The ability of a meniscus tear to heal depends primarily on its blood supply. The outer or thicker part of the meniscus receives a fairly good blood supply from the lining of the joint, whereas the inner or thin part has a poor blood supply. Thus, tears at the outer margin of the meniscus are more amenable to successful repair which can be done by placing sutures across the tear by arthroscopic techniques. If the tear is in the thin part, the cartilage will not heal and the torn fragment is typically excised. Old or chronic tears also tend to have a poorer success rate withrepair and are typically trimmed out as well.