Knee

Our Specialties

Collateral Ligament Injuries (MCL, LCL)

Anatomy

The knee is the largest joint in your body and one of the most complex. Three bones meet to form the knee joint: the thighbone (femur), shinbone (tibia), and kneecap (patella). The kneecap sits in front of the joint to provide some protection. Knee ligaments connect the thighbone to the lower leg. The four primary ligaments in the knee act like strong ropes, holding the bones together and keeping the knee stable.

  • Collateral ligaments—Found on the inside (the medial collateral ligament or MCL) and on the outside (lateral collateral ligament or LCL) of the knee, these ligaments control the sideways motion of the knee and brace it against unusual movement.
  • Cruciate ligaments—Found inside your knee joint, these ligaments cross each other to form an "X" with the anterior cruciate ligament in front and the posterior cruciate ligament in back. The cruciate ligaments control the knee's back and forth motion.

Description

The knee joint relies only on ligaments and surrounding muscles for stability, so it is easily injured. knee ligament ACL Injuries and Reconstruction Combined Knee Ligament Injuries PCL Injuries and Reconstruction sprains or tears are a common sports injury, and the MCL is injured more often than the LCL. In fact, the MCL is the most commonly injured ligament in the knee. However, due to the complex anatomy of the outside of the knee, an injury to the LCL usually includes injury to other structures in the joint, as well. Athletes who participate in direct contact sports like football or soccer are more likely to injure their collateral ligaments.

An injured ligament is considered a sprain, and is graded on following severity scale:

  • Grade 1 sprain—The ligament is mildly damaged. It has been slightly stretched but is still able to help keep the knee joint stable.
  • Grade 2 sprain—The ligament is stretched to the point where it becomes loose. This is often referred to as a partial tear of the ligament.
  • Grade 3 sprain—The ligament has been split into two pieces and the knee joint is unstable. This is commonly referred to as a complete tear of the ligament.

Symptoms

Common symptoms of collateral ligament injuries include: pain on the inside of the knee with an MCL injury; pain on the outside of the knee with an LCL injury; swelling over the site of the injury; and a feeling of instability, as if the knee may give out from under you.

Causes

Because the knee joint relies just on ligaments and surrounding muscles for stability, it is easily injured. Direct contact to the knee or hard muscle contraction, such as changing direction rapidly while running, can injure a knee ligament. Injuries to the collateral ligaments are usually caused by a force that pushes the knee sideways. These are often contact injuries, but not always. Medial collateral ligament tears often occur as a result of a direct blow to the outside of the knee, which pushes the knee inwards (toward the other knee). Blows to the inside of the knee that push the knee outwards may injure the lateral collateral ligament.

Diagnosis

Your physician will examine all the structures of your injured knee and compare them to your uninjured knee. Most ligament injuries can be diagnosed with a thorough physical examination. Other tests which may help confirm your diagnosis include magnetic resonance imaging (MRI), and X-rays, which can reveal any injury to the bone. It is possible, however, for these images to appear normal, especially if the injury occurred more than three months prior to testing.

Nonsurgical Treatment

Injuries to the MCL rarely require surgery. If only your LCL is injured, treatment may be similar to that of an MCL sprain. If your LCL injury also involves other structures in your knee, treatment will address those, as well.

  • Ice—Icing your injury is important in the healing process. The proper way to ice an injury is to apply crushed ice directly to the injured area, but over a thin cloth. Ice should not be applied directly to the skin and should be applied for no more than 15 to 20 minutes at a time, waiting at least one hour between icing sessions. Chemical cold products ("blue" ice) should not be placed directly on the skin and are not as effective.
  • Immobilization—Your doctor may apply a brace to protect your knee from the same sideways force that caused the injury, and to prevent stress on the injured ligament. Crutches may be recommended to prevent you from putting weight on your leg. You may also need to change your daily activities to avoid any risky movements.
  • Physical therapy—Your physician may suggest specific exercises to restore function to your knee and strengthen supporting leg muscles, for a more successful recovery.

Surgery

Most isolated collateral ligament injuries can be successfully treated without surgery. If the collateral ligament is torn in such a way that it cannot heal or is associated with other ligament injuries, your doctor may suggest surgery to repair it.

Recovery

Once your range of motion returns and you can walk without a limp, your doctor may allow functional progression. This is a gradual, progressive return to sports activities. For example, if you play soccer, your functional progression may start as a light jog. Then you progress to a sprint, and eventually to full running and kicking the ball. Your doctor may suggest a knee brace during sports activities, depending on the severity of your sprain.

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