Metal ion levels in ceramic-on-ceramic THR with modular necks: analysis of cobalt and chromium serum levels in 30 healthy hip patients

Background: Modular necks in total hip replacement (THR) can be a source of metal ion release. There are no data to date on the level of cobalt and chromium ions in the serum of patients with a cobalt- chrome stem and a titanium modular neck. Methods: Serum ion levels were measured in healthy volunteers with a well-functioning ceramic-on-ceramic THR. Results: Average cobalt in serum was 1.21 mu g/l for unilateral THR and 2.2 mu g/l for bilateral THR. No patient had cobalt levels higher than 2.4 mu g/l. No patient had measurable chromium levels. There were no differences in cobalt levels for hips with short necks versus hips with long necks. Conclusions: The hybrid THR Profemur (R) Xm - Procotyl (R) L with a titanium modular neck on a cobalt-chrome stem design shows no signs of abnormal toxic ion levels (cobalt or chromium) in a randomly selected group of wellfunctioning hip patients.