ABFAS ABFAS Pathology and Diagnosis 1 — Questions and Answers
Question 1: Charcot neuroarthropathy most commonly affects which joint region of the foot?
- Hallux MTP joint
- Tarsometatarsal (Lisfranc) joints (Correct answer)
- Subtalar joint
- Ankle joint
Correct answer: Tarsometatarsal (Lisfranc) joints
Charcot neuroarthropathy most commonly affects the tarsometatarsal (Lisfranc) joint complex, accounting for approximately 30–40% of cases.
Question 2: Which radiographic sign indicates avascular necrosis of the talus following a fracture?
- Hawkins sign (subchondral lucency at 6–8 weeks) (Correct answer)
- Periosteal new bone formation
- Increased talar neck cortical density acutely
- Widening of the ankle mortise
Correct answer: Hawkins sign (subchondral lucency at 6–8 weeks)
The Hawkins sign—subchondral lucency seen at 6–8 weeks post-fracture—indicates disuse osteopenia and is a positive prognostic sign that blood supply is intact.
Question 3: Plantar fasciitis is most commonly associated with pain at which location?
- Metatarsal heads
- Central plantar arch
- Medial calcaneal tubercle (Correct answer)
- Fifth metatarsal base
Correct answer: Medial calcaneal tubercle
Plantar fasciitis classically presents with pain at the medial calcaneal tubercle, the proximal attachment of the plantar fascia.
Question 4: Which skin lesion on the plantar foot is characterized by interrupted skin lines and central black dots?
- Tyloma (callus)
- Heloma durum (hard corn)
- Verruca plantaris (plantar wart) (Correct answer)
- Porokeratosis plantaris
Correct answer: Verruca plantaris (plantar wart)
Verruca plantaris interrupts normal skin lines (dermatoglyphics) and contains thrombosed capillaries appearing as central black dots, distinguishing it from callus.
Question 5: Morton's neuroma (interdigital neuroma) most commonly occurs in which web space?
- First web space
- Second web space
- Third web space (Correct answer)
- Fourth web space
Correct answer: Third web space
Morton's neuroma most commonly occurs in the third web space (between the third and fourth metatarsals), followed by the second web space.
Question 6: Tarsal coalition most commonly occurs between which two bones?
- Talus and navicular
- Calcaneus and cuboid
- Calcaneus and navicular (Correct answer)
- Navicular and medial cuneiform
Correct answer: Calcaneus and navicular
Calcaneonavicular coalition is the most common tarsal coalition (approximately 53%), followed by talocalcaneal coalition.
ABFAS ABFAS Pathology and Diagnosis 1
Charcot neuroarthropathy most commonly affects which joint region of the foot?