The Anterior Cruciate Ligament is one of the most important ligaments of the knee. It gives the knee stability so that it can prevent twisting, straightening or excessive movement of the knee joint. Although, ACL tears mostly occur in athletic injuries, they can also happen during any activities that you would land, twist, have forward movement of your tibia on the femur, or when placing excessive strain on the ACL that it cannot handle. Once your ACL tears, your knee gives out from under you and you may hear a popping sound. Special tests or an MRI can decide whether you have torn your ligament or not. In minor cases of an ACL tear, an athlete may go back to their sport but will have to deal with swelling, stiffening of the knee and an increase in pain. Minor cases most likely won’t need surgery, but may need to heal with physiotherapy and to stay away from activities that cause their knee to have more pain. Once they can do the activities without feeling any pain, they can gradually return to them. In major cases (if an athlete completely ruptures their ligament) they won’t be able to go on with the sport because the knee will feel unstable or give out during harsh movements. The athlete will usually experience severe pain, feeling of their knee popping in and out of place, and recurrent times of the knee giving way after the injury. Surgery is only suggested to people with a torn ACL, that regularly do things that require a functional ACL or that have an unstable knee.