Lateral Collateral Ligament (LCL)
The knee joint has 2 collateral ligaments; the medial collateral
ligament—MCL (inside part of knee) and the lateral collateral
ligament—LCL (outside part of knee). The LCL connects the femur (thigh
bone) to the fibula (small bone on outside of the lower leg). It
functions to protect the side to side motion of the knee and provides
rotational stability as well to a lesser extent. It has an intimate
relationship with the area of the knee that has been termed "the
posterolateral corner." This is an area of the knee that has
received significant attention in recent years as we have learned more
and more about its role in knee stability.
The LCL can be injured in a variety of ways, but usually in
combination with other ligaments in the knee. If it is injured alone,
it usually is from a direct force to the inside part of the knee,
sometimes seen in football tackles and slide tackles in soccer. More
commonly it is damaged with a pivoting or rotational injury in the
knee that damages other ligaments such as the ACL and PCL. It is also
commonly injured in knee dislocation types of injuries.
Injury to the LCL may be subtle and the athlete may have mild
instability or a feeling that the knee is giving way or shifting with
certain activities. Certainly it can have pain as the primary
complaint. This is typically pain that is located on the outside and
sometimes in the back of the knee, and usually worse with activity as
it stresses this area of injury. At the time of injury, there may be
bruising in this area and mild to moderate swelling, but it typically
will not involve the whole knee unless other structures are injured as well.
The diagnosis of this injury is made based on the history and
mechanism of the injury, some key physical exam tests that your
orthopaedic surgeon will perform, as well as the results of X-rays and
an MRI. Since LCL injuries most commonly occur with injury to other
structures, these tests are crucial to perform in order to have a
comprehensive evaluation of the knee joint.
Acute partial injuries to the LCL can be treated conservatively with
protective bracing and a gradual rehabilitation process. However,
significant and complete tears of the LCL are treated with surgery.
Depending on the location and extent of the injury, this may be a
direct repair (using your own LCL tissue) or a reconstruction with a
graft of tissue (tissue from another location, or from a donor). There
are many subtle details regarding the decision for which type of
surgery is indicated, which should be discussed with your surgeon.
