I had my hip replaced on 15 Dec. '06. It is without a doubt the best gift I've ever given myself. No running or jumping ever again, but caching has been just perfect for me. Plenty of walking through different terrain (now PAINLESS!) and being able to concentrate on the scenery, flora, fauna, sounds and smells instead of worrying about how much farther it might be, can I get down this hill and still get back up, blah, blah blah...I'm sure you can add your own list of distracting worries and irritations.
Press forward, get a great surgeon, follow the instructions and restrictions to the letter and anticipate that your life will be all yours once again. ...unless you were a pro basketball player or volleyball olympian!