What is the Medial Collateral Ligament?
The MCL (medial collateral ligament) is a broad,
thick band of tissue that runs down the inner part of
the knee, from the thighbone (femur) to about four to
six inches from the top of the shinbone (tibia). The
MCL's primary function is to prevent the leg from hyperextending
inward, but it also is part of the mechanism that stabilizes
the knee and allows it to rotate.
Injuries to the MCL commonly occur as a result of direct
blows to the outside of the knee, which can over-stretch
the ligaments on the inside of the knee and, in some
cases, cause them to tear. The tear can occur in the
middle or at either end of the ligament. It is not uncommon
for athletes to suffer tears of the MCL and ACL (anterior
cruciate ligament) at the same time. The ligament also
can be injured through repeated stress, which can cause
it to lose its normal elasticity, not unlike a worn-out
The MCL usually is injured by direct
contact to the outside of the knee. A perfect example
is a clip block in football, in which one player collides
with another player from the side. MCL tears also occur
in sports where there are a lot of quick stops and turns,
such as soccer, basketball, and skiing. Slipping on
ice, if your lower leg splays outward, can produce the
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. Most MCL injuries
are treated with braces. However, in rare cases, surgery
may be required.
There are usually three parts to an
orthopedic evaluation: medical history, physical examination,
and tests your physician may order.
will likely 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.
| PHYSICAL EXAMINATION
Your physician 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, to approximate the cause 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:
one: some tenderness and minor pain at the point of
two: 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.
three: 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 three MCL tear often occurs in
conjunction with a tear of the ACL (anterior cruciate
ligament) or, more rarely, the PCL (posterior cruciate
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.
(magnetic resonance imaging) has a greater than 90 percent
accuracy rate in assessing the severity of MCL injuries,
and is commonly used if the physical examination does
not yield a satisfactory diagnosis. A stress X-ray rarely
will 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.