when i made my ACL, it was not painful at all, just shock and scream of what happened. Few minutes later it stiffed and i couldnt walk. Then reconstruction was done but after year it happened again on the same knee. Funny is when "artifficial" ACL torn, i had no stiff, could bend leg, could walk, no blood inside, it just torn. I just wanted to say, that same injury can be different, even for same person. And worst is once you have problem with knee, it can happen again all the time and i had no prior problem before first rupture