KNEE PROBLEMS
This fact sheet contains
general information about knee problems. It includes descriptions
and a diagram of the different parts of the knee, including
bones, cartilage, muscles, ligaments, and tendons. Individual
sections of the fact sheet describe the symptoms, diagnosis,
and treatment of specific types of knee injuries and conditions.
(See index on page 6.) Information is also provided on the prevention
of knee problems.
How
Common Are Knee Problems? What Causes Them?
According to the
American Academy of Orthopaedic Surgeons, more than 4.1 million
people seek medical care each year for a knee problem.
Some knee problems
result from wear of parts of the knee, such as occurs in osteoarthritis.
Other problems result from injury, such as a blow to the knee
or sudden movements that strain the knee beyond its normal range
of movement.
How
Can People Prevent Knee Problems?
- Some knee problems,
such as those resulting from an accident, cannot be foreseen
or prevented. However, a person can prevent many knee problems
by following these suggestions:
- First warm up
by walking or riding a stationary bicycle, then do stretches
before exercising or participating in sports. Stretching the
muscles in the front of the thigh (quadriceps) and back of
the thigh (hamstrings) reduces tension on the tendons and
relieves pressure on the knee during activity.
- Strengthen the
leg muscles by doing specific exercises (for example, by walking
up stairs or hills, or by riding a stationary bicycle). A
supervised workout with weights is another pathway to strengthening
leg muscles that benefit the knee.
- Avoid sudden changes
in the intensity of exercise. Increase the force or duration
of activity gradually.
- Wear shoes that
both fit properly and are in good condition to help maintain
balance and leg alignment when walking or running. Knee problems
may be caused by flat feet or overpronated feet (feet that
roll inward). People can often reduce some these problems
by wearing special shoe inserts (orthotics). Maintain appropriate
weight to reduce stress on the knee. Obesity increases the
risk of degenerative (wearing) conditions such as osteoarthritis
of the knee.
What
Kinds of Doctors Treat Knee Problems?
Extensive injuries
and diseases of the knees are usually treated by an orthopaedic
surgeon, a doctor who has been trained in the nonsurgical and
surgical treatment of bones, joints, and soft tissues (for example,
ligaments, tendons, and muscles). Patients seeking nonsurgical
treatment of arthritis of the knee may also consult a rheumatologist
(a doctor specializing in the diagnosis and treatment of arthritis
and related disorders).
What
Are the Major Structures of the Knee? What Do They Do?
The knee joint works
like a hinge to bend and straighten the lower leg. It permits
a person to sit, stand, and pivot. The knee is composed of the
following parts (see diagram):
Structures
of the Knee
Bones
and Cartilage
The knee joint is
the junction of three bones—the femur (thigh bone or upper leg
bone), the tibia (shin bone or larger bone of the lower leg),
and the patella (kneecap). The patella is about 2 to 3 inches
wide and 3 to 4 inches long. It sits over the other bones at
the front of the knee joint and slides when the leg moves. It
protects the knee and gives leverage to muscles.
The ends of the three
bones in the knee joint are covered with articular cartilage,
a tough, elastic material that helps absorb shock and allows
the knee joint to move smoothly. Separating the bones of the
knee are pads of connective tissue called menisci, which are
divided into two crescent-shaped discs positioned between the
tibia and femur on the outer and inner sides of each knee. The
two menisci in each knee act as shock absorbers, cushioning
the lower part of the leg from the weight of the rest of the
body, as well as enhancing stability.
Muscles
There are two groups
of muscles at the knee. The quadriceps muscle comprises four
muscles on the front of the thigh that work to straighten the
leg from a bent position. The hamstring muscles, which bend
the leg at the knee, run along the back of the thigh from the
hip to just below the knee.
Ligaments
Ligaments are strong,
elastic bands of tissue that connect bone to bone. They provide
strength and stability to the joint. Four ligaments connect
the femur and tibia:
- The medial collateral
ligament (MCL) provides stability to the inner (medial) aspect
of the knee.
- The lateral collateral
ligament (LCL) provides stability to the outer (lateral) aspect
of the knee.
- The anterior cruciate
ligament (ACL), in the center of the knee, limits rotation
and the forward movement of the tibia.
- The posterior
cruciate ligament (PCL), also in the center of the knee, limits
backward movement of the tibia.
