A study of polyvinyl alcohol-hydrogel (PVA-H) artificial meniscus in vivo

The importance of knee meniscus function is now recognized, and the treatment of meniscus injury has been changing from resection to repair. However, depending on the type of injury, meniscectomy sometimes cannot be avoided. In such case, it is important to anticipate the future problem of degenerative change or osteoarthrosis in knee joint. In future, auto-graph using regenerative meniscus will be developed by tissue engineering. However, even if it will be possible, considering the healing period, the young athlete with severe meniscus injury may select meniscectomy in order to return to sports life as early as possible avoiding the long immobilization or declining sports skill. In consideration of the prognosis and circumstances in such patients, we need a artificial meniscus for salvage. To assess further the use of polyvinyl alcohol-hydrogel (PVA-H) artificial meniscus, we performed some mechanical tests about PVA-H and animal experiment. In mechanical tests, we found that a high water content PVA-H showed viscoelastic behaviour similar to that of human meniscus. Moreover, the frictional coefficient of PVA-H against natural articular cartilage was also effective. In the animal experiment using rabbits, the lateral meniscus was replaced with an artificial meniscus in one knee side and lateral meniscectomy was performed in another knee side of each rabbit. We have already reported the results up to 1 year after operation, present study investigated the results in postoperative 1.5 years. In the results, the articular cartilage state of knee joint implanted PVA-H meniscus was good even after 1.5 years, while OA change progressed in meniscectomy knee joint. In addition, neither wear nor breakage of PVA-H was observed. These results proved that an artificial meniscus using a high water content PVA-H can compensate for meniscal function and might be clinically applicable.