An anterior cruciate ligament (ACL) tear is a common knee injury, particularly among athletes. It occurs when the ACL, one of the major ligaments in the knee, is stretched or torn. Symptoms of an ACL tear include a popping sensation at the time of injury, severe pain, swelling, instability, and difficulty bearing weight on the affected leg. Treatment options for an ACL tear may include physical therapy to regain strength and stability, bracing, and in some cases, surgical reconstruction of the ligament to restore knee function and prevent long-term complications.