Testing of Silicon Nitride Ceramic Bearings for Total Hip Arthroplasty
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 (Al2O3) and Al2O3-based composite materials. In the present study, total hip bearings were made from a different ceramic material, silicon nitride (Si3N4), by sintering and hot isostatic pressing of powders. The resulting material had improved mechanical properties over modern Al2O3 THA bearings, with a flexural strength of 920 ± 70 MPa, a Weibull modulus of 19, and a fracture toughness of 10 ± 1 MPa m1/2. Unlike zirconia-based ceramics that have also been used in THA, accelerated aging of Si3N4 did not adversely affect the flexural strength. In simulated wear tests, Si3N4 acetabular cups produced low-volumetric wear whether articulating against Si3N4 or cobalt-chromium (CoCr) femoral heads. The results of this investigation suggest that Si3N4 may allow improved THA bearings that combine the reliability of metal femoral heads with the low wear advantages of ceramic materials.
B. S. Bal et al., "Testing of Silicon Nitride Ceramic Bearings for Total Hip Arthroplasty," Journal of Biomedical Materials Research - Part B: Applied Biomaterials, John Wiley & Sons, May 2008.
The definitive version is available at http://dx.doi.org/10.1002/jbm.b.31123
Materials Science and Engineering
National Insititute of Arthritis and Musculoskeletal and Skin Diseases
Keywords and Phrases
Implant Design; Joint Replacement; Orthopedic; Stress; Total Hip Arthroplasty; Wear; Wear Testing; Silicon nitride
Article - Journal
© 2008 John Wiley & Sons, All rights reserved.