What Is Osteoarthritis?
What Causes Osteoarthritis?
Who Gets Osteoarthritis?
What Are the Symptoms of Osteoarthritis?
How Is Osteoarthritis Diagnosed and Treated?
Is Surgery Useful for Osteoarthritis Pain?
Osteoarthritis Websites
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Unlike rheumatoid arthritis, which is a systemic disease primarily in
the joints, osteoarthritis reflects both damage to a joint and the reaction
by the joint to that damage. Osteoarthritis can develop in any synovial
joint but more commonly in the hand, hip, knee, and spine.
[A joint is where two or more bones meet. A synovial joint is a joint
that is lubricated with a clear blood plasma called synovial
fluid. The fluid helps maintain cartilage in and around
the joint.] Osteoarthritis produces a local tissue response, mechanical
change, and failure of function in the affected joints. Osteoarthritis
is characterized by gradual loss of cartilage within a synovial joint
(although the cartilage may actually be thicker than normal in the earlier
stages of the disease). This loss of cartilage ultimately results in
joint instability and failure.
Although osteoarthritis was traditionally believed to be a progressive,
degenerative disease, it is now clear that it is far more complicated.
Osteoarthritis is a metabolically dynamic process including both destruction
and repair that may progress episodically and that has multifactoral
causation.
Although osteoarthritis is a mechanically driven condition, the disease
process is chemically mediated. As cartilage is damaged, it becomes
thinner and develops large clefts or fissures. Water content in the
cartilage is increased, leading to swelling of the cartilage. At the
same time, enzyme activity increases, causing a reduction in the load-bearing
capacity of the cartilage. Researchers continue to study these biochemical
processes to develop pharmaceutical agents that might modify the disease
process of osteoarthritis.
Osteoarthritis generally progresses slowly. The cartilage initially
shows pitting, fibrillation, and cleft formation, but as the condition
progresses the cartilage becomes ulcerated and irregular. The earlier
stages of osteoarthritis may last years or decades, the later stages
of the disease progress more rapidly.
Osteoarthritis may be caused by biomechanical stresses affecting the articular
cartilage and subchondral bone; biochemical changes in the cartilage and
synovial membrane; and genetic stresses. Biomechanical stresses include
excessive or repetitive use of the joint, increased load to the joint
from chronic obesity, or trauma. In some sites, such as the hips and the
knees, environmental factors such as obesity or occupation may be dominant,
although not exclusive. Persons who develop osteoarthritis may be genetically
predisposed. Because osteoarthritis is so common in the older population,
some have considered it a consequence of aging, but recent data suggest
that this may not be so.
Osteoarthritis is the most common rheumatic disease and has a substantial
impact on quality of life, use of healthcare resources, and the nation’s
economy. The true prevalence of OA is difficult to ascertain because of
difficulties in defining it and determining its onset. Osteoarthritic
changes are seen in practically everyone over the age of 70 years, and
it is estimated that 10% of people over the age of 60 have significant
medical problems that can be attributed to osteoarthritis.
Age is the strongest predictor of the development and progression
of osteoarthritis because the condition is not reversible. Since people
are living longer, we expect that greater numbers of people will get
osteoarthritis. Other risk factors for osteoarthritis in the hip and
knee include obesity, trauma, certain physically demanding activities,
genetic susceptibility, and participation in high impact sports. Among
younger persons, men may be affected more often than women, whereas
women appear to be affected more frequently among the elderly. Osteoarthritis
affects all humans, though generally it is more prevalent in Europe
and the USA than in other parts of the world.
Osteoarthritis is one of the most debilitating diseases in the United
States. Osteoarthritis significantly impacts psychosocial and physical
function and is a leading cause of disability in later life. As a cause
of disability in the elderly, osteoarthritis is second only to cardiovascular
disease in western societies. Pain, the most prominent symptom in most
people with osteoarthritis, is the most important determinant of disability.
Pain. Pain is the most common
complaint in patients with osteoarthritis. Early in the course of the
disease, pain usually occurs after prolonged activity and is relived with
rest. In advanced osteoarthritis, pain may be constant. For superficial
joints, the patient can usually easily identify the joint that is the
source of discomfort. For other joints such as the hip, however, patients
may not be sure where the starts and may describe the pain as a deep,
low-grade ache. Cold or humid weather frequently makes the pain worse.
Stiffness. Patients often
report stiffness in a joint, typically when they get up in the morning
or after periods and inactivity. The stiffness is usually mild; lasts
for less than 15 to 30 minutes; and unlike generalized stiffness that
occurs with rheumatoid arthritis, is confined to the affected joints.
Like pain, humid weather or a drop in atmospheric pressure may aggravate
stiffness.
Weakness and Disability.
Patients with osteoarthritis progressively have a loss of function resulting
from the pain and stiffness. Loss of function may or may not correlate
with the degree of arthritis. The extent of disability is a crucial aspect
of the patient’s history and should be used to guide therapeutic
decisions. For example, a patient with severe radiographic evidence of
osteoarthritis who is relatively comfortable and fully functional does
not usually require treatment.
