Differences in acetabular morphology related to side and sex in a Chinese population.

The purpose of the present study was to determine the side and sex differences in acetabular dimension and orientation in normal Chinese adults, which are not known well but are important in hip joint replacement surgery. The acetabular parameters, including anteversion angle (AV.A), abduction angle (AB.A), center edge angle (CE.A), acetabular width (Ac.W) and acetabular depth (Ac.D), were measured on CT images in 100 healthy Chinese adults. The acetabular index of depth to width (Ac.D/Ac.W) was calculated by depth/width × 100. Percentage side difference (PSD) was calculated for each parameter. The absolute numbers of PSD (aPSD) were compared between the groups of right positive (right PSD > left PSD) and left positive (left PSD > right PSD) groups. There was no significant side difference in any of the parameters. Compared to men, a significant increase in AB.A (P = 0.001) and significant decreases in Ac.W (P < 0.001), Ac.D (P < 0.001) and Ac.D/Ac.W (P < 0.05) occurred in women. The differences in Ac.W and Ac.D became insignificant when adjusted for body height. aPSD did not show a significant difference between right and left positive groups in both sexes. In conclusion, the side differences in acetabular parameters in a normal individual are likely to be associated with measurement error. In addition, the larger acetabular dimension in men is attributed to greater body height independent of sex.