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.
Update Date 5/15/2014
Updated by: C. Benjamin Ma, MD, Assistant Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery, San Francisco, CA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.