Three years ago, I was playing ultimate frisbee. I planted my foot in the ground, made a strange turn and heard a crunch sound, and felt a lot of pain in my knee. I looked down, and my knee cap had popped up into my thigh. My wife came to get me and drove the car right up on to the field, and she took me to St. Paul's emergency. The staff were great. I was attended to right away, and was told clearly what would happen. Then they gave me some pain killers, and I don't remember much more than that. The next day, my torn patellar tendon was operated on.
I still have the 4 inch scar to remind me, not that I will ever forget.