Toggle Main Menu Toggle Search

Open Access padlockePrints

Explant analysis of a Maestro™ wrist prosthesis and calculation of its lubrication regime

Lookup NU author(s): Goksu KandemirORCiD, Dr Simon Smith, Professor Tom Joyce



This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).


© 2020 Elsevier LtdExplant analysis can provide key insights to understanding failures of artificial joints and thus how they might be improved for the ultimate benefit of patients. There are no previous reports of explant analysis of an artificial wrist joint. In this study, an explanted metal-on-polymer Maestro wrist was analysed both in macro and nanoscales to estimate its biotribological performance. The articulation was formed between a cobalt chromium carpal head and an ultrahigh molecular weight polyethylene bearing. The surface roughness values of its articulating surfaces and the backside of the articulation were measured. On average, the articulating surface roughness values were calculated as 0.06 ± 0.02 μm and 1.29 ± 0.63 μm for the cobalt chromium carpal head and ultrahigh molecular weight polyethylene bearing, respectively. Both surfaces had negative skewness, indicating a preponderance of valleys. On the articulating surface of the carpal head, light scratches were observed, and no impingement was observed throughout the component. The polymeric surface had a polished appearance. It had unidirectional scratches at the centre of the articulation, pits of different sizes on its articulating surface, and matt white subsurface regions. The backside of the UHMWPE bearing and the convex surface of the radial body that it was sitting on, were found to have average surface roughness values of 4.23 ± 0.69 μm and 5.57 ± 1.05 μm, respectively. The difference in the means was not significant (p > 0.05). Taking the articulating surface roughness values, the lubrication regime that the explanted Maestro wrist operated under in vivo was estimated for varying physiological conditions, i.e. varying loads, entraining velocities and lubricant viscosities. In every case considered, the explant was found to operate under boundary lubrication.

Publication metadata

Author(s): Kandemir G, Smith S, Schmidt I, Joyce TJ

Publication type: Article

Publication status: Published

Journal: Journal of the Mechanical Behavior of Biomedical Materials

Year: 2020

Volume: 110

Print publication date: 01/10/2020

Online publication date: 03/07/2020

Acceptance date: 10/06/2020

Date deposited: 20/08/2020

ISSN (print): 1751-6161

ISSN (electronic): 1878-0180

Publisher: Elsevier Ltd


DOI: 10.1016/j.jmbbm.2020.103933


Altmetrics provided by Altmetric