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8. Foot and Ankle MCQs

Practice Set 308 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 6141

Topic: 8. Foot and Ankle

What is the primary indication for surgical intervention in an acute Achilles tendon rupture?

. Patient age over 60 years.
. Complete rupture of the tendon.
. High-demand athlete.
. Large gap between tendon ends on ultrasound (>3 cm).
. Presence of a Haglund's deformity.

Correct Answer & Explanation

. Large gap between tendon ends on ultrasound (>3 cm).

Explanation

While there's ongoing debate regarding operative vs. non-operative management of Achilles tendon ruptures, surgical intervention is generally favored for high-demand athletes due to potentially lower re-rupture rates and better functional outcomes. However, a large gap between the tendon ends (>3 cm) often makes non-operative management less successful in achieving apposition and healing, thus making surgery a stronger consideration for anatomical repair. Patient age over 60 is often a relative contraindication for surgery. Complete rupture itself does not always mandate surgery, as many can be treated non-operatively, especially with early functional rehabilitation. Haglund's deformity is a pre-existing condition and not an acute indication for rupture repair.

Question 6142

Topic: 8. Foot and Ankle

What is the primary role of the fibula in lower leg stability and function?

. Primary weight-bearing bone.
. Provides origin for major knee extensors.
. Forms a critical component of the ankle mortise.
. Transmits significant axial load from the knee to the foot.
. Protects the posterior neurovascular bundle.

Correct Answer & Explanation

. Forms a critical component of the ankle mortise.

Explanation

While the fibula bears a small percentage of axial load, its primary anatomical and biomechanical role is to form the lateral wall of the ankle mortise, providing critical stability to the ankle joint by articulation with the talus and serving as an attachment site for numerous ligaments (e.g., lateral collateral ligaments of the ankle, syndesmotic ligaments). The tibia is the primary weight-bearing bone. The fibula provides origin for some lower leg muscles but not major knee extensors. The posterior neurovascular bundle is protected by the deeper muscles and fascia, not primarily the fibula itself.

Question 6143

Topic: 8. Foot and Ankle

A 75-year-old female presents with a non-displaced fracture of the talar neck. What is the most critical complication to monitor for in this fracture?

. Nonunion.
. Malunion.
. Avascular necrosis (AVN) of the talar body.
. Subtalar arthritis.
. Tarsal tunnel syndrome.

Correct Answer & Explanation

. Avascular necrosis (AVN) of the talar body.

Explanation

Talar neck fractures, even non-displaced ones, carry a significant risk of avascular necrosis (AVN) of the talar body. The talus has a precarious blood supply, primarily from small vessels entering the neck and body, with no direct muscular attachments. A fracture of the talar neck often disrupts this blood supply, leading to ischemia of the talar body. The risk of AVN increases with displacement and comminution. Nonunion and malunion are also concerns, as is post-traumatic subtalar arthritis, but AVN is the most common and devastating complication related to the unique vascular anatomy of the talus. Tarsal tunnel syndrome is less common as a primary complication.

Question 6144

Topic: 8. Foot and Ankle

What is the critical step in managing a dislocated knee that should always be performed, regardless of the presence of palpable pulses?

. Immediate operative exploration of the popliteal fossa.
. Arteriography to assess for vascular injury.
. Immediate reduction of the dislocation.
. Application of an external fixator.
. Measurement of ankle-brachial index (ABI).

Correct Answer & Explanation

. Immediate reduction of the dislocation.

Explanation

The most critical immediate step in managing any dislocated knee (assuming the patient is hemodynamically stable) is prompt reduction of the dislocation. This is a limb-saving maneuver as it can restore vascular flow if compressed by the dislocation and reduces tension on neurovascular structures. Even if pulses are palpable, a vascular injury can still exist (intimal tear, spasm), but reduction is paramount before extensive workup. Arteriography or CT angiography is indicatedafterreduction (or if pulses remain absent/diminished post-reduction). Operative exploration is only for confirmed vascular injury or non-reducible dislocations. ABI measurement is part of the vascular assessment but follows reduction.

