The Anterior Cruciate Ligament (ACL)

By: Toby K.

            The anterior cruciate ligament (ACL) is just one of four ligaments in the knee that hold together three bones; the thigh (femur), the shin (tibia), and the kneecap (patella). The ACL specifically holds together the part of the knee closes to the center of your body. If torn, the knee most likely will not be able to extend properly. Depending on the severity of the sprain, the patient may not be able to walk without excruciating pain. Most tears of the ACL are due to some sort of physical activity involving rapid turns, rapid decreases in speed, or something hitting the knee directly.

            There are three degrees of sprains of the ACL that increase in severity as the number increases. A grade 1 sprain involves the ligament to sustain mild damage caused by the ACL to be stretched a little bit. In this case the ligament is still able to stabilize the knee effectively. In a grade 2 sprain, the ligament stretches and becomes loose—this is referred to as a partial tear. A grade 3 sprain is a complete tear of the ACL causing it to tear into two pieces and not be able to stabilize the knee at all.

            Depending on the extremity of the sprain or tear, the ACL can be healed by either nonsurgical or surgical means. If the ligament is not completely torn, a doctor may issue physical therapy for the patient. The goal of this is to strengthen the muscles around the knee in order to re-stabilize the ligament. If the ligament is partially or completely torn, a doctor will have to surgically rebuild or reconstruct the ligament.

The surgery for rebuilding the ACL is a fairly common procedure that orthopedic surgeons will do relatively often. In order to reconstruct the ligament, a surgeon will make an incision in the knee and can suture the two parts of the ligament back together. If the damage to the ACL is too extreme, a graft will have to be taken from another place to put in substitute of the torn ligament. The graft can be taken from a patella tendon, a hamstring tendon, a quadriceps tendon, or a cadaver tendon. Once the graft is taken from one of these places, it is then put into the position of where the former ACL was and then sutured to the femur and the tibia. After these procedures are completed, a patient usually goes to physical therapy for about 6 months before the knee is fully healthy again.

Sources:

https://www.nlm.nih.gov/medlineplus/ency/article/007208.htm

http://orthoinfo.aaos.org/topic.cfm?topic=a00549

Top Image URL: http://sporttherapysupport.com/wp-content/uploads/2015/11/torn-acl-injruy.png

Bottom Image URL: http://cdn1.sbnation.com/imported_assets/1117615/qq1sgKneeACL.jpg