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8. Foot and Ankle MCQs

Practice Set 268 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 5341

Topic: 8. Foot and Ankle

In conjunction with the monofilament test, vibratory sensation is often assessed during diabetic foot screening. Which tuning fork is the standard recommendation for detecting large-fiber peripheral neuropathy?

. 64 Hz
. 128 Hz
. 256 Hz
. 512 Hz
. 1024 Hz

Correct Answer & Explanation

. 128 Hz

Explanation

A 128-Hz tuning fork applied to the bony prominence of the distal hallux is the standard clinical tool for evaluating vibratory sensation. Loss of vibratory perception is a sensitive, early indicator of large-fiber peripheral neuropathy in diabetic patients.

Question 5342

Topic: 8. Foot and Ankle

A physician in a resource-limited setting lacks a 10-gram monofilament. Which of the following is a validated, simple clinical alternative to specifically assess for loss of protective sensation in the diabetic foot?

. Pinprick test using a sterile 18-gauge needle
. Ipswich Touch Test using the examiner's index finger
. Two-point discrimination testing using a paperclip
. Deep tendon reflex testing of the Achilles alone
. Capillary refill time at the hallux

Correct Answer & Explanation

. Ipswich Touch Test using the examiner's index finger

Explanation

The Ipswich Touch Test (IpTT) is a validated alternative for detecting LOPS when a monofilament is unavailable. It involves lightly resting the examiner's index finger on the tips of the 1st, 3rd, and 5th toes for 1-2 seconds.

Question 5343

Topic: 8. Foot and Ankle
A 68-year-old diabetic patient with loss of protective sensation undergoes vascular screening as part of a comprehensive foot exam. The Ankle-Brachial Index (ABI) is reported as 1.45. What is the most appropriate next step in the non-invasive vascular assessment?
. Reassurance as a value greater than 1.0 is considered normal
. Immediate referral for lower extremity arterial bypass
. Measurement of the Toe-Brachial Index (TBI)
. Segmental pressure mapping of the thigh and calf
. Venous duplex ultrasound

Correct Answer & Explanation

. Measurement of the Toe-Brachial Index (TBI)

Explanation

An ABI > 1.30 indicates non-compressible, calcified medial arteries (Mönckeberg's sclerosis), which renders the ABI falsely elevated. A Toe-Brachial Index (TBI) should be obtained, as digital arteries are typically spared from medial calcification.

Question 5344

Topic: 8. Foot and Ankle

During a diabetic foot screening, a patient with established loss of protective sensation is noted to have prominent claw toe deformities and distal migration of the plantar fat pads. This deformity is primarily a result of neuropathy affecting which of the following?

. Large myelinated sensory A-beta fibers
. Small unmyelinated C fibers
. Autonomic nerve fibers causing sudomotor dysfunction
. Motor nerve fibers innervating the intrinsic foot muscles
. Motor nerve fibers innervating the extrinsic flexors of the foot

Correct Answer & Explanation

. Motor nerve fibers innervating the intrinsic foot muscles

Explanation

Diabetic motor neuropathy primarily affects the distal intrinsic muscles of the foot (lumbricals and interossei) before extrinsic muscles. This muscle imbalance leads to claw toe deformities and increased focal plantar pressures under the metatarsal heads.

Question 5345

Topic: 8. Foot and Ankle

The 5.07 Semmes-Weinstein monofilament test is specifically designed to evaluate light touch and pressure sensation in the diabetic foot. This test assesses the functional integrity of which of the following nerve fibers?

. A-alpha fibers
. A-beta fibers
. A-delta fibers
. C fibers
. Sympathetic postganglionic fibers

Correct Answer & Explanation

. A-beta fibers

Explanation

The monofilament test evaluates light touch and deep pressure, sensory modalities transmitted via large, myelinated A-beta fibers. In contrast, small-fiber function (pain and temperature) is mediated by A-delta and unmyelinated C fibers.

Question 5346

Topic: 8. Foot and Ankle

A diabetic patient with documented loss of protective sensation presents with a non-infected, un-complicated superficial plantar ulcer under the third metatarsal head. According to best practice guidelines, what is the gold standard method for offloading this specific type of ulcer?

. Custom molded therapeutic shoes
. Crutches and strict bed rest
. Removable cast walker (RCW)
. Non-removable Total Contact Cast (TCC)
. Half-shoe offloading wedge

Correct Answer & Explanation

. Non-removable Total Contact Cast (TCC)

Explanation

The non-removable Total Contact Cast (TCC) is the gold standard for offloading non-infected, non-ischemic plantar diabetic foot ulcers. It removes patient non-compliance from the equation and effectively redistributes plantar pressures away from the ulcer site.

