> Knee Dislocation
What is a Knee Dislocation?
A knee dislocation is
an emergency medical situation that can potentially
damage any or all of the structures in your knee. The
shinbone, kneecap, and thighbone are knocked out of
their normal positions by a direct, traumatic force.
Depending on which direction the bones move, the surrounding
ligaments, tendons, or cartilage may be ruptured or
strained. The blood supply or nerve connections to your
lower leg also may be damaged. Because it is difficult
to tell which knee dislocations have damaged major arteries
or veins running through the knee, all knee dislocations
should be treated as emergencies. If you suspect a knee
dislocation, an ambulance should be called immediately.
Knee dislocations can generally be
divided into four categories, depending on the forces
that caused the shinbone to move out of joint in relation
to the thighbone.
or the knee bending in the wrong direction, can move
the shinbone forward.
direct blow to the front of the shinbone can move the
forces can rotate the shinbone out of position.
to the outside or inside of the knee can move the shinbone
to the side.
Most people's knees are stable enough to withstand
a large amount of strain. High-energy collisions, like
those seen in contact sports or in other traumatic accidents,
are usually required to cause a knee dislocation. Sports
like skiing, football, and ice hockey put athletes most
at risk of knee dislocations. Less force can also cause
knee dislocations if you have a history of knee weakness.
Previous knee injuries, weak leg muscles, or poor joint
alignment may put you at risk for a knee dislocation.
A diagnosis of knee dislocation must
be made by a trained physician before any treatment
will be rendered. The ambulance will drop you off at
the emergency room, where you usually are taken to a
room where someone on the health care staff should recognize
the dislocation and take you immediately to a physician.
Most people are given narcotic painkillers as soon as
they have been moved to an area where a physician can
begin evaluating the injury.
| First Aid and Ambulance
Knee dislocations require immediate
treatment. You could be at risk for limb loss if damaged
arteries or veins are not treated within six to eight
hours after the injury. Physicians generally suggest
an ambulance be called to transport someone with a dislocated
knee to the hospital's emergency room. If you or someone
you know dislocates a knee, the following first aid
tips can help you better understand what to do:
call for an ambulance.
not attempt to move the injured knee or the injured
person unless someone is present who knows how to properly
immobilize the knee.
to prevent shock by keeping the injured person still
and calm, lying flat on his back. Cover the injured
person with a blanket.
dislocations may cause open wounds. Prevent infection
by covering the wound. Sterile dressings like gauze
are the best option. Physicians recommend covering an
open wound with a clean blanket or towel if no sterile
dressings are available and letting the paramedics deal
with it from there.
possible, do not let injured people eat or drink. They
may be going under anesthesia soon. The paramedics can
give someone an IV if they need fluids, so avoid giving
the injured person anything by mouth.
will most likely immobilize your leg and place you securely
onto a gurney in the back of the ambulance. If possible,
it is a good idea to have someone accompany you to the
hospital to assist you. Most dislocated knees feel as
though they desperately need to be popped back into
place. However, paramedics generally do not treat you
before arrival at the emergency room because there could
be complications that should be treated in the hospital.
| PHYSICAL EXAMINATION
In general, the emergency room physician
makes a thorough physical exam while deciding the best
way to put the joint back in place (reduction). You
may need to see an orthopedic surgeon or a vascular
surgeon for further treatment of your dislocated knee.
To test the integrity of ligaments and tendons in your
knee, a physician will touch or gently push the joint
to see if the shinbone moves too easily in any direction.
The emergency room physician usually feels around your
ankle and foot to check for a pulse in your lower leg.
The physician may order X-rays before putting your joint
back in place. Because a knee dislocation is a very
serious injury, it should be evaluated by an orthopedic
surgeon. After an appropriate evaluation, the joint
will be reduced, or put back into place. This is always
done by a physician, usually an orthopedic surgeon.
Further evaluation is then undertaken to determine the
extent of artery and nerve damage. Many physicians require
patients to undergo an arteriogram, which provides images
of the arteries and veins running through the knee.
Arteriograms take between ten and 15 minutes and can
be performed in the ER, the operating room, or in an
area reserved for image tests called the angiography
area. If you have damaged blood vessels, a vascular
surgeon will be consulted to restore normal blood flow
through your leg. It is imperative that vascular treatment
is rendered as quickly as possible.
When treated promptly, 60 to 70 percent of dislocated
knees return to full strength. Unfortunately, of the
remaining 30 to 40 percent, about half will be at high
risk for future dislocations or other problems like
arthritis, stiffness, or weakness. To help ensure proper
healing, it is critical to receive treatment as soon
as possible. The future health of your leg may depend
on the duration of time that the knee is dislocated.