It encloses the joint and protects it. The most common cause of osteoarthritis is aging. Tests have been done to see if overuse causes cartilage to break down, but these have been inconclusive. Another primary cause of osteoarthritis is trauma, such as an injury to a joint. Thus, a person who fractures a bone in his or her ankle is very likely to develop osteoarthritis later.
Many people develop osteoarthritis as they age.
Over time, wear and tear on the cartilage in their joints gradually breaks it down. Joints that used to function smoothly begin to develop crevices and bumps in their cartilage. This causes stiffness and pain that gradually grows worse. It also causes joints to lose their flexibility. These latter joints seem to be affected most because they are the ones that bear the weight of the body.