What is osteoarthritis? Osteoarthritis is an ongoing, progressive disease that causes inflammation, pain, stiffness and swelling of joints. The joints of the body are the areas where two or more bones meet. The ends of the bones are protected by a durable tissue called cartilage, which helps bones to move easily without damaging bone tissue. In osteoarthritis, the cartilage breaks down, or becomes torn or thin, resulting in friction on the ends of the bones as they make contact. With time, this causes the classic symptoms of osteoarthritis, such as joint pain, stiffness, and swelling. Osteoarthritis can also cause inflammation of the synovial membranes. Healthy synovial membranes line and protect the joints and allow smooth and free movement. When synovial membranes are inflamed, they become swollen, tender and warm, and are unable to move freely. Osteoarthritis is also known as degenerative joint disease, because it can get worse with time and cause deterioration of joint function, difficulty moving, and even disability. Osteoarthritis cannot be cured, but early diagnosis and treatment can help to reduce symptoms and minimize complications. Complications of osteoarthritis can be serious and include joint damage, deformity, and disability. Seek prompt medical care if you have symptoms of osteoarthritis, such as inflammation, pain, stiffness, and swelling of joints. Early diagnosis and treatment can minimize discomfort and reduce the risk of serious complications.