Anterior Cruciate Ligament (ACL) Reconstruction

The Injury

Anterior cruciate ligament injury ("ACL blowout") usually results during activity when the knee is subject to a variety of stresses, i.e. sports. Typically the foot is planted and the injured leg is either hit or the athlete is trying to make a cutting maneuver when the knee "gives out." The athlete may often feel or even hear a "pop" in their knee and is unable to keep playing. Interestingly, women seem to be 2-5 times more likely to injure their ACL compared to men. The reason for this is unknown at this time

Pain and swelling may ensue immediately or over the next 24 hours. Often the injured player gets emergency evaluation, but do to the pain and swelling, it is often difficult for the doctor or trainer to examine the ligament. X-rays don't usually show the injury and the athlete is usually advised to keep the knee wrapped, iced, and elevated for the next 5-7 days.

Usually after 7 days, the swelling and pain resolves enough for the doctor/trainer to examine and test the ACL. A simple stress maneuver is usually sufficient to make the diagnosis of an ACL tear; if there is any question an MRI can confirm the injury.

Who Benefits From Reconstructive Surgery

Not everyone who injures the ACL needs it reconstructed. You don't need your ACL to live and in fact don't need your ACL to perform most day-to-day activities (sitting, walking, climbing stairs). However, if you want to perform cutting maneuvers and want to get back to playing sports such as football, basketball, and soccer, you are probably going to want to have your ACL reconstructed. Without it you might experience inability to change directions without your knee slipping and episodes of your knee giving way.

There have also been recent studies to show that knees that don't have an ACL reconstruction may be at risk for meniscus tears, cartilage damage, and early arthritis.

Candidates for ACL Reconstruction

1. Children and young adults - Anyone less than 18 years old probably deserves to have their ACL reconstructed even if they don't currently compete in athletics. Children and young adults without an ACL have a much higher rate of cartilage damage, as they get older.
2. Athletes - An ACL will help cutting maneuvers and side-to-side movement.
3. Heavy laborers - An ACL will likely aid in carrying heavy objects while kneeling or turning.
4. Recreational athletes - Even people who want to continue to play soccer, basketball or ski will likely benefit from ACL reconstruction.
5. Anyone who has failed non-operative treatment - Anyone who is having repeated episodes of their knee giving out, despite the use of a brace or modifying their activities would likely benefit from ACL reconstruction.

The Surgery

ACL reconstruction surgery is usually performed as an outpatient procedure and takes about 2 hours to perform. The surgery is done arthroscopically through small "holes" in the knee and most of the procedure is done with the surgeon watching a television monitor. Despite most of the surgery being done with the arthroscope, a longer incision is required to harvest the tissue necessary to replace the torn ACL. This incision is what is noticeable after surgery.

The Timing of Surgery

Most people wonder why their ACL isn't reconstructed the same day it's injured. Isn't it better to do the surgery as soon as possible? In fact, it is not. Studies have shown that the ideal time to do surgery is when the initial swelling and pain have resolved and the motion has been fully restored to the injured knee. If surgery is done before this, there is a higher chance for developing a "stiff" knee after the surgery. Most surgeons will wait a few weeks before performing the surgery and may even have the patient go to physical therapy before the surgery to help restore motion.

Graft Choices

There are several options when it comes to the type of material used to reconstruct the ACL ligament and pros/cons to each choice.

1. Patella tendon or "Bone-Patella Tendon-Bone"
   This is the "time honored" method of reconstructing the ACL ligament. It makes use of a strip of the patella tendon and a piece of bone cut out of the knee cap and a piece of bone cut out of the tibia (shin bone).
   Advantages - It has proven to work well in all types of patients.
   Disadvantages - A hole has to be cut in the kneecap bone, which can weaken the kneecap. This technique also leaves a longer scar than other choices.
2. Hamstring
   This is becoming an increasingly popular method for ACL reconstruction over the last few year. This method uses two of the tendons from the hamstring muscles.
   Advantages - It leaves a much smaller scar, and is the strongest graft choice possible.
   Disadvantages - This graft does seem to "loosen" in younger female patients and probably not a good choice for an active woman or contact sports athletes.
3. Allograft
   This is a graft that comes from a cadaver.
   Advantages - You don't have to use your own tissue to make the graft (no incisions necessary)
   Disadvantages - It puts someone else's tissue into your body. Rehab can be prolonged.
4. Synthetic grafts
   These are man-made materials used to replace the ACL. They were used in the past and most did not work well.
   Advantages - none
   Disadvantage - It will probably break and you will need another surgery.

Other Associated Injuries

An ACL tear is not usually the only injury that happens to the knee when someone "blows out" the ligament. There is typically severe bone bruising and other ligaments can rupture including the Medial Collateral Ligament (MCL) or Lateral Collateral Ligament (LCL). Typically, the MCL heals without surgical repair but the LCL usually requires surgical repair if it is torn in conjunction with the ACL.

Other injuries that are seen with ACL tears are tears of the meniscus, which are the shock-absorbing cushions of the knee, and damage to the articular cartilage of the knee. Most of the injuries are addressed at the time of the ACL reconstruction surgery. If the surgeon has to repair a meniscus at the same time the ACL is reconstructed, they may not let you put weight on your knee for 6 weeks while the meniscus repair heals.

The Rehab

This is the one area of ACL Reconstruction that the patient will dedicate most of their time and energy towards. The surgery takes a day; the rehab takes a year. Most patients can expect to return to play at 6-9 months after ACL reconstruction. A typical rehab protocol includes letting the patient put full weight on their knee immediately after surgery (unless a meniscus repair was also performed), and restoring full motion to the knee as quickly as possible. Once motion has been restored, muscle strength, flexibility and coordination are re-developed.

One question the patient usually asks is if they will need to wear a brace. The answer is no, but some patients like the security of the brace and we leave up to each individual if they want to wear one.