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8. Foot and Ankle MCQs

Practice Set 257 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 5121

Topic: 8. Foot and Ankle

A 60-year-old male with long-standing diabetes mellitus is unable to feel the 5.07 Semmes-Weinstein monofilament on the plantar aspect of his first metatarsal head. According to established orthopedic principles, this specific sensory deficit places him at highest risk for developing which of the following conditions?

. Ischemic rest pain
. Plantar fasciitis
. Neuropathic arthropathy
. Tarsal tunnel syndrome
. Complex regional pain syndrome

Correct Answer & Explanation

. Neuropathic arthropathy

Explanation

Correct Answer: Neuropathic arthropathyThe absence of protective foot sensation, as demonstrated by the inability to feel the 5.07 Semmes-Weinstein monofilament, is a primary prerequisite for the development of neuropathic arthropathy (Charcot foot) and neuropathic ulcerations. Without protective sensation, patients sustain repetitive microtrauma to the bones and joints of the foot without experiencing pain, leading to progressive joint destruction, fragmentation, and deformity characteristic of Charcot arthropathy.

Question 5122

Topic: 8. Foot and Ankle

A 62-year-old female with diabetes mellitus presents for a routine foot screening. She has intact vibratory sensation and hot/cold discrimination but fails the 5.07 Semmes-Weinstein monofilament test on the plantar aspect of her forefoot. She has no history of ulceration and her skin is currently intact. What is the most appropriate initial management to prevent future neuropathic ulceration?

. Prophylactic Achilles tendon lengthening
. Total contact casting
. Daily application of topical antibiotics to the plantar foot
. Prescription of extra-depth shoes with custom accommodative orthotics
. Immediate referral for lower extremity revascularization

Correct Answer & Explanation

. Prescription of extra-depth shoes with custom accommodative orthotics

Explanation

Correct Answer: Prescription of extra-depth shoes with custom accommodative orthoticsA patient who has lost protective sensation (fails the 5.07 monofilament test) but has no active ulceration or severe deformity is classified as high-risk. The standard of care for primary prevention of neuropathic ulcers in this population is the use of extra-depth shoes with custom accommodative inserts. These devices distribute plantar pressures evenly and reduce shear forces. Total contact casting is used for active ulcer healing or acute Charcot arthropathy. Prophylactic Achilles tendon lengthening is reserved for patients with recurrent forefoot ulcerations and equinus contractures that fail conservative management.

Question 5123

Topic: 8. Foot and Ankle

Which of the following sensory modalities is specifically evaluated by the 5.07 Semmes-Weinstein monofilament to assess the risk of Charcot arthropathy in a diabetic patient?

. Proprioception
. Deep pain threshold
. Cutaneous pressure threshold
. Vibratory perception
. Temperature discrimination

Correct Answer & Explanation

. Cutaneous pressure threshold

Explanation

Correct Answer: Cutaneous pressure thresholdThe Semmes-Weinstein monofilament test specifically measures the cutaneous pressure threshold. The 5.07 monofilament provides exactly 10 grams of linear pressure before buckling. This specific threshold correlates with the minimum amount of pressure sensation required to protect the foot from unrecognized injury. Loss of this cutaneous pressure threshold is the most reliable indicator of a patient's risk for developing neuropathic ulcerations and Charcot arthropathy.

Question 5124

Topic: 8. Foot and Ankle

A 58-year-old male with diabetes mellitus is evaluated in the orthopedic clinic. He cannot feel the 5.07 Semmes-Weinstein monofilament on his plantar surface. He presents with a warm, swollen, and erythematous right foot with bounding dorsalis pedis pulses. He denies any pain or systemic symptoms like fever or chills. Radiographs show early fragmentation and subluxation of the tarsometatarsal joints. What is the most likely diagnosis?

