Fretting Induced Fracture Damage in a Ti6Al4V Total Hip Prosthesis

Abstract

Abstract Within the body, hip implants are subjected both to mechanical and corrosive effects. In narrow crevices such as in the moving surfaces of modular femoral stems, even in the case of proven materials, complex interactions occur between mechanically and corrosively induced material damage, which can strongly influence the service reliability of the implant itself. After almost a year in service, the modular femoral stem presented in this article, fractured. The stem, which had been implanted into a somewhat less than active patient, fractured possibly as a result of defective implantation and diagnosed loosening, causing fretting and corrosion which eventually resulted in the fatigue fracture of the modular hip stem. The failure analysis presented, carried out as part of an IMWF student research project at the MPA University of Stuttgart, was initiated to investigate the damage found at a number of different levels and using various different investigatory techniques in order to determine the cause of the failure and to suggest guidelines to aid in the investigation of other similar failures.