What are the symptoms of a torn or partially torn ACL?

Question

I think I may have torn mine, so I'm wondering if the symptoms match up.

Answer 1

The main symptom that distinguishes ACL tears from other knee trauma is instability in the knee joint when you bear weight on the knee when it is partially bent. With a partial tear, at the time of the injury, a person usually feels a sharp pain in the center of their knee and kneecap, and the leg gives out when you try to support your weight. The injury swells quickly and usually shows of bruising within a day or two.

Doctors manipulate the leg in a couple directions to diagnose an ACL tear - this procedure is described in the middle of this link: