Swollen/Hot Starboard Ankle

Question
Background: My rat's name is Princess, she is a pink-eyed white dumbo rat who is currently 19 months old.  She has been neutered, had surgery to fix an umbilical hernia, and also had surgery to remove a benign adenoma in her rear-most port mammary gland.  I definitely do not shy away from seeing vets, and I have a very good one who is well-versed in rat care and rat surgery.  

Situation: A few days ago, I noticed her favoring her starboard leg (if looking at the rat from above, it would be her right rear leg).  This evening, I found her limping while holding that foot up as close to her body as she could manage.  I picked her up and examined the limb.  I suppose it might be a rat's heel - when sitting back on their hind legs, it's the portion of the 'foot' on the non-furred side of the joint (where the heel and arch meet on a human).  She was not at all interested in me checking it out in depth, as it was swollen and hot to the touch (warm, where normally her feet are cool).  She kept the toes carefully together, and when I was holding her belly-up to examine it, she would grab my finger with her healthy foot to push against it, but wouldn't use the swollen limb.  

I'm not sure if I'm dealing with a fracture or an infection - the only part that troubles me is the heat coupled with the swelling (three years ago I had a few bouts with cellulitis that leaves me skittish around hot swelling).  

Do you have any advice?  

Thanks ever so much,
Patricia
A very worried rat owner

Answer
 It could be something simple like a sprain or a twist; rats often get their legs caught in the cage bars and it can leave no sign but swelling once they get themselves free.  It could also be a small fracture; rats have very thin bones in their feet and it may be difficult to tell without an x-ray what is wrong.  Other than that I'm not sure, you'd have to contact your vet for some more in-depth information.  If you think it is just a sprain you can give her Ibuprofen (children's Motrin or similar) at a dose of 0.03mg / gram of her weight every 12 hours for a maximum of 3-4 days to see if that helps bring down the swelling and pain.  Hopefully everything is all right!  Good luck!