What is a knee sprain?
A knee sprain is a joint injury that causes a stretch or tear in
one or more of the knee ligaments. A sprain can be mild, moderate,
or severe depending on the amount of damage to the ligament.
Ligaments are strong bands of tissue that connect one bone to
another. The knee joint is held together by the cruciate and
collateral ligaments. These ligaments connect the thighbone
(femur) in the upper leg to the bones in the lower leg. The
anterior and posterior cruciate ligaments cross each other inside
the knee joint and keep the thighbone from sliding or rotating
over the tibia (one of the 2 main bones in the lower leg). The
medial and lateral collateral ligaments are on either side of the
knee and keep the knee from moving side to side.
How does it occur?
A knee sprain most often occurs while playing sports, but can
occur during falling or twisting accidents. Collateral ligaments
are usually injured when hit by a force on the side opposite the
ligament. The cruciate ligaments can be injured by sudden twisting
movements or from being hit directly.
What are the symptoms?
There is usually pain and a popping sound at the time of the
injury. The knee may immediately start to swell or the swelling
may be gradual.
How is it diagnosed?
Your provider will examine the knee by moving it in different
ways. It may be necessary to have an MRI or an X-ray taken.
How is it treated?
Treatment includes the following:
- Put an ice pack on your knee for 20 to 30 minutes every 3 to 4
hours for 2 or 3 days or until the pain goes away.
- Keep your knee elevated whenever possible by placing a pillow
underneath it until the swelling goes away.
- Take an anti-inflammatory medicine or other drugs prescribed
by your healthcare provider. Adults aged 65 years and older
should not take non-steroidal anti-inflammatory medicine for
more than 7 days without their healthcare provider's approval.
After the knee pain goes away, you will probably need to do
exercises given to you by your healthcare provider or physical
therapist for many weeks.
Your provider may also recommend that you:
- Wrap an elastic bandage around your knee to keep the swelling
from getting worse.
- Use a knee immobilizer initially to protect the knee.
- Use crutches.
Usually surgery is not needed. If you have a complete ligament
tear or if several ligaments are injured at one time, surgery may
be necessary.
How long will it take to get better?
If you start participating in sports or other activities before
you have completely recovered, you may worsen your injury, which
could lead to permanent damage. Everyone recovers from injury at a
different rate. Follow your healthcare provider's instructions and
advice. In general, the longer you have symptoms before you start
treatment, the longer it will take to get better.
If you've had surgery, wait to return to sports or other
activities until your provider has told you that you can safely
return.
How can I prevent a knee sprain?
Unfortunately, most knee sprains occur during accidents that are
not preventable. However, you may be able to avoid these injuries
by having strong thigh and hamstring muscles and maintaining a
good leg stretching routine. In activities such as skiing, make
sure your ski bindings are set correctly by a trained professional
so that your skis will release when you fall.
This content is reviewed periodically and is subject to
change as new health information becomes available. The
information is intended to inform and educate and is not a
replacement for medical evaluation, advice, diagnosis or
treatment by a healthcare professional.
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