Point Defect Model, PDM: Predicting metallic implant lifetime—what we did and what we will do!

Orthopedic implant lifetime is a key health issue for patients. One in thirty Americans has an orthopedic prosthesis. In Europe, this number is not available but according to sales made by companies, this figure is likely on the same order of magnitude. Metals, stainless steels, titanium alloys, and Cobalt Chromium Molybdenum alloys used for implants must have the specificity to resist under liquid environments during usage, corrosion–friction–fretting, etc. It is worth noting that additive manufacturing is currently progressing but for implants, usual manufacturing processes are always used. Highlighting both the best mechanical and materials parameters in cases of degradation is the aim of this study, using the Point Defect Model. Contact mechanics between stainless steel and poly-mthylmetacrylate, PMMA, have been focused on. Two types of experiments were investigated: Free corrosion potential or open circuit potential and applied potential. Describing behaviors in terms of the wear and morphologies of the wear track area is the key point of this study. The authors paid attention to a synergistic approach, evaluating the contribution of wear to corrosion and vice versa. Theoretical and practical issues are related to understanding these phenomena and predicting passive film thickness. There were a few nanometers of oxides on the top surface and the material behavior depended on a few nanometers.