Development of an artificial meniscus using polyvinyl alcohol-hydrogel for early return to, and continuance of, athletic life in sportspersons with severe meniscus injury. II: animal experiments.

Due to the prognosis and sporting needs of young athletes who have severe meniscus injury, we have developed an artificial meniscus using polyvinyl alcohol-hydrogel (PVA-H). Biomechanical studies have shown that the human meniscus has various mechanical functions; in our mechanical tests, specimens of human meniscus (part I of this study) demonstrated unique viscoelastic properties. Those tests also showed that a high water-content PVA-H has very similar mechanical properties to those of human meniscus and potential as a substitutive meniscus implant. To assess further the use of PVA-H as an artificial meniscus, we have now performed animal experiments using a PVA-H with 90% water content. In rabbits, the lateral meniscus was replaced with an artificial meniscus in one knee of each animal and lateral meniscectomy was performed on the other side as a control. In the knees of meniscectomy group, degenerative changes in articular cartilage progressed with time and osteoarthritis was observed after 1 year. In the knees of the artificial meniscus group, regressive changes were initially observed, but did not progress, and knee joint function was good even after 1 year. Neither wear nor breakage were observed in artificial menisci. These results suggest that an artificial meniscus using a high water-content PVA-H might be clinically applicable.