Nonspherical femoral head shape (pistol grip deformity), neck shaft angle, and risk of hip osteoarthritis: A case–control study

Our findings indicate that pistol grip deformity is associated with hip OA. The increased prevalence of pistol grip deformity and an abnormally low neck shaft angle in unaffected hips of cases with unilateral OA suggests that they are risk factors for development of hip OA. However, both a nonspherical head shape and an increase in neck shaft angle may occur as a consequence of OA.