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8. Foot and Ankle MCQs

Practice Set 266 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 5301

Topic: 8. Foot and Ankle

According to the study by Pinzur et al. regarding current practice patterns in the treatment of Charcot foot, what is the most reliable screening tool for the presence of protective sensation?

. 128 Hz tuning fork
. 5.07 Semmes-Weinstein monofilament
. Pinprick testing
. Ankle-brachial index
. Electromyography

Correct Answer & Explanation

. 5.07 Semmes-Weinstein monofilament

Explanation

Correct Answer: 5.07 Semmes-Weinstein monofilamentPinzur et al. (Foot Ankle Int 2000) and standard orthopedic guidelines identify the 5.07 Semmes-Weinstein monofilament as the most reliable screening tool for the presence of protective sensation in diabetic patients.

Question 5302

Topic: 8. Foot and Ankle

A 62-year-old male with poorly controlled diabetes mellitus presents with a painless, swollen, and erythematous right foot. Radiographs show periarticular debris, joint subluxation, and fragmentation of the midfoot. Which of the following screening tests, if performed and acted upon years prior, might have identified his risk for this condition?

. Ankle-brachial index
. 5.07 Semmes-Weinstein monofilament testing
. Venous Doppler ultrasound
. Serum uric acid levels
. Rheumatoid factor

Correct Answer & Explanation

. 5.07 Semmes-Weinstein monofilament testing

Explanation

Correct Answer: 5.07 Semmes-Weinstein monofilament testingThe patient's presentation is classic for neuropathic (Charcot) arthropathy. The absence of protective foot sensation, which is best screened using the 5.07 Semmes-Weinstein monofilament, places patients at increased risk for developing neuropathic arthropathy.

Question 5303

Topic: 8. Foot and Ankle

When performing a Semmes-Weinstein monofilament test to evaluate protective sensation in a diabetic foot, the 5.07 monofilament is designed to buckle at a specific amount of force. What is this 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 buckle when exactly 10 grams of force is applied. Inability to detect this 10-gram force indicates a loss of protective sensation, which is a major risk factor for diabetic foot ulceration and Charcot arthropathy.

Question 5304

Topic: 8. Foot and Ankle

A diabetic patient is found to have an insensate foot when tested with the 5.07 Semmes-Weinstein monofilament. There are no active ulcers or signs of Charcot arthropathy. Which of the following is the most appropriate next step in management to prevent complications?

. Immediate prophylactic amputation
. Prescription of appropriate diabetic footwear and patient education
. Revascularization surgery
. Initiation of high-dose corticosteroids
. Application of a total contact cast

Correct Answer & Explanation

. Prescription of appropriate diabetic footwear and patient education

Explanation

Correct Answer: Prescription of appropriate diabetic footwear and patient educationOnce a patient is identified as having a loss of protective sensation (unable to feel the 5.07 monofilament), they are at high risk for ulceration. The standard of care involves preventative measures, including proper diabetic footwear, daily foot inspections, and patient education. Total contact casting is reserved for active ulcerations or acute Charcot arthropathy.

Question 5305

Topic: 8. Foot and Ankle

While evaluating a diabetic patient, a resident considers various sensory tests. Why is the 5.07 Semmes-Weinstein monofilament preferred over sharp two-point discrimination or vibratory sensation?

. It evaluates large myelinated fibers exclusively
. It is the most reliable screening tool for protective sensation
. It is the only test that predicts vascular compromise
. It requires a specialized machine to administer
. It tests for autonomic neuropathy

Correct Answer & Explanation

. It is the most reliable screening tool for protective sensation

Explanation

Correct Answer: It is the most reliable screening tool for protective sensationWhile sharp two-point discrimination, light touch, hot and cold, and vibratory sensation can be tested, the 5.07 Semmes-Weinstein monofilament is considered the most useful and reliable screening method specifically for the evaluation of protective foot sensation in a patient with diabetes mellitus.

Question 5306

Topic: 8. Foot and Ankle

Which of the following statements regarding the evaluation of the diabetic foot is most accurate?

. Vibratory sensation is the most reliable predictor of neuropathic ulceration.
. The 5.07 Semmes-Weinstein monofilament tests for the presence of protective sensation.
. Hot and cold sensation testing should replace monofilament testing in advanced diabetes.
. Loss of protective sensation decreases the risk of Charcot arthropathy due to decreased weight-bearing.
. Sharp two-point discrimination is the gold standard for diagnosing Charcot foot.

Correct Answer & Explanation

. The 5.07 Semmes-Weinstein monofilament tests for the presence of protective sensation.

