Understanding the reactivity of CoCrMo-implant wear particles
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
CoCrMo-based metal-on-metal hip implants experienced unexpectedly high failure rates despite the high wear and corrosion resistance of the bulk material. Although they exhibit a lower volumetric wear compared to other implant materials, CoCrMo-based implants produced a significantly larger 'number' of smaller wear particles. CoCrMo is nominally an extremely stable material with high Cr content providing passivity. However, despite the Co:Cr ratio in the original alloy being 2:1; chemical analyses of wear particles from periprosthetic tissue have found the particles to be composed predominately of Cr species, with only trace amounts of Co remaining. Here a correlative spectroscopy and microscopy approach has shown that these particles dissolve via a non-stoichiometric, and geometrically inhomogeneous, mechanism similar to de-alloying. This mechanism is previously unreported for this material and was not apparent in any of the regulatory required tests, suggesting that such tests are insufficiently discriminating.
Date Issued
2018-03-12
Date Acceptance
2018-01-18
Citation
npj Materials Degradation, 2018, 2 (1)
ISSN
2397-2106
Publisher
Nature Research (part of Springer Nature)
Journal / Book Title
npj Materials Degradation
Volume
2
Issue
1
Copyright Statement
© The Author(s) 2018. This article is licensed under a Creative CommonsAttribution 4.0 International License, which permits use, sharing,adaptation, distribution and reproduction in any medium or format, as long as you giveappropriate credit to the original author(s) and the source, provide a link to the CreativeCommons license, and indicate if changes were made. The images or other third partymaterial in this article are included in the article’s Creative Commons license, unlessindicated otherwise in a credit line to the material. If material is not included in thearticle’s Creative Commons license and your intended use is not permitted by statutoryregulation or exceeds the permitted use, you will need to obtain permission directlyfrom the copyright holder. To view a copy of this license, visithttp://creativecommons.org/licenses/by/4.0/
License URL
Sponsor
Commission of the European Communities
Grant Number
ERC-2010-StG-20091028
Publication Status
Published
Article Number
ARTN 8
Date Publish Online
2018-03-12