Although the theoretical attractions of the elevated rim are obvious and have been widely accepted as a mean to improve the postoperative stability, the clinical advantages have not been demonstrated. The aim of this study is to further evaluate the elevated liners contribution to stability.
Forty-six patients with 50 hips undergoing primary total hip arthroplasty (THA) were enrolled in this study, conducted in Rush Hospital, Chicago, Illinois, United State of America, between March 2001 and February 2003. We tried to determine the amount of additional stability that can be provided by elevated-rim liner compared to the non-elevated liners and the stability of the hip with a 32 mm femoral head compared to 28 mm head.
Our results showed that a 10 degree elevated-rim acetabular liners increased hip stability by an additional 8.2 degrees of internal rotation. The 32 mm head provided 7.3 degrees of internal rotation. The increases were statistically significant (p value is less than 0.0001).
The findings of this study clearly show that an elevated-rim liner, and independently the 32 mm head, may contribute to hip stability.