Sudden pain in the knee after a twist, pivot, or landing awkwardly
A popping sound or popping sensation at the time of injury
Rapid swelling within a few hours
Feeling like the knee is unstable or giving out
Trouble bearing weight on the injured leg
Loss of normal range of motion
Pain when trying to bend or straighten the knee
Tenderness around the knee joint
Difficulty continuing sports or activity after the injury
Bruising around the knee
A doctor’s exam showing positive ACL tests
MRI confirming an ACL tear