Association of mild acetabular dysplasia with an increased risk of incident hip osteoarthritis in elderly white women: The study of osteoporotic fractures

Objective. To determine if acetabular dysplasia increases the risk of incident hip osteoarthritis (OA) among elderly white women. Methods. Baseline and followup anteroposterior pelvic radiographs were obtained a mean of 8 years apart, and read for individual radiographic features (IRFs) of hip OA; summary grades (0-4) were then assigned based on the IRFs present. Acetabular dysplasia was defined by the results of measurements of the acetabular depth (<9 mm) or the center-edge angle (<30 degrees). Logistic regression analyses were performed to determine the association between acetabular dysplasia and incident hip OA, and all analyses were adjusted for age, current weight, body mass index, affected side, and investigational site. Results. The odds ratios for the association of abnormal center-edge angle and acetabular dysplasia with incident hip OA were 3.3 (95% confidence interval 1.1-10.1) and 2.8 (95% confidence interval 1.0-7.9), respectively. Conclusion. Acetabular dysplasia, defined by a decrease in the center-edge angle, is associated with a modestly increased risk of incident hip OA in elderly white women.