Health Topics
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Publication Date: May 2001
Questions and Answers About Knee Problems
Knee problems commonly occur in young people and adults.
This booklet contains general information about several knee problems.
It includes descriptions and a diagram of the different parts of the
knee. Individual sections of the booklet describe the symptoms,
diagnosis, and treatment of specific types of knee injuries and
conditions. Information on how to prevent these problems is also
provided.
What Do the Knees Do? How Do They
Work?
The knees provide stable support for the body and allow
the legs to bend and straighten. Both flexibility and stability are
needed for standing and for motions like walking, running, crouching,
jumping, and turning.
Several kinds of supporting and moving parts, including
bones, cartilage, muscles, ligaments, and tendons, help the knees do
their job. Any of these parts can be involved in pain or
dysfunction.
What Causes Knee Problems?
There are two general kinds of knee problems: mechanical
and inflammatory.
Mechanical Knee Problems
Some knee problems result from injury, such as a direct
blow or sudden movements that strain the knee beyond its normal range of
movement. Other problems, such as osteoarthritis in the knee, result
from wear and tear on its parts.
Inflammatory Knee Problems
Inflammation that occurs in certain rheumatic diseases,
such as rheumatoid arthritis and systemic lupus erythematosus, can
damage the knee.
Joint Basics
The point at which two or more bones are connected is
called a joint. In all joints, the bones are kept from grinding against
each other by padding called cartilage. Bones are joined to bones by
strong, elastic bands of tissue called ligaments. Tendons are tough
cords of tissue that connect muscle to bone. Muscles work in opposing
pairs to bend and straighten joints. While muscles are not technically
part of a joint, they're important because strong muscles help support
and protect joints.
What Are the Parts of the Knee?
Like any joint, the knee is composed of bones and
cartilage, ligaments, tendons, and muscles (see the diagram).
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 (knee cap). The patella is 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. One pad is called a meniscus
(muh-NISS-kus). The plural is menisci (muh-NISS-sky). The menisci 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. Keeping these muscles strong with exercises
such as walking up stairs or riding a stationary bicycle helps support
and protect the knee.
Tendons and Ligaments
The quadriceps tendon connects the quadriceps muscle to
the patella and provides the power to extend the leg. Four ligaments
connect the femur and tibia and give the joint strength and
stability:
- The medial collateral ligament (MCL) provides stability to the
inner (medial) part of the knee.
- The lateral collateral ligament (LCL) provides stability to the
outer (lateral) part 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.
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 the location of pain. The
patient may be asked to stand, walk, or squat to help the doctor assess
the knee's function.
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 such as
ligaments or muscles more clearly than conventional x rays. The
computer can combine individual images 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 knee tissue to produce signals
that are detected by a scanner and analyzed by a computer. This
creates a series of cross-sectional images of a specific part of the
knee. An MRI is particularly useful for detecting soft tissue damage
or disease. Like a CAT scan, a computer is 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. While the arthroscope is inside
the knee joint, removal of loose pieces of bone or cartilage or the
repair of torn ligaments and menisci is also possible.
- Biopsy--The doctor removes tissue to examine under a
microscope.
Knee Injuries and Problems
Arthritis
What Is Arthritis of the Knee?
Arthritis of the knee is most often osteoarthritis. In
this disease, the 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.* Arthritis not only affects
joints; it can also affect supporting structures such as muscles,
tendons, and ligaments.
Osteoarthritis may be caused by excess stress on the joint
from deformity, repeated injury, or excess weight. 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 often affects people at an earlier age than
osteoarthritis.
* The National Institute of Arthritis and
Musculoskeletal and Skin Diseases Information Clearinghouse has separate
publications on osteoarthritis, rheumatoid arthritis, and knee
replacement. See the end of this booklet for contact
information.
Signs and Diagnosis
Someone who has arthritis of the knee may experience pain,
swelling, and a decrease in knee motion. A common symptom is morning
stiffness that lessens as the person moves around. Sometimes the joint
locks or clicks when the knee is bent and straightened, but these signs
may occur in other knee disorders as well. The doctor may confirm the
diagnosis by performing a physical examination and examining 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 too.
Analyzing fluid from the knee joint may be helpful in diagnosing some
kinds of arthritis. The doctor may use arthroscopy to directly see
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.
Treatment
Most often osteoarthritis of the knee is treated with
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 physical
therapy and more powerful medications. In people with arthritis of the
knee, a seriously damaged joint may need to be replaced with an
artificial one. (A new procedure designed to stimulate the growth of
cartilage by 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, however, a treatment for arthritis.)
