Sudden popping sound at the time of injury
Immediate pain in the knee
Rapid swelling within a few hours
Feeling of knee instability or giving way
Difficulty bearing weight on the injured leg
Loss of full range of motion
Pain when trying to pivot, twist, or change direction
Tenderness along the knee joint
Trouble continuing sports or physical activity after the injury
Knee feels loose or unstable during walking
Diagnosis confirmed by a medical exam and imaging such as MRI