NSAID quandry

In my humble opinion I would not risk the NSAIDs
can you get a cortisone shot?

See a rheumatologist and because its in one knee I might suspect injury
Cortisone shots are great for pain relief but there are some negative side effects

I would definitely stay away from all NSAIDs. I know how hard it is and frustrating when you can't take something for pain and swelling. Did you injure your knee? Do you know why it's swollen? When I fell down my basement stairs, the docs had me wrap it in an Ace bandage (to support it) and ice the crap out of it. I also had one steroid injection shortly after and it did help relieve some of the pain and swelling for a short period.

Not being able to take NSAID's is tough because they are so effective at relieving minor inflammations, swelling and pain. I have overdone it with the NSAID's in the past and paid the price with a flare. But what I have found is that when I am in a good spot with my UC, I am able to tolerate NSAID's if I limit my usage to three doses.
Coincidentally, my wrist has been bothering me and so this morning I took Alleve and I will take it again tonight and then tomorrow morning and that's it. I do this maybe 3 times a year at most. I could probably tolerate more than two days of NSAID's but that usually does the trick for me and I am not willing to push it any further and find out the hard way again where too much is for me.
Anyway, proceed with caution. If you feel your UC is in a fragile place, don't even think about NSAID's.

Ice, compression, elevation.
At least for me, NSAIDs are not worth it.

I used Aspercreme (sp?) a couple of months ago. I was surprised that it worked as well as it did. You have to reapply every couple of hours but maybe that with some Tylenol would work. Mary