. Osteomyelitis
. Cellulitis
. Gouty arthritis
. Neuropathic arthropathy
. Deep vein thrombosis

Correct Answer & Explanation

. Neuropathic arthropathy

Explanation

Correct Answer: Neuropathic arthropathyThe clinical presentation of a warm, swollen, erythematous foot with bounding pulses in a diabetic patient who lacks protective sensation (failed 5.07 monofilament test) is highly suspicious for acute neuropathic arthropathy (Charcot foot). The radiographic findings of fragmentation and subluxation at the tarsometatarsal (Lisfranc) joints confirm the diagnosis. The bounding pulses are due to autonomic neuropathy causing autosympathectomy and increased peripheral blood flow. The lack of pain and systemic symptoms makes osteomyelitis and cellulitis less likely, especially in the absence of an open ulcer.

Question 5125

Topic: 8. Foot and Ankle

In the evaluation of a diabetic patient, the 5.07 Semmes-Weinstein monofilament is preferred over sharp two-point discrimination for assessing the risk of foot ulceration. What is the primary reason for this preference?

. It evaluates the spinothalamic tract rather than the dorsal columns
. It simultaneously assesses autonomic and sensory neuropathy
. It provides a standardized, reproducible threshold for protective pressure sensation
. It is the only test that correlates with macrovascular disease severity
. It directly measures the density of Meissner corpuscles in the dermis

Correct Answer & Explanation

. It provides a standardized, reproducible threshold for protective pressure sensation

Explanation

Correct Answer: It provides a standardized, reproducible threshold for protective pressure sensationThe 5.07 Semmes-Weinstein monofilament is the most useful screening method because it provides a standardized, objective, and reproducible measurement of cutaneous pressure threshold (10 grams of force). Sharp two-point discrimination, light touch, and vibratory sensation are subjective and more difficult to standardize across different examiners. The 10-gram threshold has been extensively validated in the literature as the critical cut-off for identifying patients at risk for neuropathic ulceration.

Question 5126

Topic: 8. Foot and Ankle

A patient with long-standing diabetes mellitus lacks protective foot sensation as determined by 5.07 monofilament testing. According to current orthopedic literature regarding the diabetic foot, this specific sensory deficit is considered a primary prerequisite for the development of which of the following destructive joint processes?

. Rheumatoid arthritis
. Osteoarthritis
. Pigmented villonodular synovitis
. Synovial chondromatosis
. Charcot foot

Correct Answer & Explanation

. Charcot foot

Explanation

Correct Answer: Charcot footCharcot foot, or neuropathic arthropathy, is a progressive, destructive joint disease that occurs in patients with profound sensory neuropathy. The loss of protective sensation (indicated by failing the 5.07 monofilament test) is a strict prerequisite for its development. Without the ability to feel pain or pressure, patients continue to bear weight on injured joints, leading to a cycle of microtrauma, inflammation, bone fragmentation, and severe deformity.

Question 5127

Topic: 8. Foot and Ankle

When performing the 5.07 Semmes-Weinstein monofilament test to screen for loss of protective sensation in a diabetic patient, what is the correct technique for applying the monofilament to the plantar aspect of the foot?

. Lightly brush the monofilament across the skin without bending it
. Rapidly tap the monofilament against the skin 10 times in succession
. Drag the monofilament from the heel to the toes with firm pressure
. Apply the monofilament perpendicular to the skin until it buckles, holding for 1 to 2 seconds
. Apply the monofilament parallel to the skin surface to assess shear sensation

Correct Answer & Explanation

. Apply the monofilament perpendicular to the skin until it buckles, holding for 1 to 2 seconds

Explanation

Correct Answer: Apply the monofilament perpendicular to the skin until it buckles, holding for 1 to 2 secondsThe correct technique for using the Semmes-Weinstein monofilament involves applying it perpendicular to the skin surface. Pressure is smoothly applied until the monofilament buckles (bends), which ensures exactly 10 grams of force is being delivered. It should be held in the buckled position for 1 to 2 seconds and then released. The patient, whose eyes should be closed, is asked to indicate when and where they feel the pressure. Brushing, tapping, or dragging the monofilament invalidates the standardized 10-gram pressure threshold.

Question 5128

Topic: 8. Foot and Ankle

Which of the following is considered the most reliable screening method for evaluating protective foot sensation in a patient with diabetes mellitus?

