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8. Foot and Ankle MCQs

Practice Set 261 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 5201

Topic: Midfoot & Hindfoot

What is the most appropriate initial management for a patient presenting with an acute, non-ulcerated Eichenholtz Stage I Charcot arthropathy of the foot?

. Immediate midfoot arthrodesis
. Intravenous antibiotic therapy
. Total contact casting (TCC)
. Open reduction and internal fixation
. Custom accommodative orthotic shoe wear

Correct Answer & Explanation

. Total contact casting (TCC)

Explanation

The cornerstone of management for acute Eichenholtz Stage I Charcot arthropathy is strict offloading and immobilization, ideally utilizing a total contact cast (TCC), to prevent further mechanical breakdown while the acute inflammation subsides.

Question 5202

Topic: 8. Foot and Ankle

While modern neuropathic (Charcot) arthropathy is most commonly seen in the foot and ankle due to diabetes mellitus, historically, severe Charcot changes of the large joints (knee) and spine were classically associated with which condition?

. Syringomyelia
. Leprosy
. Chronic alcoholism
. Tabes dorsalis
. Poliomyelitis

Correct Answer & Explanation

. Tabes dorsalis

Explanation

Tabes dorsalis, a manifestation of tertiary syphilis, was classically the most common cause of neuropathic arthropathy in the knee and spine before the antibiotic era. Syringomyelia classically affects the upper extremities (shoulder/elbow).

Question 5203

Topic: 8. Foot and Ankle

A 55-year-old diabetic male presents with a swollen, erythematous, and warm left foot without open ulcerations. Radiographs show acute fragmentation and subluxation of the tarsometatarsal joints. What is the initial recommended orthopedic management during this Eichenholtz stage I phase?

. Urgent midfoot arthrodesis
. Total contact casting and strict non-weight bearing
. Intravenous antibiotics for 6 weeks
. Excision of the cuboid and primary closure
. Surgical offloading via Achilles tendon lengthening

Correct Answer & Explanation

. Total contact casting and strict non-weight bearing

Explanation

The mainstay of treatment in the acute fragmentation phase (Eichenholtz stage I) of Charcot arthropathy is strict immobilization and offloading, typically achieved with a total contact cast (TCC). Surgery is contraindicated during the acute inflammatory phase due to a high risk of failure.

Question 5204

Topic: 8. Foot and Ankle
In a patient with diabetic neuroarthropathy of the foot, serial radiographs demonstrate absorption of fine debris, coalescence of large fracture fragments, and early sclerosis, alongside a clinical reduction in soft tissue edema. This corresponds to which stage of the Eichenholtz classification?
. Stage 0 (Inflammatory)
. Stage I (Development/Fragmentation)
. Stage II (Coalescence)
. Stage III (Reconstruction/Consolidation)
. Stage IV (Ankylosis)

Correct Answer & Explanation

. Stage II (Coalescence)

Explanation

Eichenholtz Stage II (Coalescence) is clinically marked by decreasing edema and erythema. Radiographically, it is characterized by the absorption of fine osseous debris, early fusion/coalescence of large fragments, and increasing sclerosis.

Question 5205

Topic: Midfoot & Hindfoot

A 55-year-old patient with long-standing, poorly controlled diabetes presents with a warm, swollen, erythematous, and painless foot. Radiographs demonstrate periarticular debris, bony fragmentation, and midfoot subluxation. According to the Eichenholtz classification, what is the current stage and best initial management?

. Stage 0 / Immediate open reduction and internal fixation
. Stage 1 / Total contact cast and non-weight bearing
. Stage 2 / Primary arthrodesis
. Stage 3 / Corticosteroid injections
. Stage 1 / Early rigid arthrodesis

Correct Answer & Explanation

. Stage 1 / Total contact cast and non-weight bearing

Explanation

Fragmentation, joint subluxation, and periarticular debris characterize Eichenholtz Stage 1 (Development) Charcot arthropathy. The gold standard initial treatment is immobilization and offloading, typically utilizing a total contact cast.

Question 5206

Topic: 8. Foot and Ankle

A 45-year-old male presents with a massively swollen, painless shoulder joint. Radiographs show severe destruction of the humeral head with abundant bony debris. He mentions chronic neck stiffness and frequent unrecognized burns on his hands. What is the most likely underlying etiology of his shoulder pathology?

