I am a 69 year old male. I had double knee replacement in 2017 and started skiing 35 weeks after the second surgery. (March of 2018) I was very consistent doing my therapy and also not too aggressive with the therapy. I know some people who have had setbacks because they went too hard with their therapy. My off season therapy includes hiking, swimming and trail bike riding. This year I have skied 13 days with no pain in the knees. I try to stay on groomed trails. I am more comfortable doing blues but will do an ocassional back diamond run. Check out realskiers.com for some advice on skis that are easier on the legs and knees. (silver skier selection) Good luck!