Question 6145

Topic: Ankle Trauma & Sports

What is the most appropriate management for an undisplaced, stable fracture of the lateral malleolus (Weber A)?

. Immediate surgical fixation with a plate and screws.
. Open reduction and internal fixation with a tension band.
. Non-weight bearing in a short leg cast for 6 weeks.
. Functional bracing or a walking boot with early weight bearing as tolerated.
. Skeletal traction.

Correct Answer & Explanation

. Functional bracing or a walking boot with early weight bearing as tolerated.

Explanation

Weber A fractures (fracture of the fibula distal to the syndesmosis) are typically stable injuries because the syndesmosis and deltoid ligament are intact. For undisplaced and stable fractures, functional bracing or a walking boot with early weight-bearing as tolerated is the most appropriate management. This allows for earlier return to function and typically good outcomes. Surgical fixation is not indicated for stable, undisplaced fractures. Non-weight bearing in a cast is overly conservative for this stable pattern. Skeletal traction is not relevant.

Question 6146

Topic: 8. Foot and Ankle
What is the primary goal of surgical management for a displaced intra-articular calcaneal fracture?
. Restoration of Bรถhler's angle.
. Decompression of the tarsal tunnel.
. Achieving anatomical reduction of the posterior facet and restoring hindfoot alignment.
. Early weight bearing to promote fracture healing.
. Fusion of the subtalar joint.

Correct Answer & Explanation

. Achieving anatomical reduction of the posterior facet and restoring hindfoot alignment.

Explanation

Displaced intra-articular calcaneal fractures often involve the subtalar joint. The primary goal of surgical management is to achieve anatomical reduction of the posterior facet (the articular surface between the talus and calcaneus) and restore the overall height, width, and alignment of the hindfoot. This is crucial for preventing post-traumatic subtalar arthritis, which is a common and debilitating complication. Restoration of Bรถhler's angle is a radiographic indicator of calcaneal height restoration. While tarsal tunnel syndrome can be a complication, decompression is not the primary goal of the fracture fixation. Early weight-bearing is usually contraindicated, and subtalar fusion is a salvage procedure for symptomatic arthritis, not the primary treatment for the acute fracture.

Question 6147

Topic: 8. Foot and Ankle

Which of the following is a recognized complication of posterior screw fixation for a medial malleolus fracture?

. Injury to the saphenous nerve.
. Peroneal tendon irritation.
. Syndesmotic malreduction.
. Injury to the posterior tibial artery or nerve.
. Damage to the Achilles tendon.

Correct Answer & Explanation

. Injury to the posterior tibial artery or nerve.

Explanation

Posterior screw fixation of the medial malleolus (often used for vertical fractures or to avoid anterior hardware) requires careful technique due to the proximity of the posterior tibial neurovascular bundle (posterior tibial artery, posterior tibial nerve) to the posterior aspect of the tibia. Screws that are too long or improperly angled can injure these structures. The saphenous nerve is more anterior-medial. Peroneal tendons are lateral. Syndesmotic malreduction is related to fibular fixation. Achilles tendon is posterior but superficial to these structures.

Question 6148

Topic: 8. Foot and Ankle

Which of the following is the MOST important consideration when assessing the skin and soft tissues of a rheumatoid foot for potential surgical intervention?

. Presence of rheumatoid nodules on the dorsum of the foot
. Generalized skin discoloration due to chronic inflammation
. Presence of active ulceration, especially over bony prominences
. Thickness of the subcutaneous fat layer
. Distribution of hair follicles on the toes

Correct Answer & Explanation

. Presence of active ulceration, especially over bony prominences

Explanation

The presence of active ulceration, particularly over bony prominences (e.g., prominent metatarsal heads, bunions), is a critical finding that typically contraindicates immediate elective surgery. Ulcerations increase the risk of infection and compromise wound healing. These must be addressed and healed prior to any reconstructive procedure. Rheumatoid nodules and skin discoloration are chronic findings but less acutely problematic for immediate surgery than active ulceration.

