A novel ultra high molecular weight polyethylene-hyaluronan microcomposite for use in total joint replacements. II. Mechanical and tribological property evaluation.

The mechanical and tribological properties of a new biomaterial, an ultra high molecular weight polyethylene-hyaluronan (UHMWPE-HA) microcomposite, were investigated in this article, which is Part II of a two-part study. Part I presented the synthesis and physical/chemical characterization of the novel microcomposites. The microcomposite was developed for bearing surfaces of total joint replacements and was designed to enhance lubrication and improve wear resistance compared to noncrosslinked UHMWPE. Pin-on-flat wear tests with cross-path motion demonstrated significant decreases for both the wear and wear rate of UHMWPE with the presence of hyaluronan (HA) within and on the microcomposite. Compared to noncrosslinked UHMWPE, a maximum decrease of 56% in wear and a maximum decrease of 31% in wear rate were observed at 1.0 million cycles. Inferior tensile properties were observed for the microcomposites when compared to noncrosslinked UHMWPE, which resulted from poor intermolecular entanglement of the UHMWPE caused by low remolding temperature throughout microcomposite manufacturing. Similar results were observed for the sham control, which was processed in the same way as the microcomposite, except for the addition of HA.