Deterioration mechanisms of joint prosthesis materials. Several solutions by ion implantation surface treatments.

Materials for orthopaedic implants can fail for several combined reasons: corrosion, fatigue and wear for metals, wear and creep for polymers, fracture for ceramics. Some typical cases are analysed and it is demonstrated that ion implantation improves metals and polymers used for joint prosthesis. Implantations of nitrogen, oxygen and argon ions modify the structure of a 2-500 nm thick layer in the materials. The results of friction tests on the couple metal-polymer are correlated with the surface properties.