Large diameter chrome cobalt modular heads in hip replacement surgery have caused one of the biggest challenges to face orthopaedic surgeons, manufacturers and regulators in a generation. Increasing numbers of retrieved implants offer the opportunity to look in detail at the modes of failure of these devices. We have examined the mechanical behaviour of the head taper/trunnion using a variety of techniques including:
mechanical testing in a custom-made jig 3D nano-precision form profilometry (RedLux) optical 3D microscopy with focus variation technology electro-chemical testing.Background
Methods