Knee Ligament Injuries: PCL, LCL, MCL, and ACL Injury

Ligament injuries in the knee - such as an anterior cruciate ligament (ACL) -- are dreaded by professional and amateur athletes alike. They can be painful and debilitating. They can even permanently change your lifestyle.

But there's good news. While an ACL injury or other ligament damage once ended the career of many an athlete, treatment has become much more successful.

brace on knee

So what's behind these feared injuries? Ligaments are tough bands of tissue that connect the bones in your body. Two important ligaments in the knee, the ACL and posterior cruciate ligament (PCL), connect the femur or thigh bone with the tibia, one of the bones of the lower leg. Too much stress on these ligaments can cause them to stretch too far -- or even snap.

ACL injury and other ligament injuries can be caused by:

  • Twisting your knee with the foot planted
  • Getting hit on the knee
  • Extending the knee too far
  • Jumping and landing on a flexed knee
  • Stopping suddenly when running
  • Suddenly shifting weight from one leg to the other

These injuries are common in soccer players, football players, basketball players, skiers, gymnasts, and other athletes.

There are four ligaments in the knee that are prone to injury:

  • Mentioned above, the anterior cruciate ligament (ACL) is one of the two major ligaments in the knee. It connects the thigh bone to the shin bone in the knee. ACL injuries are a common cause of disability in the knee. In the U.S., 95,000 people get them every year. They are more common in women than men.
  • The posterior cruciate ligament (PCL) is the second major ligament in the knee connecting the thigh bone to the shin bone in the knee.
  • The lateral collateral ligament (LCL) connects the thigh bone to the fibula, the smaller bone of the lower leg on the lateral or outer side of the knee.
  • The medial collateral ligament (MCL) also connects the thigh bone to the shin bone on the medial or in side of the knee.

What Does a Knee Ligament Injury Feel Like?

An ACL injury -- or other ligament injury -- is sometimes hard to diagnose. Symptoms of a knee ligament injury are:

  • Pain, often sudden and severe
  • A loud pop or snap during the injury
  • Swelling
  • A feeling of looseness in the joint
  • Inability to put weight on the point without pain

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If they're not treated at the time, ACL injuries and other types of ligament injuries may act up months or years later. They can make your knee give out when you twist or pivot.

To diagnose an ACL or other ligament injury, your doctor will give you a thorough exam. If your knee is swollen with blood, your doctor may use a needle to drain it. You may need X-rays, MRI (Magnetic Resonance Imaging) scans, or other tests.

What's the Treatment for a Knee Ligament Injury?

Happily, a mild to moderate knee ligament injury may heal on its own given time. To speed the healing, you can:

  • Rest the knee. Avoid putting excess weight on your knee if it's painful to do so. You may need to use crutches for a time.
  • Ice your knee to reduce pain and swelling. Do it for 20-30 minutes every 3-4 hours for 2-3 days, or until the pain and swelling is gone.
  • Compress your knee. Use an elastic bandage, straps, or sleeves on your knee to control swelling.
  • Elevate your knee on a pillow when you're sitting or lying down.
  • Wear a knee brace to stabilize the knee and protect it from further injury.
  • Take anti-inflammatory painkillers. Non-steroidal anti-inflammatory drugs (NSAIDs), like Advil, Aleve, or Motrin, will help with pain and swelling. However, these drugs can have side effects and they should be used only occasionally, unless your doctor specifically says otherwise.
  • Practice stretching and strengthening exercises if your doctor recommends them. Stretching and strengthening exercises can help reduce stress to the knee if performed in a pain-free manner. Ask your doctor to recommend a physical therapist for guidance.

Fortunately, most collateral ligament tears do not require surgery. However certain tears as well as secondary concerns may benefit from surgery.

Unfortunately, the cruciate ligaments -- ACL and PCL -- cannot be repaired. Once they are completely torn or stretched beyond their limits, that's it. The only option is a reconstruction. In this procedure, tendons are taken from other parts of your leg or a cadaver to replace the torn ligament.

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A ligament reconstruction for an ACL or PCL injury is complicated and involved. It's not the right choice for everyone. Some people who have pain or severe instability in their knees may choose to have it. So might professional athletes -- or devoted amateurs -- who really want to return to their previous level of activity.

But if the pain is not a problem, you may choose to skip the surgery and accept the risk of some permanent instability in your leg. You may also opt for a custom-made brace. Talk over the treatment options with your doctor.

When Will I Feel Better After a Knee Ligament Injury?

Recovery time depends on how severe your knee ligament injury is. People also heal at different rates. In most cases, physical therapy can help after surgery to minimize complications and speed recovery.

While you recover -- If your medical team agrees -- you could take up a new activity that won't hurt your knee. For instance, runners could try swimming.

Whatever you do, don't rush things. Don't try to return to your old level of physical activity until:

  • You can fully bend and straighten your knee without pain.
  • You feel no pain in your knee when you walk, jog, sprint, or jump.
  • Your knee is no longer swollen.
  • Your injured knee is as strong as your uninjured knee.

If you start using your knee before it's healed, you could cause permanent damage.

How Can I Prevent a Knee Ligament Injury?

Knee ligament injuries are hard to prevent since they're usually the result of an accident. But taking some precautions might lower your risks. You should:

  • Keep your thigh muscles strong with regular stretching and strengthening.
  • Warm up with light activities before taking part in more aggressive activities.
  • Maintain flexibility.
  • Never abruptly increase the intensity of your workout. Make changes slowly.

WebMD Medical Reference Reviewed by David Zelman, MD on November 18, 2015

Sources

SOURCES: 

American Academy of Orthopedic Surgeons:  ''Posterior Cruciate Ligament (PCL) Tear.'' 

American Academy of Orthopedic Surgeons:  ''Knee Ligament Injuries.'' 

Davis, M. Expert Guide to Sports Medicine, American College of Physicians Press, 2005. 

Rouzier, P. The Sports Medicine Patient Advisor, second edition, SportsMed Press, 2004. 

U.S. National Library of Medicine MedLine: ''ACL Reconstruction.''

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