Anterior Cruciate Ligament (ACL)

The anterior cruciate ligament (ACL) is one of four major ligaments of the knee.  A ligament is a strong fibrous material that connects two bones together. The anterior cruciate ligament (ACL) function is to stabilize the knee.  That means that it keeps it from sliding.  It is found in the center of the knee.  It is injured frequently when a person makes a sudden shift in direction.  The ligament accidentally is twisted against the femur (thigh) bone.  People frequently describe hearing a pop and then the leg gives out.  The knee swells up very quickly due to bleeding within the knee.  Other structures such as the meniscus (spacer cartilage) and surface of the joint may be injured at the same time.  A direct blow to the knee may also injure the anterior cruciate ligament (ACL).

Your doctor will ask you how you injured your knee then examine it to determine if there is damage to the anterior cruciate ligament (ACL).  He will check for damage to other ligaments and the menisci.  The next step is to take x rays and to review an MRI to confirm the diagnosis. Treatment usually starts a period of physical therapy to restore motion and start to restore strength.  Reconstructive surgery is often recommended for those who place significant demands on their knees such as athletes and heavy laborers. 

Reconstructive surgery consists of arthroscopy to replace the torn ligament with a tendon.  Choices include the knee cap tendon (patellar tendon) or hamstring tendons.  The source may be the patients own tendons or a tendon from a donor.  All these options for reconstructive surgery have their advantages and all of them have about a 90% success rate with goal of returning to the same level of activity the patient had prior to injury