I know people who've had one knee done at a time, as well as both at once. Regardless, after physical therapy, lots of hard work, they all seem to be doing fantastic! IMO, medical science has evolved so beautifully, they can do wonders. Of course every patient is different, but after the 2 back surgeries I've had (need more and 2 hip replacements), I feel better than I have in years. Nobody wants surgery, but if it makes a profound difference in your life, I say, Go With It!