Modification of a Simplified Hip Joint Simulator Into an ISO 14242-1 Compliant Design and a Comparison of Wear Test Results

Vesa Saikko*, Omar Morad, Raine Viitala

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

3 Citations (Scopus)

Abstract

The ISO 14242-1 standard for hip joint simulator wear testing specifies a set of test conditions for the simulation of normal level walking in optimal conditions. Since some of the established simulators, such as the 12-station HUT-4, are not ISO 14242-1 compliant, the present study was carried out to answer the following question. Does wear produced in ISO 14242-1 conditions differ from that obtained earlier with the simplified HUT-4 hip joint simulator for similar specimens in normal level walking, optimal conditions? The established HUT-4 hip joint simulator was made ISO compliant by an implementation of a number of modifications. One of the modifications was the design and construction of a novel servo-electric load actuator with a proven dynamic response. The other modifications were related to the Euler sequence of motions, acetabular abduction angle, enclosure of the lubricant chamber, and temperature control. A 5 million-cycle wear test with thin, largediameter VEXLPE liners resulted in a wear rate close to that obtained earlier with the HUT-4. The burnished bearing surface in both tests was in agreement with clinical retrieval studies. It appeared that a more simple, inexpensive hip joint simulator can reproduce clinical wear mechanisms. However, the simulator must meet certain basic requirements. The most important of these is likely to be the correct type of multidirectional relative motion, for which biaxial motion is sufficient. It is emphasized that the present study was not intended to show a similarity in wear produced by the ISO 14242-1 and HUT-4 wear test systems.

Original languageEnglish
Article number051703
Number of pages8
JournalJournal of Tribology
Volume144
Issue number5
DOIs
Publication statusPublished - May 2022
MoE publication typeA1 Journal article-refereed

Keywords

  • artificial joints
  • biotribology
  • extensively cross-linked polyethylene
  • hip joint simulator
  • ISO 14242-1
  • sliding
  • total hip prosthesis
  • vitamin E stabilization
  • wear
  • wear mechanisms

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