I have known a few people who have had total knee replacement (both at once)
and they have all had good success/results. 2 of them said they would have had it done years ago had they known it would work so well.
These are mostly people in their late 60's and 70's, and the only hard part for them was therapy/recover afterwards. It is rough to go thru, but if a 70+ y.o. can do it, most anyone should make it thru.
For them it really added to giving them back their ability, and they all commented on that.
Good luck with whatever you do, and I hope you get some long awaited relief.