What are Collateral Ligament Injuries?
The collateral ligaments are found on the sides of your knee. They control the side to side motion of your knee.
- The medial collateral ligament (MCL) is on the inside. It connects the femur to the tibia.
- The lateral collateral ligament (LCL) is on the outside. It connects the femur to the fibula (the smaller bone in the lower leg).
Because the knee joint relies on just these ligaments and surrounding muscles for stability, it is easily injured. Any direct contact to the knee or hard muscle contraction — such as changing direction rapidly while running — can injure a knee ligament.
Injured ligaments are considered sprains and are graded on a severity scale.
Grade 1 Sprains. The ligament is mildly damaged in a Grade 1 Sprain. It has been slightly stretched, but is still able to help keep the knee joint stable.
Grade 2 Sprains. A Grade 2 Sprain stretches the ligament to the point where it becomes loose. This is often referred to as a partial tear of the ligament.
Grade 3 Sprains. This type of sprain is most commonly referred to as a complete tear of the ligament. The ligament has been torn in half or pulled directly off the bone, and the knee joint is unstable.
The MCL is injured more often than the LCL. Due to the more complex anatomy of the outside of the knee, if you injure your LCL, you usually injure other structures in the joint, as well.
What are the symptoms of collateral ligament injuries?
- Pain at the sides of your knee. If there is an MCL injury, the pain is on the inside of the knee; an LCL injury may cause pain on the outside of the knee.
- Swelling over the site of the injury.
- Instability — the feeling that your knee is giving way.
How are collateral ligament injuries treated?
Non Surgical Care
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 for 15 to 20 minutes at a time, with at least 1 hour between icing sessions. Chemical cold products (blue ice) should not be placed directly on the skin and are not as effective.
Bracing. Your knee must be protected from the same sideway force that caused the injury. You may need to change your daily activities to avoid risky movements. A hinged knee brace will likely be recommended to protect the injured ligament from stress. To further protect your knee, you may be given crutches to keep you from putting weight on your leg.
Physical therapy. Your doctor may suggest strengthening exercises. Specific exercises will restore function to your knee and strengthen the leg muscles that support it.
Surgical Management
Most isolated medial 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, surgery may be necessary.
Stress X-rays are helpful in determining the competence of the ligament. If the integrity of the ligament appears non-functional, surgical repair or surgical reconstruction (a graft) may be indicated.Â
 MACI (Matrix-induced Autologous Chondrocyte Implantation)
MACI is a two-step procedure in which new cartilage cells are grown and then implanted in the cartilage defect.
This cartilage procedure entails taking some of your own cartilage cells, growing them in a lab and implanting them into your cartilage defect (injury site) embedded on a special collagen membrane. It is a two-step procedure.
The process begins with a minimally invasive biopsy, called an arthroscopy procedure, to procure a sample of your cartilage cells (chondrocytes). This sample is then sent to a laboratory and allowed a period of time to grow.
During a second minimally invasive procedure, your cartilage cell sample will be embedded on a special collagen membrane, then implanted into your knee by your MACI specialist. Learn more about MACI at https://www.maci.com/patients/about-maci/
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