

Correct Answer & Explanation

. Triple arthrodesis.

Explanation

For a painful, rigid, end-stage cavus foot with significant degenerative arthritis of the subtalar and midtarsal joints (often involving the talonavicular and calcaneocuboid joints), triple arthrodesis is the most appropriate surgical option. This procedure involves fusing the subtalar, talonavicular, and calcaneocuboid joints, providing stability, pain relief, and significant deformity correction at the expense of motion. Soft tissue releases and isolated forefoot osteotomies are insufficient for end-stage arthritis and rigid deformities involving the hindfoot and midfoot.

Question 6197

Topic: 8. Foot and Ankle

What is the primary deformity present in a pes cavus foot, irrespective of its specific sub-type (cavovarus, calcaneocavus, etc.)?

. Midfoot abduction.
. Increased hindfoot valgus.
. Elevation of the medial longitudinal arch.
. Fixed ankle equinus.
. Excessive subtalar joint pronation.

Correct Answer & Explanation

. Elevation of the medial longitudinal arch.

Explanation

The defining characteristic of a pes cavus foot is an abnormally elevated medial longitudinal arch. This high arch can be associated with various other deformities such as forefoot equinus, hindfoot varus, and claw toes, leading to different subtypes (cavovarus is most common). However, the elevated arch is the fundamental feature. Midfoot abduction, increased hindfoot valgus, and excessive pronation are characteristic of flatfoot deformities.

Question 6198

Topic: 8. Foot and Ankle

When evaluating a patient with a cavus foot, why is it crucial to test for sensation, particularly light touch and proprioception, in the lower extremities?

. To rule out vascular insufficiency.
. To assess for diabetic neuropathy.
. To identify potential peripheral nerve entrapment syndromes.
. To detect underlying neurological conditions like Charcot-Marie-Tooth disease or spinal cord lesions.
. To quantify pain severity in a standardized manner.

Correct Answer & Explanation

. To detect underlying neurological conditions like Charcot-Marie-Tooth disease or spinal cord lesions.

Explanation

A significant percentage of cavus foot deformities have an underlying neurological etiology, most commonly Charcot-Marie-Tooth (CMT) disease, but also conditions like Friedreich's ataxia, spinal dysraphism, or spinal cord tumors. Sensory deficits (e.g., stocking-glove sensory loss in CMT) are key diagnostic findings in these conditions. A thorough neurological exam including sensory testing is essential to identify the primary cause, which significantly impacts prognosis and management. While diabetic neuropathy can cause cavus foot, and nerve entrapment can occur, the overarching reason for sensory testing inanycavus foot evaluation is to screen for generalized or focal neurological disease.

Question 6199

Topic: 8. Foot and Ankle

Which specific deformity of the hindfoot is most commonly associated with a cavus foot, contributing to the 'cavovarus' description?

. Calcaneal valgus.
. Hindfoot equinus.
. Hindfoot varus.
. Calcaneal dorsiflexion.
. Subtalar joint abduction.

Correct Answer & Explanation

. Hindfoot varus.

Explanation

The most common and characteristic hindfoot deformity associated with a cavus foot is hindfoot varus (inversion). This combination is termed 'cavovarus foot.' The varus alignment of the hindfoot often develops as a compensation for a plantarflexed forefoot (especially the first ray), helping the foot to achieve a plantigrade position. This leads to the characteristic 'peek-a-boo' sign and increased pressure on the lateral border of the foot.

Question 6200

Topic: 8. Foot and Ankle

A cavus foot with a flexible forefoot but a rigid hindfoot varus that does not correct with the Coleman block test primarily requires which type of surgical correction for the hindfoot?

. Soft tissue release of the plantar fascia and intrinsic muscles.
. Dorsiflexion osteotomy of the first metatarsal.
. Lateral closing wedge osteotomy of the calcaneus (Dwyer osteotomy).
. Peroneus longus to brevis tendon transfer.
. Triple arthrodesis for fusion of the hindfoot joints.

Correct Answer & Explanation

. Lateral closing wedge osteotomy of the calcaneus (Dwyer osteotomy).

Explanation

If the hindfoot varus is rigid and does not correct with the Coleman block test, it indicates that the deformity is intrinsic to the calcaneus or subtalar joint and is not solely compensatory for a forefoot deformity. In such cases, a lateral closing wedge osteotomy of the calcaneus (Dwyer osteotomy) is the most common and effective procedure to directly correct the rigid hindfoot varus by creating a valgus alignment. Triple arthrodesis is reserved for severe, painful, arthritic, or recalcitrant rigid deformities, typically after failure of osteotomy or when joint degeneration is present.

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