A study of sarcogenicity associated with Co-Cr-Mo particles implanted in animal muscle

A study has been made of the sarcogenicity of particles of cobalt-chromium-molybdenum alloy. The particles were implanted as a dry powder into a surgical incision into the dorsal paraspinal muscle of adult female rats and guinea pigs. Two preparations were used. In one, the particles had a size range of 100-250 micrometers. This preparation was implanted into 51 Wistar rats. In the other, the particles had a size range of 0.5-50 micrometers, 85% being in the range 0.5-5 micrometers. This preparation was implanted into 61 Wistar rats, 53 hooded rats, and 46 Dunkin Hartley guinea pigs. Sham operations were carried out on a control group of 50 Wistar rats. No malignant neoplasms developed at the test or control operation sites during the time periods for which the animals survived. This negative finding contrasts with that from a previous study by Health, Freeman and Swanson, who observed sarcomas in rats at sites of intramuscular injection of cobalt-chromium-molybdenum particles suspended in horse serum. Possible explanations for this difference in results are discussed.