Not as common as isolated ACL or MCL injuries, but they can wreak just
as much havoc on the knees.
The collateral ligaments can be found on either side of the knee, with
the MCL (short for medial collateral ligament) on the inner side and the
LCL (short for lateral collateral ligament)on the outer side. You can
think of the MCL and LCL as the knee’s stabilizers, providing for
some of the knee’s ability to steadily rotate sideways without buckling,
while also bracing it against unnatural movements. Although ligament sprains
are the most common type of knee injury, isolated (only the ligament involved
was injured) sprains usually happen more often to the ACL or MCL, which
in turn get most of the attention.
However, isolated LCL injuries do occur and are usually the result of an
excessive force or direct impact to the inside of the knee that pushes
it outward and sideways. This force can be brought on by play in collision
sports like football, soccer, and ice hockey, for example, but they also
happen in skiing and ice skating athletes, where the risk of high torque
force to the knee is also present. As would be expected, the most common
initial symptom of an LCL injury is the presence of pain at the outside
of the knee. This pain may be accompanied by swelling and instability,
or a feeling that the knee is “giving out.”
When assessing a patient for a suspected LCL injury, a doctor will perform
a physical examination to evaluate the injured knee and compare it to
the non-injured knee. He or she may also order imaging examinations including
X-ray or MRI, to determine the extent of the injury and to see if any
other knee structures were injured during the incident.
As is the case with other ligamentous injury types, LCL injuries are referred
to as “sprains,” and a grading scale of severity is applied
to them. Grade 1 sprains involve mild damage to the ligament but present
with no apparent instability or gapping of the joint when a stress test
is administered. Grade 2 sprains indicate a partial joint gapping or “tear”
of 5-10 mm upon stress testing with the knee at a flexion of 30 degrees.
Finally, grade 3 LCL sprains indicate wide gapping of more than 10 mm
with the knee at 30 degrees of flexion. Grade 3 sprains are considered
“complete” tears, with the LCL splitting into two pieces and
rendering the knee joint unstable.
Treatment for injury to the LCL depends on the grade but customarily begins
with non-surgical options including ice, bracing, and physical therapy.
Ice therapy is intended to help reduce swelling and inflammation the injured
ligament while bracing helps to protect the injured knee against further
damage from the sideways force that caused the initial injury. Physical
therapy can also be an extremely beneficial treatment option to help restore
function to the knee, while also strengthening the muscles that surround
it so that they can further protect it from injury in the future. When
the LCL is torn or injured in such a way that these treatment options
fail to provide adequate resolution to the problem, surgery may be indicated
to repair the tear and to help restore the knee to an optimal level of function.
Though an LCL sprain might sound ominous, when isolated (meaning there
are no other injured knee structures involved) these injuries usually
have a good prognosis of resolution without surgery and rarely result
in disability, long-term. As one can imagine, the lower the grade of injury,
the faster the recovery period in most cases. However, even with grade
3 sprains, return to sport can often take place around the 8-week point
post-injury.
Sources:
https://now.aapmr.org/medial-and-lateral-collateral-ligament-injuries/
https://orthoinfo.aaos.org/en/diseases--conditions/collateral-ligament-injuries/