This proposal will examine the potential technical and economic benefits of surface treatment of orthopedic devices using Plasma Source Ion Implantation, or PSII, a new and innovative approach to ion implantation, recently demonstrated by Prof. John R. Conrad at the University of Wisconsin. The program will assess the technical and economic benefits associated with the application of PSII to nitrogen ion implantation of orthopedic total joint replacement devices, in particular femoral hip and knee joints. Conventional ion implantation, a line-of-sight process, has been shown to be effective in improving the surface properties of orthopedic devices. In the non-line-of sight PSII process, the target is placed directly in the plasma source and is pulse-biased to a high negative potential relative to the chamber walls. Ions are accelerated normal to the target surface, across the plasma sheath thus eliminating not only the line-of-sight problems of conventional ion implantation, but also the retained dose problem inherent to beamline ion implantation. Phase I of this proposed research program has three purposes: (1) to establish the effectiveness of PSII in the implantation of orthopedic devices. (2) to compare PSII with the performance provided by the currently available accelerator technology, and (3) to evaluate technical issues which must be resolved in Phase II, leading to a commercial product development of PSII for orthopedic applications in Phase III.