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.
Osteoarthritis (OA) of the hip is an important cause of musculoskeletal disability in the elderly (1). Epidemiologic studies have identified several risk factors for hip OA, including increasing age, male sex, excess body weight, trauma, low serum vitamin D levels, occupation, and leisure time physical activity (1-5). In addition, clinical studies of patients with hip OA suggest that anatomic abnormalities of the hip that are present at birth or that develop during childhood may result in accelerated or premature joint degeneration (6). Examples of abnormalities include congenital hip subluxation, slipped capital femoral epiphysis, and Legg-Calve
ยด-Perthes disease. Subclinical acetabular dysplasia is another abnormality of the hip anatomy that has been reported to predispose individuals to hip OA. Murray (7), Stulberg and colleagues (8), and Harris (9) estimated that between 25% and 40% of cases of hip OA may be due to subclinical acetabular dysplasia. Recently, 3 cross-sectional studies, 2 of which focused on women and 1 on men, evaluated hip radiographs for changes in both hip OA and acetabular dysplasia, and all 3 studies failed to identify an association between these 2 disorders (10-12). However, prevalent hip OA may alter hip geometry, such that the true premorbid prevalence of acetabular dysplasia cannot be assessed, and to date, no prospective studies have been done.
To determine if radiographic evidence of acetabular dysplasia in hips without OA increased the risk of incident hip OA, we performed a nested case-control study in white women ages 65 years and older who were