* Brand names included in this booklet 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.
Cartilage Injuries and Disorders
What Is Chondromalacia?
Chondromalacia (KON-dro-mah-LAY-she-ah), also called
chondromalaciapatellae, refers to softening of the articular cartilage
of the knee cap. This disorder occurs most often in young adults and can
be caused by injury, overuse, parts out of alignment, or muscle
weakness. Instead of gliding smoothly across the lower end of the thigh
bone, the knee cap rubs against it, thereby roughening the cartilage
underneath the knee cap. The damage may range from a slightly abnormal
surface of the cartilage to a surface that has been worn away to the
bone. Chondromalacia related to injury occurs when a blow to the knee
cap tears off either a small piece of cartilage or a large fragment
containing a piece of bone (osteochondral fracture).
Symptoms and Diagnosis
The most frequent symptom is a dull pain around or under
the knee cap that worsens when walking down stairs or hills. A person
may also feel pain when climbing stairs or when the knee bears weight as
it straightens. 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, it's not performed
unless the condition requires extensive treatment.
Treatment
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 doesn't bend more than 90 degrees.
Electrical stimulation may also be used to strengthen the muscles. If
these treatments don't improve the condition, the doctor may perform
arthroscopic surgery to smooth the surface of the cartilage and "wash
out" the cartilage fragments that cause the joint to catch during
bending and straightening. In more severe cases, surgery may be
necessary to correct the angle of the knee cap and relieve friction with
the cartilage or to reposition parts that are out of alignment.
Injuries to the Meniscus
What Causes Injuries to the Meniscus?
The meniscus is easily injured by the force of rotating
the knee while bearing weight. A partial or total tear 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.
Symptoms
Generally, when people injure a meniscus, they feel some
pain, particularly when the knee is straightened. If the pain is mild,
the person may continue moving. Severe pain may occur if a fragment of
the meniscus catches between the femur and the 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 makes the knee swell. 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. Although symptoms of meniscal injury
may disappear on their own, they frequently persist or return and
require treatment.
Diagnosis
In addition to listening to the patient's description of
the onset of pain and swelling, the doctor may perform a physical
examination and take x rays of the knee. The examination may include a
test in which the doctor bends the leg, then rotates the leg outward and
inward while extending it. Pain or an audible click suggests a meniscal
tear. An MRI may be recommended to confirm the diagnosis. Occasionally,
the doctor may use arthroscopy to help diagnose and treat a meniscal
tear.
Treatment
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 started with guidance from a doctor and
physical therapist or exercise therapist. The therapist will make sure
that the patient does the exercises properly and without risking 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 not straightening it 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 (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 is more extensive, the doctor may perform
arthroscopic or open surgery to see the extent of injury and to repair
the tear. The doctor can sew the meniscus back in place if the patient
is relatively young, if the injury is in an area with a good blood
supply, and if the ligaments are intact. Most young athletes are able to
return to active sports after meniscus 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, osteoarthritis is more likely to develop in
the knee if the meniscus is removed. Medical researchers are
investigating a procedure called an allograft, in which the surgeon
replaces the meniscus with one from a cadaver. A grafted meniscus is
fragile and will shrink and tear easily. Researchers have also attempted
to replace a meniscus with an artificial one, but this procedure is even
less successful than an allograft.
Recovery after surgical repair takes several weeks, and
postoperative 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 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 ACL.
Ligament Injuries
What Are the Causes of Anterior and Posterior Cruciate
Ligament Injuries?
Injury to the cruciate ligaments is sometimes referred to
as a "sprain."* The ACL is most often stretched or torn (or both) by a
sudden twisting motion (for example, when the feet are planted one way
and the knees are turned another).
The PCL is most often injured by a direct impact, such as
in an automobile accident or football tackle.
* The National Institute of Arthritis and
Musculoskeletal and Skin Diseases Information Clearinghouse has a
separate publication on sprains and strains. See the end of this booklet
for contact information.
Symptoms and Diagnosis
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. The doctor may perform several tests to see
whether the parts of the knee stay in proper position when pressure is
applied in different directions. A thorough examination is essential. An
MRI is very accurate in detecting a complete tear, but arthroscopy may
be the only reliable means of detecting a partial one.
Treatment
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 brace to protect the knee during activity.
