Testing of silicon nitride ceramic bearings for total hip arthroplasty

✍ Scribed by B. Sonny Bal; Ashok Khandkar; R. Lakshminarayanan; Ian Clarke; Aaron A. Hoffman; Mohamed N. Rahaman

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 415 KB
• Volume: 87B
• Category: Article
• ISSN: 1552-4973
• DOI: 10.1002/jbm.b.31123

✦ Synopsis

Abstract

Modern ceramic bearings used in total hip arthroplasty (THA) consist of a femoral head (ball) articulating inside a hemispherical acetabular cup (socket); the ball and socket are made of alumina (Al~2~O~3~) and Al~2~O~3~‐based composite materials. In the present study, total hip bearings were made from a different ceramic material, silicon nitride (Si~3~N~4~), by sintering and hot isostatic pressing of powders. The resulting material had improved mechanical properties over modern Al~2~O~3~ THA bearings, with a flexural strength of 920 ± 70 MPa, a Weibull modulus of 19, and a fracture toughness of 10 ± 1 MPa m^1/2^. Unlike zirconia‐based ceramics that have also been used in THA, accelerated aging of Si~3~N~4~ did not adversely affect the flexural strength. In simulated wear tests, Si~3~N~4~ acetabular cups produced low‐volumetric wear whether articulating against Si~3~N~4~ or cobalt‐chromium (CoCr) femoral heads. The results of this investigation suggest that Si~3~N~4~ may allow improved THA bearings that combine the reliability of metal femoral heads with the low wear advantages of ceramic materials. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008