Other ligaments are
part of the knee capsule, which is a protective, fiber-like
structure that wraps around the knee joint. Inside the capsule,
the joint is lined with a thin, soft tissue, called synovium.
Tendons
Tendons are tough
cords of tissue that connect muscle to bone. In the knee, the
quadriceps tendon connects the quadriceps muscle to the patella
and provides power to extend the leg. The patellar tendon connects
the patella to the tibia. Technically, it is a ligament, but
it is commonly called a tendon.
How
Are Knee Problems Diagnosed?
Doctors use several
methods to diagnose knee problems.
- Medical history—the
patient tells the doctor details about symptoms and about
any injury, condition, or general health problem that might
be causing the pain.
- Physical examination—the
doctor bends, straightens, rotates (turns), or presses on
the knee to feel for injury and discover the limits of movement
and location of pain.
- Diagnostic tests—the
doctor uses one or more tests to determine the nature of a
knee problem.
- X ray (radiography)—an
x-ray beam is passed through the knee to produce a two-dimensional
picture of the bones.
- Computerized axial
tomography (CAT) scan—x rays lasting a fraction of a second
are passed through the knee at different angles, detected
by a scanner, and analyzed by a computer. This produces a
series of clear cross-sectional images ( slices”) of the knee
tissues on a computer screen. CAT scan images show soft tissues
more clearly than normal x rays. Individual images can be
combined by computer to give a three-dimensional view of the
knee.
- Bone scan (radionuclide
scanning)—a very small amount of radioactive material is injected
into the patient's bloodstream and detected by a scanner.
This test detects blood flow to the bone and cell activity
within the bone, and can show abnormalities in these processes
that may aid diagnosis..
- Magnetic resonance
imaging (MRI)—energy from a powerful magnet (rather than x
rays) stimulates tissues of the knee to produce signals that
are detected by a scanner and analyzed by computer. This creates
a series of cross-sectional images of a specific part of the
knee. An MRI is particularly sensitive for detecting damage
or disease of soft tissues, such as ligaments and muscles.
As with a CAT scan, a computer can be used to produce three-dimensional
views of the knee during MRI.
- Arthroscopy—the
doctor manipulates a small, lighted optic tube (arthroscope)
that has been inserted into the joint through a small incision
in the knee. Images of the inside of the knee joint are projected
onto a television screen.
Index
to Knee Injuries and Problems
- Cartilage
Injuries and Disorders
- Arthritis
of the Knee
- Ligament
Injuries
- Tendon
Injuries and Disorders
- Other
Knee Injuries
Cartilage
Injuries and Disorders
Chondromalacia
What
Is Chondromalacia?
Chondromalacia (pronounced
KON-DRO-MAH-LAY-SHE-AH), also called chondromalacia patellae,
refers to softening of the articular cartilage of the kneecap.
The disorder occurs most often in young adults and may be caused
by trauma, overuse, parts out of alignment, or muscle weakness.
Instead of gliding smoothly across the lower end of the thigh
bone, the kneecap rubs against it, thereby roughening the cartilage
underneath the kneecap. The damage may range from a slight abnormality
of the surface of the cartilage to a surface that has been worn
away completely to the bone. Traumatic chondromalacia occurs
when a blow to the knee cap tears off either a small piece of
articular cartilage or a large fragment containing a piece of
bone (osteochondral fracture).
What
Are the Symptoms of Chondromalacia? How Is It Diagnosed?
The most frequent
symptom of chondromalacia is a dull pain around or under the
kneecap that worsens when walking down stairs or hills. A person
may also feel pain when climbing stairs or during other activities
when the knee bears weight as it is straightened. The disorder
is common in runners and is also seen in skiers, cyclists, and
soccer players. A patient's description of symptoms and a followup
x ray usually help the doctor make a diagnosis. Although arthroscopy
can confirm the diagnosis of chondromalacia, it is not performed
unless the condition requires extensive treatment.
How
Is Chondromalacia Treated?
Many doctors recommend
that patients with chondromalacia perform low-impact exercises
that strengthen muscles, particularly the inner part of the
quadriceps, without injuring joints. Swimming, riding a stationary
bicycle, and using a cross-country ski machine are acceptable
as long as the knee is not bent more than 90 degrees. Electrical
stimulation may also be used to strengthen the muscles. If these
treatments fail to improve the condition, the physician may
perform arthroscopic surgery to smooth the surface of the articular
cartilage and wash out” cartilage fragments that cause the joint
to catch during bending and straightening. In more severe cases
of chondromalacia, surgery may be necessary to correct the angle
of the kneecap and relieve friction involving the cartilage
or to reposition parts that are out of alignment.
