Understanding Knee Ligaments: ACL, PCL, MCL, and LCL Explained
- Team VSON
- 28 minutes ago
- 2 min read
Your knee is a complex joint that depends on four key ligaments for stability and function: the ACL, PCL, MCL, and LCL. These structures work together to keep the knee strong, stable, and aligned during movement. At Vail-Summit Orthopaedics & Neurosurgery (VSON), our knee specialists—Dr. Richard Cunningham, Dr. Terrell Joseph, Dr. Max Seiter and Dr. William Sterett—help patients of all activity levels recover from ligament injuries and get back to doing what they love.
In this post, we break down the role of each ligament, how injuries happen, and when to seek expert care.
ACL: Anterior Cruciate Ligament
The ACL is one of the most commonly injured ligaments in the knee, especially in athletes involved in pivoting sports like soccer, skiing, or basketball. It connects the femur (thighbone) to the tibia (shinbone) and helps control forward motion and rotation of the knee.
Common causes of ACL injuries:
Sudden stops or direction changes
Landing awkwardly from a jump
A “pop” sound followed by swelling and instability
PCL: Posterior Cruciate Ligament
The PCL lies behind the ACL and is responsible for preventing the tibia from sliding too far backward. It’s thicker and stronger than the ACL and is often injured by a direct blow to the front of the knee—such as in car accidents or contact sports.
Signs of a PCL Injury:
Pain behind the knee
Difficulty walking downhill or descending stairs
Swelling and reduced motion
MCL: Medial Collateral Ligament
The MCL is located on the inside of the knee and helps stabilize the joint against inward forces. Injuries typically occur when the outside of the knee is struck during sports or a fall.
Symptoms of an MCL Tear:
Pain on the inner side of the knee
Swelling and tenderness
Feeling like the knee may “give out”
LCL: Lateral Collateral Ligament
The LCL supports the outside of the knee and helps prevent it from buckling outward. LCL injuries are less common but can occur during sports that involve twisting motions or if the inside of the knee is struck.
Indicators of an LCL Injury:
Outer knee pain and swelling
Weakness or instability
Bruising on the outer knee
Why Choose VSON for Knee Ligament Injuries?
Whether you're dealing with a torn ACL or a sprained MCL, the team at VSON offers the highest level of orthopedic care. Dr. Richard Cunningham, Dr. Terrell Joseph, Dr. Max Seiter and Dr. William Sterett are renowned for their expertise in treating knee ligament injuries using cutting-edge technology and a patient-first approach.
We offer:
Diagnoses: Onsite imaging and clinical evaluations to identify the extent of your injury.
Personalized Treatment Plans: From bracing and rehab to surgical reconstruction, we tailor care to your goals.
Athlete-Focused Recovery: We understand the importance of getting back to peak performance—safely and efficiently.