Hey you're me 15 years ago. I stopped the sports and switched to sustained low damage exercise like cycling, hiking, swimming etc. While you can't undo the damage done if you have a very high level of fitness, you can reduce the effects of the further progression of time. Better be as fit as a 50 year old with some damage when you're 70 than as fit as a 70 year old with some damage.

End game is not pretty. My ex wife didn't do any fitness stuff at all and she's walking with a stick while I'm doing 30km hikes at 3000m...