Thanks everybody! Yesterday I spent some time with someone who had had a knee replacement about 3 years ago. She was very encouraging and helpful and was able to answer a lot of my questions and fears, so now I feel better about it.

The one thing she did stress, though, was how important it was to do all the bending and straightening exercise they give you afterwards, otherwise it'll all be for naught and they'll have to go in and do it again.

Thanks again for your responses! I appreciate you all.