[DennisP]

I don't know whether the "knees over toes guy" exercises would help your specific problem but that guy had multiple knee surgeries when he was young, and injuries to the other knee where he skipped recommended surgery, and now his knees are amazingly capable. Might be worth checking out. It starts very gently and you never work through pain. All the physical therapists I could find talking about it were very positive on the program, as long as you take it slow.