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

Abstract

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.

Effect of wear, acetabular cup inclination angle, load and serum degradation on the friction of a large diameter metal-on-metal hip prosthesis

“…2 of test 2 from (Saikko, 2016a). Hence, the test was a continuation of the earlier, adverse condition, 3 million cycle wear test with a 3 kN peak load, in which the wear rate was as high as 150 mg/10 6 cycles.…”

“…Two different load profiles were used so that the peak load value was either 2 kN or 3 kN (Saikko, 2015;Saikko, 2016a). The former was considered a normal value, and the latter an increased value caused by obesity (Bergmann et al, 2001;Bergmann et al, 2010).…”

“…High friction is also likely to coincide with high wear. Therefore, friction measurement was added to an established, multidirectional HUT-4 hip joint simulator used earlier in MoM wear studies (Saikko, 2005;Saikko et al, 2013;Saikko, 2015;Saikko, 2016a).…”

Tribocorrosion of hard-on-hard total hip replacements with metal and ceramic counterfaces under standard and adverse loading conditions

“…Saikko [30] demonstrated that under adverse loading conditions the gravimetric wear rate was not able to show a difference in performance of simulator tested hard-on-hard bearings unless the testing conditions passed a so-V et al [31] have also shown evidence of material degradation in hard-on-hard bearings with AgCrN coatings, despite no visible damage or gravimetric mass loss. Changes of the sliding regime to anything representing less than ideal conditions (i.e.…”

“…As discussed, the industry and research community are becoming increasingly interested in the effects of adverse loading situations and daily living activities on the performance of total hip replacements [23,24,30,31]. A continuous simple twin-peak profile may not be the best method for assessing these devices before they are implanted in patients.…”