Ceramic failure after total hip arthroplasty with an alumina-on-alumina bearing.
BACKGROUND
The mechanical properties of alumina ceramic, now in its third generation, have been markedly improved through the evolution of design features and manufacturing processes and the introduction of proof-testing. Nonetheless, because of the lack of ductility of alumina ceramic, there is concern regarding the risk of fracture during insertion or in vivo use. The purpose of the present study was to present a multicenter review of primary total hip arthroplasties performed with use of a polyethylene-ceramic composite liner combined with a ceramic femoral head, with particular attention to failure of the ceramic bearing.


METHODS
We evaluated 357 primary total hip arthroplasties that had been performed in 319 patients with use of a contemporary alumina-on-alumina bearing design incorporating a polyethylene-ceramic composite liner within a titanium-alloy shell coupled with a 28-mm-diameter ceramic femoral head. The procedures were performed at four participating centers from 1998 to 2001. Ceramic failure without trauma occurred in six hips (1.7%). All of these hips were revised, and the retrieved alumina implants were examined by means of visual inspection and scanning electron microscopy equipped with energy-dispersive x-ray spectrometry.


RESULTS
Two femoral heads fractured during the first postoperative year, and four alumina liners fractured after an average of 36.8 months in vivo. All four of the explanted alumina liners revealed evidence of rim contact with the metal neck of the femoral component. Composition analysis confirmed that surface-stain materials were titanium particles transferred from the femoral component.


CONCLUSIONS
Despite the theoretical improvement in the fracture toughness of a polyethylene-alumina composite liner, a relatively high rate of catastrophic ceramic bearing surface failure was still observed at the time of short-term follow-up. This finding prompted us to discontinue the use of this type of alumina bearing design.
Park
Youn-Soo
YS
Department of Orthopedic Surgery, Sungkyunkwan University School of Medicine, Samsung Medical Center, 50 Ilwon-Dong, Kangnam-Ku, Seoul 135-710, South Korea. yspark@smc.samsung.co.kr
Hwang
Sung-Kwan
SK
Choy
Won-Sik
WS
Kim
Yong-Sik
YS
Moon
Young-Wan
YW
Lim
Seung-Jae
SJ
D000328:Adult; D000368:Aged; D000537:Aluminum Oxide; D002516:Ceramics; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D011475:Prosthesis Failure
D000537:Aluminum Oxide