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Wear and surface analysis of 38 mm ceramic-on-metal total hip replacements under standard and severe wear testing conditions

Williams, S.R.; Wu, J.J.; Unsworth, A.; Khan, I.

Authors

S.R. Williams

Profile image of Junjie Wu

Junjie Wu junjie.wu@durham.ac.uk
Honorary Professor

A. Unsworth

I. Khan



Abstract

The purpose of this study was to compare the wear of zirconia-toughened alumina (ZTA) and alumina femoral heads tested against as-cast CoCrMo alloy acetabular cups under both standard and severe wear conditions. A new severe test, which included medio-lateral displacement of the head and rim impact upon relocation, was developed. This resulted in an area of metal transfer and an area of increased wear on the superior-anterior segment of the head that were thought to be due to dislocation and rim impact respectively. While the wear of all ceramic heads was immeasurable using the gravimetric method, the wear rates for the metallic cups from each test were readily calculated. An average steady state wear rate of 0.023 ± 0.005 mm3/106 cycles was found for the cups articulating against ZTA under standard wear conditions. A similar result had previously been obtained for the wear of cups articulated against alumina heads of the same size (within the same laboratory). Under severe wear conditions an increase in the metallic cup steady state wear rate was found with the ZTA and alumina tests giving 0.623 ± 0.252 and 1.35 ± 0.154 mm3/106 cycles respectively. Wear of the ceramic heads was detected using atomic force microscopy which showed, under severe wear conditions, a decrease in polishing marks and occasional grain removal. The surfaces of the ZTA heads tested under standard conditions were virtually unchanged from the unworn samples. Friction tests showed low friction factors for all components, pre and post wear.

Citation

Williams, S., Wu, J., Unsworth, A., & Khan, I. (2011). Wear and surface analysis of 38 mm ceramic-on-metal total hip replacements under standard and severe wear testing conditions. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 225(8), 783-796. https://doi.org/10.1177/0954411911404773

Journal Article Type Article
Acceptance Date Jan 17, 2011
Online Publication Date Jun 2, 2011
Publication Date 2011-08
Deposit Date Jan 4, 2012
Journal Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine
Print ISSN 0954-4119
Electronic ISSN 2041-3033
Publisher SAGE Publications
Peer Reviewed Peer Reviewed
Volume 225
Issue 8
Pages 783-796
DOI https://doi.org/10.1177/0954411911404773
Public URL https://durham-repository.worktribe.com/output/1523506