ACETABULAR DYSPLASIA AND OSTEOARTHRITIS OF THE HIP IN ELDERLY WHITE WOMEN

Objectives-To examine the association of acetabular dysplasia and oste oarthritis (OA) of the hip among elderly white women. Methods-Pelvic r adiographs from a sample of 165 white women aged 65 and above with rad iographic hip OA and 88 white women aged 65 and above without radiogra phic changes of hip OA were read for evidence of acetabular dysplasia by a single trained investigator. Acetabular dysplasia was assessed us ing measurements of the centre edge angle and the acetabular depth, wh ich are both reduced in this condition. Odds ratios for the associatio n between acetabular dysplasia and hip OA were estimated using logisti c regression analysis. Results-Fourteen (3.4%) hips had a centre edge angle < 25 degrees, 46 (11.2%) hips had an acetabular depth of < 9 mm, and 54 (13.2%) hips had acetabular dysplasia defined as either of the above. Hips with OA had a small, but not statistically significant, i ncreased prevalence of abnormal centre edge angle (odds ratio: 1.43; 9 5% confidence intervals: 0.46, 4.46), abnormal acetabular depth (1.47; 0.78, 2.77) and acetabular dysplasia (1.33; 0.74, 2.40). Conclusion-T hese results do not support the hypothesis that mild acetabular dyspla sia accounts for a substantial proportion of hip OA in elderly white w omen. A study with a much larger sample size would be required to rule out a weak association between dysplasia and hip OA of the magnitude actually observed in our study.