Does hip morphology predispose to femoral head osteonecrosis?

Femoral head osteonecrosis (ON) presents in about 10% of all total hip arthroplasty (THA) patients in united states (1). There have been a variety of traumatic and atraumatic factors identified as risk factors for ON, but the etiology and pathogenesis still remains unclear. Ollivier et al.’s work is trying to shed a light on the anatomical associations with idiopathic ON. In this study, hip morphology was compared (obtained by CT scan) between patients who had idiopathic femoral head ON and a matched control group of patients to determine whether any observed differences could have possible associations with the disease process. In this study, there was significant differences between the two groups and found ON group to be associated with a decreased femoral neck-shaft angle of <129°, greater femoral neck anteversion (femoral neck version of >17°), less acetabular coverage (lateral center-edge angle of <32°) and less acetabular version <19° (2).