Functional And Structural Remodeling Of The Meniscus With Growth And Injury

Sonia Bansal, University of Pennsylvania


The meniscus is a unique and complex fibrocartilaginous tissue in the knee and plays a vital role in joint function. Unfortunately, there is a high prevalence of meniscal injury and subsequent joint degeneration. The healthy maturation and injury-related degeneration of the meniscus remodeling processes are related to the structure-function relationship present in the tissue. To first understand the remodeling of the meniscus with growth, meniscus explants were assessed structurally and functionally in fetal, juvenile, and adult joints. To determine tissue remodeling after injury, a large animal model of meniscus injury was developed and joints were assessed one, three, or six months after clinically relevant injuries. We found that with growth, the radial network evolved to be more anisotropic and that this correlated with a decreased protective ability of the tissue with respect to notch defects that sever the circumferential network. This study therefore indicated that both the circumferential and dynamic radial fiber networks are relevant components when considering the impact of injuries on joints. The large animal model developed in herein indicated the resilient and dynamic nature of the meniscus in response to clinically relevant injuries. Specifically, an injury that maintains load transfer (vertical longitudinal tear) did not cause substantial adverse impacts to the joint until the six-month time point, at which point only histological evidence of degeneration was seen. However, a clinically relevant and unloading injury (destabilization of the medial meniscus) was progressively detrimental to the joint from the one-month time point onwards. This finding indicates the importance of a homeostatic loading environment for meniscus health. These studies work together to illustrate the importance of loading on the meniscus and its remodeling. These diametrically opposed processes, one of growth and maturation and the other of injury and degeneration, serve to direct strategies for tissue engineered meniscus replacements and clinical decision making for the treatment of meniscal injuries.