Medical Information
What is a meniscus tear?
A meniscus tear is a
common knee joint injury. This rubbery tissue acts as a shock absorber between
the upper and lower leg bones. Each knee has two C-shaped menisci (plural of
meniscus): a lateral meniscus on the outer side of the knee and a medial
meniscus on the inner side of the knee. A meniscus tear can limit your knee
function. See a picture of the
knee and the menisci 
.
How is the meniscus injured or torn?
A meniscus
tear usually occurs with a twisting or pivoting motion and often with the foot
planted and the knee partially flexed (for example, when lifting or playing
tennis). Other knee injuries, such as a torn ligament, can happen at the same
time. In older people whose menisci are worn (degenerated), the menisci may
tear more easily. Meniscus tears are rare in young children.
How will I know if I have a meniscus tear?
The
symptoms of a meniscus tear often vary. In a typical minor tear, there may be pain and swelling at first. These
symptoms usually go away in 2 to 3 weeks.
In a typical
moderate tear, you may feel pain at the side or center
of the knee, depending on where the tear is located. You likely are still able
to walk. Swelling increases gradually over 2 to 3 days and may make the knee
feel stiff and limit bending. There's often sharp pain when twisting or
squatting. These symptoms go away but tend to recur with minor twisting or
overuse.
In severe tears, pieces of the
torn meniscus can dislocate into the joint space. This can make the knee catch,
pop, or lock. The knee can also feel "wobbly" or unstable, or can give way
without warning. You may not be able to straighten it. The knee may swell and
become stiff right after the injury, or over 2 to 3 days.
Older
people whose menisci are worn may not be able to think of a specific event that
caused the tear, or they may recall symptoms developing after a minor incident
such as rising from a squatting position. Pain and minimal swelling are often
the only symptoms.
How will my doctor diagnose a meniscus tear?
Your
doctor will ask how the injury happened and whether you have ever had any other
knee injuries. A physical examination is done to determine if a torn meniscus
is the cause of your pain and to rule out other knee injuries.
He
or she will do a physical examination of both knees to evaluate tenderness,
range of motion, and knee stability. X-rays are usually done. Based on your
symptoms and the physical examination, your doctor may diagnose a meniscus
tear. He or she may suggest that you follow up with an
orthopedic surgeon, although it is not always
necessary. Your doctor or the orthopedic surgeon may order further diagnostic
testing, usually MRI or arthroscopy.
If the initial pain with the
injury is severe, you might go to the emergency room. With less severe pain,
you might wait to see if the swelling and pain go away. Often, people end up
going to a doctor when pain and swelling recur with use.
How will an MRI help in diagnosing a meniscus tear?
Magnetic resonance imaging (MRI) is a test that provides pictures of
organs and structures, such as the menisci, inside the body. It produces these
images by using a magnetic field and pulses of radio wave energy. MRI typically
gives a good picture of the location and size of a meniscus tear and also
provides images of the ligaments, cartilage, and tendons.
MRIs of the knee are most helpful to confirm the diagnosis of a meniscus tear
and to detect associated injuries to the ligament, cartilage, and
tendons.
How is arthroscopy used in diagnosis and treatment of a meniscus tear?
Your doctor may recommend arthroscopy instead of MRI to
directly view the structures in your knee, including your meniscus, especially
when your symptoms indicate that surgery is needed. Larger tears usually cause
more pain and immediate swelling and stiffness, although swelling may also
develop over 2 to 3 days. The knee may lock, catch, buckle (suddenly give way),
or pop. If other injuries occurred with the meniscus tear, especially torn
ligaments, there is increased pain, swelling, and difficulty walking. Often
arthroscopy is done in these cases, because surgical repair of the meniscus
and/or other knee structures may be needed. Surgical repair is usually done
during the initial arthroscopy. During arthroscopy, a thin viewing scope,
called an arthroscope, is inserted into the knee joint through a small incision
in the skin.
What are discomforts or risks of having an MRI or arthroscopy?
You will not feel any effects from the actual MRI.
But the table you lie on may be hard, and the room may be chilly. You may
become uncomfortable from lying in one position for a long time. Some people
feel uneasy or anxious (claustrophobic) inside a standard, closed-type MRI
machine. If this keeps you from lying still, you can be given medicine to help
you relax. You may want to talk with your doctor about the availability of an
open MRI machine, which is less confining than a standard MRI.
During arthroscopy, bleeding within the joint can occur. There is a small
risk of infection, formation of a blood clot in your leg, or nerve or joint
damage. Rarely, a serious condition called
compartment syndrome can occur if pressure builds
within the leg. When this occurs, immediate medical treatment is needed to
release the pressure.
After arthroscopy, you may notice swelling
of the skin around the incision. This is temporary and should disappear within
2 weeks. It is normal for the site to feel tender for about a week. A small
amount of bleeding from the incision site can be expected. Ask your doctor how
much drainage to expect.
It may take several weeks for your knee
to recover from arthroscopy. Your doctor will give you pain medicine and
recommend rehabilitation exercises for you to do during your recovery period.
You may have some soreness and pain after the procedure. Your doctor may also
instruct you to apply ice to the joint-and possibly elevate it-to reduce
swelling and pain. Keep the bandages that cover your incision clean and
dry.
How is a meniscus tear treated?
How your doctor
treats your meniscus tear depends upon the size and location of the tear, when
the injury happened, and your pain, age, health status, and activity level, as
well as your surgeon's preference. Treatment options include:
- Nonsurgical treatment
with rest, ice, compression, elevation, and physical therapy. This may include
wearing a temporary knee brace.
- Surgical repair to sew the tear
together.
- Partial meniscectomy, which is surgery to remove the torn
section.
- Total meniscectomy, which is
surgery to remove the entire meniscus. This is generally avoided, because this
option increases the risk for
osteoarthritis in the knee.
Other knee injuries (most commonly to the anterior
cruciate ligament [ACL] and/or the medial collateral ligament) may occur at the
same time as a meniscus tear. Your doctor may be able to determine this with
the physical examination. In these cases, treatment for the meniscus tear will
follow the plan for treating the other knee injury.
For more
information, see the topic
Meniscus Tear.
