Tribological Properties of Poly(vinyl alcohol) Hydrogel in Response to Ceramic Femoral Component

Many biomaterials have been proposed as artificial articular cartilage in partial or total joint replacement. Poly(vinyl alcohol) (PVA) hydrogel is a kind of artificial cartilage and it exhibits excellent mechanical and biocompatibility properties. In this study, the friction tests under reciprocating motion were conducted to determine the tribological properties of PVA hydrogel in response to ceramic femoral component. The friction coefficient testing of PVA hydrogel against ceramic femoral component was performed by a three-factor, two-level designed experiment. The three factors studied were load, lubrication and sliding speed. Longer term friction tests were conducted under constant load and cyclic load to evaluate friction variations in 30 min. The friction coefficient between PVA hydrogel and ceramic femoral component was found to depend significantly on load, lubrication and sliding speed. The friction coefficient increased as load and sliding speed increased. The friction coefficient decreased when the lubricant was changed from Ringer s solution (RS) to hyaluronic acid (HA). In longer term tests, the friction coefficient in constant load tests was significantly lower that in cyclic load tests. The wear of PVA hydrogel under constant load was identified by environmental scanning electron microscopy (ESEM). It is indicated that the biphasic lubrication property is the key feature for PVA hydrogel. These results may be useful in the tribological design of artificial cartilage in joint replacement.