Osteoarthritis is a deterioration of cartilage and overgrowth of bone often due to "wear and tear". Rheumatoid arthritis is the inflammation of a joint's connective tissues, such as the synovial membranes, which leads to the destruction of the articular cartilage.
A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, and David R. Eltz. Previously reviewed by C. Benjamin Ma, MD, Assistant Professor, Chief, Sports Medicine and Shoulder Service, UCSF Dept of Orthopaedic Surgery (9/22/2011).