Osteoarthritis is a condition in which the cartilage that protects and cushions the joints breaks down over time. Eventually, the bones—formerly separated by the cartilage—rub against each other, resulting in damage to the tissue and underlying bone and causing painful joint symptoms.

Osteoarthritis, sometimes called degenerative joint disease or osteoarthrosis, is the most common form of arthritis. It most often affects the joints of the spine, fingers, thumbs, hips, knees, or toes.