Injuries
to the Meniscus
What
Is the Cause of Injuries to the Meniscus?
The two menisci are
easily injured by the force of rotating the knee while bearing
weight. A partial or total tear of a meniscus may occur when
a person quickly twists or rotates the upper leg while the foot
stays still (for example, when dribbling a basketball around
an opponent or turning to hit a tennis ball). If the tear is
tiny, the meniscus stays connected to the front and back of
the knee; if the tear is large, the meniscus may be left hanging
by a thread of cartilage. The seriousness of a tear depends
on its location and extent.
What
Are the Symptoms of Injury?
Generally, when people
injure a meniscus, they feel some pain, particularly when the
knee is straightened. The pain may be mild, and the person may
continue activity. Severe pain may occur if a fragment of the
meniscus catches between the femur and tibia. Swelling may occur
soon after injury if blood vessels are disrupted, or swelling
may occur several hours later if the joint fills with fluid
produced by the joint lining (synovium) as a result of inflammation.
If the synovium is injured, it may become inflamed and produce
fluid to protect itself. This causes swelling of the knee. Sometimes,
an injury that occurred in the past but was not treated becomes
painful months or years later, particularly if the knee is injured
a second time. After any injury the knee may click, lock, or
feel weak. Symptoms of meniscal injury may disappear on their
own but frequently, symptoms persist or return and require treatment.
How
Is Meniscal Injury Diagnosed?
In addition to listening
to the patient's description of the onset of pain and swelling,
the physician may perform a physical examination and take x
rays of the knee. The examination may include a test in which
the doctor flexes (bends) the leg then rotates the leg outward
and inward while extending it. Pain or an audible click suggests
a meniscal tear. An MRI test may be recommended to confirm the
diagnosis. Occasionally, the doctor may use arthroscopy to help
diagnose and treat a meniscal tear.
How
Is an Injured Meniscus Treated?
If the tear is minor
and the pain and other symptoms go away, the doctor may recommend
a muscle-strengthening program. Exercises for meniscal problems
are best performed with initial guidance from a doctor and physical
therapist or exercise therapist. The therapist will make sure
that the patient does the exercises properly and without risk
of new or repeat injury. The following exercises after injury
to the meniscus are designed to build up the quadriceps and
hamstring muscles and increase flexibility and strength.
- Warming up the
joint by riding a stationary bicycle, then straightening and
raising the leg (but avoiding straightening the leg too much).
- Extending the
leg while sitting (a weight may be worn on the ankle for this
exercise).
- Raising the leg
while lying on the stomach.
- Exercising in
a pool, including walking as fast as possible in chest-deep
water, performing small flutter kicks while holding onto the
side of the pool, and raising each leg to 90 degrees in chest-deep
water while pressing the back against the side of the pool.
If the tear to a
meniscus is more extensive, the doctor may perform either arthroscopic
surgery or open surgery” to see the extent of injury and to
repair the tear. The doctor can suture (sew) the meniscus back
in place if the patient is relatively young, the injury is in
an area with a good blood supply, and the ligaments are intact.
Most young athletes are able to return to vigorous sports with
meniscus-preserving repair.
If the patient is
elderly or the tear is in an area with a poor blood supply,
the doctor may cut off a small portion of the meniscus to even
the surface. In some cases, the doctor removes the entire meniscus.
However, degenerative changes, such as osteoarthritis, are more
likely to develop in the knee if the meniscus is removed. Medical
researchers are currently investigating a procedure called an
allograft, in which the surgeon replaces the meniscus with one
from a cadaver. A grafted meniscus is fragile and may shrink
and tear easily. Researchers have also attempted to replace
a meniscus with an artificial one, but the procedure is even
less successful than an allograft.
Recovery after surgery
to repair a meniscus takes several weeks longer and post-operative
activity is slightly more restricted than when the meniscus
is removed. Nevertheless, putting weight on the joint actually
fosters recovery. Regardless of the form of surgery, rehabilitation
usually includes walking, bending the legs, and doing exercises
that stretch and build up the leg muscles. The best results
of treatment for meniscal injury are obtained in people who
do not show articular cartilage changes and who have an intact
anterior cruciate ligament.
