A radiographic analysis of the contribution of hallux valgus interphalangeus to the total valgus deformity of the hallux

Abstract

Introduction: The hallux valgus interphalangeus deformity is described as rare, but improved outcomes in hallux valgus surgery is associated with its surgical correction via an Akin osteotomy. The hypothesis of this study is that hallux valgus interphalangeus makes a contribution to the total valgus deformity of the hallux. Methods: A radiographic analysis of 285 foot x-rays utilising a standardised radiographic and measurement technique was performed. Results: The average contribution of the interphalangeal angle (IPA) to the total valgus deformity of the hallux (TVDH) across the whole study population was a mean (SD) of 37.9% (21.2). The average contribution of IPA to TVDH was greater in feet without hallux valgus (58.0%) when compared to feet with hallux valgus (28.3%). Hallux valgus interphalangeus is common, particularly in Caucasians (p=0.01) and makes a significant contribution to the total valgus deformity of the hallux (p <0.01). The contribution to total valgus deformity of the hallux is more significant in mild hallux valgus. There is an inverse relationship between the interphalangeal angle and other angular measurements in the foot. Conclusion: Hallux valgus interphalangeus is a common entity and its significant contribution to the total valgus deformity of the hallux dictates that hallux valgus interphalangeus must be incorporated in management algorithms. The total valgus deformity of the hallux should replace the isolated concepts of hallux valgus and hallux valgus interphalangeus.