An anterior cruciate ligament (ACL) injury is the extreme stretching or tearing of the anterior cruciate ligament in the knee. The ACL is one the four main ligaments within the knee that connects the femur and the tibia – and one of the most commonly injured. A tear may be partial or complete.

Ligaments are large bands of tissue that connect bones to one another. The other three ligaments that connect the femur and the tibia are the medial collateral ligament (MCL), lateral collateral ligament (LCL) and the posterior cruciate ligament (PCL). The ACL runs diagonally across the middle of the knee from the underside of the femur to the top of the tibia. The ACL prevents the tibia from sliding out in front of the femur, as well as provides rotational stability to the knee.

In general, the incidence of ACL injury is higher in people who participate in high-risk sports, such as basketball, football, skiing, and soccer and female athletes have a higher injury incidence than male athletes. These injuries occur from slowing down suddenly or cutting or pivoting with a firmly planted foot. According to medical research, females are seven times more likely to suffer an ACL injury than males. One of the reasons for this is the fact that the “Q” (Quadriceps) angle, where femur and tibia meet, is greater as a result of the wider pelvis of a woman. This biomechanical difference tends to pull the kneecap of a woman out to the side in a way that a male knee is not.

Additionally, women tend to have looser knee joints. And their hamstring muscles are generally weaker than their quadriceps, which further adds stress to the joint.

When an ACL is torn, the patient may feel or hear a pop in the knee and experience significant pain, possible swelling and knee instability. Within a few hours there is a large amount of knee swelling, a loss of full range of motion, pain or tenderness along the joint line and discomfort while walking. Once in an orthopedist’s office, specific tests are performed to determine if there is an actual tear and the extent of the damage.

The test may include both physical observation and x-ray. By pulling the shin bone forward, the orthopedic specialist can feel for an ACL tear. The shin bone will move extreme forward, if there is a tear. The pivot shift maneuver detects abnormal motion of the knee joint when there in an ACL tear present. This test is usually performed while the patient is under anesthesia. The physician will also evaluate x-rays of the knee to asses for possible associated fractures and a MRI may be ordered to further evaluate the extent of ligament or cartilage damage.

Initial treatment includes cold compression and anti-inflammatory medications, followed by stretching, exercise and rehabilitative therapy.

The ACL does not heal on its own, although the surrounding knee muscles can be built up through exercise and rehabilitation. Severe ACL injuries may require surgery. Dr. Mark Sanders of the Sanders Clinic for Orthopaedic Surgery and Sports Medicine in Houston and Pasadena performs an ACL Reconstruction procedure with an advanced accelerated rehabilitation program that’s returning athletes to their sports in three months.

Dr. Sanders is an orthopedic surgeon and sports medicine doctor specializing in knee and shoulder injuries. If you are experiencing knee pain and feel you may be suffering from a torn ACL, log onto www.sandersclinic.net to learn more about ACL injuries and treatment, or call 1.888.8 DR MARK (24/7).