For a completely torn ACL in an active athlete and motivated person, 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 synthetic ligaments have been tried in
experiments, the results have not been as good as with human tissue. One
of the most important elements in a patient's successful recovery after
cruciate ligament surgery is a 4- to 6-month exercise and rehabilitation
program that may involve using special exercise equipment at a
rehabilitation or sports center. Successful surgery and rehabilitation
will allow the patient to return to a normal lifestyle.
What Is the Most Common Cause of Medial and Lateral
Collateral Ligament Injuries?
The MCL is more easily injured than the LCL. The cause is
most often a blow to the outer side of the knee that stretches and tears
the ligament on the inner side of the knee. Such blows frequently occur
in contact sports like football or hockey.
Symptoms and Diagnosis
When injury to the MCL occurs, a person may feel a pop and
the knee may buckle sideways. Pain and swelling are common. A thorough
examination is needed to determine the kind and extent of the injury. To
diagnose a collateral ligament injury, the doctor exerts pressure on the
side of the knee to determine the degree of pain and the looseness of
the joint. An MRI is helpful in diagnosing injuries to these
ligaments.
Treatment
Most sprains of the collateral ligaments will heal if the
patient follows a prescribed exercise program. In addition to exercise,
the doctor may recommend ice packs to reduce pain and swelling and 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 ACL, which usually requires
surgical repair.
Tendon Injuries and Disorders
What Causes 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. Also,
trying to break a fall may cause the quadriceps muscles to contract 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 because in sports that require
jumping, such as basketball, the muscle contraction and force of hitting
the ground after a jump strain the tendon. After repeated stress, the
tendon may become inflamed or tear.
Symptoms and Diagnosis
People with tendinitis often have tenderness at the point
where the patellar tendon meets the bone. In addition, they may feel
pain during 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 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.
Treatment
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. For a partial tear, the doctor
might apply a cast without performing surgery.
Rehabilitating a partial or complete tear of a tendon
requires an exercise program 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 repeat injury. A rehabilitation program may last 6
months, although the patient can return to many activities before
then.
What Causes Osgood-Schlatter Disease?
Osgood-Schlatter disease is caused by repetitive stress or
tension on 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 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.
Symptoms and Diagnosis
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, the motion of the
knee is not affected. Pain may last a few months and may recur until the
child's growth is completed.
Osgood-Schlatter disease is most often diagnosed by the
symptoms. An x ray may be normal, or show an injury, or, more typically,
show that the growth area is in fragments.
Treatment
Usually, the disease resolves without treatment. Applying
ice to the knee when pain 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 moderate or less stressful sports
activities may need to wear knee pads for protection and apply ice to
the knee after activity. If there is a great deal of pain, sports
activities may be limited until discomfort becomes tolerable.
What Causes Iliotibial Band Syndrome?
This is an overuse condition in which inflammation results
when a band of a tendon rubs 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.
Symptoms and Diagnosis
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 typically based on the symptoms, such as pain at the
outer bone, and exclusion of other conditions with similar symptoms.
Treatment
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 isn't
stretched too tightly over the bone.
Other Knee Injuries
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. This problem usually arises
spontaneously in an active adolescent or 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. A person with this
condition may eventually develop osteoarthritis.
Lack of a blood supply can cause bone to break down
(avascular necrosis).* The involvement of several joints or the
appearance of osteochondritis dissecans in several family members may
indicate that the disorder is inherited.
* The National Institute of Arthritis and
Musculoskeletal and Skin Diseases Information Clearinghouse has a
separate publication on avascular necrosis. See the end of this booklet
for contact information.
Symptoms and Diagnosis
If normal healing doesn't occur, cartilage separates from
the diseased bone and a fragment breaks loose into the knee joint,
causing weakness, sharp pain, and locking of the joint. An x ray, MRI,
or arthroscopy can determine the condition of the cartilage and can be
used to diagnose osteochondritis dissecans.
Treatment
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 cartilage growth. Research is being
done to assess the use of cartilage cell and other tissue transplants to
treat this disorder.
What Is Plica Syndrome?
Plica (PLI-kah) syndrome occurs when plicae (bands of
synovial tissue) are irritated by overuse or injury. Synovial plicae are
the remains 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
this syndrome.
Symptoms and Diagnosis
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 those of some other knee
problems, plica syndrome is often misdiagnosed. Diagnosis usually
depends on excluding other conditions that cause similar symptoms.
Treatment
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 an elastic bandage to the
knee, and do strengthening exercises. A cortisone injection into the
plica folds helps about half of those treated. If treatment fails to
relieve symptoms within 3 months, the doctor may recommend arthroscopic
or open surgery to remove the plicae.
