ABFAS Patient Assessment and Evaluation 3 â Questions and Answers
Question 1: Which radiographic parameter is used to quantify the severity of hallux valgus on a weight-bearing AP foot radiograph?
- Calcaneal inclination angle
- Hallux abductus angle (Correct answer)
- Talar-first metatarsal angle (lateral)
- Meary's angle
Correct answer: Hallux abductus angle
The hallux abductus angle, measured between the longitudinal axes of the first metatarsal and proximal phalanx, quantifies hallux valgus deformity on AP view.
Question 2: During the Coleman block test, placing a 1-inch block under the lateral forefoot of a patient with a cavovarus deformity reveals a flexible hindfoot varus. What does this finding indicate?
- The hindfoot deformity is fixed and requires calcaneal osteotomy
- The forefoot drives the hindfoot varus and soft tissue correction may suffice (Correct answer)
- Subtalar arthrodesis is mandated
- Tibialis posterior transfer should be the primary procedure
Correct answer: The forefoot drives the hindfoot varus and soft tissue correction may suffice
A flexible hindfoot varus on Coleman block test indicates that forefoot-driven deformity is the primary problem, allowing hindfoot correction with forefoot procedures alone.
Question 3: When interpreting a bone scan for osteomyelitis, which phase is most specific for distinguishing osteomyelitis from soft tissue infection?
- Flow phase
- Blood pool phase
- Delayed static phase (Correct answer)
- 24-hour phase
Correct answer: Delayed static phase
The delayed static (3-hour) phase shows focal increased uptake in osteomyelitis; combined with flow and blood pool, three-phase positivity is more specific for bone infection.
Question 4: A patient presents with acute gouty arthritis of the first MTP joint. Which laboratory finding would confirm the diagnosis definitively?
- Elevated serum uric acid >7 mg/dL
- Elevated ESR and CRP
- Negatively birefringent needle-shaped crystals on joint aspiration (Correct answer)
- Hyperuricosuria on 24-hour urine
Correct answer: Negatively birefringent needle-shaped crystals on joint aspiration
Identification of monosodium urate crystalsâneedle-shaped and negatively birefringent under polarized lightâon synovial fluid analysis is the gold standard for gout diagnosis.
Question 5: A child presents with painless limping and a shortened limb with external rotation deformity. Frog-leg radiographs show medial joint space widening. What is the most likely diagnosis?
- Legg-Calvé-Perthes disease
- Slipped capital femoral epiphysis (Correct answer)
- Developmental dysplasia of the hip
- Transient synovitis
Correct answer: Slipped capital femoral epiphysis
External rotation deformity, limb shortening, and medial joint space widening on frog-leg radiograph are classic findings of slipped capital femoral epiphysis.
Question 6: When performing a biomechanical examination, a patient demonstrates early heel rise and inability to maintain heel contact during the midstance phase. Which condition is most likely responsible?
- Equinus deformity (Correct answer)
- Calcaneal gait
- Hallux limitus
- Peroneal spasm
Correct answer: Equinus deformity
Equinus deformity (limited ankle dorsiflexion) causes early heel rise as the patient compensates to advance the tibia over the foot during midstance.
Question 7: Which MRI sequence is most sensitive for detecting bone marrow edema in early Charcot neuroarthropathy?
- T1-weighted
- T2-weighted
- STIR (Short TI Inversion Recovery) (Correct answer)
- Gradient Echo
Correct answer: STIR (Short TI Inversion Recovery)
STIR sequences suppress fat signal, making bone marrow edema appear bright and highly conspicuous, providing greatest sensitivity for early Charcot changes.
ABFAS Patient Assessment and Evaluation 3
Which radiographic parameter is used to quantify the severity of hallux valgus on a weight-bearing AP foot radiograph?