1. A chronic, noninflammatory degenerative joint disease marked by degeneration of the articular cartilage, hypertrophy of bone at the margins, and changes in the synovial membrane, accompanied by pain and stiffness.
2. A degenerative joint disease (DJD), which is a progressive disorder of the joints caused by gradual loss of cartilage and resulting in the development of bony spurs and cysts at the margins of the joints.

The most common type of arthritis which is characterized by inflammation, degeneration and eventual loss of the cartilage of the joints of fingera, hands, feet, spine, and large weight-bearing joints; for example, the hips and knees.

A chronic systemic disease, classified as a type of collagen disease (widespread pathologic changes in the connective tissue), characterized by inflammatory changes throughout the body's connective tissues.

It usually strikes during the most productive years of adulthood (ages 20 to 40), although some people are affected as infants or in old age.

The cause is unknown, and there may not be one specific cause. In about 75 per cent of patients the onset is gradual, with only mild symptoms at first. These may include malaise, fever, weight loss, and morning joint stiffness.

Some joints may become swollen, painful, and inflamed. Most patients have increasingly severe and frequent attacks with subsequent joint damage and deformity.

Besides the joint changes, there is atrophy of muscles, bones, and the skin adjacent to the affected joint or joints. The most evident lesions are subcutaneous nodules, usually over bony prominences such as the elbows.