Overstretched or Torn Ligaments of the Knee

Ligaments are strong, but flexible, bands of tissue that connect bones around joints to stabilize them. In the knee joint, there are four main ligaments: the medial collateral ligament (MCL), lateral collateral ligament (LCL), anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). If these ligaments are overstretched or hit, injury can occur.

  • The MCL and LCL run along each side of your knee. Injuries to these ligaments typically occur because the knee is hit from the outside or inside or twisted awkwardly.
  • The ACL, which is in the middle of your knee, can be injured if you stop moving too suddenly, change direction too quickly, make a wrong landing from a jump or get hit in the knee from the front.
  • The PCL, which is located deeper within the knee behind the ACL, can be injured if your knee is hit with a great deal of force while it is bent.

A knee ligament injury can be either partial (the ligament is loose and partially torn) or complete (the ligament is completely torn).

Though knee ligament injuries can happen to anyone who is active, they’re more common in athletes – especially ACL tears and MCL tears.

Symptoms, Diagnosis and Outlook

The signs and symptoms of a knee ligament injury are:

  • Pain and swelling of the knee (MCL and LCL injuries cause pain on the sides of the knee, while ACL and PCL injuries cause pain in the center)
  • A popping sound at the time of injury
  • An unstable feeling in the affected knee
  • Inability to bear weight on the affected knee
  • A loss in range of motion

The pain and swelling may go away when you rest, but then return when you’re active. If you can’t walk or the pain and swelling don’t improve after a few days of rest, make an appointment with an orthopaedic and sports medicine specialist. He or she can diagnose your injury through a physical exam and magnetic resonance imaging (MRI) when indicated. A quick diagnosis is important to prevent further damage to your knee.

Some knee ligament injuries require surgery to fully restore the function of the knee. This is especially true if you’re an athlete looking to return to your sport. Mild knee ligament injuries can sometimes be rehabilitated with only rest and possibly physical therapy, guided by your doctor’s advice.

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Top-Ranked by U.S. News & World Report

Penn State Health includes the Milton S. Hershey Medical Center, ranked as one of the best orthopedic providers in the country by U.S. News & World Report. This honor was earned because our doctors consistently deliver exceptional patient care and outcomes through their commitment to advanced treatments, translational research and provider training.

Coordinated, Specialized Care Through a Dedicated Institute

Our orthopaedic specialists work together through our dedicated Penn State Bone and Joint Institute. There, they focus on providing you with multidisciplinary, tailored care and state-of-the-art treatments and technologies. This produces the highest-quality patient outcomes. All physicians at the institute are fellowship-trained and subspecialize in additional niche areas of orthopaedics, including arthritis care and joint arthroplasty (joint replacement surgery).

Designated as a Blue Distinction® Center

Penn State Bone and Joint Institute is a Blue Distinction Center for Knee and Hip Replacement. This superior designation from BlueCross BlueShield is only given to health care facilities and providers that stand out for their expertise in delivering specialty knee and hip replacement care. Our surgeons specialize in a range of pain-relieving procedures, including partial knee replacement, total joint arthroplasty, joint preservation surgery and complex revision surgery. They perform more than 1,000 joint replacement procedures every year.

Confidence in Treatment Through Education

We developed a special joint replacement education website just for patients undergoing joint arthroplasty. The website takes you step by step through the joint replacement process. From things to consider before choosing surgery to recovery after surgery, you’ll find the information you need to help you feel confident in your decision to undergo joint replacement.

Advancing Orthopaedic Medicine Through Research

The doctors and researchers in our Center for Orthopaedic Research and Translational Science at the Milton S. Hershey Medical Center are committed to advancing our field through scientific discovery and education. As the only academic medical center in central Pennsylvania, Hershey Medical Center is a national leader in research, in partnership with Penn State College of Medicine, and on the leading edge of new treatment options, including clinical trials.

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