Hello, I was just diagnosed today with Osteoarthritis along with the Rheumatoid Arthritis that I have had.  I know it has been since 2009 when you posted this but I wanted to respond anyway.  I am 39 years old and the pain in my back gets so bad sometimes I want to throw up.  I can tell you that the pain of RA is not good, but the pain of both together is ridiculous.  My doctor said the the primary pain in my back, knees, and hips were mostly osteo due to wear and tear.  I can honestly tell you that  I can almost tell the difference between the two, with mine anyway (everyone is different)  I have arthritis in every joint of my body including my face.  I was also told knee replacements may be in my future so yes you can have both.