National Institute of Arthritis and
Musculoskeletal and Skin Diseases
Questions and Answers About
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 bonesthe 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 historythe patient tells the doctor details about
symptoms and about any injury, condition, or general health
problem that might be causing the pain.
- Physical examinationthe 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 teststhe 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) scanx 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.
- Arthroscopythe 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
|