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Does a micro-grooved trunnion stem surface finish improve fixation and reduce fretting wear at the taper junction of total hip replacements? A finite element evaluation

Lookup NU author(s): Dr Ariyan Ashkanfar, Professor Tom Joyce

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

Abstract

© 2017 Elsevier Ltd. The generation of particulate debris at the taper junction of total hip replacements (THRs), can cause failure of the artificial hip. The taper surfaces of femoral heads and trunnions of femoral stems are generally machined to a certain roughness to enhance fixation. However, the effect of the surface roughness of these surfaces on the fixation, wear and consequently clinical outcomes of the design is largely unknown. In this study, we asked whether a micro-grooved trunnion surface finish (1) improves the fixation and (2) reduces the wear rate at the taper junction of THRs. We used 3D finite element (FE) models of THRs to, firstly, investigate the effect of initial fixation of a Cobalt-Chromium femoral head with a smooth taper surface mated with a Titanium (1) micro-grooved and (2) smooth, trunnion surface finishes. Secondly, we used a computational FE wear model to compare the wear evolution between the models, which was then validated against wear measurements of the taper surface of explanted femoral heads. The fixation at the taper junction was found to be better for the smooth couplings. Over a 7 million load cycle analysis in-silico, the linear wear depth and the total material loss was around 3.2 and 1.4 times higher for the femoral heads mated with micro-grooved trunnions. It was therefore concluded that smooth taper and trunnion surfaces will provide better fixation at the taper junction and reduce the volumetric wear rates.

Publication metadata

Author(s): Ashkanfar A, Langton DJ, Joyce TJ

Publication type: Article

Publication status: Published

Journal: Journal of Biomechanics

Year: 2017

Volume: 63

Pages: 47-54

Print publication date: 03/10/2017

Online publication date: 10/08/2017

Acceptance date: 29/07/2017

Date deposited: 16/12/2017

ISSN (print): 0021-9290

ISSN (electronic): 1873-2380

Publisher: Elsevier Ltd

URL: https://doi.org/10.1016/j.jbiomech.2017.07.027

DOI: 10.1016/j.jbiomech.2017.07.027

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