Papers by Author: Christian Kaddick

Abstract: Wear of the articulation partners in artificial joints for hip or knee is known to influence the in vivo survival rate of the implants. Wear amount can be strongly increased if third body wear occurs in the joint gap. Alumina ceramic is noted for a good wear resistance even under these worst case conditions. We tested the wear behaviour of the new dispersion ceramics ZTA (Zirconia Toughened Alumina) and ATZ (Alumina Toughened Zirconia) in comparison to alumina for the couplings ceramic on PE and ceramic on ceramic in a hip joint simulator in presence of third body particles.

Abstract: Wear of hip implants is a significant problem for the life expectancy of artificial joints. By using alumina ceramic on ceramic couplings the wear can be decreased. But for further improvement of the safety of THR the aim is the development of new ceramic materials. For orthopaedic applications an Alumina Toughened Zirconia Ceramic ATZ (80% ZrO2-20%Al2O3) and a Zirconia Toughened Alumina ZTA (25% ZrO2-75%Al2O3) were tested regarding their tribological behaviour by means of hip simulator testing after hydrothermal treatment. The absolute wear amount for the aged samples after 5 million cycles is slightly increased on a very low level, but even less wear than for common alumina pairings. In consideration of these excellent results both dispersion ceramics are highly suitable for long term applications.

Abstract: Alumina and zirconia have been used for hip joint prostheses for decades. With mixtures of both materials (ZTA and ATZ) mechanical strength can be increased. The resistance against damaging of the surface of the ceramic articulation partners head and liner was investigated using a special luxation apparatus (PI-3:1997-07, Endolab GmbH, Thansau, Germany). Both new ceramic materials ZTA and ATZ showed a better resistance against roughening and damaging of the stressed surface areas during the luxation test compared to alumina.

Abstract: It is well known, that wear of the articulation partners of hip joint prostheses affect the long-term durability of the implants in vivo. The wear is dramatically increased if particles in the artificial joint gap act as third body. Those particles can also occur after a fracture of a ceramic component. Until now there are some different guidelines which coupling (metal-polyethylene, ceramic-polyethylene, ceramic-ceramic) should be used for revision. We tested and compared the wear behaviour of a ceramic-PE-pairing and a ceramic-ceramic-pairing under third body wear conditions with alumina-particles in a hip joint simulator.