I was 77 when I had my TKR three years ago. Before the surgery I had the cortisone shots (3) about 4 months apart with some relief but finally accepted the idea that surgery needs to be done. My surgeon had a MRI done to build the replacement parts and give him an accurate look into the knee before surgery. After surgery I was fitted with a prescription leg sleeve to control the swelling along with a water/ice & pump cooler. I wore the sleeve 24/7 and attached the cooler wrap whenever I was sitting down including in bed. My suggestion is to ask for a replacement sleeve because they get dirty after wearing it 24/7 and it needs to be purchased from a doctor, I think I found a vein specialist that sole them in pairs for about $50-70 a set.
Shortly after surgery I made my first walk while I was in the hospital, only about 20 feet out and back of my room (with a walker), but each day after I added another 20 feet to the exercise. By the time I had a PT therapist at home I was doing about a quarter of a mile a day (with a cane or walker, mostly for stability).
Before surgery I had 5 goals:
1. Walk & sit without pain
2. Sleep without pain
3. Walk up stairs without pain
4. Walk down stairs without pain
5. Get down on my knees without pain
Within a few days I accomplished #1, #2 came after a few weeks, #'s 3 & 4 took me a year to do with confidence and #5 I do with kneed pads, mostly because my knee cap is numb and it feels funny.
One last note, a few years prior to my journey with TKR I lost a lot of weight, about 70lbs, for another reasons and I believe it made a difference.