Background: We examined the role of the geometry of acetabulum in the development of osteoarthritis in young men. Contrary to previous studies we evaluated the significance of the anterior, posterior and total coverage of the femoral head, the influence of the femoral neck and the consequence of acetabular retroversion on standardized x-rays.

Material and Methods: Men (n=78) aged 26–55 years (case-group) were selected from the Danish Hip Arthroplasty Register. This group was compared to a control-group (n=78) selected from men of the same age group received as trauma patients. Anterior/posterior pelvic radiographs were evaluated taking into account the degree of pelvic rotation and tilt.

Results: Femoral head coverage, femoral head-neck ratio and centre edge angle were significantly smaller in the case-group, acetabular index angle and modified ACM-angle were significantly bigger. Anterior, posterior and total coverage of femoral head showed no difference. The frequency of acetabular retroversion was greater among cases.

Interpretation: Osteoarthritis of young men is associated with a small superior acetabular coverage, a steep acetabular roof, a small acetabular depth, a thickened femoral neck and acetabular retroversion.