Explanation

Correct Answer: The 5.07 Semmes-Weinstein monofilament tests for the presence of protective sensation.Patients with diabetes mellitus should be screened for the presence of protective foot sensation. The most reliable screening tool for this is the ability to feel the 5.07 Semmes-Weinstein monofilament. Loss of this sensation increases the risk of neuropathic ulcerations and neuropathic arthropathy.

Question 5307

Topic: 8. Foot and Ankle

A 50-year-old female with a history of diabetes mellitus presents for a foot examination. She is able to feel light touch and hot/cold sensations but cannot feel the 5.07 Semmes-Weinstein monofilament. What is the clinical significance of this finding?

. She has normal protective sensation.
. She has isolated autonomic neuropathy.
. She lacks protective sensation and is at risk for neuropathic ulceration.
. She requires an immediate vascular surgery consultation.
. She has a primary motor neuropathy.

Correct Answer & Explanation

. She lacks protective sensation and is at risk for neuropathic ulceration.

Explanation

Correct Answer: She lacks protective sensation and is at risk for neuropathic ulceration.The inability to feel the 5.07 Semmes-Weinstein monofilament indicates a loss of protective sensation, regardless of the ability to feel other modalities like light touch or temperature. This specific deficit places the patient at an increased risk for the development of neuropathic ulcerations and neuropathic arthropathy.

Question 5308

Topic: 8. Foot and Ankle

A 55-year-old male with a 15-year history of poorly controlled type 2 diabetes mellitus presents for a routine foot examination. The physician uses a Semmes-Weinstein monofilament to test for loss of protective sensation. Which of the following monofilament sizes and its corresponding buckling force is the standard threshold for diagnosing loss of protective sensation in the foot?

. 4.17 monofilament (1 gram)
. 5.07 monofilament (10 grams)
. 6.10 monofilament (75 grams)
. 3.61 monofilament (0.4 grams)
. 4.56 monofilament (4 grams)

Correct Answer & Explanation

. 5.07 monofilament (10 grams)

Explanation

Correct Answer: BThe 5.07 Semmes-Weinstein monofilament, which buckles at 10 grams of force, is the most reliable and widely accepted screening tool for detecting the loss of protective sensation in diabetic patients. Inability to feel this monofilament indicates an increased risk for neuropathic ulceration and Charcot arthropathy.

Question 5309

Topic: 8. Foot and Ankle

A 60-year-old female with long-standing diabetes mellitus presents with a swollen, warm, and erythematous right foot. She denies any trauma and reports no pain. Radiographs reveal fragmentation and subluxation of the tarsometatarsal joints. The loss of protective sensation in this patient, leading to repetitive microtrauma and joint destruction, is best explained by which of the following theories of Charcot arthropathy?

. Neurovascular theory
. Neurotraumatic theory
. Autoimmune theory
. Infectious theory
. Ischemic theory

Correct Answer & Explanation

. Neurotraumatic theory

Explanation

Correct Answer: BThe neurotraumatic theory postulates that loss of protective sensation (peripheral neuropathy) allows for repetitive, unrecognized microtrauma to the foot and ankle, leading to progressive joint destruction, subluxation, and fragmentation. The neurovascular theory suggests that autonomic neuropathy leads to increased blood flow (AV shunting) and active bone resorption, weakening the bone. Both likely play a role, but repetitive microtrauma due to lack of sensation defines the neurotraumatic theory.

Question 5310

Topic: 8. Foot and Ankle

A 62-year-old diabetic male is found to have absent sensation to the 5.07 Semmes-Weinstein monofilament on the plantar aspect of his foot. He subsequently develops a neuropathic ulcer under the first metatarsal head. Which of the following biomechanical abnormalities is most commonly associated with increased plantar forefoot pressures and subsequent ulceration in this population?

. Achilles tendon lengthening
. Gastrocnemius-soleus equinus contracture
. Tibialis anterior overactivity
. Peroneus brevis weakness
. Plantar fascia rupture

Correct Answer & Explanation

. Gastrocnemius-soleus equinus contracture

Explanation

Correct Answer: BGastrocnemius-soleus equinus contracture is a common biomechanical abnormality in diabetic patients. It limits ankle dorsiflexion, leading to increased peak plantar pressures under the forefoot (especially the metatarsal heads) during the stance phase of gait. This increased pressure, combined with a loss of protective sensation, strongly predisposes the patient to neuropathic ulceration.

Question 5311

Topic: 8. Foot and Ankle

A 58-year-old male with diabetes mellitus and peripheral neuropathy presents with a non-healing ulcer on the plantar aspect of his midfoot. Radiographs show a collapsed medial longitudinal arch with a 'rocker-bottom' deformity. Which of the following is the most appropriate initial management for the acute, active phase of this condition?

