Effect of elevated-rim acetabular liner and 32-mm femoral head on stability in total hip arthroplasty.
OBJECTIVE
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.


METHODS
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.


RESULTS
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).


CONCLUSIONS
The findings of this study clearly show that an elevated-rim liner, and independently the 32 mm head, may contribute to hip stability.
Qassem
Duwairi M
DM
Department of Orthopedic Surgery, Rush Presbyterian St. Luke's Medical Center, Chicago, Illinois 60612, USA. diwairi@go.com
Smith
Karlson B
KB
D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation* / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D007593:Joint Instability / Q000517:prevention & control*; D008297:Male; D015207:Osteoarthritis, Hip / Q000175:diagnosis / Q000601:surgery; D011336:Probability; D011474:Prosthesis Design; D011475:Prosthesis Failure; D016059:Range of Motion, Articular / Q000502:physiology; D012494:Sampling Studies; D016896:Treatment Outcome