Published online by Cambridge University Press: 22 February 2011
Fatigue phenomena of high-density alumina ceramic hip joint endoprosthesis with ceramic-to-ceramic articulating components were analyzed for retrieved ex-vivo objects and for in-vitro tests in hip-joint simulators. Scanning electron microscope investigations were employed. The cyclical compression between ball and cup causes severe shear stresses to form below the bearing surfaces. Locally changing subsurface maxima of contact stresses can generate fatigue cracks starting at subsurface microstructural defects and grain boundaries. The fatigue fractures are regarded as being identified with the tribological surfaces of the simulator specimens and of the ex-vivo prostheses retrieved because of fracture.