I often get OA flares in my knees and hands. I don't think there is any rhyme or reason as to which joints will act up or if all will act up at the same time. Most of the time of a flare is during very damp and/or cold weather. I will go on Celebrex for a few weeks until the pain is back under control. If there is swelling, my rheumy will put me on a short course of prednisone.