Osteoarthritis is really not a very accurate term. It is a degenerative condition which happens to everyone’s joint surfaces with time to a greater or lesser extent. The suffix ‘itis’ usually indicates an inflammatory condition.This is why the term osteoarthritis (OA) is inaccurate. A much better term is Degenerative Joint Disease (DJD) or osteoarthrosis.
In contrast rheumatoid arthritis and its many variants belong to a different group of true inflammatory disease, which affects multiple joints usually and does not spare any particular part of the joint. The end result of both groups is similar; that is destruction of the ‘articular surfaces’ coating the bone ends in the joint.