Debris From Failed Ceramic-on-Ceramic and Ceramic-on-Polyethylene Hip Prostheses

To compare the properties of wear debris between ceramic-on-ceramic and ceramic-on-polyethylene total hip prostheses, particles were isolated and characterized from tissue biopsies obtained at revision arthroplasty or autopsy from two similar uncemented modular hip systems. Group A hips (11 patients; mean, 31 months in vivo) had titanium shells with alumina inserts, alumina femoral heads, and titanium alloy stems. Group B hips (seven patients; mean, 42 months) were the same as Group A but with polyethylene acetabular inserts. Particles were characterized using an electrical resistance particle analyzer, scanning electron microscope, and energy dispersive xray spectroscope. Most of the particles in Group A were ceramic, whereas most of the particles in Group B were polyethylene. Metal particles from the femoral stem and the acetabular shell also were present. If one Group A hip with impingement is excluded, the rate of particle production is significantly lower in the ceramic-on-ceramic group than in the ceramic-on-polyethylene group. With the number of samples available, no significant difference in average size could be detected among the different types of particles or among the groups.