Menisci are fibrocartilagenous structures in the knee joint that act to distribute the load from the femur to the tibia. Menisci are frequently torn as a result of sporting activity or degenerative tears associated with aging. Approximately 12.5% of annual visits to orthopedic surgeons are related to knee injury, and of those visits, 43% are directly related to meniscal injuries (see review by McBride and Reid, 1988). Some tears do not heal because they either occur in the avascular region of the meniscus or are too complex for repair. Therefore, the common treatment for these types of tears is either complete or partial meniscectomy depending on the severity of the tear. However, meniscectomies have been shown to lead to degenerative arthritis in the knee. Therefore, in an effort to prevent premature arthritis caused by removal of the meniscus or a portion of the meniscus, meniscal replacement strategies are being investigated.

This article will detail the basic structure and function of meniscal tissue and the attachments of the menisci to the surrounding structures. The strengths and weaknesses of various meniscal replacement strategies will be discussed, including autografts, meniscal allografts, synthetic prosthesis, and tissue-engineered constructs. The success of meniscal replacements likely depends on their ability to restore normal meniscal function both biologically and biomechanically. Previous studies indicate that a number of biomechanical criteria are important for proper meniscal function, such as the material properties and geometry of the replacement tissue as well as the attachment of the replacement to the tibial plateau.