They are good videos.
As I get older, I often wonder about how my knees will fair in the coming years. Touch wood, I've never had any knee issues, but I know mates who do and it causes serious pain and discomfort. I can only image the pain since it would be present whenever you stand or walk. Sometimes even sitting can be painful.
I think a lot of knee injuries are RSI related while genetics rolls the dice for the rest of the game.
Would be good to hear from others who have had knee injuries and how you fared post treatment.