current findings provide preliminary evidence for the ability of an artificial PCU meniscal implant to delay or prevent osteoarthritic changes in knee joint following complete medial meniscectomy.

The development of a synthetic meniscal implant that does not require surgical attachment but still provides the biomechanical function necessary for joint preservation would have important advantages. We present a computational-experimental approach for the design optimization of a free-floating polycarbonate-urethane (PCU) meniscal implant. Validated 3D finite element (FE) models of the knee and PCU-based implant were analyzed under physiological loads. The model was validated by comparing calculated pressures, determined from FE analysis to tibial plateau contact pressures measured in a cadaveric knee in vitro. Several models of the implant, some including embedded reinforcement fibers, were tested. An optimal implant configuration was then selected based on the ability to restore pressure distribution in the knee, manufacturability, and long-term safety. The optimal implant design entailed a PCU meniscus embedded with circumferential reinforcement made of polyethylene fibers. This selected design can be manufactured in various sizes, without risking its integrity under joint loads. Importantly, it produces an optimal pressure distribution, similar in shape and values to that of natural meniscus. We have shown that a fiber-reinforced, free-floating PCU meniscal implant can redistribute joint loads in a similar pattern to natural meniscus, without risking the integrity of the implant materials.

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.

The menisci play an important role in the knee joint biomechanics [1]. Clinical studies have shown that the loss of the meniscus leads to degenerative arthritis attributed to the changes in load distribution and the loss of proprioception [2]. Clearly, there is a substantial need to protect the articular cartilage by either repairing or replacing the menisci. There are many difficulties dealing with both fresh frozen or cryopreserved allograft menisci, and the complexities of meniscal repairs may contribute to uneven distribution of load, instability and recurrence of degenerative damage. Hence there is a need for the development of an artificial meniscus that is available at the time of surgery in several sizes that can accommodate most patients.

The medial meniscus plays an important role in the knee joint [1]. Meniscus dysfunction due to tear is a common knee injury which leads to degenerative arthritis, attributed primarily to the changes in knee load distribution [2]. Clearly, there is a substantial need to protect the articular cartilage by either repairing or replacing the menisci. A “floating” Polycarbonate-Urethane (PCU) meniscal implant (Fig. 1a) is proposed as a solution for restoring the function of the missing meniscus and for the reduction of pain, through improved tibial and femoral pressure distribution. The implant is composed of PCU embedded with polyethylene reinforcement fibers (“Dyneema®”, DSM), and its design is based on the geometry of the articulating surfaces of the femur and tibia. Our goal was to develop an optimal meniscal implant design (in terms of composition and geometry), whose contact pressure with the tibial plateau (TP) would be similar to that of the natural meniscus and be able resist mechanical failure of any of its components. We hereby present one aspect of the implant bench-tests, finite element (FE) analyses of the implant in the medial knee under physiological relevant loading conditions.