I have IBD related arthritis and was able to tolerate ibuprofen at high doses for years, but eventually the party was over. I had to stop it due to liver inflammation and pouchitis. Both ailments turned around, but now I only take NSAIDs for two week intervals when I am having a severe flare. For maintenance I take Azulfidine and Simponi for the inflammation. For the residual pain i take Norco and Robaxin (muscle relaxer).
Hopefully, once your rectum is removed, your arthritis symptoms will abate. One thing you can do to help to calm the rectal inflammation is to use Rowasa and/or hydrocortisone enemas until your next surgery. Tyenol may help with the pain, but it does zero for inflammation.
Jan