My mother has had both knees done, the first about 10 years ago when she was 70. One worked like magic, she hobbled in on sticks, walked out a week later without them. The other has had a succession of problems, it got infected shortly after being put in and again last year after she fell and twisted it. On both occasions it had to come out and they put a spacer in and kept her dosed up with high powered anti biotics till it was all clear. With the spacer they put her leg in a splint so it couldn’t bend and she had to hobble about on crutches. The joint is back in now and seems to be working well [touching every bit of wood I can find].
When this stuff works, its brilliant, you get your old life back, but the problems can be pretty major. It is worth persevering, it has been a long and rocky road for my mother, but she is properly mobile again and pretty good for nearly 80.
I had some major work on my right wrist about 18 months ago and haven’t regretted it for a second. Swamp girl has one plastic hip and is getting the other done soon, we are a right bunch of crocks here, nearly as many replacement parts as my bike.