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 6581
Topic: 8. Foot and Ankle
A 24-year-old male presents with severe midfoot pain after falling from a horse with his foot caught in the stirrup. Examination reveals marked plantar ecchymosis. Radiographs show widening of the space between the first and second metatarsal bases. The primary ligament injured connects which two anatomical structures?
Correct Answer & Explanation
. Medial cuneiform to the base of the second metatarsal
Explanation
The Lisfranc ligament is an essential interosseous stabilizing structure of the midfoot. It originates on the lateral aspect of the medial cuneiform and inserts onto the medial aspect of the base of the second metatarsal.
Question 6582
Topic: 8. Foot and Ankle
A 58-year-old diabetic male presents with a warm, swollen, and erythematous midfoot. He denies any recent trauma or fever. Radiographs show disorganization of the midfoot joints, fragmentation, and a 'rocker-bottom' deformity. There are no signs of osteomyelitis or open wounds. What is the most appropriate initial management for this presentation?
Correct Answer & Explanation
. Application of a total contact cast (TCC).
Explanation
This patient presents with acute Charcot neuroarthropathy, characterized by inflammation, bone and joint destruction, and deformity in the setting of neuropathy. The most critical initial management step in the acute phase (Eichenholtz Stage I) is strict immobilization and off-loading to prevent further collapse and deformity. A total contact cast (TCC) is the gold standard for this, as it evenly distributes pressure, reduces edema, and protects the foot. Surgical reconstruction is typically reserved for stable deformities in the chronic phase (Eichenholtz Stage III) or for severe unstable deformities causing ulceration. Antibiotics are not indicated without evidence of infection. Custom orthotics are for stable, chronic deformities, and bed rest alone is not as effective as TCC.
Question 6583
Topic: 8. Foot and Ankle
A 42-year-old weekend warrior feels a 'pop' in his posterior ankle while playing tennis. Clinical examination demonstrates a positive Thompson test. If nonoperative management is chosen, the healing relies heavily on the vascular watershed area of the Achilles tendon. Where is this hypovascular zone located?
Correct Answer & Explanation
. 2 to 6 cm proximal to the calcaneal insertion
Explanation
The Achilles tendon has a distinct hypovascular zone located approximately 2 to 6 cm proximal to its insertion on the calcaneus. This anatomic watershed area correlates closely with the most common site of tendon rupture.
Question 6584
Topic: 8. Foot and Ankle
A 30-year-old equestrian falls from his horse, sustaining an axial load to a plantarflexed foot. Examination reveals plantar ecchymosis. Weight-bearing radiographs show 3 mm of widening between the medial cuneiform and the base of the second metatarsal without visible fractures. What is the most appropriate management?
Correct Answer & Explanation
. Primary arthrodesis of the first, second, and third tarsometatarsal joints
Explanation
The patient has a purely ligamentous Lisfranc injury. Evidence suggests that primary arthrodesis of the medial column tarsometatarsal joints yields superior functional outcomes and lower revision rates compared to ORIF for purely ligamentous Lisfranc injuries.
Question 6585
Topic: Midfoot & Hindfoot
A 58-year-old male with long-standing, poorly controlled diabetes presents with a swollen, red, and warm right foot for 3 weeks. He denies systemic symptoms, and there are no open ulcers. Radiographs show periarticular debris, fragmentation, and subluxation of the midfoot joints. What is the most appropriate initial management?
Correct Answer & Explanation
. Total contact casting and strict non-weight-bearing
Explanation
The clinical and radiographic presentation is classic for Eichenholtz Stage I (Fragmentation) Charcot arthropathy. The gold standard for initial management in the absence of an open wound or active infection is immobilization and offloading, typically using a total contact cast.
Question 6586
Topic: 8. Foot and Ankle
A 24-year-old gymnast sustains an axial load injury to her plantarflexed foot. Weight-bearing radiographs demonstrate a 3 mm diastasis between the base of the first and second metatarsals. What is the anatomic origin and insertion of the primary ligamentous structure ruptured in this injury pattern?
Correct Answer & Explanation
. Medial cuneiform to the base of the second metatarsal
Explanation
The scenario describes a Lisfranc injury. The Lisfranc ligament is the primary stabilizer of the tarsometatarsal complex. It is a thick interosseous ligament that originates on the lateral aspect of the medial cuneiform and inserts onto the medial aspect of the base of the second metatarsal. There is no direct ligamentous connection between the base of the first and second metatarsals, making the Lisfranc ligament crucial for structural integrity.
