Are You Considering Having
ACL Surgery?

Has ACL surgery been recommended to treat your knee sprain? An ACL tear can be a significant injury. What does ACL reconstruction surgery involve? How long is the rehab? Is surgery necessary? Learn what you should know about this procedure before you go under the knife.

What is an ACL tear?

The ACL is one of the four main ligaments of the knee. The four are: the medial collateral, lateral collateral, posterior cruciate (PCL), and the anterior cruciate (ACL). These ligaments connect one bone to another and assist in providing stability to the knee. A knee sprain is an injury to any of these ligaments.

ACL Injury

The ACL functions to help control rotation and limits the ability of the tibia to move forward. A tear of the ACL generally occurs when the knee rotates inward while the foot is in contact with the ground. Although injuries to the ACL can occur with contact, most ACL tears are non-contact injuries. Skiing, soccer, and basketball are common sport activities that have a high incidence of ACL tears. ACL injuries are also more common in girls than in boys.

ACL Injury

Who needs ACL Surgery?

ACL tears are diagnosed by MRI. Only those with complete ACL tears are surgical candidates. Partial ACL tears or knee sprains do well with physical therapy treatment. Frequently, when the ACL is completely torn, other structures including the medial meniscus and medial collateral ligament can also be torn. Injuring all three of these structures is called the “terrible triad”.

If the ACL is completely torn, surgery is not always required. Age and level of activity play an important role in deciding whether surgery is necessary. An older adult that is not involved in agility activities will not need surgery. Not having the ACL reconstructed does increase the risk of having further meniscus tears.

A younger more active person would significantly benefit from having ACL surgery as it will allow them to return to normal activity. Without having the ACL repaired the risk of the knee giving way or buckling remains and does the risk of meniscus tears.

What does ACL Reconstruction Involve?

When the ACL is torn, it is not technically repaired as the ends of the ligament cannot be reattached. Instead, the ACL is reconstructed by creating a new ligament. There are three main options for reconstructing the ACL ligament: use of the patella tendon, the hamstring, and an allograft.

Using the patella tendon for reconstruction of the ACL has been the ‘gold standard’ ACL surgery. The benefit of using the patella tendon is that it is a bone-tendon-bone graft. The middle third of the patella tendon is harvested with taking a small bone fragment from the patella above and the tibial below.

ACL Surgery

The benefit to this bone-tendon-bone graft is the strength of the fixation. Bone heals well when attached to bone, which is what this type of graft delivers. The biggest issue with utilizing the patella graft is the development of anterior knee pain. When anterior knee pain is present, the rehabilitation progress is slowed. The hamstring is another potential graft source. Although this technique does not create the bone-tendon-bone fixation, using the hamstring does not disrupt the patella tendon and reduces the risk of anterior knee pain.

Finally, the use of an allograft can be used for the new ligament. An allograft is cadaver tissue, most commonly from the Achilles, hamstring, or patella tendon. The benefit to using an allograft is there is no need for a secondary surgery to harvest the graft. Most ACL reconstructions are done via an arthroscopic procedure. Surgery takes a couple of hours and frequently is done on an outpatient basis. Following surgery you will be on crutches (the length of time varying based on your surgeon). Physical therapy frequently is initiated within two weeks after surgery.

Physical Therapy

The specific physical therapy protocol will be determined by the physician and influenced by the specific procedure and graft utilized. Focus immediately after surgery is on minimizing swelling, obtaining full knee extension, and initiating quad activity. Swelling is the enemy as the greater the swelling, the stiffer the knee, and the more difficult it will be to initiate quad activity. Utilizing ice therapy on a consistent basis will be greatly helpful in controlling post-operative swelling.

Although ACL surgery is common, it does not come without risk of complications. Complications following surgery can include infection, knee stiffness, anterior knee pain, and graft failure.

Regular physical therapy will be part of a successful surgical outcome. Early therapy emphasis will focus on reducing swelling and restoring full range of motion with progression toward strengthening, balance exercises, and eventually running and jumping. Recovery from surgery back to full sports activities will usually require six months of rehabilitation.

With any surgery, including ACL surgery, seek more than one opinion before deciding on a surgeon. Communicate with your surgeon to determine what surgical procedure will be best for your situation. Rehabilitation following surgery will require dedication and effort. Follow the recommendations of your surgery and physical therapist to ensure the best outcome possible.


• Most ACL tears are non contact injuries

• Females have a higher incidence of ACL tears

• Meniscus tears are frequently associated with ACL injuries

• Surgery to reconstruct the ACL can involve utilizing a patella tendon, hamstring tendon, or allograph.

• Early post operative goals include: control swelling, full knee extension, and quad activation

• Most people return to sports within 4 months after surgery

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Phys Sportsmed. 2010 Oct;38(3):61-8.Current concepts in ACL Injuries.Cheatham SA, Johnson DL

Am J Orthop (Belle Mead NJ). 2011 Feb;40(2):92-7.Partial tears of the anterior cruciate ligament: diagnosis and treatment.Tjoumakaris FP, Donegan DJ, Sekiya JK

Knee Surg Sports Traumatol Arthrosc. 2011 Mar;19(3):462-72. Epub 2010 Oct 15.Does autograft choice determine intermediate-term outcome of ACL reconstruction?Magnussen RA, Carey JL, Spindler KP

Have you had ACL surgery?

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