Hi ReadingMama, I can't help much with the Crohn's arthritis, but I can tell you about my knee surgery.
I woke up out of anesthesia fighting and kicking, causing my surgical knee to hemorrhage. Most people at rehab took about a week to be able to ride the stationary bikes with a full rotation, but I could only do partial rotations until on the third week I got mad, and took a hot bath before rehab, then took TWO pain pills as soon as I was done with the bath. I was high at the gym, but I leaned away from my bad knee and finally got the pedals all the way around.
I didn't make much progress with my first rehab, so the doctor prescribed me another series. When it was over, the PT wrote to the dr that there was nothing more she could do for me. I was sent back to work, which involved a lot of walking, but at least the dr gave me restrictions so I wouldn't have to lift push or pull stuff.
That's when my bad leg started swelling pretty bad, from slightly above my knee down to my toes. I remember the tight shiny skin; the bottom of my foot swelled up so much that I couldn't stand on it flat, it rocked back and forth.
I had to take more time off, and the swelling went down enough that I went back to work again. I swelled after one shift, and changed my status to part time, with each day I worked followed by a day off.
Sometimes my other ankle and foot swelled, so my job told me I had to go back to the dr to rule out heart/kidney problems, since it was on both side. Labs came back fine. I fell at home on two different occasions, and quit my job because I was worried I'd fall there.
I had to use a cane at least 75% of the time, sometimes even in the house. After about two months, the swelling came down a bit, and I was bored, and it was spring, so I decided to ride my bike, since walking caused me so much pain and swelling. It felt so good to be moving around I almost cried. I gradually worked up to long distances and being able to ride over the overpass to get to the store and the library (we had one vehicle, so I couldn't drive while hubby was working).
Because of all the biking, I lost quite a bit of the weight I'd gained from sitting around all day except for housework on good days. And my swelling went down a lot, and I noticed I could walk further before it bothered me. So I rode even more.
I stopped bike riding when I got another job, but later on that job wasn't for me, and I didn't get back into riding as much because of the extreme summer heat. Now I'm building myself back up since it's cooled off (I live in the south). But even during the times I wasn't riding, my knee/ankle/foot hardly swelled up past 2+ (except for a few times, and then it didn't stay swollen as long).
Looking back, I think I required more rehab than what I was given before being sent back to my former life that included a lot of walking, and I wasn't given long enough time off when the swelling came back when I returned to work at the first place.
Do what you have to do to get the rest of your swelling down, and then take it easy on your knee whenever you can. You sound like a slow healer like I was, and I think by us walking on it too soon might have triggered the extreme swelling. But biking didn't hurt me once I got out of rehab, it didn't cause swelling if I didn't over do it, and over time I actually recovered a lot more than I did with the doctor and the PT that gave up on me too soon.
A lot of people at this alternative health site seem to love apple cider vinegar to as a remedy for arthritis, including one man who also has Crohns arthritis: http://www.earthclinic.com/CURES/arthritis.html
Do a search for turmeric and arthritis because that looks promising too.
PS: a bath chair helped me a lot, we found one fairly cheap at Walmart. Hubby had to finally install a hand held shower though, but I loved that chair so much I still use it after I wash my hair, even though I don't need to anymore (unless I have a rare bad knee day).
Good luck, get well soon, and ((((HUGS))))