OSTEOARTHRITIS OF THE HIP-JOINT AND ACETABULAR DYSPLASIA IN WOMEN

Objective-To investigate the suggestion that osteoarthritis (OA) of th e hip joint is often caused by subclinical acetabular dysplasia among elderly British women. Methods-We examined 393 hip joints from the rad iographs of a sample of women aged 60-75 years undergoing intravenous urography. Acetabular dysplasia was assessed using measurements of the centre-edge (CE) angle and acetabular depth (AD), which are both redu ced in this condition. OA was assessed using an overall grade based on the Kellgren and Lawrence system and by measurement of minimum joint space (MJS). Results-MJS was the more repeatable measure of OA, and sh owed a strong correlation with overall grade (Spearman rank correlatio n coefficient r(s)=-0.61, p < 0.01). IMJS was significantly negatively correlated with CE angle (Pearson correlation coefficient r=-0.25, p < 0.001) and AD (r=-0.11, p < 0.05). Consistent with these findings, t here was a weak but significant positive correlation between overall g rade of OA and one of the two measures (CE angle) of acetabular dyspla sia. Conclusions These results do not support the hypothesis that mild degrees of acetabular dysplasia account for a substantial proportion of hip OA in elderly women. Changes in hip joint geometry as a result of OA may be responsible for the weak negative association observed.