Arthritis
of the Knee
What
Is Arthritis of the Knee?
Arthritis of the
knee is most often osteoarthritis, a degenerative disease where
cartilage in the joint gradually wears away. In rheumatoid arthritis,
which can also affect the knees, the joint becomes inflamed
and cartilage may be destroyed.1 Arthritis not only affects
joints, it may also affect supporting structures such as muscles,
tendons, and ligaments.
Osteoarthritis may
be caused by excess stress on the joint, such as from repeated
injury, deformity, or if a person is overweight. It most often
affects middle-aged and older people. A young person who develops
osteoarthritis may have an inherited form of the disease or
may have experienced continuous irritation from an unrepaired
torn meniscus or other injury. Rheumatoid arthritis usually
affects people at an earlier age than osteoarthritis.
What
Are the Signs of Knee Arthritis and How Is It Diagnosed?
A person who has
arthritis of the knee may experience pain, swelling, and a decrease
in knee motion. A common symptom is morning stiffness that lessens
after moving around. Sometimes the knee joint locks or clicks
when the knee is bent and straightened, but these signs may
also occur in other knee disorders. The doctor may confirm the
diagnosis by performing a physical examination and taking x
rays, which typically show a loss of joint space. Blood tests
may be helpful for diagnosing rheumatoid arthritis, but other
tests may be needed as well. Analysis of fluid from the knee
joint may be helpful in diagnosing some kinds of arthritis.
The doctor may use arthroscopy to directly visualize damage
to cartilage, tendons, and ligaments and to confirm a diagnosis,
but arthroscopy is usually done only if a repair procedure is
to be performed.
How
Is Arthritis of the Knee Treated?
Most often osteoarthritis
of the knee is treated with analgesics (pain-reducing medicines),
such as aspirin or acetaminophen (Tylenol):* nonsteroidal anti-inflammatory
drugs (NSAIDs), such as ibuprofen (Motrin, Nuprin, Advil); and
exercises to restore joint movement and strengthen the knee.
Losing excess weight can also help people with osteoarthritis.
Rheumatoid arthritis of the knee may require a treatment plan
that includes physical therapy and use of more powerful medications.
In people with arthritis of the knee, a seriously damaged joint
may need to be surgically replaced with an artificial one. (Note:
A new procedure designed to stimulate the growth of cartilage
using a patient's own cartilage cells is being used experimentally
to repair cartilage injuries at the end of the femur at the
knee. It is not a treatment for arthritis.)
Ligament
Injuries
Anterior
and Posterior Cruciate Ligament Injury
What
Are the Causes of Injury to the Cruciate Ligaments?
Injury to the cruciate
ligaments of the knee is sometimes referred to as a "sprain."
The anterior cruciate ligament is most often stretched, torn,
or both by a sudden twisting motion (for example, when the feet
are planted one way and the knees are turned another way). The
posterior cruciate ligament is most often injured by a direct
impact, such as in an automobile accident or football tackle.
What
Are the Symptoms of Cruciate Ligament Injury? How Is Injury
Diagnosed?
Injury to a cruciate
ligament may not cause pain. Rather, the person may hear a popping
sound, and the leg may buckle when he or she tries to stand
on it. To diagnose an injury, the doctor may perform several
tests to see if the parts of the knee stay in proper position
when pressure is applied in different directions. A thorough
examination is essential to the diagnosis. An MRI is very accurate
in detecting a complete tear, but arthroscopy may be the only
reliable means of detecting a partial tear.
How
Are Cruciate Ligament Tears Treated?
For an incomplete
tear, the doctor may recommend that the patient begin an exercise
program to strengthen surrounding muscles. The doctor may also
prescribe a protective knee brace for the patient to wear during
activity. For a completely torn anterior cruciate ligament
in an active athlete
and motivated patient, the doctor is likely to recommend surgery.
The surgeon may reattach the torn ends of the ligament or reconstruct
the torn ligament by using a piece (graft) of healthy ligament
from the patient (autograft) or from a cadaver (allograft).
Although repair using synthetic ligaments has been tried experimentally,
the procedure has not yielded as good results as use of human
tissue. One of the most important elements in a patient's successful
recovery after cruciate ligament surgery is following an exercise
and rehabilitation program for 4 to 6 months that may involve
the use of special exercise equipment at a rehabilitation or
sports center. Successful surgery and rehabilitation will allow
the patient to return to a normal full lifestyle.
