A: The short answer to your question is no. But that doesn't mean there's nothing you can do about it. Osteoarthritis is caused by the degeneration of cartilage, and it cannot be reversed. Where two bones meet to form a joint the ends of the bones are covered with cartilage, which is a tough slippery material that allows the bones to glide smoothly over each other. At the most mobile joints (called synovial joints), which are the hips, knees, shoulders, elbows, wrists, fingers, ankles and toes, the cushioning cartilage can wear down. The reasons are not known, but it is partly a function of aging. Close to 50% of Americans ages 65 and over have arthritis.