Well, it's kinda SFR... I am getting a new knee tomorrow. I have missed my last hunting season because of the bum leg, and I plan on trying to wear the new one out on the stream bank, and in the field and woods.
Seriously, though, I echo Brian's thoughts. I know a surfer in his late 50's who got a new knee a few years ago, and soon after he recovered from the surgery and went thru some physical therapy, he was surfing again at a performance level much closer to that of his former younger self .
Good luck sir. This IS a great area to have that done, becoming a nearly routine operation. Lots of great doctors and technology available here, and the re-hab is usually pretty quick too. Hope all goes well.
Did the same thing last year after missing the chukar hunting and ski seasons for lack of mobility. Hope yours goes as well as mine. I spent the summer backpacking, bought a new retrierver last spring and already have him on pheasants and getting ready for winter duck hunting. Looking forward to OP steelheading. Good luck with your new knee.