When I was doing local I was 24 and developed knee pain after a year and a half. I didn't know how to float back then so every shift was a double clutch. When I would complain everyone would say that there's no way it was because of clutchin. Well as soon as I started driving autos it went away complete. I'm no doctor but that seems like too big of coincidence for me.
Try callogen peptide powders. Im getting up there in age, close to 30 now, and started taking it. You wouldn't believe the difference it makes in terms of joint health. Stuff really works.