Metal release and excretion from cementless titanium alloy total knee replacements

Concentrations of titanium, aluminum, and vanadium were measured in the ser um and urine of patients with titanium alloy cementless primary total knee arthroplasty components. patients were categorized in one of five groups. I n Group 1, the patellar and tibial articulating surfaces were made of carbo n fiber reinforced ultrahigh molecular weight polyethylene. In Group 2, the patellar and tibial surfaces were made of ultrahigh molecular weight polye thylene, In Group 3, the femoral titanium alloy articulating surface was ni trogen ion implanted with ultrahigh molecular weight polyethylene patellar and tibial articulating surfaces. Patients in Group 4 had failed patellar c omponents, and Group 5 was comprised of age and gender matched control subj ects without implants, Serum concentrations of titanium were approximately 50 times greater in patients with failed patellar components (Group 4) and approximately 10 times greater in patients with carbon fiber reinforced pol yethylene bearing surfaces (Group 1) when compared with Groups 2 and 3 and the control subjects (Group 5), For aluminum and vanadium, no detectable di fferences were observed among any of the groups, In addition, analysis of 2 4-hour urine samples showed no significant differences in titanium, aluminu m, or vanadium concentrations among any of the groups. Elevated serum titan ium levels may serve as a marker of patellar component failure or accelerat ed femoral component wear in total knee replacements with titanium alloy be arings. The toxicologic ramifications of these findings are unknown.