The cause depends on the type of arthritis some causes include injury which causes degenerative arthritis, abnormal metabolism, infections like that in osteoarthritis and an overactive immune system.

It is difficult to determine the exact causes of arthritis. Any number of reasons can contribute to the development of this problem. Possible risk factors include: age, heredity, weight, prior injuries, occupational hazards (jobs requiring a lot of physical strength), high level sports, and/or other related medical illnesses. Although none of these risk factors are determined to be conclusively evident, they can possibly contribute to the development or progression of arthritis.