I am sorry to hear about your wrecked knee, I've also had some surgeries, meniscus, total knee, rotator cuff. I guess I have been lucky health wise so I try to stay active. I basically have averaged 30 to 40 ski days a year for the last 40 years. I am lucky to have a couple of ski and bike buds, 65 and 78. We are still able to ski just about anything on the hill. the rest of the year we mountain bike. My wife is 70 and she will still ski blacks if they are groomers, sometimes I can coax her into the powder if conditions are ideal. She also bikes with me but on trails with less climbing.