Torn Anterior Cruciate Ligament (ACL)

The anterior cruciate ligament (ACL), one of the four major ligaments in the knee, keeps the knee stable, prevents one bone from moving upon the other bone, and preserves the normal biomechanics of the knee. Sometimes called “the seatbelt of the knee,” the ACL can be stretched or torn due to sudden twists, turns or stops. A torn ACL is the most common ligament injury in the knee that we see at Alexander Orthopaedics.

What are the symptoms of a torn ACL?

Someone with a torn ACL typically experiences a popping sensation and the feeling that the knee is giving out underneath them, followed by severe pain and rapid swelling. Other torn ACL symptoms include: 

  • Difficulty walking and bearing weight
  • Tenderness along the joint
  • Loss of range of motion
  • A feeling of instability

What causes a torn ACL?

Most ACL tears occur due to a sport- or fitness-related injury. Typically, the foot is planted and the knee locks and twists at the same time, causing the ligament to be torn. This can happen when changing direction rapidly, slowing down or stopping suddenly, landing from a jump incorrectly, or direct contact or collision.

What are the risk factors for a torn ACL?

According to Harvard Medical School (HMS), female gymnasts and soccer players are particularly prone to ACL tears. Several other factors can increase your risk for an ACL tear, including: 

  • Sports: Participation in certain sports, including basketball, soccer, gymnastics and football.
  • Equipment: Using sports equipment that is poorly maintained or wearing footwear that doesn’t fit properly.
  • Gender: Women are more likely to tear their ACL due to their anatomy and muscle function.

How is a torn ACL diagnosed?

When you are getting evaluated for an ACL injury, you will first receive a physical examination to evaluate swelling and bruising, as well as areas of tenderness and stability issues. The Lachman test, the anterior drawer test, and the pivot-shift test may also be used to test the stability of the ACL.

After the physical examination, the doctor may order X-rays to determine whether or not there are any fractures. The physician may also perform the Lachman’s test to determine if the ACL is intact. An MRI scan can be ordered to evaluate whether or not any other knee ligaments or cartilage have been injured.

ACL injuries are classified by the following grading system:

Grade 1

The injury is typically mild, including microscopic, tiny tears that may stretch the ligament out of shape but do not impact the overall stability of the knee joint.

Grade 2

The injury is moderate, where the ligament is partially torn. The knee can be somewhat unstable and give way while walking.

Grade 3

The injury is severe, and the ligament is torn completely in half, no longer providing stability to the knee joint.

How do you prevent ACL tears?

Whether you are an athlete or just like to keep active, here are some tips on how to prevent ACL tears: 

  • Always warm-up and stretch before participating in athletic activities
  • Do exercises that strengthen the leg and core muscles
  • Never push yourself too hard or too fast
  • Wear shoes that are comfortable and supportive, and that fit your sport
  • Practice proper technique when training and exercising
  • Make sure you get plenty of rest

What is the difference between a partial ACL tear vs. complete ACL tear?

Tears in the ACL can be partial or complete. There are two bundles in an ACL, meaning the ACL is made up of two different strands of ligaments. Partial ACL tears occur when only one of the bundles tear or one portion of one of the bundles tears. 

According to Dr. Vladimir Alexander, a founding partner of Alexander Orthopaedics, “partial tears can sometimes be left alone and can heal on their own, but certain people feel unstable even with a partial tear. If they feel unstable either clinically or sub-clinically — meaning the doctor can’t tell they’re unstable but the patient can tell they’re unstable — those patients generally need [their ACL] to be reconstructed, as well.”

What is the treatment for a torn ACL?

Nonsurgical treatment

A torn ACL doesn’t heal on its own, but nonsurgical treatment is suitable for children patients, adult patients who are not very active, or patients with Grade I or Grade II tears. 

  • RICE: Initial treatment for a partial tear typically involves resting the joint, applying ice to the injured area, compressing the swelling with a bandage, and elevating the injured area.
  • Medication: Taking a nonsteroidal anti-inflammatory, like ibuprofen, can ease swelling and relieve pain.
  • Physical therapy: Learning rehabilitation exercises from a physical therapist can help you build strength in the leg muscles and regain range of motion in the knee. 
  • Knee braces: Wearing a knee brace can help protect the knee from instability.

Also, Dr. Alexander says that, in cases where patients are older or have arthritic knees, the ACL is torn slowly over time. In these circumstances, reconstruction is not recommended, because it will actually make the knee too tight and create more bone-on-bone pressure, pain, and problems.

While not having surgery can lead to a quicker recovery, it’s also important to be careful in cases of complete tears. “If you don’t fix a complete ACL tear, they have abnormal biomechanics and they end up needing a knee replacement prematurely because the knee ends up wearing out prematurely,” says Dr. Alexander.

Surgical treatment

For people in their 20s and 30s, as well as middle-aged adults who are active, surgery is typically recommended in cases of a complete tear. In ACL reconstruction surgery, the surgeon replaces the damaged ligament with a segment of tendon, which comes from another part of your knee or from a donor. 

“There has been some push to do some ACL repair as opposed to reconstruction,” says Dr. Alexander. “That has been shown not to work very well. So, reconstructions have come back into favor as opposed to ACL repair. Those have a very high failure rate.” 

Rehabilitation therapy is required after reconstruction surgery to restore stability and function to the knee.

What is the torn ACL recovery process?

It can take anywhere from six to nine months to restore normal knee function. Walking on a torn ACL, bending your knee, or putting weight on it too soon can increase damage and pain, but it depends on the grade of the injury. If the injury is mild, you might be able to walk on a torn ACL after a few weeks of rehabilitative therapy. 

It’s essential to work with an experienced physical therapist and surgeon to recognize the right balance of exercise and rest to rehabilitate the knee in the best way possible. 

At Alexander Orthopaedics, we work with you to develop a personalized treatment plan for your torn ACL diagnosis, treatment and recovery. 

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