The in-vivo performance of Ti-6Al-4V titanium alloy as a bearing surface for total knee replacement was evaluated by analysis of 29 retrieved Miller-Galante prostheses. Retrieved implants were subjected to routine analysis, and a qualitative damage score was assigned to each component. The mean time from the primary procedure to the revision was 54 months. Nineteen of 29 revisions were performed for complications relating to metal-backed patellar component failure.
Nonparametric multi-way frequency analysis identified significant correlations between femoral component damage and the extent of damage to the patellar polyethylene and the underlying metal backing. Femoral component damage did not correlate with tibial articular surface damage.
Analysis of retrieved Miller-Galante femoral components revealed that significant wear was almost exclusively seen in association with metal on metal wear against a failed metal backed patellar component. In the absence of these extreme wear conditions, we have not observed significant problems associated with Ti-6Al-4V as a bearing surface in total knee replacements at follow-ups of 7 years.