I normally have knee flexion of about 120, and it's a pretty hard limit, and pain starts if I try to push past that. I slipped and fell the other day, and my knee was forcibly flexed way past that. I now have constant knee pain, and it hurts a lot when shifting my weight through the joint. It's not as painful when I'm off it, but walking and doing anything that involves weight bearing, especially with the knee bent, is painful. My pain levels increase the more I'm on it.

What could I have done to it by having had flexion forced like that?