Surgical implants frequently become surrounded by fibrous tissue. In order to investigate the mechanisms which cause this fibrosis, fibroblastic cells in culture were exposed to powders of cobalt-chromium-molybdenum alloy simulating the wear debris of metal-on-metal joint replacements. Collagen production during periods of up to 20 d was assayed by measurement of soluble and insoluble hydroxyproline. No stimulation of collagen production was seen with any of the concentrations of metal powder tested. It is therefore suggested that fibrosis around joint replacements is not caused by direct stimulation of fibroblasts by metallic wear debris. © 1986.
Thomas, I. T., & Evans, E. J. (1986). The effect of cobalt-chromium-molybdenum powder on collagen formation by fibroblasts in vitro. Biomaterials, 7(4), 301–304. https://doi.org/10.1016/0142-9612(86)90055-4