Question 6149

Topic: 8. Foot and Ankle

During the examination of a patient with rheumatoid arthritis and symptoms suggestive of Tarsal Tunnel Syndrome, the MOST specific physical finding would be:

. Numbness and tingling in the first web space
. Tenderness over the medial malleolus and the course of the posterior tibial nerve
. Positive Tinel's sign posterior to the medial malleolus
. Weakness of ankle dorsiflexion
. Pain with passive inversion of the foot

Correct Answer & Explanation

. Positive Tinel's sign posterior to the medial malleolus

Explanation

A positive Tinel's sign posterior to the medial malleolus, where the posterior tibial nerve passes through the tarsal tunnel, is the most specific physical examination finding for Tarsal Tunnel Syndrome. It indicates irritation or compression of the nerve. Tenderness over the area is supportive, but Tinel's sign directly assesses nerve irritability. Numbness in the first web space is more indicative of deep peroneal nerve impingement, and weakness of ankle dorsiflexion is associated with common peroneal nerve or deep peroneal nerve issues higher up.

Question 6150

Topic: Forefoot

A patient with long-standing rheumatoid arthritis presents with a severe hallux valgus deformity and significant MTP joint pain. When assessing the range of motion of the first MTP joint, you observe a significant restriction in dorsiflexion. This finding is MOST indicative of:

. Flexible hallux valgus
. Early stage synovitis
. Hallux rigidus (degenerative arthritis of the first MTP joint)
. Neuroma formation in the first web space
. Peroneal nerve entrapment

Correct Answer & Explanation

. Hallux rigidus (degenerative arthritis of the first MTP joint)

Explanation

Significant restriction in dorsiflexion of the first MTP joint, especially when associated with pain, is a hallmark feature of hallux rigidus (degenerative arthritis of the first MTP joint). In rheumatoid arthritis, the chronic inflammation and joint destruction can lead to severe arthritic changes, resulting in pain and stiffness, particularly with dorsiflexion required for normal gait push-off. While synovitis can cause pain, markedrestrictionsuggests structural arthritic changes.

Question 6151

Topic: 8. Foot and Ankle

In a patient with rheumatoid arthritis experiencing chronic metatarsalgia, palpation of the interdigital web spaces elicits sharp, shooting pain radiating into the toes. This finding, while not exclusive to RA, should prompt consideration of:

. MTP joint synovitis
. Plantar plate rupture
. Morton's neuroma
. Stress fracture of a metatarsal shaft
. Tarsal coalition

Correct Answer & Explanation

. Morton's neuroma

Explanation

Sharp, shooting pain radiating into the toes from the interdigital web spaces, particularly with direct palpation or a 'Mulder's click,' is highly suggestive of Morton's neuroma (interdigital neuroma). While MTP joint synovitis is common in RA and can cause metatarsalgia, the radiating, nerve-like pain is more characteristic of neuroma formation. Plantar plate rupture typically causes MTP joint instability and pain without radiating symptoms. Stress fractures cause localized bone pain.

Question 6152

Topic: Forefoot

When assessing the lesser toe deformities in a rheumatoid foot, a key distinction between a hammer toe and a claw toe is:

. A hammer toe involves MTP joint hyperextension, while a claw toe involves MTP joint flexion.
. A hammer toe involves PIP joint flexion with DUP extension, while a claw toe involves MTP hyperextension, PIP flexion, and DIP flexion.
. A hammer toe is always flexible, whereas a claw toe is always rigid.
. A hammer toe affects only the second toe, while a claw toe affects all lesser toes.
. Claw toes are never associated with MTP joint subluxation, unlike hammer toes.

Correct Answer & Explanation

. A hammer toe involves PIP joint flexion with DUP extension, while a claw toe involves MTP hyperextension, PIP flexion, and DIP flexion.

