Prosthetic metals interfere with the functions of human osteoblast cells in vitro.

The release of metals from total joint prostheses may contribute to periprosthetic bone loss manifested as osteolysis. The effects of titanium, cobalt, and chromium on human osteogenic sarcoma cells (osteoblastlike cells) were investigated in vitro. Titanium, cobalt, and chromium at concentrations of 1, 10, and 100 ng/ml did not cause any changes in the cell growth, viability, and injury after 72-hour incubation with the cells. Titanium, cobalt, and chromium at concentrations ranging from 0.01 to 100 ng/ml significantly enhanced the release of interleukin-1 beta and tumor necrosis factor-alpha by lipopolysaccharide stimulated human osteogenic sarcoma cells, whereas they did not alter the release of transforming growth factor-beta 1. Cobalt at concentrations ranging from 0.1 to 100 ng/ml significantly enhanced the release of interleukin-6, but titanium and chromium did not. Cobalt and chromium at concentrations of 10 and 100 ng/ml significantly inhibited the release of osteocalcin by human osteogenic sarcoma cells, whereas titanium had no effect. Titanium, cobalt, and chromium at concentrations of 10 and 100 ng/ml significantly inhibited the synthesis of Type I collagen by human osteogenic sarcoma cells. Cobalt and chromium inhibited the cell proliferation in response to lipopolysaccharide stimulation, whereas titanium did not. The data presented in this article suggest that the metal induced disregulation of cytokine release and osteoblast dysfunction may play an important role in the induction of osteolysis in patients with total joint arthroplasties.