Osteoarthritis (OA) is a chronic (long-lasting) disease and the most common form of arthritis. Some people call it degenerative joint disease or “wear and tear” arthritis. It occurs most frequently in the hands, hips, and knees.
Osteoarthritis mostly affects cartilage (KAR-til-uj). The surface layer of cartilage breaks down and wears away. These changes usually develop slowly and get worse over time. OA can cause pain, stiffness, and swelling. In some cases it also causes reduced function and disability; joint pain and stiffness can become severe enough to make daily tasks difficult.