Surgery: Purpose of ACL Surgery

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The anterior cruciate ligament (ACL) is the stabilizing force in your knee. A common injury in athletes, an ACL tear or injury doesn't always require surgery to repair. When it does, the process can be quite extensive. Keep reading to find out if you should have ACL surgery and why.

Diagnosis Related to ACL Surgery

The anterior cruciate ligament, or ACL, is an important ligament in your knee. This ligament provides stability to the knee. Despite its strength, this ligament can be easily torn.

An ACL tear is one of the most common injuries among athletes, with between 100,000 and 200,000 ACL ruptures each year in the United States alone.

The majority of these injuries happen outside of professional sports but do happen a lot in athletes. Football is one of the most high-risk sports for ACL injuries, and women athletes are more likely to have an ACL rupture than men.

When an ACL injury occurs, you will probably have some pain, swelling, and maybe even trouble walking. When your doctor first examines the injury, it may be difficult to make a full diagnosis because of the swelling at the injury site.

Your doctor may have you do the following things, referred to by the acronym R-I-C-E, before confirming a diagnosis:

  • Rest: Avoid weight bearing on the injured knee.
  • Ice: Ice packs can help decrease pain and swelling.
  • Compression: Use an elastic bandage or compression wrap around your knee.
  • Elevate: Lie with your injured knee propped up.

It may take several weeks of rehabilitation therapy, either with a physical therapist or at home, before you have more comprehensive medical treatment, such as surgery, for an ACL injury.

A knee brace or crutches may help to stabilize your knee while you complete therapy. The goal during this time is to reduce pain and swelling, strengthen your muscles, and maintain a full range of motion for your knee.

For people who are mostly inactive or play sports only casually, physical therapy may be enough to manage an ACL injury. Younger people or those who play sports more competitively may opt for surgical repair.

Person with knee pain may have a torn ACL and need ACL surgery
 Jan-Otto / iStock / Getty Images

Criteria

Your doctor might recommend surgical repair for an ACL injury for the following reasons:

  • You are an athlete and want to continue playing your sport.
  • More than one ligament is torn.
  • The meniscus of your knee is also torn.
  • Your knee buckles during everyday activity.

Ultimately, the decision of whether to do surgery or not depends on what you hope to get out of your recovery. Younger patients tend to choose surgery over more conservative management.

If you decide to have a surgical repair done, you have to commit to a lengthy rehabilitation process. Most rehab programs after ACL surgery require 10 to 12 weeks of intensive physical therapy and strength-building. Even after repair, athletes must also realize that they may not return to their former level of play.

A study reports that’s up to a third of athletes who have ACL repair end up having another tear in the same or opposite knee within two years of the original injury. A longer recovery period may help reduce the risk of re-injury, according to the research.

Tests and Labs

Evaluation should occur as soon as possible after an ACL injury. The initial examination usually includes a visual assessment of swelling, pain, and gait. These initial exams are limited due to pain and swelling in most cases. Your doctor will mainly focus on asymmetry and the presence of hemarthrosis (bleeding in the knee joint).

These knee examinations can be pretty accurate at diagnosing and ACL tear, but there are other tests that increase the reliability of the diagnosis:

  • Knee arthroscopy: This is a surgical procedure that allows a doctor to visualize the inside of your knee through small incisions and a camera inserted through the opening. This and magnetic resonance imaging (MRI) are the definitive tests for diagnosing an ACL tear, or additional injuries within the knee after an ACL rupture, in the U.S.
  • Magnetic resonance imaging: An MRI is the primary way to diagnose and ACL in the U.S., according to the American Academy of Family Physicians. A complete series of scans includes anterior-posterior, lateral, tunnel, and sunrise views. An MRI can also help catch collateral injuries (injuries that occur alongside an ACL injury or tear). Collateral injuries happen in up to 75% of ACL injuries.
  • Lachman test: A passive movement test that examines the stability of the ACL. When performing the Lachman test, your doctor will have you lay down, and feel the movement of your ligaments as your knee bends. Video of Lachman test.
  • Anterior drawer test: Similar to the Lachman test, during the anterior drawer test, your doctor will have you lay down and bend your knee with your foot resting on a table. Holding your foot down, your doctor will pull and push at your calf to test the stability of the ACL. Video of anterior drawer test.
  • Pivot shift test: During this test, you will lay down with your leg straight. The examiner will lift your leg, rotating at the knee to test stability. See the test Video of pivot shift test.
  • X-rays and ultrasound: These scans can also provide imaging, although not in as great detail as an MRI.
  • Lab testing: In addition to scans and physical examinations to test your ACL, your doctor will also perform routine lab testing as a part of the standard pre-operative process.

A Word From Verywell

An ACL injury doesn’t always require surgery. If you are older, or live a more sedentary lifestyle, you might opt for conservative management and physical therapy. For younger, or more active and athletic people, surgical repair is possible.

You have to be willing to commit a lot of time and dedication to the rehabilitation process, which can take up to three months. Athletes usually do not return to play after ACL surgery for about a year.

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  5. Paterno MV, Rauh MJ, Schmitt LC, Ford KR, Hewett TE. Incidence of second ACL injuries 2 years after primary ACL reconstruction and return to sport. Am J Sports Med. 2014 Jul;42(7):1567-73. doi:10.1177/0363546514530088

  6. SportsMED Orthopaedic Surgery & Spine Center. ACL exam Lachmans test, pivot shift, drawer test performed by Dr. Eric Janssen. 2011.