Have you had any work done to your knee(s) before?
My dad has had 5 knee surgeries due to dirt bike wreaks but they are all the old school butcher jobs. Anyways what I'm getting at is my dads knees are fucked and I've had home pull gluten out of his diet and he's shocked at how much better his knees and whole body feels and he can now go up/down stairs normal instead baby steps/having to have both feet on the same step before moving to the next. He told me yesterday that they feel good enough again now that he probably won't be getting both his knees replaced like he thought several months ago.

Not sure how much you believe in the whole gluten deal but its worth a shot since you have nothing to lose.