Osteoarthritis is classified as an anti-inflammatory condition. According to this classification there is no swelling, or inflammation, in or around the affected joints. However, researchers now know that , although there is usually no swelling in the early stages of osteoarthritis, inflammation is often apparent as the disease becomes more progressive. This may be caused by small pieces of cartilage that break off and float around inside the joint. This disturbs other soft tissues inside the joint and can cause pain and swelling between bones. As a result, a person may have difficulty moving the joint.

The condition known as inflammatory osteoarthritis typically affects middle aged women. It appears suddenly and affects the last and middle joints of the fingers. It causes sudden pain and swelling of these affected joints. Inflammatory osteoarthritis is generally treated with nonsteroidal anti-inflammatory drugs and, very rarely, corticosteroid injections directly into the affected joints.