Morphology of the first metarsal head as a risk factor for hallux valgus interphalangeus

Abstract

Introduction: Hallux valgus interphalangeus (HVI) has a poorly understood aetiology. First metatarsophalangeal joint stability, influenced by first metatarsal head shape, may be linked to HVI. We hypothesised that first metatarsal head shape is a risk factor for HVI. No published article could be found in the literature investigating this hypothesis. Methods: 127 standardised foot radiographs were analysed retrospectively. The hallux valgus angle (HVA) and interphalangeus angle (IPA) were measured. The first metatarsal head shape was divided into chevron, round and flat groups. Statistical analysis was then performed to investigate the relationship between first metatarsal head shape and the occurrence of HVI. Results: There was no statistically significant relationship between first metatarsal head shape and the occurrence of HVI. There was however a negative relationship between HVA and HVI. Conclusion: The morphology of the first metatarsal head does not seem to be a risk factor for HVI. A known negative relationship between HVA and IPA is reinforced.