. Sharp two-point discrimination
. Light touch sensation
. 5.07 Semmes-Weinstein monofilament
. Vibratory sensation
. Hot and cold sensation

Correct Answer & Explanation

. 5.07 Semmes-Weinstein monofilament

Explanation

Correct Answer: 5.07 Semmes-Weinstein monofilamentPatients with diabetes mellitus should be routinely screened for the presence of protective foot sensation. The most reliable and widely accepted screening tool for the presence of protective sensation is the ability to feel the 5.07 Semmes-Weinstein monofilament. Inability to feel this monofilament indicates a loss of protective sensation, placing the patient at high risk for neuropathic ulcerations and Charcot arthropathy.

Question 5129

Topic: 8. Foot and Ankle

The 5.07 Semmes-Weinstein monofilament is the gold standard for detecting loss of protective sensation in the diabetic foot. This specific monofilament is calibrated to buckle at what amount of applied linear force?

. 1 gram
. 5 grams
. 10 grams
. 50 grams
. 100 grams

Correct Answer & Explanation

. 10 grams

Explanation

Correct Answer: 10 gramsThe 5.07 Semmes-Weinstein monofilament is calibrated to deliver exactly 10 grams of linear pressure when applied perpendicular to the skin until it buckles. The inability to perceive 10 grams of pressure correlates strongly with the loss of protective sensation and an increased risk of foot ulceration.

Question 5130

Topic: Midfoot & Hindfoot

A diabetic patient is found to have absent protective sensation on 5.07 Semmes-Weinstein monofilament testing. According to the literature, this patient is at increased risk for developing neuropathic (Charcot) arthropathy. Which of the following best describes the neurovascular theory of this condition's pathogenesis?

. Ischemic necrosis of bone due to microvascular disease
. Autonomic neuropathy leading to bounding pulses and increased osteoclastic activity
. Motor neuropathy causing intrinsic muscle wasting and cavus deformity
. Venous stasis leading to periosteal reaction
. Direct bacterial invasion of the joint space

Correct Answer & Explanation

. Autonomic neuropathy leading to bounding pulses and increased osteoclastic activity

Explanation

Correct Answer: Autonomic neuropathy leading to bounding pulses and increased osteoclastic activityThe neurovascular theory of Charcot arthropathy postulates that autonomic neuropathy leads to a loss of sympathetic tone. This results in arteriovenous shunting, bounding pulses, and hyperemia. The increased local blood flow stimulates osteoclastic bone resorption, leading to osteopenia and subsequent periarticular fractures and fragmentation.

Question 5131

Topic: 8. Foot and Ankle

A 65-year-old patient with long-standing diabetes mellitus fails to perceive the 5.07 Semmes-Weinstein monofilament on the plantar aspect of the foot. The loss of this specific sensory modality primarily indicates dysfunction of which of the following nerve fiber types?

. Unmyelinated C fibers
. Small myelinated A-delta fibers
. Large myelinated A-beta fibers
. Preganglionic sympathetic fibers
. Postganglionic parasympathetic fibers

Correct Answer & Explanation

. Large myelinated A-beta fibers

Explanation

Correct Answer: Large myelinated A-beta fibersThe Semmes-Weinstein monofilament tests for cutaneous pressure and light touch, which are mediated by large, myelinated A-beta nerve fibers. Loss of function in these fibers leads to the loss of protective sensation. Small myelinated A-delta fibers and unmyelinated C fibers primarily transmit pain and temperature sensation.

Question 5132

Topic: 8. Foot and Ankle

A patient with diabetes mellitus lacks protective sensation as determined by the 5.07 Semmes-Weinstein monofilament test. They subsequently develop a neuropathic ulcer. What is the most common anatomic location for this ulceration to occur?

. Dorsum of the proximal interphalangeal joints
. Plantar aspect of the metatarsal heads
. Medial malleolus
. Plantar aspect of the heel
. Tip of the distal phalanx of the hallux

Correct Answer & Explanation

. Plantar aspect of the metatarsal heads

Explanation

Correct Answer: Plantar aspect of the metatarsal headsIn patients with diabetic neuropathy and loss of protective sensation, the most common location for neuropathic ulceration is the plantar aspect of the metatarsal heads. This is due to the high peak plantar pressures experienced in these areas during the stance phase of gait, often exacerbated by intrinsic muscle wasting (motor neuropathy) that leads to claw toe deformities and distal migration of the plantar fat pad.

