I keep having these sharp pains behind my knee toward the outside and when I get them my knee gives out. I never know when it will happen and am starting to walk with my knee bent so I don't completely put all my weight onto it.
I just went through the same thing but I actually tore the ligament. See an ortho, my problem is my patello-femoral joint sucks and my knee pops and this time it popped so hard that it tore my patello-femoral ligament. You don't want that to happen!