Knee Ligament Injuries: A Closer Look at ACL, MCL, PCL, and LCL Tears
What is a ligament? Many people find ligaments confusing, but in reality, they are quite simple. All ligaments in the body are tight bands of collagen that attach to two different bones AND cross a joint. Crossing a joint is key. They don't stretch, and they don't contract. Just by virtue of where they are, ligaments provide stability to a joint. Think about an ankle sprain that we have all done. You are simply tearing the lateral ankle ligaments. Ligaments hold shoulders in place and kneecaps in place. The four ligaments of the knee are:
The anterior cruciate ligament (ACL)
The posterior cruciate ligament (PCL)
The medial collateral ligament (MCL)
The lateral collateral ligament (LCL)
All four have different functions and tear with varying stresses to the knee.
Cruciate VS. Collateral Ligaments
The ACL and PCL are cruciate ligaments, as they cross each other within the knee joint, forming an "X" shape. These ligaments help control the forward and backward movement of the knee, providing stability and preventing excessive rotation.
The MCL and LCL are collateral ligaments, as they run along the sides of the knee joint and provide stability against lateral (sideways) movements. These ligaments prevent the knee from extending too far inwards or outwards, ensuring the knee stays stable and secure during activities.
The most common types of knee injuries are ACL and MCL tears, whereas injuries to the LCL are the least common. However, damage to any of these ligaments can cause knee instability and pain and affect your ability to perform everyday activities.
What Causes Knee Ligament Injuries?
Knee ligament injuries are prevalent, especially among athletes who engage in physically demanding sports, such as skiing, lacrosse, soccer, hockey, or football. Additionally, repeated stress and overuse, previous injuries, or age-related wear and tear can also put you at risk of a knee ligament injury.
A torn knee ligament is often caused by:
Cutting or pivoting maneuvers that forcefully twist the knee
Sudden stopping
Awkwardly landing from a jump
Hyperextending the knee
A hard blow to the knee
It's not uncommon for multiple knee ligament injuries to occur simultaneously. For example, a person might suffer damage to the ACL, MCL, and meniscus. This injury is known as the unhappy triad.
Which Knee Ligament Did I Injure?
The only way to know for sure which ligament is damaged is to get an accurate diagnosis from an orthopaedic knee specialist. However, here are some of the most common symptoms patients experience following ligament injuries:
ACL Tears
Feeling or hearing a "pop" at the time of injury is common
Severe pain
Immediate swelling or within a few hours
Unable to put your full weight on the knee or difficulty walking
Feeling like the knee may give out
Limited range of motion
MCL Tears
Pain on the inner side of your knee
Stiffness
Feeling unstable when walking
A locking sensation when straightening or bending the knee
A popping sound when the injury occurs
LCL Tears
Pain, bruising, or tenderness on the outside of the knee
Swelling
A catching sensation in the knee during movement
Feeling like the knee could give way
PCL Tears
Pain behind the knee, especially when squatting or kneeling
Tenderness, particularly in the back of the knee
Mild to moderate swelling
Feeling like the knee is unstable
Why Do Some Ligaments Heal Well Without Surgery, and Which Ones?
The MCL typically does a good job of healing without surgery, although you need the proper bracing and physical therapy. The ACL, unfortunately, never heals without surgery. Why is that?
The MCL is positioned outside of the knee joint, meaning away from the toxins and enzymes of the synovial fluid. Plus, being surrounded by muscles, the MCL has a good blood supply to help with healing.
The ACL, being inside the joint, is actually in a hostile environment for healing. So when we are evaluating you with a torn ACL, we aren’t wondering if the ACL can heal; we are evaluating whether you can perform all of the activities that are important to you without an ACL or whether you need this ligament fixed.
Likewise, the PCL is inside the joint for the most part, and the LCL is mostly outside of the joint.
There is a lot to discuss on any torn ligament in the knee. When developing a treatment plan, Dr. Sterett will consider not only the type and extent of the injury but also the desired level of activity you want to return to.
Get Back in the Game with Team Sterett’s Expert Care
Dr. Sterett and his team of sports medicine specialists at Vail-Summit Orthopaedics & Neurosurgery are the preferred choice for those wanting the highest level of care for knee ligament injuries.
Contact Team Sterett today for personalized knee injury treatment that will get you back to your peak performance. Call (970) 476-7220 today or request a consultation using our online form.
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