[The role of the alloy-specific elements iron, cobalt, chromium and nickel in aseptic loosening of total hip joint prosthesis].

The cause of aseptic loosening of total hip joint prostheses is still largely unexplained. In addition to mechanical forces, material factors may also be instrumental. In 16 patients with loosened hip prostheses who underwent re-operation (8 X Huggler-Weber, 8 X McKee-Farrar), the concentration of the alloy-specific elements cobalt, chromium, nickel and iron were determined in 58 tissue samples by means of neutron activation and emission spectrum analysis. An increase in the element concentrations was found in all the tissue samples, and this was unrelated to the time elapsed since implantation. The chromium concentration in particular was significantly elevated in all the tissue samples, in some patients with McKee-Farrar prostheses up to 10,000 times the norm. In view of the known toxicity of cobalt, chromium and nickel in high doses it seems that the presence of unphysiologically high concentrations of these elements in the vicinity of total hip joint prostheses represents an explanation of some of the loosened prostheses.