The lateral collateral ligament (LCL) may be injured or torn during contact sports, such as football and hockey, or sports that involve quickly turning or changing direction, such as soccer and basketball. LCL injuries are commonly reported after the following instances:

  • Direct blow to the inside of the knee, such as during a football tackle
  • Quickly changing directions or pivoting on one foot, such as in soccer or basketball
  • Landing awkwardly from a jump, such as during volleyball or basketball

People may also note instability in their knee, particularly with side-to-side or pivoting activities.

Isolated LCL tears are less common than other ligament injuries, such as medial collateral ligament (MCL) or anterior cruciate ligament (ACL) tears. They are most often seen in athletes and alongside other injuries, such as knee dislocations.

What Is the Lateral Collateral Ligament?

The LCL is one of the 4 main stabilizing ligaments of the knee. Ligaments are strong fibrous bands that connect bone to other bone. The LCL is located on the outside of the knee and connects the femur (thighbone) to the fibula (a slim bone that runs down the outside of the calf and forms part of the ankle joint).

See Guide to Knee Joint Anatomy


While the LCL is located on the outside of the knee, the medial collateral ligament (MCL) is located on the inside. Together, the LCL and MCL limit the knee’s side-to-side movement.

See Soft Tissue of the Knee Joint

The other two main ligaments, the anterior cruciate ligament (ACL) and posterior collateral ligament (PCL), limit the tibia’s (shin bone) and femur’s back-and-fourth movement.


The LCL Injury Grading System

An LCL injury may be diagnosed when the ligament is overstretched or torn. Ligament injures are referred to as sprains or tears. A doctor may refer to an LCL injury by its grade, which is based on severity:

  • Grade I tears refer to a slightly or mildly overstretched LCL and does not usually affect knee stability.
  • Grade II tears refer to a ligament that has been severely stretched or partially torn and may cause some joint instability.
  • Grade III tears refer to a complete tear of the LCL. A completely torn LCL may make it difficult to put weight on the affected knee.

Generally, the grade of the tear will affect symptoms.

Dr. Michael McCabe is an orthopedic surgeon specializing in sports medicine and general orthopedics at Apex Orthopedics & Sports Medicine. He previously served as a sports medicine specialist at Walter Reed National Military Medical Center in Bethesda, MD, caring for a variety of patient populations including Wounded Warriors and United States Congress.

Dr. Michael Khadavi is a sports medicine physician specializing in spine care, musculoskeletal ultrasound, regenerative medicine, and sports-related injuries. He practices at Apex Orthopedics & Sports Medicine. Dr. Khadavi is an educator in regenerative medicine and has been an invited lecturer at the American Academy of Physical Medicine and Rehabilitation, Association of Academic Physiatrists, Major League Soccer, and Stanford University.