Morphological Difference of Polyethylene Section in Knee Arthroplasty

ABSTRACT

The purpose of this study is to see the value of transsectional morphology of polyethylene for evaluation of wear and characteristics of ultra-high molecular weight polyethylene. Retrieved nineteen polyeth- ylene tibial components were examined for this study. Ten components were the directly molded 1900 Himont polyethylene, and 9 components were the machined GUR 415 polyethylene. Transsection of polyethylene(thickness 60 - 150 micron) was obtained by microtome and was examined microscopical- ly for the fusion defects, subsurface white bands, and delamination as a mode of wear. Significant differ- ences between two groups of polyethylene were found. Fusion defects greater than 100 micron were observed in 5 among 9 GUR 415 polyethylene. Subsurface white band were observed in 7 among 9 GUR 415 polyethylene. Delamination was found in 6 arnong 9 GUR 415 polyethylene. Neither fusion defects greater than 100 micron, nor delamination were observed in 1900 Himont polyethylene. Morphological examination of polyethylene section is an efficient way to differentiate the polyethylene and to evaluate the wear behavior of retrieved polyethylene. This study suggests that delamination of polyethylene tibial components is influenced by resin type and / or manufacturing method.