Question 6587
Topic: 8. Foot and Ankle
A 55-year-old poorly controlled diabetic male presents with a warm, erythematous, and swollen right foot without an open ulcer. Radiographs reveal periarticular fragmentation, subluxation, and joint debris at the midfoot. According to the Eichenholtz classification, he is in Stage 1 of Charcot neuroarthropathy. What is the gold standard initial non-operative treatment?
Correct Answer & Explanation
. Total contact casting with strict non-weight bearing
Explanation
The patient is in the acute fragmentation phase (Stage 1) of Eichenholtz Charcot neuroarthropathy, characterized clinically by a hot, swollen foot and radiographically by osteopenia, fragmentation, and joint subluxation. The gold standard treatment during this acute, destructive phase is strict immobilization and offloading, typically achieved with a total contact cast (TCC). Surgery is generally contraindicated during the acute inflammatory phase due to severe bone quality and high failure rates.
Question 6588
Topic: 8. Foot and Ankle
Fluoroquinolone antibiotics are known to carry a black box warning for an increased risk of tendon ruptures, particularly involving the Achilles tendon. What is the primary molecular mechanism underlying this adverse effect?
Correct Answer & Explanation
. Upregulation of matrix metalloproteinases (MMPs) leading to accelerated collagen degradation
Explanation
Fluoroquinolones increase the expression of matrix metalloproteinases (MMPs) and decrease collagen synthesis in tenocytes. This combination leads to a net degradation of the extracellular matrix, compromising tendon strength and increasing the risk of rupture.
Question 6589
Topic: 8. Foot and Ankle
A 40-year-old male ruptures his Achilles tendon. If he opts for non-operative management utilizing an early functional rehabilitation protocol, which of the following is the most likely outcome compared to surgical repair?
Correct Answer & Explanation
. Similar re-rupture rate and equivalent functional outcomes
Explanation
Recent high-level evidence demonstrates that non-operative management with early functional rehabilitation yields similar re-rupture rates and functional outcomes compared to surgery. It also completely avoids the risk of surgical wound complications.
Question 6590
Topic: 8. Foot and Ankle
A patient presents with weakness in ankle plantarflexion and a diminished Achilles tendon reflex. Which nerve root is most likely compressed?
Correct Answer & Explanation
. S1
Explanation
The S1 nerve root primarily provides motor innervation to the gastrocnemius-soleus complex for ankle plantarflexion. It is also the primary root tested by the Achilles deep tendon reflex.
Question 6591
Topic: 8. Foot and Ankle
A 40-year-old male complains of severe midfoot pain after falling from a ladder. Weight-bearing radiographs reveal a widened space between the first and second metatarsal bases and a small avulsion fracture (fleck sign) in the interspace. Which ligament is primarily injured?
Correct Answer & Explanation
. Lisfranc ligament (medial cuneiform to 2nd metatarsal base)
Explanation
The fleck sign is highly specific for a Lisfranc injury. It represents a bony avulsion of the Lisfranc ligament, which originates from the lateral aspect of the medial cuneiform and attaches to the medial base of the second metatarsal.
Question 6592
Topic: 8. Foot and Ankle
A 45-year-old male sustains a displaced talar neck fracture with associated subtalar and tibiotalar dislocations (Hawkins Type III). Which of the following arteries provides the predominant blood supply to the body of the talus, rendering the body at exceptionally high risk for avascular necrosis in this injury pattern?
Correct Answer & Explanation
. Artery of the tarsal canal
Explanation
The artery of the tarsal canal, a branch of the posterior tibial artery, supplies the majority of the talar body. In a Hawkins Type III fracture-dislocation, the three major blood supplies (tarsal canal, sinus tarsi, and deltoid branches) are heavily disrupted.
Question 6593
Topic: 8. Foot and Ankle
A 45-year-old woman presents with severe burning pain, hyperalgesia, and skin color changes in her right foot 3 months after a crush injury. She is diagnosed with Complex Regional Pain Syndrome (CRPS). According to the IASP diagnostic criteria, CRPS Type II is distinguished from CRPS Type I strictly by the presence of which of the following?
Correct Answer & Explanation
. An identifiable, documented major nerve injury
Explanation
Complex Regional Pain Syndrome (CRPS) is divided into Type I (formerly Reflex Sympathetic Dystrophy or RSD) and Type II (formerly Causalgia). The defining distinction is that CRPS Type II occurs after an identifiable, distinct peripheral nerve injury, whereas CRPS Type I occurs without a demonstrable focal nerve lesion.
