The effect of grinding conditions on the toxicity of cobalt-chrome-molybdenum particles in vitro.

Powders of cobalt-chrome-molybdenum alloy were produced by grinding larger particles for 8 h in water, serum or joint fluid. They were administered, in low doses (0.05-0.5 mg/ml) for 1-6 d, to human dermal fibroblasts in vitro. Particles were ground in a biological fluid in order to simulate conditions in an artificial hip joint. Such particles adhered to, or were phagocytosed by, the cells far less than those ground in water. The toxicity of the alloy was linked with a failure of test cells to grow as quickly as the controls - particles ground in water were the most toxic.