Effect of random variation of input and various daily activities on wear in a hip joint simulator

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2020-06-09
Department
Department of Mechanical Engineering
Major/Subject
Mcode
Degree programme
Language
en
Pages
7
Series
Journal of Biomechanics, Volume 106
Abstract
The ISO 14242-1 standard specifies fixed, simplified, sinusoidal motion and double-peak load cycles for wear testing of total hip prostheses. In order to make the wear simulation more realistic, random variation was added for the first time to the motion and load control signals of a hip joint simulator. For this purpose and for the simulation of various daily activities, computer-controlled, servo-electric drives were mounted on a biaxial hip simulator frame and successfully introduced. Random variation did not result in a statistically significant difference in the wear factor of large diameter VEXLPE liners compared with fixed sinusoidal waveforms. However, level walking according to biomechanical literature surprisingly resulted in a 134 per cent higher, and jogging in a 57 per cent lower wear factor compared with the fixed sinusoidal waveforms. These wear phenomena were likely to be caused by a variation in the lubrication conditions and frictional heating. Simplified motion waveforms may result in an underestimation of wear in walking.
Description
Keywords
Computer-controlled hip simulator, Extensively cross-linked UHMWPE, Orthopedic biomechanics, Servo-drive, Wear of artificial joints
Other note
Citation
Viitala , R & Saikko , V 2020 , ' Effect of random variation of input and various daily activities on wear in a hip joint simulator ' , Journal of Biomechanics , vol. 106 , 109831 . https://doi.org/10.1016/j.jbiomech.2020.109831