. Open reduction and internal fixation of the midfoot
. Intravenous antibiotics and immediate debridement
. Total contact casting and non-weight bearing
. Custom orthotics and accommodative shoe wear
. Achilles tendon lengthening and midfoot exostectomy

Correct Answer & Explanation

. Total contact casting and non-weight bearing

Explanation

Correct Answer: CThe patient is presenting with acute Charcot arthropathy (active phase), characterized by a rocker-bottom deformity and midfoot ulceration. The gold standard for initial management of acute Charcot arthropathy is immobilization and offloading, most effectively achieved with a total contact cast (TCC). Surgery is generally contraindicated in the acute, inflammatory phase unless there is a severe, unstable deformity that cannot be braced or an acute infection.

Question 5312

Topic: 8. Foot and Ankle

A 50-year-old female with diabetes mellitus is evaluated in the clinic. She has a history of a neuropathic ulcer that has since healed. Her physician performs a screening examination to assess her risk for future ulcerations and neuropathic arthropathy. According to the literature, which of the following physical examination findings is the most reliable indicator of an at-risk foot?

. Absent dorsalis pedis pulse
. Inability to perceive a 128-Hz tuning fork
. Inability to perceive the 5.07 Semmes-Weinstein monofilament
. Loss of two-point discrimination at 5 mm
. Absent Achilles tendon reflex

Correct Answer & Explanation

. Inability to perceive the 5.07 Semmes-Weinstein monofilament

Explanation

Correct Answer: CThe most reliable screening tool for the presence of protective sensation, and thus the risk for neuropathic ulcerations and Charcot arthropathy, is the ability to feel the 5.07 Semmes-Weinstein monofilament. While other tests like tuning forks assess vibratory sense, the 5.07 monofilament is the gold standard for protective sensation.

Question 5313

Topic: 8. Foot and Ankle

A 65-year-old male with diabetes mellitus presents with a warm, swollen, and red left foot. He has a history of peripheral neuropathy. To differentiate between acute Charcot arthropathy and osteomyelitis, which of the following imaging modalities is considered the most sensitive and specific?

. Plain radiography
. Three-phase technetium-99m bone scan
. Magnetic resonance imaging (MRI)
. Computed tomography (CT)
. Ultrasound

Correct Answer & Explanation

. Magnetic resonance imaging (MRI)

Explanation

Correct Answer: CDifferentiating acute Charcot arthropathy from osteomyelitis can be challenging as both present with a red, hot, swollen foot. MRI is the most sensitive and specific imaging modality for distinguishing between the two. Osteomyelitis typically shows diffuse marrow edema and may have associated soft tissue fluid collections, sinus tracts, or cortical destruction adjacent to an ulcer, whereas Charcot changes are often periarticular and subchondral.

Question 5314

Topic: 8. Foot and Ankle

A 54-year-old diabetic patient with a history of Charcot arthropathy presents with a chronic, recurrent plantar ulceration under the cuboid despite strict compliance with total contact casting and custom accommodative footwear. Radiographs demonstrate a stable midfoot with a prominent plantar bony exostosis. What is the most appropriate next step in management?

. Below-knee amputation
. Exostectomy of the prominent bone
. Arthrodesis of the transverse tarsal joint
. Continued total contact casting for another 6 months
. Split-thickness skin grafting of the ulcer

Correct Answer & Explanation

. Exostectomy of the prominent bone

Explanation

Correct Answer: BIn a patient with a stable Charcot deformity who develops recurrent ulceration over a bony prominence despite optimal conservative management (offloading, TCC, custom footwear), surgical intervention is indicated. An exostectomy (removal of the bony prominence) is the most appropriate procedure to relieve the localized pressure and allow the ulcer to heal.

Question 5315

Topic: 8. Foot and Ankle

Autonomic neuropathy plays a significant role in the pathogenesis of diabetic foot complications. Which of the following clinical findings is a direct result of autonomic neuropathy in the diabetic foot?

. Claw toe deformities
. Loss of proprioception
. Dry, scaly skin with decreased sweating
. Absent deep tendon reflexes
. Weakness of the intrinsic foot muscles

Correct Answer & Explanation

. Dry, scaly skin with decreased sweating

Explanation

Correct Answer: CAutonomic neuropathy in diabetic patients leads to sympathetic denervation, which causes a loss of sweating (anhidrosis). This results in dry, scaly, and cracked skin, providing a portal of entry for bacteria. It also causes arteriovenous shunting, leading to warm feet with bounding pulses. Claw toe deformities and intrinsic muscle weakness are due to motor neuropathy, while loss of proprioception and reflexes are due to sensory neuropathy.