Question 5347

Topic: 8. Foot and Ankle

During a screening examination of a diabetic foot with loss of protective sensation, the examiner notes dry, cracking skin, bounding pedal pulses, and distended dorsal foot veins despite elevation. These specific findings are most directly attributable to:

. Motor neuropathy
. Large-fiber sensory neuropathy
. Autonomic neuropathy
. Peripheral arterial disease
. Deep vein thrombosis

Correct Answer & Explanation

. Autonomic neuropathy

Explanation

Autonomic neuropathy causes sudomotor dysfunction (anhidrosis leading to dry, cracking skin) and loss of sympathetic vascular tone. This sympathetic denervation leads to arteriovenous shunting, manifesting as bounding pulses and distended veins.

Question 5348

Topic: 8. Foot and Ankle

When using the 10-gram monofilament to screen for loss of protective sensation, which specific combination of plantar sites is most commonly recommended to identify the majority of patients at risk for ulceration?

. Heel, midfoot, and base of the fifth metatarsal
. Plantar aspect of the 1st, 3rd, and 5th metatarsal heads and plantar distal hallux
. Dorsum of the foot, medial malleolus, and lateral calcaneus
. Tips of all five toes and the central heel pad
. Medial arch and lateral arch exclusively

Correct Answer & Explanation

. Plantar aspect of the 1st, 3rd, and 5th metatarsal heads and plantar distal hallux

Explanation

Standardized screening protocols recommend testing the plantar aspect of the distal hallux and the 1st, 3rd, and 5th metatarsal heads. These locations represent the highest-risk areas for increased peak plantar pressures and subsequent ulceration.

Question 5349

Topic: 8. Foot and Ankle

A 12-year-old male presents with multiple painless bony prominences around the knees and ankles. Genetic testing reveals a mutation in the EXT1 gene. Which of the following is the most likely mechanism of inheritance for this condition?

. Autosomal Recessive
. Autosomal Dominant
. X-linked Dominant
. X-linked Recessive
. Sporadic mutation only

Correct Answer & Explanation

. Autosomal Dominant

Explanation

Correct Answer: BHereditary Multiple Exostoses (HME), also known as diaphyseal aclasis, is inherited in an Autosomal Dominant fashion. It is primarily associated with mutations in the EXT1 (Chromosome 8) and EXT2 (Chromosome 11) genes, which encode glycosyltransferases involved in heparan sulfate synthesis.

Question 5350

Topic: 8. Foot and Ankle

A 12-year-old male presents with multiple painless bony prominences around the knees and ankles. Genetic testing reveals a mutation in the EXT1 gene. What is the primary biochemical defect associated with this condition?

. Defective synthesis of Type II collagen
. Impaired synthesis of heparan sulfate glycosaminoglycans
. Constitutive activation of the PTHrP receptor
. Overexpression of the GNAS1 protein
. Deficiency in alkaline phosphatase activity

Correct Answer & Explanation

. Impaired synthesis of heparan sulfate glycosaminoglycans

Explanation

Correct Answer: BMultiple Hereditary Exostoses (MHE) is caused by mutations in EXT1 or EXT2 genes. These genes encode glycosyltransferases involved in the synthesis of heparan sulfate (HS) glycosaminoglycans. A deficiency in HS leads to abnormal chondrocyte proliferation and maturation in the growth plate, resulting in exostosis formation.

Question 5351

Topic: 8. Foot and Ankle

A newborn presents with short trunk disproportionate dwarfism. Radiographic evaluation reveals marked delay in ossification of several centers. Which of the following ossification centers is characteristically delayed or completely absent at birth in Spondyloepiphyseal Dysplasia Congenita?

. Distal radius
. Proximal tibial epiphysis
. Iliac wings
. Vertebral bodies
. Pubic bone

Correct Answer & Explanation

. Pubic bone

Explanation

A classic radiographic hallmark of SED Congenita at birth is the delayed or absent ossification of the pubic bones, as well as the calcaneus, talus, and knee epiphyses.

Question 5352

Topic: 8. Foot and Ankle

A newborn is evaluated for severe disproportionate short stature. Radiographic survey reveals absent ossification of the pubic bones, calcaneus, talus, and distal femoral epiphyses. Which of the following histological findings is most characteristic of the cartilage in this patient's underlying condition?