Explanation

A claw toe is characterized by MTP joint hyperextension, PIP joint flexion, and DIP joint flexion. A hammer toe primarily involves PIP joint flexion with a neutral or hyperextended DIP joint. While both involve PIP flexion, the involvement of the MTP and DIP joints differentiates them. Claw toes are strongly associated with MTP joint subluxation or dislocation due to the imbalance of intrinsic and extrinsic muscles, common in RA. Flexibility varies for both deformities.

Question 6153

Topic: 8. Foot and Ankle

A senior registrar is examining a rheumatoid foot and observes a severe, rigid pes planovalgus deformity. What radiographic finding would MOST directly correlate with this clinical observation and suggest significant structural damage?

. Metatarsal stress fractures
. Joint space narrowing and subchondral sclerosis of the first MTP joint
. Erosions and collapse of the talonavicular joint with associated hindfoot valgus
. Hallux valgus interphalangeus
. Prominent osteophytes at the ankle joint

Correct Answer & Explanation

. Erosions and collapse of the talonavicular joint with associated hindfoot valgus

Explanation

A rigid pes planovalgus deformity in RA is often driven by inflammatory destruction and collapse of the midfoot, particularly the talonavicular joint. Erosions, subluxation, and subsequent collapse of the talonavicular joint lead to progressive loss of the medial longitudinal arch and a fixed hindfoot valgus, which is the hallmark of this severe deformity. The other options describe forefoot or ankle pathology, which are distinct from the primary drivers of rigid midfoot collapse.

Question 6154

Topic: 8. Foot and Ankle

When assessing nerve function in a patient with advanced rheumatoid foot deformity, which nerve is MOST commonly implicated in compressive neuropathies due to hindfoot valgus and midfoot collapse?

. Deep peroneal nerve
. Superficial peroneal nerve
. Sural nerve
. Saphenous nerve
. Posterior tibial nerve

Correct Answer & Explanation

. Posterior tibial nerve

Explanation

The posterior tibial nerve passes through the tarsal tunnel, an osteofibrous canal posterior to the medial malleolus. In patients with severe hindfoot valgus and midfoot collapse (pes planovalgus), the mechanical changes can tension and compress the posterior tibial nerve within the tarsal tunnel, leading to Tarsal Tunnel Syndrome. The other nerves are less commonly affected by these specific deformities.

Question 6155

Topic: 8. Foot and Ankle

A patient with long-standing rheumatoid arthritis exhibits significant atrophy of the intrinsic foot muscles. Which of the following deformities is a direct consequence of this intrinsic muscle weakness?

. Hallux rigidus
. Hammer toes and claw toes
. Bunionette deformity
. Flatfoot deformity (pes planus)
. Haglund's deformity

Correct Answer & Explanation

. Hammer toes and claw toes

Explanation

Intrinsic muscle weakness and imbalance are key contributors to the development of lesser toe deformities such as hammer toes and claw toes in rheumatoid arthritis. The loss of intrinsic muscle function allows the extrinsic flexors and extensors to overpower the digits, leading to characteristic MTP hyperextension, PIP flexion, and DIP flexion or extension. While flatfoot can be associated, toe deformities are more directly linked to intrinsic muscle dysfunction.

Question 6156

Topic: 8. Foot and Ankle

During the examination of a patient with rheumatoid arthritis, you notice an inability to voluntarily extend the toes at the MTP joints. This finding, combined with MTP joint subluxation, suggests a deficiency in which structure?

. Flexor digitorum longus tendon
. Extensor digitorum longus tendon
. Plantar plate
. Joint capsule and collateral ligaments
. Intrinsic foot muscles

Correct Answer & Explanation

. Plantar plate

Explanation

The plantar plate is a fibrocartilaginous structure that reinforces the plantar aspect of the MTP joint capsule. In rheumatoid arthritis, chronic synovitis often leads to attenuation and eventual rupture of the plantar plate. This significantly destabilizes the MTP joint, leading to dorsal subluxation or dislocation of the phalanx on the metatarsal head, and a consequent inability to maintain the toes in a neutral or extended position during weight bearing. While intrinsic muscles also play a role, direct mechanical instability due to plantar plate pathology is critical for subluxation.

