What is the Lateral Collateral Ligament?
The LCL (lateral collateral ligament) is a thin
band of tissue that runs along the outside of the knee
and connects the thighbone (femur) to the fibula, which
is the small bone that runs down the side of the knee
and connects to the ankle. Similar to the MCL (medial
collateral ligament), the LCL's primary function is
to stabilize the knee as it moves through its arc of
Tears to the LCL commonly occur as a result of direct
blows to the inside of the knee, which can over-stretch
the ligaments on the outside of the knee and, in some
cases, cause them to tear. The tear can occur in the
middle of the ligament or at either end. The ligament
can also be injured through repeated stress, which can
cause it to lose its normal elasticity. Most knee injuries
are to the ligaments that support the knee, not the
knee joint itself. In rare cases, LCL tears in children
produce breaks of the thighbone (femur) or shinbone
(tibia), called epiphyseal fractures, which require
LCL tears occur in sports that require
a lot of quick stops and turns, such as soccer, basketball,
and skiing, or in sports in which there are violent
collisions, such as football or hockey.
If the torn ligament does not heal
sufficiently to provide proper support for the knee,
you may experience instability in the joint, and you
will be more susceptible to re-injury. Grade 3 injuries
often require surgery.
There usually are three parts to an
orthopedical evaluation: medical history, a physical
examination, and tests that your physician may order.
will ask you how you injured your knee, how it has been
feeling since the injury, and if your knee has been
previously injured. Physicians also typically ask about
other conditions, such as diabetes and allergies, and
medications currently being taken. You may also be asked
about your physical and athletic goals - information
that will help the doctor decide what treatment might
be best for you in achieving those goals.
Your doctor will check for pain or
tenderness along the inside of the knee, and will exert
pressure on the outside of your knee while your leg
is bent and straight, in order to determine the severity
of the injury. Depending on the degree of pain or looseness
of your knee joint, the injury will be classified as
one of three grades:
1: Some tenderness and minor pain at the point of the
injury. This indicates that there have been small tears
within the ligament.
2: Noticeable looseness in the knee (the knee "opening
up" approximately five millimeters) when manipulated
by hand; major pain and tenderness at the inside of
the knee; swelling, in some cases. This indicates that
there have been larger tears within the ligament, but
the ligament is not completely torn.
3: Considerable pain and tenderness at the inside of
the knee; some swelling and marked joint instability.
The knee opens up approximately one centimeter when
manipulated. A grade 3 LCL tear means the ligament is
completely torn, and often occurs in combination with
a tear of the ACL (anterior cruciate ligament).
In some cases, your immediate pain and swelling may
make it too difficult for your physician to accurately
gauge the severity of the injury. If this occurs, you
may be asked to wear a light splint and ice and elevate
your knee until the swelling and pain lessen, so that
an accurate diagnosis can be made.
Should your physician require a closer look, these tests
may be conducted:
(magnetic resonance imaging) has a greater than 90 percent
accuracy rate in assessing the severity of LCL injuries,
and is commonly used if the physical examination does
not yield a satisfactory diagnosis. A stress X-ray may
also be used to look for ligament tears. This test is
like a normal X-ray, except that the doctor or technician
will hold the knee open from the side so that any widening
of the joint space will be evident on the X-ray. Anesthesia
may be required to obtain such a view.