. Disorganized physeal zones with clusters of large, atypical chondrocytes
. Deficient mineralization of the zone of provisional calcification
. PAS-positive cytoplasmic inclusions within chondrocytes
. Loss of the normal columnar arrangement in the proliferative zone only
. Accumulation of keratan sulfate in the extracellular matrix

Correct Answer & Explanation

. PAS-positive cytoplasmic inclusions within chondrocytes

Explanation

The clinical picture of absent epiphyseal ossification centers at birth is classic for SEDC. Histologically, SEDC is characterized by PAS-positive cytoplasmic inclusions in chondrocytes, representing rough endoplasmic reticulum engorged with abnormal type II collagen.

Question 5353

Topic: 8. Foot and Ankle

A patient with a suspected deep tissue infection in the foot is found to have a high level of C-reactive protein (CRP). What is the primary role of CRP in the innate immune response?

. Directly neutralizing bacterial toxins.
. Activating cytotoxic T lymphocytes.
. Acting as an opsonin and activating the classical complement pathway.
. Mediating allergic reactions through IgE binding.
. Suppressing inflammatory cytokine production.

Correct Answer & Explanation

. Acting as an opsonin and activating the classical complement pathway.

Explanation

C-reactive protein (CRP) is an acute-phase reactant produced by the liver in response to inflammation, primarily stimulated by IL-6. CRP acts as an opsonin, binding to phosphocholine on microbial membranes and damaged host cells, thereby facilitating their recognition and phagocytosis by macrophages. Importantly, CRP can also activate the classical complement pathway, leading to pathogen clearance. It's a non-specific indicator of inflammation and infection.

Question 5354

Topic: 8. Foot and Ankle

A 45-year-old construction worker presents with chronic low back pain radiating into his left buttock and posterior thigh, worsening with prolonged sitting and lifting. Physical examination reveals a positive straight leg raise test at 45 degrees on the left, diminished left ankle dorsiflexion strength (4/5), and decreased sensation in the first web space. Deep tendon reflexes are symmetrical. Which of the following anatomical structures is most likely compressed?

. L3 nerve root
. L4 nerve root
. L5 nerve root
. S1 nerve root
. Sciatic nerve (extra-spinal)

Correct Answer & Explanation

. L5 nerve root

Explanation

The patient's symptoms (pain radiating to buttock/posterior thigh), motor weakness (ankle dorsiflexion), and sensory deficit (first web space) are classic signs of L5 radiculopathy. An L5 compression typically affects ankle dorsiflexion (tibialis anterior), toe extension (extensor hallucis longus), and sensation in the dorsum of the foot, including the first web space. The positive straight leg raise test further supports nerve root compression. S1 compression would typically involve plantarflexion weakness and sensory loss in the lateral foot, with a diminished Achilles reflex.

Question 5355

Topic: 8. Foot and Ankle

A 30-year-old male sustains a traumatic knee dislocation with gross instability in all planes. What is the most crucial initial step in his acute management?

. Immediate surgical exploration for ligament repair
. Reduction of the dislocation
. Detailed assessment of neurovascular status
. MRI of the knee to identify torn ligaments
. Application of a knee immobilizer

Correct Answer & Explanation

. Detailed assessment of neurovascular status

Explanation

In traumatic knee dislocations, there is a high incidence of associated neurovascular injury, particularly to the popliteal artery and peroneal nerve. Therefore, the most crucial initial step, after gross reduction if needed, is a detailed assessment of the neurovascular status of the extremity, including ankle-brachial index (ABI), Doppler assessment, and neurological exam. Missed vascular injury can lead to limb loss. While reduction is urgent, it should be followed by diligent neurovascular checks. MRI and surgery come later, once the limb is stable and perfused.

Question 5356

Topic: 8. Foot and Ankle

A 35-year-old sedentary patient presents with insidious onset of unilateral heel pain, particularly worse with the first steps in the morning and after periods of rest. The pain is localized to the plantar aspect of the heel. Physical examination reveals tenderness at the origin of the plantar fascia on the medial calcaneal tuberosity. What is the most effective initial non-operative treatment?

. Corticosteroid injection into the plantar fascia
. Surgical release of the plantar fascia
. Custom orthotics with arch support and heel cup
. Stretching exercises for the plantar fascia and Achilles tendon
. Extracorporeal shockwave therapy (ESWT)

Correct Answer & Explanation

. Stretching exercises for the plantar fascia and Achilles tendon

Explanation

The patient's symptoms are highly consistent with plantar fasciitis. The most effective initial non-operative treatment involves a combination of stretching exercises for the plantar fascia and Achilles tendon, activity modification, night splints, and appropriate footwear. While orthotics can be helpful, stretching is considered a cornerstone of treatment. Corticosteroid injections provide temporary relief but carry risks, and ESWT is typically reserved for recalcitrant cases. Surgical release is a last resort.