Medial
and Lateral Collateral Ligament Injury
What
Is the Most Common Cause of Injury to the Medial Collateral
Ligament?
The medial collateral
ligament is more easily injured than the lateral collateral
ligament. It is most often caused by a blow to the outer side
of the knee, which often happens in contact sports like football
or hockey, that stretches and tears the ligament on the inner
side of the knee.
What
Are the Symptoms of Collateral Ligament Injury? How Is Injury
Diagnosed?
When injury to the
medial collateral ligament occurs, a person may feel a pop and
the knee may buckle sideways. Pain and swelling are common.
A thorough examination is essential to determine the nature
and extent of injury. To diagnose a collateral ligament injury,
the doctor exerts pressure on the side of the knee to determine
the degree of pain and looseness of the joint. An MRI is helpful
in diagnosing injuries to these ligaments.
How
Are Collateral Ligament Injuries Treated?
Most sprains of the
collateral ligaments will heal if the patient follows a prescribed
exercise program. In addition to exercise, the doctor may recommend
that the patient apply ice packs to reduce pain and swelling
and wear a small sleeve-type brace to protect and stabilize
the knee. A sprain may take 2 to 4 weeks to heal. A severely
sprained or torn collateral ligament may be accompanied by a
torn anterior cruciate ligament, which usually requires surgical
repair.
Tendon
Injuries and Disorders
Tendinitis
and Ruptured Tendons
What
Are the Causes of Tendinitis and Ruptured Tendons?
Knee tendon injuries
range from tendinitis (inflammation of a tendon) to a ruptured
(torn) tendon. If a person overuses a tendon during certain
activities such as dancing, cycling, or running, the tendon
stretches like a worn-out rubber band and becomes inflamed.
Movements such as trying to break a fall may cause excessive
contraction of the quadriceps muscles and tear the quadriceps
tendon above the patella or the patellar tendon below the patella.
This type of injury is most likely to happen in older people
whose tendons tend to be weaker. Tendinitis of the patellar
tendon is sometimes called jumper's knee. This is because in
sports requiring jumping, such as basketball, the muscle contraction
and force of hitting the ground after a jump strain the tendon.
The tendon may become inflamed or tear after repeated stress.
What
Are the Symptoms of Tendon Injuries? How Are Injuries Diagnosed?
People with tendinitis
often have tenderness at the point where the patellar tendon
meets the bone. They also may feel pain during faster movements,
such as running, hurried walking, or jumping. A complete rupture
of the quadriceps or patellar tendon is not only painful but
also makes it difficult for a person to bend, extend, or lift
the leg against gravity. If there is not much swelling, the
doctor will be able to feel a defect in the tendon near the
tear during a physical examination. An x ray will show that
the patella is lower in position than normal in a quadriceps
tendon tear and higher than normal in a patellar tendon tear.
The doctor may use an MRI to confirm a partial or total tear.
How
Are Knee Tendon Injuries Treated?
Initially, the doctor
may ask a patient with tendinitis to rest, elevate, and apply
ice to the knee and to take medicines such as aspirin or ibuprofen
to relieve pain and decrease inflammation and swelling. If the
quadriceps or patellar tendon is completely ruptured, a surgeon
will reattach the ends. After surgery, the patient will wear
a cast for 3 to 6 weeks and use crutches. If the tear is only
partial, the doctor might apply a cast without performing surgery.
A partial or complete
tear of a tendon requires an exercise program as part of rehabilitation
that is similar to but less vigorous than that prescribed for
ligament injuries. The goals of exercise are to restore the
ability to bend and straighten the knee and to strengthen the
leg to prevent a repeat knee injury. A rehabilitation program
may last 6 months, although the patient can return to many activities
before then.
Osgood-Schlatter
Disease
What
Are the Causes of Osgood-Schlatter Disease?
Osgood-Schlatter
disease is caused by repetitive stress or tension on a part
of the growth area of the upper tibia (the apophysis). It is
characterized by inflammation of the patellar tendon and surrounding
soft tissues at the point where the tendon attaches to the tibia.
The disease may also be associated with an avulsion injury,
in which the tendon is stretched so much that it tears away
from the tibia and takes a fragment of bone with it. The disease
most commonly affects active young people, particularly boys
between the ages of 10 and 15, who play games or sports that
include frequent running and jumping.
What
Are the Symptoms of Osgood-Schlatter Disease? How Is It Diagnosed?