Question 5133

Topic: 8. Foot and Ankle

A 55-year-old diabetic patient presents for a routine foot examination. The physician uses a 5.07 Semmes-Weinstein monofilament. The inability to feel this monofilament places the patient at highest risk for which of the following combinations of complications?

. Ischemic rest pain and gangrene
. Neuropathic ulceration and Charcot arthropathy
. Deep vein thrombosis and pulmonary embolism
. Plantar fasciitis and Achilles tendinopathy
. Osteosarcoma and pathologic fracture

Correct Answer & Explanation

. Neuropathic ulceration and Charcot arthropathy

Explanation

Correct Answer: Neuropathic ulceration and Charcot arthropathyAs highlighted in the core orthopedic literature, the absence of protective foot sensation (indicated by the inability to feel the 5.07 monofilament) places patients at a significantly increased risk for the development of neuropathic ulcerations and neuropathic (Charcot) arthropathy. Without protective sensation, repetitive microtrauma goes unnoticed, leading to tissue breakdown and joint destruction.

Question 5134

Topic: 8. Foot and Ankle

While the 5.07 Semmes-Weinstein monofilament is used to test for protective sensation, which monofilament size is classically used to establish the threshold for normal sensation in the foot?

. 2.83
. 3.61
. 4.17
. 5.07
. 6.10

Correct Answer & Explanation

. 4.17

Explanation

Correct Answer: 4.17The 4.17 Semmes-Weinstein monofilament corresponds to 1 gram of linear pressure and is used to establish the threshold for normal sensation in the foot. The 5.07 monofilament corresponds to 10 grams of pressure and is the threshold for protective sensation. The 6.10 monofilament corresponds to 75 grams of pressure and indicates a severe loss of sensation.

Question 5135

Topic: 8. Foot and Ankle
A patient who cannot feel the 5.07 Semmes-Weinstein monofilament presents with a swollen, erythematous, and warm right foot. Radiographs reveal periarticular debris, fragmentation of the tarsometatarsal joints, and subluxation. According to the Eichenholtz classification of neuropathic arthropathy, what stage does this represent?
. Stage 0
. Stage I
. Stage II
. Stage III
. Stage IV

Correct Answer & Explanation

. Stage I

Explanation

The Eichenholtz classification describes the natural history of Charcot arthropathy. Stage I (Development/Fragmentation) is characterized clinically by a red, hot, swollen foot and radiographically by periarticular debris, fragmentation, and subluxation/dislocation. Stage II (Coalescence) shows absorption of debris and early fusion. Stage III (Reconstruction/Consolidation) shows remodeling and stable arthrosis. Stage 0 is a newer addition describing a clinical presentation of a hot, swollen foot with normal radiographs.

Question 5136

Topic: 8. Foot and Ankle

A 60-year-old patient with diabetes mellitus is evaluated in the clinic. Sensation testing reveals an inability to detect the 5.07 Semmes-Weinstein monofilament. The foot has normal alignment, bounding pulses, and no history of ulceration. What is the most appropriate initial management strategy to prevent future complications?

. Prophylactic Achilles tendon lengthening
. Prescription of custom-molded accommodative footwear and daily foot inspection
. Total contact casting
. Immediate referral for lower extremity bypass surgery
. Arthrodesis of the midfoot

Correct Answer & Explanation

. Prescription of custom-molded accommodative footwear and daily foot inspection

Explanation

Correct Answer: Prescription of custom-molded accommodative footwear and daily foot inspectionFor a diabetic patient with a loss of protective sensation but no current ulceration or severe deformity, the mainstay of treatment is prevention. This includes patient education on daily foot inspection, proper hygiene, and the use of accommodative, well-fitting footwear (often custom-molded orthotics or extra-depth shoes) to distribute plantar pressures and prevent ulceration. Total contact casting is reserved for active ulcerations or acute Charcot arthropathy.

