Effect of alumina femoral head on clinical results in cemented total hip arthroplasty: old versus current alumina.
BACKGROUND
The wear rate of polyethylene against alumina was demonstrated to be lower than against metal, and the results of early clinical studies of alumina-on-polyethylene combination were as good as expected, but the long-term results of alumina ceramic heads were not as good, as reported by several authors. The purpose of this study was to assess the clinical results over 10 years of cemented total hip arthroplasty (THA) with two types of alumina head: old and current alumina.


METHODS
We compared the clinical results of these two types of alumina used for cemented THA. The first type was old alumina (containing 7% yttria), and 77 hips with a 28-mm head (group I) were included. The second type was current alumina (highly purified alumina), and 50 hips with a 26-mm head (group II) and 88 hips with a 22-mm head (group III) were included. The mean follow-up was 17 years 4 months in group I, 12 years 3 months in group II, and 10 years in group III.


RESULTS
The Kaplan-Meier survival analysis, with revision for any reason as the endpoint, predicted 10-year survival rates of 90.8%, 100%, and 97.5% for groups I, II, and III, respectively. The survival curves differed significantly only between groups I and II. The probabilities of 10-year survival of the pros-theses with radiological loosening as the endpoint were 77.2%, 91.6%, and 96.5%, respectively. The survival curves showed significant differences only between groups II and III.


CONCLUSIONS
The old alumina showed a higher wear rate and rougher surface on the femoral head than did the current alumina in our previous study. The clinical results also indicated superiority of current alumina over old alumina. The difference in the size of the femoral head (26 vs. 22 mm) did not affect the clinical results.
Kawanabe
Keiichi
K
Department of Orthopaedic Surgery, Faculty of Medicine, Kyoto University, Shogoin, Sakyo-ku, Japan.
Tanaka
Kenji
K
Tamura
Jiro
J
Shimizu
Motoyuki
M
Onishi
Eijiro
E
Iida
Hirokazu
H
Nakamura
Takashi
T
D000328:Adult; D000537:Aluminum Oxide; D019644:Arthroplasty, Replacement, Hip; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012189:Retrospective Studies; D015019:Yttrium
D015019:Yttrium; D000537:Aluminum Oxide; C091417:yttria