ACL Injuries

The Anterior Cruciate Ligament (ACL) is the ligament responsible for stabilizing an individual's knee. The tearing of the ACL is one of the most common knee injuries reported, particularly in sports. To learn more about the ACL and how to prevent and treat ACL tears, please click on the questions listed below.

The Anterior Cruciate Ligament (ACL) is an important structure responsible for stabilizing the knee. It is located at the front of the knee between the shin bone (tibia) and the thigh bone (femur). The ACL is critical to performing any type of rotational activity, particularly sports.

An ACL tear involves some discontinuity of the fibers that make up the ACL, and are among the most common knee injuries reported. In some cases, the entire ACL may be torn, while at other times, there may only be a partial tear.

An ACL tear can occur from a number of different causes, including a fall, a slip on the ice or any injury that results in a twisting of the knee.

It is very common for other injuries to occur at the same time as an ACL tear. The most common of these injuries is damage to the meniscus, the shock absorber located between the shin and thigh bones. Damage to cartilage or other ligaments inside the knee can also occur.

Women, particularly young women, are at a higher risk for ACL tears than men. There is also an increased risk if someone has family members, particularly multiple family members, who have torn an ACL or if that individual has torn the ACL in one of his or her knees in the past.

The most common symptoms of a torn ACL include:

  • Pain
  • Swelling of the knee
  • Instability of the knee

A torn ACL can be diagnosed by a physical examination that tests the functioning of the ACL, followed by X-rays or a MRI to confirm the diagnosis.

Unfortunately, the ACL cannot heal itself. Proper medical treatment is required to repair an ACL tear.

When there is a complete rupture and the ligament is not functioning, the best treatment consists of surgery, including the reconstruction of a new ligament. If the patient has only experienced a partial tear, and the knee is not unstable, physical therapy and non-operative measures can often be effective.

During an ACL reconstruction, the surgeon uses either the patient's knee tissue or donor knee tissue to replace the torn ligament. The surgeon inserts an arthroscope (camera) into the knee that allows him or her to see inside the knee joint.

More than 100,000 ACL reconstructions are performed each year in the United States. Although, in the past, this surgery was performed using somewhat large incisions, today's new minimally invasive surgical techniques allow the surgeon to operate using much smaller incisions.

In the past, age was an important consideration and older patients frequently did not have the option for ACL reconstruction. Now, however, the activity level of the patient is most important when considering ACL reconstruction. This change has opened the possibility for older individuals who are diagnosed with ACL tears to lead more active lifestyles after surgery.

There are several consequences of not undergoing ACL reconstruction. Some risks include knee pain, an unstable knee, the inability to play sports, and an increased risk of arthritis and other ligament or tissue damage.

Typically, patients will need approximately six months before they are able to return to unrestricted activity. In some instances, it may take up to one year for the knee to return to normal.

There are certain exercises that may reduce the risk of an individual experiencing an ACL tear. These exercises include neuromuscular exercises and other exercises which help control the position of the knee when landing and performing sporting activity, as well as strengthen the muscles within the leg. More resources for athletes can found at almost any sports training facility.