Is hip capsule morphology associated with hip pain in patients without another structural correlate?

Purpose: Prior studies examining the influence of hip capsule morphology in femoroacetabular impingement (FAI) patients, showed an association between hip pain and an increased ratio between anterior to posterior hip capsule volume. Moreover, capsulotomy is discussed as a treatment option in FAI patients, which is thought to reduce potential pressure on the femoral head and thus relieves pain. In clinical practice, not infrequently patients with hip pain do not present any structural correlates on MRI. Until now, no study has examined the hip capsule morphology in a general population (not only in FAI patients) and there is no deeper understanding of the relationship of the hip capsule morphology and the occurrence of pain.Therefore, the goals of this study were to assess (i) whether hip capsule morphology is associated with hip pain in patients without any other structural abnormality that would explain pain on MRI and (ii) which features of hip capsule morphology could potentially contribute to hip pain in those patients.