. Advanced osteoarthritis
. Charcot neuroarthropathy secondary to Syringomyelia
. Charcot neuroarthropathy secondary to Diabetes Mellitus
. Chronic septic arthritis
. Avascular necrosis

Correct Answer & Explanation

. Charcot neuroarthropathy secondary to Syringomyelia

Explanation

Upper extremity Charcot joints are highly characteristic of syringomyelia, which causes sensory dissociation (loss of pain/temperature) in the arms. Diabetic Charcot arthropathy typically affects the foot and ankle.

Question 5207

Topic: 8. Foot and Ankle

The neurovascular theory of the pathogenesis of Charcot neuroarthropathy postulates that joint destruction is primarily initiated by which of the following mechanisms?

. Repetitive microtrauma on a profoundly insensate foot
. Sympathetic denervation leading to hyperemia and active bone resorption
. Motor neuropathy causing intrinsic muscle imbalance and secondary subluxation
. Glycosylation of ligaments causing profound stiffness and joint failure
. Direct bacterial invasion via minor neurotrophic ulcerations

Correct Answer & Explanation

. Sympathetic denervation leading to hyperemia and active bone resorption

Explanation

The neurovascular theory suggests that autonomic (sympathetic) neuropathy leads to increased blood flow (hyperemia) and active osteoclastic bone resorption, weakening the bone. This contrasts with the neurotraumatic theory, which emphasizes repetitive unperceived microtrauma.

Question 5208

Topic: 8. Foot and Ankle

In a patient with diabetic Charcot neuroarthropathy, structural collapse of the longitudinal arch resulting in plantar prominence of the cuboid and navicular (rocker-bottom foot deformity) most frequently occurs during which Eichenholtz stage?

. Stage 0 (Inflammatory)
. Stage 1 (Development/Fragmentation)
. Stage 2 (Coalescence)
. Stage 3 (Reconstruction)
. Stage 4 (Ankylosis)

Correct Answer & Explanation

. Stage 1 (Development/Fragmentation)

Explanation

The active destruction, capsular laxity, and bony fragmentation that lead to midfoot collapse (rocker-bottom foot) occur during Eichenholtz Stage 1. Early offloading is critical to prevent this severe deformity.

Question 5209

Topic: 8. Foot and Ankle

A 62-year-old diabetic male with an Eichenholtz Stage 1 Charcot arthropathy of the midfoot presents with a non-healing, non-infected plantar ulcer directly overlying a massive cuboid prominence. What is the most appropriate surgical management?

. Immediate open reduction and rigid internal fixation with arthrodesis
. Exostectomy of the prominence and delay arthrodesis until Eichenholtz Stage 2 or 3
. Below-knee amputation
. Immediate multi-stage arthrodesis with a ring external fixator
. Isolated percutaneous Achilles tendon lengthening

Correct Answer & Explanation

. Exostectomy of the prominence and delay arthrodesis until Eichenholtz Stage 2 or 3

Explanation

Arthrodesis during the active, hyperemic fragmentation phase (Stage 1) has a high failure rate due to poor bone quality and active resorption. The preferred management for a recalcitrant ulcer over a prominence in Stage 1 is a simple exostectomy to offload the skin, delaying fusion until the disease coalesces (Stage 2/3).

Question 5210

Topic: 8. Foot and Ankle

A 45-year-old patient develops a rapidly progressive, painless, and massively swollen shoulder joint. Radiographs show severe osseous destruction, debris, and subluxation. Which of the following underlying conditions is the most likely etiology for this presentation?

. Diabetes mellitus
. Syringomyelia
. Tertiary syphilis
. Leprosy
. Chronic alcoholism

Correct Answer & Explanation

. Syringomyelia

Explanation

Charcot arthropathy of the upper extremity, particularly the shoulder and elbow, is classically caused by syringomyelia. Diabetes mellitus typically affects the foot and ankle, while syphilis historically affected the knee and hip.

Question 5211

Topic: 8. Foot and Ankle

A 55-year-old diabetic male presents with a warm, erythematous, and swollen foot. Radiographs show periarticular debris, fragmentation of the tarsal bones, and subluxation. According to the Eichenholtz classification, what is the current stage and most appropriate initial management?

. Stage 0; observation
. Stage 1; total contact casting
. Stage 2; custom orthoses
. Stage 3; surgical arthrodesis
. Stage 1; urgent debridement

Correct Answer & Explanation

. Stage 1; total contact casting

Explanation

The patient is in Eichenholtz Stage 1 (fragmentation), characterized by active inflammation, debris, and bone fragmentation. The gold standard initial treatment is offloading with a total contact cast.

