ACL

Anterior cruciate ligament

ACL refers to the anterior cruciate ligament, which is one of the four ligaments found in the knee. The primary function of this ligament is to prevent excessive forward movement of the tibia (shin bone), which is the bone that sits directly beneath the femur. The ACL also provides stability in the knee and allows for angulation and rotation in the joint. The ACL extends from its attachment at the posterior of the femur to the anterior of the tibia.

Ligaments are a tough and fibrous tissue. Three other ligaments help to stabilize the knee – the posterior cruciate ligament (PCL) and the medial and lateral collateral ligament, but it is the ACL that is most commonly injured.

How does ACL injury occur?

ACL injury most often occurs as the result of an acute injury to the knee, and is most commonly seen in high-impact sports and activities that involve high speeds and rapid changes in direction. Sports exhibiting these qualities include football, soccer, lacrosse, rugby, tennis, basketball, skiing, gymnastics and hockey, to name a few. ACL injuries also occur as a result of trauma or work-related accidents.

What happens in an ACL injury?

An ACL injury involves a tear or rupture of the tendon, and is usually a result of pivoting while simultaneously exerting high rotational forces on the knee.

How do I know if I have torn my ACL?

• If you hear a “popping” noise at the time of the injury.
• If you experience instability of the knee joint, and the feeling that the knee will “give way.”
• If there is swelling of the knee joint.
• f there is pain in the knee joint when walking.

Why is an ACL tear considered such a serious injury?

Tearing the ACL results in a decreased stability in the knee joint. In fact, people who have sustained such an injury often complain of the feeling that their knee is going to “give out” on them. This sensation is a result increased sliding between the shin bone and the femur. Each time the knee “gives way,” damage could be done to the cartilage in the joint, making the individual more susceptible to arthritis and meniscus tears.

Am I likely to experience an ACL tear?

As I said earlier, these injuries most often occur in high-impact or high-speed sports where participants are required to pivot and change direction suddenly. Less frequently, ACL injuries are seen in the workplace and in car accidents and other traumas. Thus, if you are not involved in high-impact or fast-moving sports, you are less likely to suffer from such an injury.

What do I do if I suspect an ACL injury?

Go see a doctor immediately. The doctor will perform some tests which can determine whether or not the ACL has been torn. These tests include the following:

• The Lachman test. During this test, the shin bone is pulled forward to determine the function of the ACL. If the physician is able to pull the shin bone forward much more than normal, it is likely that the ACL has been torn.
• The pivot shift maneuver. This test is most easily performed on the operating table when the patient is anesthetized, and helps to determine abnormal movement of the knee, which would indicate a tear in the ACL.
• X-Rays. This method will be used to detect any fractures in the bones.
• MRIs. This test might be used to detect any cartilage or ligament damage, but is most often not necessary in determining an ACL tear.

So I’ve torn my ACL. What’s next? Surgery?

Well, an important decision must be made about proceeding with surgery or not. To make this decision, the following factors must be considered:

• Activity level of the patient
• Age and overall health of patient
• Knee stability
• Likelihood that patient will comply with post-operative rehabilitation

Some individuals can continue with their everyday lives as they used to without having to undergo surgery, but participation in sports and certain activities will likely be limited. Any sports or activities that require pivoting and putting the knee under high stress would not be allowed, as they would cause further damage to the already unstable knee.

A young, healthy and active individual who wants to resume their usual activities and sports will most likely opt for the surgery.

What does ACL reconstructive surgery involve?

ACL reconstructive surgery involves rebuilding the ligament. However, it is impossible to repair the actual ACL, so pieces of other ligaments in the body must be used. The patellar ligament, the hamstrings tendon and donor tendons are often used to take the place of the torn ACL.

Women Are More Susceptible to ACL injury

Apparently, results consistently show that in competitive, high-impact sports the occurrence of ACL injury is 10 times higher in women compared to men.

Why is that?

Well, let me begin by stating the obvious – men and women are built differently. While no true reason has been determined for the higher susceptibility of women to experience an ACL tear, there have been many speculations. Here are a few of them:

• Hormone cycles in women. Hormone cycles influence ligaments, like they would with any other tissue. More specifically, a higher occurrence of ACL injury has been observed in women who are in their pre-ovulatory phase. Another interesting observation – women who are on oral contraceptives are less likely to suffer from an ACL injury than women who are not on the pill.
• Anatomical reasons. Structurally, men are generally larger than women. This holds true for the size of the ACL. Women have a narrower ACL compared to men.
• Athletic posture. It has been observed that women stand more erect during sports, while men get into a more crouched position with their center of mass closer to the ground, making them more able to react to a force. More injuries occur when people are standing in a more upright position.

Is there any way I can prevent ACL injury during sport?

• Neuromuscular conditioning. Studies have shown that neuromuscular conditioning has made women less likely to experience an ACL injury.
• Posture. Try to change the position you assume on the field. Standing in a more crouched position could decrease your chances of getting injured.