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
such as 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).
How Can People Prevent Knee
Problems?
Some knee problems, such as those resulting from an
accident, can't be foreseen or prevented. However, a person can prevent
many knee problems by following these suggestions:
- Before exercising or participating in sports, warm up by walking
or riding a stationary bicycle, then do stretches. 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 way to
strengthen the leg muscles that support 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 can be caused by flat feet or overpronated feet (feet that
roll inward). People can often reduce some of these problems by
wearing special shoe inserts (orthotics). Maintain a healthy weight to
reduce stress on the knee. Obesity increases the risk of degenerative
(wearing) conditions such as osteoarthritis of the knee.
What Types of Exercise Are Most
Suitable for Someone With Knee Problems?
Three types of exercise are best for people with
arthritis:
- Range-of-motion exercises help maintain normal joint
movement and relieve stiffness. This type of exercise helps maintain
or increase flexibility.
- Strengthening exercises help keep or increase muscle
strength. Strong muscles help support and protect joints affected by
arthritis.
- Aerobic or endurance exercises improve function of the
heart and circulation and help control weight. Weight control can be
important to people who have arthritis because extra weight puts
pressure on many joints. Some studies show that aerobic exercise can
reduce inflammation in some joints.
Where Can People Find More
Information About Knee Problems?
National Institute of Arthritis and Musculoskeletal and
Skin
Diseases Information Clearinghouse
National Institutes
of Health
1 AMS Circle
Bethesda, MD 20892-3675
Phone:
301-495-4484 or
877-22-NIAMS (226-4267) (free of charge)
TTY:
301-565-2966
Fax: 301-718-6366
http://www.niams.nih.gov/
The clearinghouse provides information about various forms
of arthritis and rheumatic disease and bone, muscle, and skin diseases.
It distributes patient and professional education materials and refers
people to other sources of information. Additional information and
updates can also be found on the NIAMS Web site.
American Academy of Orthopaedic Surgeons
P.O. Box 2058
Des Plaines, IL 60017
Phone: 800-824-BONE (2663) (free of charge)
www.aaos.org
The academy provides education and practice management services for orthopaedic surgeons and allied health professionals. It also serves as an advocate for improved patient care and informs the public about the science of orthopaedics. The orthopaedist's scope of practice includes disorders of the body's bones, joints, ligaments, muscles, and tendons. For a single copy of an AAOS brochure, send a self-addressed stamped envelope to the address above or visit the AAOS Web site.
American College of Rheumatology
1800 Century
Place, Suite 250
Atlanta, GA 30329
Phone: 404-633-3777
Fax:
404-633-1870
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 this Web site.
American Physical Therapy Association
1111 N.
Fairfax Street
Alexandria, VA 22314
Phone: 800-999-APTA (2782)
(free of charge)
www.apta.org
The association publishes a free brochure titled "Taking
Care of the Knees."
Arthritis Foundation
1330 West Peachtree
Street
Atlanta, GA 30309
Phone: 404-872-7100 or 800-283-7800 (free
of charge)
or call your local chapter (listed in the local telephone
directory)
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 can provide addresses and phone numbers for
local chapters and physician and clinic referrals.
Acknowledgments
The NIAMS gratefully acknowledges the assistance of
Barbara Mittleman, M.D., and James Panagis, M.D., M.P.H., NIAMS, NIH;
John H. Klippel, M.D., Arthritis Foundation, Atlanta, Georgia; Frank A.
Pettrone, M.D., Arlington/Vienna, Virginia; and W. Norman Scott, M.D.,
Beth Israel Medical Center, New York, New York, in the preparation and
review of this booklet.
The mission of the National Institute of Arthritis and Musculoskeletal
and Skin Diseases (NIAMS) is to support research into the causes, treatment,
and prevention of arthritis and musculoskeletal and skin diseases; the
training of basic and clinical scientists to carry out this research;
and the dissemination of information on research progress in these diseases.
The NIAMS Information Clearinghouse is a public service sponsored by
the NIAMS that provides health information and information sources.
Additional information and research updates can be found on the NIAMS
Web site at http://www.niams.nih.gov/.
This booklet is not copyrighted. Readers are encouraged to
duplicate and distribute as many copies as needed.
Additional copies of this booklet are available from
National Institute of Arthritis and Musculoskeletal
and
Skin Diseases (NIAMS) Information Clearinghouse
National Institutes
of Health (NIH)
1 AMS Circle
Bethesda, MD 20892-3675
NIH Publication No. 01-4912