SEDL / STP / STP1346-EB / STP12836S

Clinical Wear Performance of Metal-on-Metal Hip Arthroplasties

Rieker, CB
Research scientists, Sulzer Orthopedics, Winterthur,

Köttig, P
Research scientists, Sulzer Orthopedics, Winterthur,

Schön, R
Research scientists, Sulzer Orthopedics, Winterthur,

Windler, M
Research scientists, Sulzer Orthopedics, Winterthur,

Wyss, UP
Research manager, Sulzer Orthopedics, Winterthur,

Pages: 13    Published: Jan 1998

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Abstract

Thirty old (1^st generation) Cobalt-Chromium metal-on-metal (Müller design) hip components and 83 new (2^nd generation) Cobalt-Chromium metal-on-metal (METASUL™ design) hip components were examined for their in-vivo wear behaviour. The in-vivo wear behaviour of these retrievals was compared with their in-vitro wear behaviour. A running-in period of about one year is observed where the in-vivo wear rate for the whole bearing is approximately 25 μm/year. After this running-in period, the measured in-vivo wear rate of the whole bearing decreases to about 5 μm/year. A very good consistency is found between the in-vitro and in-vivo wear rate. The examination of the wear pattern shows abrasive wear for all the prostheses and some adhesive-fatigue wear areas for 10 per cent of the prostheses. The observed wear rate is independent of the wear mechanisms.

The metal-on-metal bearing can be considered as a very low wear articulation system.