[Material-specific wear of ceramic/ceramic sliding surfaces in revised hip endoprostheses--clinical and technological considerations].

After more than 8 years of "in-vivo"-experience with ceramic bearing surfaces in hip endoprostheses clinical and tribological aspects of damage-analysis in 29 cases of retrieved Al2O3 prostheses are performed. The balls and sockets are investigated in view of wear-quantification by relative metric determination and wear-quantification by SCAN-microscopy. In 2/3 of all cases the microstructure average grain standard was superelevated. As hypothesis of the destruction mechanism an avalanche-like acceleration of grain-excavations is discussed.