Best wishes for a speedy recovery. I'm sure it will be nice to be more mobile again. I've seen four done in my family so far and it's always made a HUGE positive difference. Hoping yours will be as well!
My dad's had both knees replaced a few year's ago. We hiked in Yellowstone this summer and Colorado this fall and he keeps up fine. His only complaint was not doing it earlier. Listen to the doctor and best wishes.