Fatigue of biomaterials: a review

Fatigue fracture and wear have been identified as some of the major problems associated with implant failure of medical devices. The actual in vivo mechanisms are complex and involve the hostile body environment. The response of the host tissue to wear debris is a real issue. Fatigue-wear corrosion and environmental stress cracking are common. Although fatigue fracture and wear are frequently reported in orthopaedic applications such as hip joint prostheses, they can be fatal in mechanical heart valves. While it is not possible to avoid failure, recent work has focused on predictive tools to enable more accurate prediction so as to avoid catastrophic failure in vivo. This paper presents an overview of fatigue fracture problems in metallic, polymeric and ceramic implant materials, looks at some recent techniques of testing and discusses the future development of fracture and wear resistant biomaterials.