my nephew is now 7 and was dx'ed with Juvinelle RA when he was 5. I myself was dx'ed with it when I was 14, when I had orthoscopic surgery and the dr said I had more arthritis in my knees than the average 65 year old.
My nephew was on meds everyday for a year and is now off the meds, he had knee pain as well. It never stopped him. He ran and played baseball and gym and wrestled.
good luck!