Question 5357

Topic: 8. Foot and Ankle

A 25-year-old female presents with bilateral foot pain, flatfoot deformity, and posterior tibial tendon dysfunction. She has a history of rheumatoid arthritis. Which of the following is the most appropriate initial non-operative treatment?

. Rigid ankle-foot orthosis (AFO)
. Custom-molded orthotics with medial arch support
. Surgical reconstruction of the posterior tibial tendon
. Corticosteroid injection into the posterior tibial tendon sheath
. Physical therapy focusing on intrinsic foot muscle strengthening

Correct Answer & Explanation

. Custom-molded orthotics with medial arch support

Explanation

In patients with flexible flatfoot and posterior tibial tendon dysfunction (PTTD), especially those with inflammatory arthritis, custom-molded orthotics with medial arch support are the cornerstone of initial non-operative management. They help support the arch, reduce stress on the posterior tibial tendon, and prevent further progression of the deformity. A rigid AFO may be needed for more advanced, rigid deformities. Surgical reconstruction is reserved for failed conservative treatment. Corticosteroid injections are generally avoided due to the risk of tendon rupture.

Question 5358

Topic: 8. Foot and Ankle

Regarding the surgical treatment of acute Achilles tendon rupture, what is the primary advantage of percutaneous repair compared to open repair?

. Lower risk of re-rupture
. Earlier return to sports
. Reduced risk of wound complications and infection
. Stronger repair construct
. Less need for post-operative rehabilitation

Correct Answer & Explanation

. Reduced risk of wound complications and infection

Explanation

The primary advantage of percutaneous Achilles tendon repair compared to open repair is a reduced risk of wound complications, including infection, dehiscence, and scar-related issues, due to smaller incisions. While re-rupture rates are generally comparable between modern open and percutaneous techniques, and functional outcomes are similar, the soft tissue envelope benefits are distinct for percutaneous methods.

Question 5359

Topic: Forefoot

A 60-year-old female presents with progressively worsening pain in her first metatarsophalangeal (MTP) joint, stiffness, and a painful 'bump' dorsally. Radiographs show joint space narrowing, dorsal osteophytes, and subchondral sclerosis. What is the most appropriate initial management?

. Cheilectomy
. MTP joint arthrodesis
. Corticosteroid injection
. Stiff-soled shoes with a rocker bottom modification
. Excisional arthroplasty (Keller procedure)

Correct Answer & Explanation

. Stiff-soled shoes with a rocker bottom modification

Explanation

The patient's symptoms and radiographic findings are consistent with hallux rigidus (osteoarthritis of the first MTP joint). Initial non-operative management includes stiff-soled shoes with a rocker bottom modification, which limits motion at the MTP joint and reduces stress. Activity modification, NSAIDs, and stretching can also be beneficial. Cheilectomy is a surgical procedure for earlier stages, while arthrodesis or excisional arthroplasty are for advanced stages or failed cheilectomy.

Question 5360

Topic: 8. Foot and Ankle

A 65-year-old female presents with severe, intractable pain in her right foot, described as burning and hypersensitivity to touch, following a remote ankle fracture 6 months ago. The foot is swollen, cool, mottled, and shows patchy osteopenia on radiographs. What is the most likely diagnosis?

. Peripheral neuropathy
. Complex regional pain syndrome (CRPS) Type I
. Deep vein thrombosis (DVT)
. Recurrent ankle fracture
. Tarsal tunnel syndrome

Correct Answer & Explanation

. Complex regional pain syndrome (CRPS) Type I

Explanation

The constellation of symptoms (severe burning pain, allodynia/hyperalgesia, swelling, temperature changes, skin discoloration, and patchy osteopenia) developing after a traumatic event is classic for Complex Regional Pain Syndrome (CRPS) Type I (formerly Reflex Sympathetic Dystrophy). It involves dysregulation of the autonomic nervous system. Peripheral neuropathy typically involves sensory loss, not hypersensitivity to the extent of CRPS. DVT would not present with such chronic skin changes and sensory abnormalities. Tarsal tunnel syndrome is a specific nerve compression, not a global pain syndrome.

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