Arthritis is a non-infectious, progressive disorder of the joints. The normal articular joint cartilage is smooth, white, and translucent. In early arthritis or joint degeneration, the cartilage becomes yellow and opaque with localized areas of softening and roughening of the surfaces. As degeneration progresses, the soft areas become cracked and worn, exposing bone under the cartilage. Eventually, osteophytes (spurs of new bone) covered by cartilage form at the edge of the joint. As mechanical wear increases, the cartilage cells are unable to repair themselves.