Menisci function to distribution load and increase stability of the knee joint. Both partial and complete meniscectomy have been shown to increase the incidence of osteoarthritis. Meniscal replacement with allograft, synthetic or tissue engineered replacements, could act to reduce the incidences of osteoarthritis. The success of meniscal replacements 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. The goals of this project are to quantify the relationship between structure and function for meniscal attachments, and to define a more sophisticated constitutive model of the attachments. Specifically this project will 1) determine the mechanical properties of the anterior and posterior medial meniscal attachments, 2) quantify the thickness of the ligamentous, uncalcified fibrocartilage, calcified fibrocartilage and subchondral bone zones in the meniscal attachments, as well as the depth, number and frequency of interdigitations between the calcified fibrocartilage and subchondral bone. The glycosaminoglycan and collagen orientation within the attachments will also be determined. Lastly, the project will 3) model the attachments as fiber-reinforced poroelastic to predict the behavior of the attachments. The results of these Aims will then be used to quantify a relationship between the structure and function of the native meniscal attachments. This data can then be used to develop, design and evaluate meniscal replacements, including tissue engineered constructs. A successful meniscal replacements will work to prevent joint degeneration following menisectomy.