The wear of cross-linked polyethylene against itself.
Cross-linked polyethylene (XLPE) may have an application as a material for an all-plastic surface replacement finger joint. It is inexpensive, biocompatible and can be injection-moulded into the complex shapes that are found on the ends of the finger bones. Further, the cross-linking of polyethylene has significantly improved its mechanical properties. Therefore, the opportunity exists for an all-XLPE joint, and so the wear characteristics of XLPE sliding against itself have been investigated. Wear tests were carried out on both reciprocating pin-on-plate machines and a finger function simulator. The reciprocating pin-on-plate machines had pins loaded at 10 N and 40 N. All pin-on-plate tests show wear factors from the plates very much greater than those of the pins. After 349 km of sliding, a mean wear factor of 0.46 x 10(-6) mm3/N m was found for the plates compared with 0.021 x 10(-6) mm3/N m for the pins. A fatigue mechanism may be causing this phenomenon of greater plate wear. Tests using the finger function simulator give an average wear rate of 0.22 x 10(-6) mm3/N m after 368 km. This sliding distance is equivalent to 12.5 years of use in vivo. The wear factors found were comparable with those of ultra-high molecular weight polyethylene (UHMWPE) against a metallic counterface and, therefore, as the loads across the finger joint are much less than those across the knee or the hip, it is probable that an all-XLPE finger joint will be viable from a wear point of view.
Joyce
T J
TJ
Centre for Biomedical Engineering, School of Engineering, University of Durham.
Ash
H E
HE
Unsworth
A
A
D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D005384:Finger Joint / Q000502:physiology; D006801:Humans; D007595:Joint Prosthesis; D008422:Materials Testing; D008954:Models, Biological; D011095:Polyethylenes; D011474:Prosthesis Design; D011475:Prosthesis Failure; D013499:Surface Properties; D016474:Weight-Bearing / Q000502:physiology
D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D011095:Polyethylenes