Question 5137

Topic: 8. Foot and Ankle

A 55-year-old diabetic patient is being evaluated in the orthopedic clinic. The physician uses a 5.07 Semmes-Weinstein monofilament to test for protective sensation on the plantar aspect of the foot. How much linear pressure (force) does this specific monofilament exert when it buckles?

. 1 gram
. 5 grams
. 10 grams
. 25 grams
. 50 grams

Correct Answer & Explanation

. 10 grams

Explanation

Correct Answer: 10 gramsThe 5.07 Semmes-Weinstein monofilament is the gold standard for screening for the loss of protective sensation in the diabetic foot. When applied perpendicular to the skin until it bends or buckles, the 5.07 monofilament exerts exactly 10 grams of linear force. Inability to detect this 10-gram force indicates a loss of protective sensation, placing the patient at high risk for neuropathic ulceration.

Question 5138

Topic: 8. Foot and Ankle

A 60-year-old male with a 15-year history of poorly controlled type 2 diabetes mellitus is unable to detect the 5.07 Semmes-Weinstein monofilament on the plantar aspect of his foot. According to established orthopedic literature, this specific clinical finding indicates an increased risk for which of the following?

. Ischemic rest pain
. Neuropathic ulceration and Charcot arthropathy
. Deep vein thrombosis
. Plantar fasciitis
. Tarsal tunnel syndrome

Correct Answer & Explanation

. Neuropathic ulceration and Charcot arthropathy

Explanation

Correct Answer: Neuropathic ulceration and Charcot arthropathyPatients with diabetes mellitus should be routinely screened for the presence of protective foot sensation. In the absence of protective foot sensation (defined by the inability to feel the 5.07 Semmes-Weinstein monofilament), patients are at a significantly increased risk for the development of neuropathic ulcerations and neuropathic (Charcot) arthropathy due to repetitive unrecognized microtrauma.

Question 5139

Topic: 8. Foot and Ankle

When utilizing the Semmes-Weinstein monofilament to screen for loss of protective sensation in a diabetic foot, what is the correct technique for application?

. Dragging the filament lightly across the plantar skin from heel to toe
. Pressing the filament perpendicular to the skin until it buckles for 1 to 2 seconds
. Tapping the filament rapidly over the metatarsal heads
. Pressing the filament parallel to the skin until the patient reports pain
. Applying continuous pressure with the filament for 60 seconds

Correct Answer & Explanation

. Pressing the filament perpendicular to the skin until it buckles for 1 to 2 seconds

Explanation

Correct Answer: Pressing the filament perpendicular to the skin until it buckles for 1 to 2 secondsThe proper technique for using a Semmes-Weinstein monofilament involves holding the filament perpendicular to the skin surface and applying pressure until the filament bends or buckles. The pressure should be held for approximately 1 to 2 seconds and then released. This ensures that a standardized amount of force (10 grams for the 5.07 monofilament) is delivered to the testing site.

Question 5140

Topic: 8. Foot and Ankle

The inability to feel the 5.07 Semmes-Weinstein monofilament is a manifestation of somatic sensory neuropathy. Which of the following findings in the diabetic foot is primarily a result of concurrent autonomic neuropathy?

. Claw toe deformity
. Loss of proprioception
. Warm and dry skin with bounding pulses
. Achilles tendon contracture
. Inability to detect a 128-Hz tuning fork

Correct Answer & Explanation

. Warm and dry skin with bounding pulses

Explanation

Correct Answer: Warm and dry skin with bounding pulsesDiabetic neuropathy affects sensory, motor, and autonomic nerves. Sensory neuropathy leads to loss of protective sensation (tested via the 5.07 monofilament). Motor neuropathy leads to intrinsic muscle wasting and claw toe deformities. Autonomic neuropathy leads to a loss of sympathetic tone, resulting in arteriovenous shunting, bounding pulses, and decreased sweating (anhidrosis), which causes warm, dry, and cracking skin.

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