Question 5212

Topic: Midfoot & Hindfoot

The pathogenesis of Charcot arthropathy is classically described by two main theories. The "neurovascular theory" attributes the initial bone destruction and fragmentation to which of the following mechanisms?

. Repeated microtrauma due to loss of pain sensation
. Autonomic neuropathy causing increased peripheral blood flow and active bone resorption
. Direct invasion of the bone by neurotropic viruses
. Spontaneous avascular necrosis from large vessel occlusion
. Autoimmune destruction of articular cartilage

Correct Answer & Explanation

. Autonomic neuropathy causing increased peripheral blood flow and active bone resorption

Explanation

The neurovascular theory posits that autonomic neuropathy leads to loss of sympathetic tone, causing arteriovenous shunting and hyperemia. This hyperemic state washes out bone mineral, leading to osteopenia and susceptibility to fracture.

Question 5213

Topic: 8. Foot and Ankle

A 55-year-old poorly controlled diabetic presents with an erythematous, warm, and swollen right foot. Radiographs show periarticular fragmentation and debris without signs of coalescence. According to the Eichenholtz classification, what is the appropriate management?

. Rigid internal fixation and arthrodesis
. Immediate below-knee amputation
. Intravenous antibiotics and surgical debridement
. Total contact casting and strict non-weight bearing
. Customized accommodative footwear with weight-bearing as tolerated

Correct Answer & Explanation

. Total contact casting and strict non-weight bearing

Explanation

The patient is in Eichenholtz Stage I (Developmental/Fragmentation), characterized by erythema, warmth, and bony fragmentation. The standard of care is immobilization via total contact casting and non-weight bearing until the acute phase subsides.

Question 5214

Topic: Midfoot & Hindfoot

The neurotraumatic and neurovascular theories are postulated for the development of Charcot arthropathy. Which of the following best describes the core principle of the neurovascular theory?

. Loss of protective sensation leading to repetitive undetected microtrauma
. Autonomic neuropathy causing an exaggerated hyperemic response and osteoclastic resorption
. Avascular necrosis of the subchondral bone from microvascular thrombosis
. Impaired venous return leading to chronic edema and joint laxity
. Direct bacterial invasion via sensory nerve pathways causing joint destruction

Correct Answer & Explanation

. Autonomic neuropathy causing an exaggerated hyperemic response and osteoclastic resorption

Explanation

The neurovascular theory of Charcot arthropathy suggests that autonomic neuropathy leads to a loss of sympathetic vascular tone. This results in local hyperemia, increased blood flow, and subsequent increased osteoclastic bone resorption and joint weakening.

Question 5215

Topic: Midfoot & Hindfoot

A 50-year-old diabetic patient presents with a swollen, warm, and red foot without open ulcers. To differentiate an acute Eichenholtz Stage I Charcot arthropathy from acute osteomyelitis, which imaging modality is most specific?

. Plain radiographs
. Three-phase Technetium-99m bone scan
. Indium-111 labeled white blood cell (WBC) scan
. Contrast-enhanced CT scan
. Ultrasound of the foot

Correct Answer & Explanation

. Indium-111 labeled white blood cell (WBC) scan

Explanation

An Indium-111 labeled WBC scan (especially when combined with a Tc-99m bone marrow scan) is highly specific for differentiating osteomyelitis from acute Charcot arthropathy. Charcot arthropathy alone will typically not show focal accumulation of labeled WBCs.

Question 5216

Topic: 8. Foot and Ankle
A 55-year-old diabetic patient presents with a swollen, warm, and erythematous left foot. Radiographs show osteopenia, bony fragmentation, and joint subluxation at the midfoot. According to the Eichenholtz classification, what is the current stage and most appropriate initial management?
. Stage 0 (Prodromal); start IV antibiotics
. Stage I (Developmental); total contact casting and non-weight bearing
. Stage II (Coalescence); immediate arthrodesis
. Stage III (Reconstruction); custom orthotic shoe wear
. Stage I (Developmental); immediate open reduction and internal fixation

Correct Answer & Explanation

. Stage I (Developmental); total contact casting and non-weight bearing

Explanation

Eichenholtz Stage I (Developmental) is characterized by a warm, swollen extremity with radiographic fragmentation, subluxation, and debris. The gold standard initial treatment is immobilization and offloading, typically with a total contact cast.

