Wear simulation of UHMWPE for total hip replacement with a multidirectional motion pin-on-disk device: Effects of counterface material, contact area,and lubricant
V. Saikko et T. Ahlroos, Wear simulation of UHMWPE for total hip replacement with a multidirectional motion pin-on-disk device: Effects of counterface material, contact area,and lubricant, J BIOMED MR, 49(2), 2000, pp. 147-154
The wear of nonirradiated ultra-high molecular weight polyethylene (UHMWPE)
was studied with a circularly translating pin-on-disk (CTPOD) device. With
this simple device, the wear of the acetabular cup is simulated. Two shape
s of a polyethylene pin were used: flat wear faces of 3.0 and 8.9 mm in dia
meter. The load was always 70.7 N. Tests were done against stainless steel
plates in serum, albumin, and gamma-globulin lubricants and against alumina
plates in serum. With 3.0-mm-in-diameter wear faces, the wear factors were
an order of magnitude lower than the average clinical wear factors of poly
ethylene acetabular cups. With 8.9-mm-in-diameter wear faces, the wear fact
ors and wear mechanisms were consistent with clinical ones. The mean wear f
actor against stainless steel in serum was 1.46 times higher than that agai
nst alumina, and the difference was statistically significant. The mean wea
r factors in albumin and gamma globulin were close to that in serum; the di
fferences were not statistically significant. The results indicate that alb
umin and gamma globulin are the fractions of synovia that influence the wea
r of polyethylene. A practical test parameter combination for the CTPOD dev
ice has new been established for future studies of modified and new materia
ls and of lubricants. (C) 2000 John Wiley & Sons, Inc.