Benign response to particles of diamond and SiC: bone chamber studies of new joint replacement coating materials in rabbits.

Wear particles from total joint replacements are thought to accelerate prosthetic loosening. Diamond coating may improve the smoothness and wear characteristics of the femoral head component of total hip replacements, and thus increase their longevity. The brittleness of a thin diamond coat may be overcome by using an SiC-whisker diamond composite. This study describes the reactions of regenerating bone tissue to phagocytosable particles of diamond and SiC, using implanted bone harvest chambers in rabbits. The particles were dispersed in hyaluronan and introduced into a canal transversing the implant. The tissue that entered the canal during the following 3 weeks was then harvested. In previous studies using this model, particles of high density polyethylene, bone cement and chromium-cobalt all caused an inflammatory reaction and a marked decrease in the amount of ingrown bone. In the present study, neither the diamond nor the SiC particles caused any decrease in bone formation. It appears that particles of diamond and SiC are comparatively harmless.