Question 5217

Topic: 8. Foot and Ankle

A 30-year-old male presents with a mass intimately attached to the Achilles tendon. Pathology shows nests of pale cells with prominent nucleoli that stain positive for HMB-45 and S-100. What cytogenetic translocation defines this 'melanoma of soft parts'?

. t(12;22)(q13;q12)
. t(X;18)(p11;q11)
. t(11;22)(q24;q12)
. t(2;13)(q35;q14)
. t(12;16)(q13;p11)

Correct Answer & Explanation

. t(12;22)(q13;q12)

Explanation

Clear cell sarcoma (melanoma of soft parts) typically occurs in the tendons and aponeuroses of the foot and ankle. While it shares immunohistochemical markers with melanoma, it is defined by the EWSR1-ATF1 fusion from t(12;22)(q13;q12).

Question 5218

Topic: 8. Foot and Ankle

A surgeon is performing an ankle arthrodesis. To ensure robust fusion, the construct must withstand significant bending and torsional forces. The primary contribution to the construct's resistance against these forces comes from maximizing the Area Moment of Inertia of which component(s)?

. The individual screws used for fixation
. The bone graft material itself
. The overall geometric configuration of the screws and plates (if used) relative to the joint line
. The tensile strength of the soft tissues around the ankle
. The size of the joint capsule

Correct Answer & Explanation

. The overall geometric configuration of the screws and plates (if used) relative to the joint line

Explanation

For an ankle arthrodesis, the primary contribution to the construct's resistance against bending and torsional forces comes from maximizing the Area Moment of Inertia of the overall geometric configuration of the screws and plates (if used) relative to the joint line. This creates a stable, stiff construct where the fixation elements are strategically placed to distribute forces and resist deformation. While individual screw MOI and bone graft strength are important, it is the composite MOI of the entire fixation construct that is paramount for robust fusion. Soft tissue and joint capsule size are less relevant to structural mechanical stability.

Question 5219

Topic: 8. Foot and Ankle

A surgeon is considering the use of a plate for an Achilles tendon repair augmentation. What type of plate would be most suitable in this context?

. A locking plate for rigid fixation.
. A reconstruction plate for contouring.
. A very small, thin plate with minimal holes, primarily used as a washer or for small avulsion fragments.
. A biodegradable plate to avoid permanent hardware.
. A tension band plate to convert distraction into compression.

Correct Answer & Explanation

. A very small, thin plate with minimal holes, primarily used as a washer or for small avulsion fragments.

Explanation

While not a common primary fixation for Achilles repair, if a plate is considered (e.g., for large avulsion fragments or specific augmentation), a very small, thin plate with minimal holes might be used, often functioning more as a 'washer' plate or for securing small avulsion fragments to the calcaneus. Biodegradable plates could also be an option for temporary support. However, Achilles tendon repair is primarily a soft tissue repair, often augmented with sutures, anchor, or open repair. If bone is involved (e.g., avulsion), small fragment fixation is key. The question is a bit unusual. Let's re-evaluate. If used, it's typically for avulsion of a small fragment of bone from the calcaneus, not for the tendon itself. For this, a small fragment plate acting as a buttress or washer, or even a biodegradable plate to avoid removal, would be considered. A thin plate for small fragments fits best here as a general option. The most suitable, assuming bone fragment involvement, would be a small fragment plate acting as a washer/buttress or biodegradable, but the option that captures the essence of a minimal, supportive role is a 'very small, thin plate with minimal holes, primarily used as a washer or for small avulsion fragments'.

Question 5220

Topic: 8. Foot and Ankle

When performing syndesmotic screw fixation following an ankle fracture, which principle is MOST important to adhere to?

. Maximizing interfragmentary compression across the syndesmosis.
. Using a fully threaded screw of cortical type.
. Ensuring the screw acts as a position screw, not a lag screw.
. Placing the screw perpendicular to the tibia for maximum stability.
. Always using a bioabsorbable screw to prevent re-operation.

Correct Answer & Explanation

. Ensuring the screw acts as a position screw, not a lag screw.

Explanation

Syndesmotic screws are typically used as position screws. The goal is to reduce the syndesmosis and hold it in its anatomical position, not to compress it excessively. Excessive compression can lead to restricted ankle motion, pain, and potentially chondrolysis. Therefore, a fully threaded screw inserted through three or four cortices (depending on technique) acts as a position screw, maintaining the reduction without generating undue compression. While a fully threaded cortical screw is commonly used, theprincipleof it acting as a position screw is paramount.

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