Imperial College London


Faculty of EngineeringDepartment of Materials

Vice-Dean (Research), Faculty of Engineering



+44 (0)20 7594 6755m.p.ryan




B338Royal School of MinesSouth Kensington Campus






BibTex format

author = {Koronfel, MA and Goode, AE and Weker, JN and Tay, SER and Stitt, CA and Simoes, TA and Mosselmans, JFW and Quinn, P and Brydson, R and Hart, A and Toney, MF and Porter, AE and Ryan, MP},
doi = {10.1038/s41529-018-0029-2},
journal = {npj Materials Degradation},
title = {Understanding the reactivity of CoCrMo-implant wear particles},
url = {},
volume = {2},
year = {2018}

RIS format (EndNote, RefMan)

AB - 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.
AU - Koronfel,MA
AU - Goode,AE
AU - Weker,JN
AU - Tay,SER
AU - Stitt,CA
AU - Simoes,TA
AU - Mosselmans,JFW
AU - Quinn,P
AU - Brydson,R
AU - Hart,A
AU - Toney,MF
AU - Porter,AE
AU - Ryan,MP
DO - 10.1038/s41529-018-0029-2
PY - 2018///
SN - 2397-2106
TI - Understanding the reactivity of CoCrMo-implant wear particles
T2 - npj Materials Degradation
UR -
UR -
VL - 2
ER -