People with this
disease experience pain just below the knee joint that usually
worsens with activity and is relieved by rest. A bony bump that
is particularly painful when pressed may appear on the upper
edge of the tibia (below the knee cap). Usually, motion of the
knee is not affected. Pain may last a few months and may recur
until a child's growth is completed.
Osgood Schlatter
disease is most often diagnosed by the symptoms. An x ray may
be normal, or show an avulsion injury, or, more typically, show
that the apophysis is in fragments.
How
Is Osgood-Schlatter Disease Treated?
Usually, the disease
disappears without treatment. Applying ice to the knee when
pain first begins helps relieve inflammation and is sometimes
used along with stretching and strengthening exercises. The
doctor may advise the patient to limit participation in vigorous
sports. Children who wish to continue participating in moderate
or less stressful sports may need to wear knee pads for protection
and apply ice to the knee after activity. If a great deal of
pain is felt during sports activities, participation may be
limited until any remaining discomfort is tolerable.
Iliotibial
Band Syndrome
What
Causes Iliotibial Band Syndrome?
This is an overuse
inflammatory condition due to friction (rubbing) of a band of
a tendon over the outer bone (lateral condyle) of the knee.
Although iliotibial band syndrome may be caused by direct injury
to the knee, it is most often caused by the stress of long-term
overuse, such as sometimes occurs in sports training.
What
Are the Symptoms of Iliotibial Band Syndrome and How Is It Diagnosed?
A person with this
syndrome feels an ache or burning sensation at the side of the
knee during activity. Pain may be localized at the side of the
knee or radiate up the side of the thigh. A person may also
feel a snap when the knee is bent and then straightened. Swelling
is usually absent and knee motion is normal. The diagnosis of
this disorder is usually based on the patient's symptoms, such
as pain at the lateral condyle, and exclusion of other conditions
with similar symptoms.
How
Is Iliotibial Band Syndrome Treated?
Usually, iliotibial
band syndrome disappears if the person reduces activity and
performs stretching exercises followed by muscle-strengthening
exercises. In rare cases when the syndrome doesn't disappear,
surgery may be necessary to split the tendon so it is not stretched
too tightly over the bone.
Other
Knee Injuries
Osteochondritis
Dissecans
What
Is Osteochondritis Dissecans?
Osteochondritis dissecans
results from a loss of the blood supply to an area of bone underneath
a joint surface and usually involves the knee. The affected
bone and its covering of cartilage gradually loosen and cause
pain. A person with this disruption of the joint may eventually
develop osteoarthritis. This disorder usually arises spontaneously
in an active adolescent or a young adult. It may be due to a
slight blockage of a small artery or to an unrecognized injury
or tiny fracture that damages the overlying cartilage.
The bone undergoes
avascular necrosis (degeneration from lack of a blood supply).
2 The involvement of several joints or the appearance of osteochondritis
dissecans in several family members may indicate that the disorder
is inherited.
What
Are the Symptoms of Osteochondritis Dissecans? How Is It Diagnosed?
If spontaneous healing
doesn't occur, cartilage eventually separates from the diseased
bone and a fragment breaks loose into the knee joint, causing
locking of the joint, weakness, and sharp pain. An x ray, MRI,
or arthroscopy can determine the condition of the cartilage
and be used to diagnose osteochondritis dissecans.
How
Is Osteochondritis Dissecans Treated?
If cartilage fragments
have not broken loose, a surgeon may fix them in place with
pins or screws that are sunk into the cartilage to stimulate
a new blood supply. If fragments are loose, the surgeon may
scrape down the cavity to reach fresh bone and add a bone graft
and fix the fragments in position. Fragments that cannot be
mended are removed, and the cavity is drilled or scraped to
stimulate new growth of cartilage. Research is currently being
done to assess the use of cartilage cell transplants and other
tissues to treat this disorder.
Plica
Syndrome
Plica (pronounced
PLI-KAH) syndrome occurs when plicae (bands of remnant synovial
tissue) are irritated by overuse or injury. Synovial plicae
are remnants of tissue pouches found in the early stages of
fetal development. As the fetus develops, these pouches normally
combine to form one large synovial cavity. If this process is
incomplete, plicae remain as four folds or bands of synovial
tissue within the knee. Injury, chronic overuse, or inflammatory
conditions are associated with development of this syndrome.
