RELEASE AND EXCRETION OF METAL IN PATIENTS WHO HAVE A TOTAL HIP-REPLACEMENT COMPONENT MADE OF TITANIUM-BASE ALLOY

Serum concentration and urinary excretion of titanium, aluminum, and vanadium were measured for patients who had a well functioning cementless primary total hip replacement of one of two different designs, for patients who had a loose total hip replacement that was to be revised, and for control subjects who had no implant. Serum concentrations of titanium were elevated approximately twofold in the patients who had a loose implant, compared with the values for the control subjects. No major differences in terms of urine concentration of titanium, serum concentration of aluminum, or urine concentration of aluminum were observed among any of the groups that were studied. Concentrations of vanadium were uniformly low in all groups. CLINICAL RELEVANCE: There is much concern regarding the possibly toxic effects of the release of metal from orthopaedic implants, particularly cementless total joint-replacement components. In the present study, patients who had a loose total hip replacement of titanium-base alloy had an increased serum concentration of titanium. The toxicological importance of this finding is not known. The concentration of aluminum, which has well documented toxic effects, in the serum or urine of patients who had a total hip-replacement component of titanium-base alloy was not elevated in comparison with contemporaneous control subjects in this study.