Koronfel, MA, Goode, AE, Gomez-Gonzalez, MA et al. (8 more authors) (2019) Chemical Evolution of CoCrMo Wear Particles: An in Situ Characterization Study. Journal of Physical Chemistry C, 123 (15). pp. 9894-9901. ISSN 1932-7447
Abstract
The unexpected high failure rates of CoCrMo hip implants are associated with the release of a large number of inflammatory wear particles. CoCrMo is nominally a stable material; however, previous chemical speciation studies on CoCrMo wear particles obtained from periprosthetic tissue revealed only trace amounts of Co remaining despite Co being the major component of the alloy. The unexpected high levels of Co dissolution in vivo raised significant clinical concerns particularly related to the Cr speciation in the dissolution process. At high electrochemical potentials, the alloy’s Cr-rich passive film breaks down (transpassive polarization), facilitating alloy dissolution. The potential release of the carcinogenic Cr(VI) species in vivo has been a subject of debate. While the large-scale Co dissolution observed on in vivo produced particles could indicate a highly oxidizing in vivo environment, Cr(VI) species were not previously detected in periprosthetic tissue samples (except in the specific case of post-mortem tissue of diabetic patients). However, Cr(VI) is likely to be an unstable (transient) species in biological environments, and studies on periprosthetic tissue do not provide information about intermediate reaction products or the exposure history of the wear particles. Here, an in situ spectromicroscopy approach was developed, utilizing the high chemical resolution of synchrotron radiation, to study CoCrMo reactivity as a function of time and oxidizing conditions. The results reveal limited Co dissolution from CoCrMo particles, which increases dramatically at a critical electrochemical potential. Furthermore, in situ XAS detected only Cr(III) dissolution, even at potentials where Cr(VI) is known to be produced, suggesting that Cr(VI) species are extremely transient in simulated biological environments where the oxidation zone is small.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © 2019 American Chemical Society. This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in Journal of Physical Chemistry C, To access the final edited and published work see https://doi.org/10.1021/acs.jpcc.9b00745 |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) |
Funding Information: | Funder Grant number EPSRC EP/M028143/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 13 Jun 2019 14:21 |
Last Modified: | 01 Apr 2020 00:38 |
Status: | Published |
Publisher: | American Chemical Society |
Identification Number: | 10.1021/acs.jpcc.9b00745 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:147179 |