In 2002, when I was 22, I was carrying a planter down a grassy
hill and slipped. My right knee twisted. I did not go to a doctor to have it looked at. Now, if I sit in one place for too long, it stiffens and causes pain. Today, I was in the backseat of a SUV for 2 hours, then sat in a conference for an hour. I stood up, instantly got excruciating pain in my knee and sat back down. A few minutes later, I fainted. I came too fairly quickly, the pain gradually went away and now is fine.