SYMPOSIA PAPER Published: 01 January 1999
STP14274S

Metal-On-Metal Hip Replacements: Wear Performance and Cellular Response To Wear Particles

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This study examined the clinical wear performance of second-generation metal-on-metal (M-M) total hips and evaluated the cellular reaction to, and characteristics of, the wear particles. Twenty cobalt chrome (CoCr) M-M THRs were studied, including ten Metasul conventional total hips (THRs), and ten McMinn surface replacements (SRs). As in the first-generation M-M hips, wear ranged from undetectable to 32 μm in the SR femoral shells (ave 15.7 ± 14 μm) and from undetectable to 19 μm in the THR balls (ave 10.1 ± 7 μm). Self-polishing of third body scratches was evident. Two THRs exhibited clusters of micropits, which had been described on first-generation M-M hips but these did not appear to correlate with accelerated wear. CoCr particles were either dense or amorphous and were mostly in the nanometer size range. There were generally fewer macrophages in the tissues than seen with M-PE THRs, and there was a more inflammatory response to bone cement particles compared with metal particles. Nevertheless, the long-term response to these very small CoCr particles should be monitored.

Author Information

Campbell, P
Implant Retrieval Laboratory, Joint Replacement Institute, Orthopaedic Hospital, Los Angeles, CA
McKellop, H
Orthopaedic Hospital, Los Angeles, CA
Alim, R
University of Southern California, Los Angeles, CA
Mirra, J
Orthopaedic Hospital, Los Angeles, CA
Nutt, S
University of Southern California, Los Angeles, CA
Dorr, L
University of Southern California, Los Angeles, CA
Amstutz, HC
Joint Replacement Institute, Orthopaedic Hospital, Los Angeles, CA
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Details
Developed by Committee: F04
Pages: 193–209
DOI: 10.1520/STP14274S
ISBN-EB: 978-0-8031-5409-4
ISBN-13: 978-0-8031-2608-4