Feel a pop, then pain in your knee? It could be an ACL tear
You're playing tag with your kids, hitting a fast tennis return shot, landing after a gymnastics vault, evading a football tackle or jumping off a rock onto the beach. Suddenly, you feel a pop in your knee, then immediate pain followed by swelling. You may have just injured or torn your anterior cruciate ligament, or ACL.
Source: Medical Xpress
