Fractography of a neck failure in a double-modular hip implant

• Ti–6Al–4V implants are susceptible to crevice-corrosion because of fluid penetration.
• Furthermore, the load used during surgery to press-fit the tapered joint together appears to be inadequate, since fretting damage has also been commonly observed.
• The combination of fretting and crevice-corrosion significantly reduces the fatigue strength of the Ti–6Al–4V neck in double-modular hip implants.

The tapered joints of modular hip implants are prone to fretting and crevice-corrosion. This can lead to total failure in under a year, especially for heavier, more active implant recipients. In this study, fractography of a failed Profemur Z implant showed that a life limiting fatigue crack was nucleated on the anterolateral surface of the implant's neck. The fatigue crack nucleation area appeared to have both more fretting damage and a higher corrosion rate than on other surfaces of the neck.