Surface-engineered metal-on-metal bearings improve the friction and wear properties of local area contact in total joint arthroplasty

Metal-on-metal articulating total joint arthroplasty has the potential to eliminate polyethylene-wear-induced osteolysis and aseptic loosening around the prosthesis. Metal surface coatings, however, are subject to delamination in areas of local contact. Various studies have been conducted to reduce metal wear debris and corrosion by introducing surface treatments. In this study we applied carbon ion implantation (CII) and diamond-like carbon (DLC) films to a cobalt-chrome alloy substrate by plasma source ion implantation. Once the films were prepared, we put them through simple geometry wear tests under high contact pressure (an average load of 1030 MPa) to establish the tribological properties during the phase of local contact that leads to severely increased wear in total joint arthroplasty. The CII-coated bearings showed less wear, lower friction coefficients, and higher resistance to catastrophic damage compared to uncoated Co-Cr alloy and DLC couples, even under high contact pressure. The CII-coated surface offers potential advantages as a hard coating for articulating joints.