Question 6594
Topic: 8. Foot and Ankle
The classical Lisfranc ligament is essential for the stability of the midfoot. Which of the following correctly describes its anatomical origin and insertion?
Correct Answer & Explanation
. Medial cuneiform to the base of the second metatarsal
Explanation
The Lisfranc ligament is a strong interosseous ligament that originates from the lateral aspect of the medial cuneiform and inserts onto the medial aspect of the base of the second metatarsal. There is no direct transverse ligamentous connection between the bases of the first and second metatarsals.
Question 6595
Topic: 8. Foot and Ankle
According to the Eichenholtz classification of Charcot neuroarthropathy, a patient presenting with an erythematous, warm, swollen foot, with radiographs showing osteopenia, periarticular fragmentation, and joint subluxation is in which stage?
Correct Answer & Explanation
. Stage 2
Explanation
Eichenholtz Stage 1 is the Development/Fragmentation phase, clinically presenting as a warm, red, swollen foot (mimicking infection). Radiographically, there is debris, fragmentation, and joint subluxation. Stage 0 is the prodromal phase (swelling, warmth, but normal radiographs). Stage 2 is Coalescence (decreased swelling, early fusion/sclerosis). Stage 3 is Consolidation (remodeling, stable deformity).
Question 6596
Topic: Midfoot & Hindfoot
A 55-year-old diabetic male presents with an acutely swollen, erythematous, and warm right foot without open wounds or signs of systemic infection. Radiographs reveal midfoot osteopenia and early fragmentation of the tarsometatarsal joints. Which treatment is most appropriate at this stage?
Correct Answer & Explanation
. Total contact casting and strict non-weight bearing
Explanation
The patient is in the acute fragmentation phase (Stage 1) of Eichenholtz Charcot arthropathy. The gold standard treatment during this acute, hyperemic phase is immobilization and offloading, typically achieved using a total contact cast.
Question 6597
Topic: 8. Foot and Ankle
The Lisfranc ligament is a critical stabilizing structure of the midfoot. Between which two osseous structures does the primary band of the Lisfranc ligament course?
Correct Answer & Explanation
. Second metatarsal base to the medial cuneiform
Explanation
The Lisfranc ligament is a stout interosseous ligament that connects the lateral aspect of the medial cuneiform to the medial aspect of the base of the second metatarsal. Notably, there is no direct ligamentous connection between the bases of the first and second metatarsals, making this interval inherently vulnerable to injury.
Question 6598
Topic: 8. Foot and Ankle
A 28-year-old male sustains a displaced Hawkins Type III fracture of the talar neck. Which artery provides the primary blood supply to the body of the talus, placing it at high risk for avascular necrosis?
Correct Answer & Explanation
. Artery of the tarsal canal
Explanation
The artery of the tarsal canal, a branch of the posterior tibial artery, provides the dominant blood supply to the talar body. Disruption of this supply in talar neck fractures significantly increases the risk of avascular necrosis.
Question 6599
Topic: 8. Foot and Ankle
During minimally invasive repair of an Achilles tendon rupture, the sural nerve is at risk of iatrogenic entrapment. Where is the sural nerve most intimately related to the lateral border of the Achilles tendon, increasing this risk?
Correct Answer & Explanation
. 10 cm proximal to the calcaneal insertion
Explanation
The sural nerve crosses the lateral border of the Achilles tendon approximately 10 cm proximal to its insertion on the calcaneus. Proximal lateral suture placement during minimally invasive repair poses the highest risk of nerve entrapment.
Question 6600
Topic: Midfoot & Hindfoot
In the pathogenesis of Charcot neuropathic osteoarthropathy in diabetic patients, the 'neurovascular theory' suggests that autonomic neuropathy drives the disease process through which of the following mechanisms?
Correct Answer & Explanation
. Loss of sympathetic tone resulting in localized hyperemia and active bone resorption
Explanation
The neurovascular theory of Charcot arthropathy postulates that autonomic neuropathy leads to a loss of sympathetic vascular tone in the extremity. This results in significant arteriovenous shunting and localized hyperemia. The increased blood flow 'washes out' bone by enhancing osteoclastic bone resorption, weakening the architecture and predisposing the bone to microfractures and ultimate collapse.
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