Binkie, I can't help you with the thumb surgery, but check out the threads in this forum. There are at least two on the first page about
thumb surgery.
When you get to knee replacement, I'm your girl; I had one replaced nearly three years ago.
I am curious as to how you came to have such severe multiple joint involvement, which we usually hear about only from people who have taken steroid medications over an extended period. And just as a matter of caution, I'd definitely get a second opinion before embarking on so many surgeries; it's just prudent to be sure.
Good luck, and let us know how things go for you.