Common Knee
Injuries
About The Knee:
The bones of the knee,
the femur and the tibia, meet to form a
hinge joint. The joint is protected in
front by the patella (kneecap).
The knee joint is cushioned by articular
cartilage that covers the ends of the tibia
and femur, as well as the underside of the
patella. The lateral meniscus and medial
meniscus are pads of cartilage that further
cushion the joint, acting as shock absorbers
between the bones.
Ligaments help to stabilize the knee. The
collateral ligaments run along the sides of
the knee and limit sideways motion. The
anterior cruciate ligament, or ACL, connects the tibia to the
femur at the center of the knee. Its
function is to limit rotation and forward
motion of the tibia. (A damaged ACL is
replaced in a procedure known as an ACL
Reconstruction.) The posterior cruciate
ligament, or PCL (located just behind the
ACL) limits backward motion of the tibia.
These components of your knee, along with
the muscles of your leg, work together to
manage the stress your knee receives as you
walk, run and jump.
Common Knee Injuries:
Patellar Tendon
Strain
The patellar tendon
is a very strong
tendon which extends
for a short distance
below the knee cap
(patellar). It is
used whenever the
knee bends under load
e.g. jumping,
squatting, kicking
etc. The most common
injury is an over use
injury by overwork
although a sudden
injury can occur if
the knee is blocked
whilst traveling from
the bent to straight
leg position e.g. if
you catch the ground
whilst running or
kicking.
Knee-cap
Dislocation
Knee-cap dislocation
occurs when the
knee-cap slips or has
been pulled out
sideways under the
influence of the
contracting
quadriceps muscle
group. Usually the
knee-cap returns to
it's correct position
and a certain amount
of swelling and
discomfort is
apparent.
Patello-Femoral
Syndrome (PFS)
The patella, commonly
referred to as the
"knee cap", and its
tendon transmit power
from the quadriceps
to the lower leg.
Normally, as the knee
bends, the patella
slides smoothly along
a groove in the thigh
bone. However, under
certain conditions
the patella may
experience forces
which push it against
the sides of the
groove, causing pain.
Additionally,
inflammation and
roughening of the
smooth underside of
the patella may
occur. Collectively,
this process is
referred to as
patello-femoral
syndrome (PFS).
Medial Collateral
ligament strain
This ligament
protects the
inner-side of the
knee and can be
injured by a twisting
strain on the knee
such as can occur in
a tackle or if your
foot slips whilst
running. It is also
possible to suffer
from an overuse
injury to this
ligament. If the
collateral ligament
is completely torn or
torn in such a way
that ligament fibers
cannot heal, you may
need surgery. Repair
may bring good
results, with a
return to good knee
stability. After
satisfactory
rehabilitation, many
people resume their
previous levels of
activity.
Lateral Collateral
ligament strain
The lateral
collateral ligament
(LCL) connects the
thighbone to the
other bone in the
lower portion of your
leg (fibula) and
stabilizes the outer
side. Similar to the
medial ligament, the
lateral ligament can
be damaged by a
twisting action on
the knee and
sometimes both
ligaments are damaged
at the same time.
Anterior Cruciate
Ligament (ACL)
injuries
The ACL prevents
the shinbone from
sliding forwards
beneath the
thighbone. The ACL
can be injured in
several ways:
Posterior Cruciate
Ligament (PCL)
injuries
The posterior
cruciate ligament, or
PCL, is not injured
as frequently as the
ACL. PCL sprains
usually occur because
the ligament was
pulled or stretched
too far, a blow to
the front of the
knee, or a simple
misstep. PCL injuries
disrupt knee joint
stability because the
shinbone can sag
backwards. The ends
of the thighbone and
shinbone rub directly
against each other,
causing wear and tear
to the thin, smooth
articular cartilage.
This abrasion may
lead to arthritis in
the knee.
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