Last spring I had both knee joints replaced, the right on Mar19th and the left on April 30th. On September 4th I departed for Bozeman, day-hiked around in Yellowstone for three days and then headed up to Big Timber for a 6-day elk hunt. I was able to keep up with my guide and had a great time! I didn't score on an elk but had 3 close calls. I'm headed back this fall, God willing.
I will pass along the advice I got because it seamed to work for me. Go into surgery light and strong. Do the physical therapy like you MEAN it! Four hours after I woke up after my first knee operation was completed the PTs came in and told me I had to take at least two steps on my knew knee. I got up, put my weight on it. It didn't hurt so I took those two steps. When they told me I could get back in bead I told them that they could go to bed if they wanted but I was going to walk all the way to the door (of the hospital room). I did it. You can do it too!
Good luck! Don't give up, don't give in. When you get to feeling like it ain't worth it, reread the previous sentence.
JMC