Zirconia has been found to produce one of the lowest rates of polyethylene wear debris when used with ultrahigh molecular weight polyethylene for the articulating surface of a prosthesis. A zirconia coating can combine these useful surface properties with the well known bulk properties of common medical alloys. Due to the lack of chemical cohesion of zirconia with the elements of cobalt chromium alloy, even deposition techniques which blend the interface between coating and substrate (functionally gradient interface) are not producing sufficient adhesion. Implant Sciences Corporation proposes to demonstrate that a combination of a chemical bonding layer with fully blended interfaces is a solution to the adhesion problem when the layers are formed using energetic metal ions of the appropriate species. The proposed coating process is omni-directional, has a very high rate of throughput, and is proven for large batch commercial production. Orthopedic manufacturers are greatly interested in extending the working lifetimes of their total joint replacement components. The proposed coating method combines the wear rates of ceramic surfaces with the established manufacturing capability of traditional alloy prostheses. The combination results in maximum gain in performance for minimum cost impact. Several hundred thousand total joint replacement operations are performed each year.
