After riding since I was a kid, I got a searing pain in my knee after a long ride one day. Hurt for most of a week. Twisting at the knee to get into my car would make me scream. Didn't ride the bike for a week or two after that to let it settle down. Next long ride, it came back. Very frustrating. Anyway, I got clipless pedals and the pain went away, never to return even after several years.