Removal of cartilage. When people tear cartilage in the knee joint, it's usually a meniscus teat. This semi-circular cartilage rings the periphery of the knee joint and helps cushion impact. The meniscus is avascular, except at the edges furthest away from the joint. The meniscus often tears in this low blood supply area and in not repairable. The torn part is excised arthroscopically, leaving the remainder intact.