CHONDROPROTECTIVE EFFECTS OF A POLYCARBONATE-URETHANE MENISCAL IMPLANT: SEMI-QUANTITATIVE RESULTS IN A SHEEP MODEL

摘要

The menisci play a critical role in load-bearing and stability of the knee joint [1]. Damage or removal of the meniscus leads to alterations in the magnitude and distribution of stresses in the knee, which have been associated with degenerative osteoarthritis [2]. Clearly, there remains a need to develop means of protecting the articular cartilage following meniscal injury by either repairing or replacing the menisci. While allograft meniscal replacements can improve joint stability and function, they often provide little benefit in preventing osteoarthritic changes [3]. The development of an artificial meniscus that is available at the time of surgery in several sizes that can accommodate most patients would provide important therapeutic potential for treatment meniscal injury. A novel Polycarbonate-Urethane (PCU) meniscal implant (Fig. 1) has been developed to meet these requirements. PCU is an elastic yet tough material with a high resistance to tear, providing an attractive material for this application since it offers excellent mechanical and tribological properties comparable to those of natural cartilage [4]. Though explored in other biomedical applications against metal bearing surfaces, no data exists on the performance of PCU against articular cartilage under load. We hypothesized that an artificial PCU meniscus could provide a protective effect on the underlying cartilage subject to joint loading. Initial results of this study, including gross inspection and qualitative assessment of the underlying cartilage, were presented previously [5]. In this study, we evaluated the histological changes in the knee in a semi-quantitative approach, using a modified Mankin grading scale [6]. Thus, we aim to substantiate our hypothesis that a PCU meniscal implant can prevent or delay degenerative changes in the post-meniscectomized knee.