I'm a 68 y/o male and in 2022, I had both knees replaced. I ran many marathons in my 30s and 40s, but what damaged my knees was osteoarthritis. I did see a surgeon who recommended I first work with a trainer to strengthen my quads and hamstring muscles.

I did that (I still work with a trainer), but my knees were bone on bone and painful. My surgeon used the Stryker/Mako robotic assistant during the replacement surgery.

My life has changed dramatically, and for the better. I'm in the gym 6 days a week - 3 days cardio on a rowing machine and 3 days of weight training for lower and upper body, and core exercises everyday.

Find a good ortho surgeon - ideally someone in his/her mid 30s to mid 40s, with a solid pedigree from a medical school or residency, using the latest technology. You might not need any replacements yet. Give exercise a chance. Either way, I think it will work out fine.

Finally, ignore most of the posters on here with bad results from joint replacements. Most of these are due to not getting in shape ahead of surgery, and not doing the required therapy/exercise post surgery.

All the best!