Wear comparison between a dual mobility total hip prosthesis and a typical modular design using a hip joint simulator

Tribology International

2016

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This is an electronic reprint of the original article. This reprint may differ from the original in pagination and typographic detail. Author(s):Saikko, Vesa Title: Effect of increased load on the wear of a large diameter metal-on-metal modular hip prosthesis with a high inclination angle of the acetabular cup All material supplied via Aaltodoc is protected by copyright and other intellectual property rights, and duplication or sale of all or part of any of the repository collections is not permitted, except that material may be duplicated by you for your research use or educational purposes in electronic or print form. You must obtain permission for any other use. Electronic or print copies may not be offered, whether for sale or otherwise to anyone who is not an authorised user. AbstractIn some earlier hip simulator studies of large-diameter metal-on-metal (MoM) hip prostheses high, unexplained variation in wear has been observed. In the present study it was found that high variation occurs when the tribological endurance limit of the MoM device in question is being approached. When the limit is exceeded, high wear takes place uniformly, and the variation is low. Below the limit, both the wear and its variation are low. The endurance limit was exceeded by increasing the peak load from 2 kN to 3 kN, to simulate obesity. The acetabular cup inclination angle was high, 70°. Potential clinical wear problems can be predicted by hip simulator studies provided that relevant adverse test conditions are included.

Section: Discussionmentioning

confidence: 99%

Effect of increased load on the wear of a large diameter metal-on-metal modular hip prosthesis with a high inclination angle of the acetabular cup

Tribology International

2016

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“…Wear of conventional UHMWPE inserts of total hip prostheses has been found to be insensitive to the inlination angle of the cup, 48° vs. 60° [21]. With large-diameter MoM however, the wear increased steeply with increasing angle [15].…”

Section: Discussionmentioning

confidence: 99%

Adverse condition testing with hip simulators

2015

Biotribology

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Recent clinical failures and abnormal sounds observed in certain prosthetic hip designs have directed attention to adverse condition hip simulator testing. In the present study, hip simulator wear and friction tests were made with a macroscopic separation of the bearing surfaces in the swing phase, steep acetabular cup position, increased load, poor or lacking lubrication, roughened bearing surfaces including titanium third bodies, and with combinations of these. The only conditions that resulted in squeaking were dry sliding with alumina-on-alumina and metal-on-metal, and an extreme peak load of 4 kN with serum lubricated metal-on-metal. The wear rate of metal-on-metal increased by an order of magnitude when the cup position was steep, 64 degrees, compared with the optimal position of 48 degrees. The increase of the peak load from 2 kN to 3 kN with the cup position of 48 degrees increased the running-in wear of metal-on-metal, but the steady state wear rates were equally low, of the order of 1 mg per one million cycles. Crosslinked polyethylene was the superior cup material under adverse conditions, including dry sliding and roughened femoral head.

“…Another recent validation of the HUT-4 was the fact that a steep angle (60°) did not increase the wear of the polyethylene cup [19]. In the future, the available hip simulator capacity should definitely be utilized more systematically for thorough evaluations of new designs prior to clinical trials so that the likelihood of clinical disasters could be reduced.…”

Section: Discussionmentioning

confidence: 99%

The effect of acetabular cup position on wear of a large-diameter metal-on-metal prosthesis studied with a hip joint simulator

Tribology International

Ahlroos

Revitzer

et al. 2013

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All material supplied via Aaltodoc is protected by copyright and other intellectual property rights, and duplication or sale of all or part of any of the repository collections is not permitted, except that material may be duplicated by you for your research use or educational purposes in electronic or print form. You must obtain permission for any other use. Electronic or print copies may not be offered, whether for sale or otherwise to anyone who is not an authorised user. CoCr-on-CoCr prostheses were run in the HUT-4 hip joint simulator so that a steep angle was included. With a correct position, the tribological behaviour was excellent, the wear rate being 0.1 mm 3 /10 6 cycles. In the steepest position, lubrication failed and the wear rate was two orders of magnitude higher. This study stresses the importance of rigorous pre-clinical testing.