Question 6157

Topic: 8. Foot and Ankle

Which of the following findings on physical examination would lead you to classify a pes planovalgus deformity in a rheumatoid patient as 'rigid' rather than 'flexible'?

. Positive 'too many toes' sign
. Pain with palpation of the posterior tibial tendon
. Inability of the medial longitudinal arch to reconstitute on a single heel-rise test
. Tightness of the Achilles tendon demonstrated by restricted ankle dorsiflexion
. Tenderness over the sinus tarsi

Correct Answer & Explanation

. Inability of the medial longitudinal arch to reconstitute on a single heel-rise test

Explanation

The inability of the medial longitudinal arch to reconstitute or 'lift off' the ground during a single heel-rise test (or standing on toes) is the classic clinical criterion for a rigid flatfoot. This indicates fixed bony deformities or joint fusions rather than reducible deformities. A flexible flatfoot will show some correction. While other findings may be present, the heel-rise test directly assesses flexibility of the arch.

Question 6158

Topic: 8. Foot and Ankle

A 60-year-old female with long-standing rheumatoid arthritis reports severe pain under the second and third metatarsal heads, particularly with ambulation. On examination, the plantar fat pad appears to have migrated distally, and you palpate tenderness over the second and third MTP joint capsules. Which of the following is the MOST appropriate initial conservative management strategy to address her pain?

. Corticosteroid injections into the MTP joints
. Custom orthotics with metatarsal pads proximal to the metatarsal heads
. Surgical plantar plate repair
. Rigid arch supports
. Immobilization in a walking boot

Correct Answer & Explanation

. Custom orthotics with metatarsal pads proximal to the metatarsal heads

Explanation

Custom orthotics with metatarsal pads placedproximalto the metatarsal heads (to offload them) are a cornerstone of conservative management for metatarsalgia caused by plantar fat pad migration and MTP joint pathology in RA. This helps redistribute pressure, protecting the exposed metatarsal heads. Steroid injections offer temporary relief but don't address biomechanics. Rigid arch supports might aggravate existing midfoot issues or not target forefoot pain directly. Surgical repair is a last resort. Immobilization is for acute, severe conditions.

Question 6159

Topic: 8. Foot and Ankle

When assessing for ankle involvement in a rheumatoid patient, which specific range of motion limitation is MOST commonly observed and significantly impacts gait?

. Restricted inversion
. Restricted eversion
. Restricted dorsiflexion
. Restricted plantarflexion
. Restricted subtalar motion

Correct Answer & Explanation

. Restricted dorsiflexion

Explanation

Restricted ankle dorsiflexion is a very common and functionally significant limitation in rheumatoid arthritis of the ankle. Adequate dorsiflexion (typically 10-20 degrees) is essential for smooth progression through the stance phase of gait and for clearance during the swing phase. Loss of dorsiflexion leads to compensatory mechanisms like premature heel-off, knee hyperextension, or 'steppage' gait, significantly impacting mobility. Subtalar motion affects inversion/eversion, not dorsiflexion/plantarflexion.

Question 6160

Topic: 8. Foot and Ankle

You are examining a patient with rheumatoid arthritis who has painful plantar callosities. Which of the following areas is LEAST likely to develop significant callosities due to direct pressure from typical rheumatoid foot deformities?

. Under the first metatarsal head
. Under the second and third metatarsal heads
. Under the navicular bone
. Under the fifth metatarsal head
. Under the heads of the proximal phalanges of the lesser toes

Correct Answer & Explanation

. Under the navicular bone

Explanation

Callosities in rheumatoid arthritis develop under areas of increased pressure. While MTP joint pathology (subluxation/dislocation) leads to prominent metatarsal heads (1st, 2nd, 3rd, 5th) and subsequent callosities, and plantarflexed DIP joints can lead to callosities under the tips of the toes, the navicular bone is usually superiorly located and does not typically bear direct plantar weight in a way that causes isolated callosities, even with arch collapse. With arch collapse, the entire medial column may sag, but discrete navicular callosities are uncommon.

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