D. Pienkowski et al., LOW-VOLTAGE SCANNING ELECTRON-MICROSCOPIC IMAGING OF ULTRAHIGH-MOLECULAR-WEIGHT POLYETHYLENE, Journal of biomedical materials research, 29(10), 1995, pp. 1167-1174
Submicron ultrahigh-molecular-weight polyethylene (UHMWPE) wear partic
les from total joint prostheses may contribute to implant failure thro
ugh particle-mediated aseptic loosening. The purpose of this study was
to examine the microstructure of virgin UHMWPE powder to determine it
s morphology for future comparison with wear debris. A new method of l
ow-voltage scanning electron microscopy (LVSEM) in an oil-free vacuum
was applied, which produced high-resolution images of UHMWPE micromorp
hology, while minimizing specimen damage and obviating the need for im
age processing. GUR 415 UHMWPE virgin powder particles were examined b
y using routine high-voltage SEM, LVSEM, and image analyses. LVSEM sho
wed that UHMWPE particles were composed of submicron-size spherical su
bparticles connected by numerous nanometer-size fibrils. These spheric
al subparticles had a highly textured surface morphology seen only by
LVSEM. Fracture of the nanometer-size fibrils was observed. Routine hi
gh-voltage SEM obfuscates the intricate and delicate UHMWPE micromorph
ology as well as the damage done by the accompanying high-voltage elec
trons. This study suggests that the micromorphology of wear particles
previously studied with routine high-voltage SEM was overlooked or dam
aged, justifies the need for LVSEM in future studies, and raises the q
uestion of what is the true morphology of polyethylene wear debris ret
rieved from human tissues. (C) 1995 John Wiley & Sons, Inc.