Dont know if it is your RA, but my ankles are swelling too. My left is worse than my right. I am pretty sure that left one has some OA problem, but at least I am still walking. The heat seems to make my swelling worse each summer. Now on Prednisone, I think that contributes to the problem as well.
I try elevating my legs as much as I can during the day. Also cut down on the salt, i.e. not use the salt shaker and try to stay away from high salt foods like potato chips. These things sometimes help me.
Hope you are feeling better soon.