What
Are the Symptoms of Plica Syndrome? How Is It Diagnosed?
People with this
syndrome are likely to experience pain and swelling, a clicking
sensation, and locking and weakness of the knee. Because the
symptoms are similar to symptoms of some other knee problems,
plica syndrome is often misdiagnosed. Diagnosis usually depends
on the exclusion of other conditions that cause similar symptoms.
How
Is Plica Syndrome Treated?
The goal of treatment
is to reduce inflammation of the synovium and thickening of
the plicae. The doctor usually prescribes medicine such as ibuprofen
to reduce inflammation. The patient is also advised to reduce
activity, apply ice and compression wraps (elastic bandage)
to the knee, and do strengthening exercises. If this treatment
program fails to relieve symptoms within 3 months, the doctor
may recommend arthroscopic or open surgery to remove the plicae.
A cortisone injection into the region of the plica folds helps
about half of the patients treated. The doctor can also use
arthroscopy to confirm the diagnosis and treat the problem.
Other
Sources of Information on Knee Problems
- American
Academy of Orthopaedic Surgeons
6300 N. River Road
Rosemont, IL 60018-4262
847/823-7186
800/346-2267
World Wide Web address: http://www.aaos.org
The academy publishes several brochures on the knee, including
Knee Arthroscopy” and Total Knee Replacement,” which doctors
can obtain and give to their patients. Single copies of two
other pamphlets, Arthroscopy” and Total Joint Replacement,”
are available free to the public if a self-addressed, stamped
envelope is provided.
- American
Physical Therapy Association
1111 N. Fairfax Street
Alexandria, VA 22314
800/999-APTA (2782)
World Wide Web address: http://www.apta.org
The association has published a free brochure titled Taking
Care of the Knees.”
- Arthritis
Foundation
1330 Peach Tree Street
Atlanta, GA 30309
404/872-7100
800/283-7800 or call your local chapter (listed in the local
telephone directory)
World Wide Web address: http://www.arthritis.org
The Foundation has several free brochures about coping with
arthritis, taking nonsteroid and steroid medicines, and exercise.
A free brochure on protecting your joints is titled Using
Your Joints Wisely.” The foundation also provides doctor referrals.
- American
College of Rheumatology/Association of Rheumatology Health
Professionals
60 Executive Park South, Suite 150
Atlanta, GA 30329
404/633-3777
Fax: 404/633-1870
World Wide Web address: http://www.rheumatology.org
This national professional organization can provide referrals
to rheumatologists and allied health professionals, such as
physical therapists. One-page fact sheets are available on
various forms of arthritis. Lists of specialists by geographic
area and fact sheets are also available on ACR's web site.
- National
Arthritis and Musculoskeletal and Skin Diseases Information
Clearinghouse (NAMSIC)
National Institutes of Health
1 AMS Circle
Bethesda, MD 20892-3675
Phone: 301/495-4484
TTY: 301/ 565-2966
Automated faxback system: 301/881-2731
World Wide Web address: http://www.nih.gov/niams
The Clearinghouse has additional information about some of
the knee problems described in this fact sheet, including
osteoarthritis and avascular necrosis, as well as information
about total knee replacement and arthritis and exercise. Single
copies of fact sheets and information packages on these topics
are available free upon request.
*Brand
names included in this fact sheet are provided as examples only,
and their inclusion does not mean that these products are endorsed
by the National Institutes of Health or any other Government
agency. Also, if a particular brand name is not mentioned, this
does not mean or imply that the product is unsatisfactory.
Acknowledgments
The NIAMS gratefully
acknowledges the assistance of Frank A Pettrone, M.D., of Arlington/Vienna,Virginia;
W. Norman Scott, M.D., of Beth Israel Medical Center in New
York, New York; and James Panagis, M.D., M.P.H., and John H.
Klippel, M.D., of the National Institutes of Health, in the
preparation and review of this fact sheet.
The
National Arthritis and Musculoskeletal and Skin Diseases Information
Clearinghouse (NAMSIC) is a public service sponsored by the
NIAMS that provides health information and information sources.
The NIAMS, a part of the National Institutes of Health (NIH),
leads the Federal medical research effort in arthritis and musculoskeletal
and skin diseases. The NIAMS sponsors research and research
training throughout the United States as well as on the NIH
campus in Bethesda, MD, and disseminates health and research
information.
JW
9/97
Office of Scientific and Health Communications
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