From the case:
First metatarsophalangeal angle
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1st metatarsophalangeal angle also known as hallux valgus angle (HVA).
Case Discussion
The 1st metatarsophalangeal angle or hallux valgus angle (HVA) is the angle formed by the intersection of longitudinal axes of the diaphyses of the 1st metatarsal and the proximal phalanx.
It is a useful radiographic measurement in the assessment of hallux valgus.