Question 5316

Topic: 8. Foot and Ankle

A 48-year-old male with type 1 diabetes mellitus is diagnosed with acute Charcot arthropathy of the midfoot. He is placed in a total contact cast. Which of the following clinical markers is the most reliable indicator that the acute, active phase of Charcot arthropathy has resolved and the patient can transition to accommodative footwear?

. Normalization of serum inflammatory markers (ESR and CRP)
. Radiographic evidence of complete bony consolidation
. Skin temperature of the affected foot within 1 to 2 degrees Celsius of the contralateral foot
. Return of protective sensation to the 5.07 monofilament
. Resolution of the rocker-bottom deformity

Correct Answer & Explanation

. Skin temperature of the affected foot within 1 to 2 degrees Celsius of the contralateral foot

Explanation

Correct Answer: CThe transition from the acute (active) phase to the chronic (coalescent/consolidated) phase of Charcot arthropathy is primarily determined clinically. The most reliable indicator of resolution of the acute inflammatory phase is the equalization of skin temperatures between the affected and unaffected foot (typically within 1 to 2 degrees Celsius). Radiographic consolidation lags behind clinical resolution. Protective sensation rarely returns.

Question 5317

Topic: 8. Foot and Ankle

A 59-year-old female with diabetes mellitus and profound peripheral neuropathy presents with a painless, swollen right ankle. Radiographs reveal severe destruction of the tibiotalar joint with fragmentation and subluxation. She is diagnosed with Charcot arthropathy of the ankle. Compared to midfoot Charcot arthropathy, ankle Charcot arthropathy is associated with a higher risk of which of the following?

. Spontaneous resolution without intervention
. Instability requiring surgical arthrodesis or amputation
. Development of a rocker-bottom deformity
. Isolated motor neuropathy
. Rapid return of protective sensation

Correct Answer & Explanation

. Instability requiring surgical arthrodesis or amputation

Explanation

Correct Answer: BCharcot arthropathy of the ankle and hindfoot is generally more challenging to treat than midfoot Charcot. Because of the significant weight-bearing forces and the lack of inherent stability in the ankle joint compared to the midfoot, ankle Charcot is associated with a much higher risk of severe instability. This often necessitates prolonged immobilization and has a higher rate of requiring surgical intervention, such as tibiotalocalcaneal arthrodesis or even amputation, to achieve a stable, plantigrade foot.

Question 5318

Topic: 8. Foot and Ankle

Quantitative vibration perception testing using a biothesiometer is performed on a diabetic patient's hallux. Which of the following vibration perception threshold (VPT) values is most highly predictive of future foot ulceration?

. > 5 Volts
. > 10 Volts
. > 15 Volts
. > 25 Volts
. > 50 Volts

Correct Answer & Explanation

. > 25 Volts

Explanation

A Vibration Perception Threshold (VPT) greater than 25 Volts on a biothesiometer is considered highly predictive of an increased risk for diabetic foot ulceration. This indicates significant large-fiber neuropathy.

Question 5319

Topic: 8. Foot and Ankle
A 68-year-old diabetic male with a Wagner Grade 1 plantar ulcer undergoes non-invasive vascular testing. His Ankle-Brachial Index (ABI) is reported as 1.45. What is the most appropriate next step to assess the patient's lower extremity arterial perfusion?
. Reassure the patient that perfusion is excellent
. Obtain a Toe-Brachial Index (TBI)
. Perform immediate surgical debridement
. Initiate urgent hyperbaric oxygen therapy
. Measure transcutaneous oxygen pressure (TcPO2) at the thigh level

Correct Answer & Explanation

. Obtain a Toe-Brachial Index (TBI)

Explanation

An ABI > 1.3 is falsely elevated due to medial arterial calcification (Mönckeberg's sclerosis), which is common in diabetics. A Toe-Brachial Index (TBI) should be obtained because digital arteries are less susceptible to calcification.

Question 5320

Topic: 8. Foot and Ankle

During a diabetic foot screening, the examiner notes dry, fissured skin and bounding pedal pulses despite known sensory neuropathy. These findings are most directly attributed to which of the following pathophysiologic mechanisms?

. Large-fiber sensory nerve demyelination
. Autonomic denervation leading to arteriovenous shunting and anhidrosis
. Upregulation of the sorbitol pathway in motor endplates
. Proximal atherosclerotic disease of the popliteal artery
. Advanced glycation end-product deposition in the epidermis

Correct Answer & Explanation

. Autonomic denervation leading to arteriovenous shunting and anhidrosis

Explanation

Autonomic neuropathy results in sudomotor dysfunction (anhidrosis) leading to dry, cracking skin. It also causes loss of sympathetic vascular tone, resulting in arteriovenous shunting and bounding pulses.

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