Medial Collateral Ligament (MCL)
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 MCL is actually fairly
complex in its structure and attachments, connecting the femur (thigh
bone) to the tibia (shin bone) preventing excessive side to side
translation of these 2 bones. It also has very important attachments
to the meniscus or cartilage cushion inside the knee on the medial
side (inside part). This helps to stabilize the meniscus and prevent
it from moving more than it should. It also has a very small role in
rotational stability of the knee and anterior to posterior (forward to
backward) translation of the lower leg.
A tear in the MCL occurs as a relatively common injury in certain
sports such as football, soccer and basketball as it typically results
from another player falling on, or striking the outside of the knee
joint. This applies a "valgus" force to the knee which
describes the situation where the knee assumes a more
"knock-kneed" position rapidly. This applies a significant
stretch to this ligament and can lead to partial or complete tears.
This has become a relatively common mechanism of injury, especially in
collegiate football linemen, so much in-fact that many college
programs require their linemen to wear special knee braces to help
prevent this injury as the pile of players fall on one another
routinely at the line of scrimmage. There is actually a small amount
of scientific evidence to support this idea.
Typically with an injury to the MCL, the player will experience pain
and possibly a "pop" on the medial or inside part of the
knee. There may be a small amount of swelling and eventually bruising
in this area, but typically the swelling is not dramatic and does not
involve the entire knee. The bruising pattern can also demonstrate the
specific area of the injury and sometime the mechanism as well. The
player will have pain, however this may resolve nearly 100% even
within a few days for minor injuries and low grade partial tears. With
larger and more severe injuries, the pain may persist and the player
may experience a sense of instability or shifting of the bones while
walking or attempting to return to play.
The diagnosis is made based on the history of the injury (how it
happened) and the symptoms that are present at the time of evaluation,
as well as some specific physical exam tests that your orthopaedic
surgeon will perform. This is typically how the extent and grade of
the injury is determined. X-rays and an MRI are important to obtain as
well to identify, in detail, the location of the injury within the
ligament and any associated injuries. The injury location is a key
piece of information as it will affect the prognosis for healing
without surgery.
Most injuries to the MCL can be treated conservatively, or without
surgery. It does however require a certain amount of bracing to
protect the ligament and allow the body to heal it. Typically the body
is capable of this and players can return to play without
restrictions, but the time at which this occurs is variable depending
on the extent of the injury. If surgery is required, there is a chance
to directly repair the ligament in some cases. If this is not
possible, due to either the location or extent of the injury, or if it
is a chronic injury, then a graft reconstruction (replacement with
other tissue) is used.
