ACETABULAR DYSPLASIA PREDICTS OSTEOARTHRITIS OF THE HIP. THE ROTTERDAM STUDY

Background: It has been proposed that in a part of patients with primary hip OA, the disease occurs as a consequence of mild forms of acetabular dysplasia, which persist into adult life.Objectives: To investigate the association between acetabular dysplasia and progression of hip OA in a population-based sample of elderly subjects.Methods: In 367 men and 508 women of 55 years and older from the Rotterdam Study, a population based, single center cohort study of chronic diseases in the elderly; X-rays of the hip at baseline and follow-up (mean follow-up time of 6.6 years) were evaluated. We included those participants with a Kellgren & Lawrence score at baseline of grade 0 or 1 in both hips. Progression of hip OA was defined as a decrease of joint space width of the hip (≥1.0 mm) at follow-up or an incident THR at follow-up. Acetabular dysplasia was assessed using the center-edge angle (CE) of Wiberg and the acetabular depth. The association between acetabular dysplasia and progression of the hip was assessed by calculating odds ratios, using multivariate regression analysis.Results: In the present study population, with a mean age of 65.7 (± 6.6) years, 13.8% had progression. We found strong independent associations between acetabular dysplasia and progression of the hip. These associations were independent of known determinants of progression, such as age, gender, and BMI. The assessed associations may possible be underestimated because of the relatively high mean age of the study population and the excluded participants with evident radiological OA (Kellgren & Lawrence ≥ grade 2). Association between acetabular dysplasia and hip osteoarthritis in the elderly crude (OR) adjusted (OR) CE angle < 30 2.4 (1.8-3.4) 2.8 (2.0-4.0) CE angle < 25 3.7 (2.0-6.7) 4.0 (2.1-7.4) Acetabular depth < 9 mm 2.8 (1.9-4.1) 2.8 (1.9-4.2) Adjusted for: age, gender, BMI and follow-up time. usted for: age, gender, BMI and follow-up time.Conclusion: This study shows that acetabular dysplasia is a strong independent determinant of progression of hip OA.Citation: , volume , supplement , year 2004, page Session: Advances in osteoarthritis – Clinical epidemiology