Diagnosing Osteoarthritis
The physician takes a medical history and examines the patient. In general,
patients are late middle age or older and have joint pain and stiffness
that is aggravated by activity and relieved by rest. The most commonly
affected joints include the hips, knees, cervical and lumbar spine, distal
interphalangeal joints, proximal interphalangeal joints, and the first
carpometacarpal joint of the hand. Osteoarthritis is less common in the
shoulders, elbows, and wrists.
The physician will also notice that the affected joint or area feels tender
and the joint may be enlarged or even deformed. The joint may seem to
crunch or crack when it is moved, and, in rare cases, may be swollen.
Most joints with moderate to severe osteoarthritis are limited in motion.
Limitation of motion may be caused by pain, inflammation, tissue damage,
or deformity. The physician will look for functional limitations, such
as difficulty walking, standing from a seated position, fastening buttons
on clothing, or writing.
Laboratory Tests and X-Ray Results.
Laboratory and radiology tests can be useful, but the diagnosis of osteoarthritis
is almost always based on the medical evaluation. X-rays typically show
narrowing of the joint and bone problems and can confirm the diagnosis
and show the extent of the disease; however, radiographic abnormalities
can also be found in people who do not have osteoarthritis and can be
helpful in identifying another disease that resulted in osteoarthritis.
Results of blood and urine tests are usually normal, and are not useful
in diagnosing osteoarthritis. Synovial fluid analysis often yields abnormal
but nonspecific results. Nevertheless, the presence of abnormal laboratory
results may rule out other types of arthritis, identify metabolic disorders
associated with osteoarthritis, and alert the physician to another disease
process, such as infection or malignancy. Other diagnostic procedures,
such as synovial membrane biopsy, radionuclide bone scanning, arthroscopy,
and interosseous phlebography, play limited and selective roles in evaluation.
Treatment for Osteoarthritis
Treatment for osteoarthritis includes both medication and nondrug approaches.
Drug therapy for pain management is most effective when combined with
nondrug strategies, such as nutritional, physical, educational, and cognitive-behavioral
interventions.
Drug Therapy
Medications for the treatment of osteoarthritis include oral, intra-articular,
and topical treatments.
Oral medications include:
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Acetaminophen |
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COX-2-specific inhibitors |
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Nonselective NSAIDs |
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Nonacetylated salicylate |
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Tramadol |
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Opioids |
Intra-articular medications include:
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Glucocorticoids |
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Hyaluronan |
Topical medications include:
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Capsaicin |
Acetaminophen. Widely accepted
clinical guidelines recommend that acetaminophen is the oral analgesic
to try first for mild to moderate pain. If successful, acetaminophen is
the preferred long-term analgesic because of its overall cost, efficacy,
and toxicity profile.
Patients with mild pain should try the prescribed drug for several weeks
before assuming that the treatment is ineffective.
Despite the fact that acetaminophen is one of the safest analgesics, it
can cause liver or kidney problems. Acetaminophen should be used with
caution in patients who drink alcohol.
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs).
NSAIDs such as aspirin, ibuprofen, and naproxen are widely used analgesics
because these are effective in treating acute and chronic pain and in
inflammatory muscle conditions. The COX-2 selective NSAIDs are commonly
used for arthritis pain. The American Pain Society (APS) has endorsed the COX-2 selective NSAIDs
as the drug class of choice for the initial management of moderate to
severe arthritis pain unless the patient is at significant risk for hypertension
or kidney disorder. The American College of Rheumatology (ACR) guidelines recommend the use of NSAIDs for patients who do not have a favorable response
with acetaminophen.
There may be an increased risk of heart problems in patients who are using
NSAIDs. Therefore, low-dose aspirin should be taken by patients who are
treated with either a nonselective NSAID or a COX-2 selective NSAID and
who are at risk for a heart attack. The decision to treat with these drugs
over a long period of time must be made case-by-case by a physician and
patient after carefully weighing the risks and benefits.
People respond differently to the various NSAIDs; therefore, a physician
may try different NSAIDs at full doses for at least 2 weeks when patients
do not respond to the first NSAID administered.
Tramadol. Tramadol is a centrally
acting oral analgesic. Tramadol has been well studied for general pain,
but has been less well studied for its use in osteoarthritis. Both the
APS and ACR recommend the use of tramadol for patients who have NSAID intolerance (particularly gastrointestinal)
or pain that is refractory to NSAIDs. The most common side effects occurring
with tramadol include nausea, constipation, and drowsiness. Seizures are
rare, but may occur in patients who are rapidly titrated to high doses
or in patients with systemic lupus erythematosus. Tramadol is not a controlled
substance, and reports of abuse are rare.
Opioids. Few controlled studies
of opioids have been performed in patients with osteoarthritis; however,
those that have been completed clearly indicated the efficacy and clinical
usefulness of these drugs in treating moderate to severe arthritis pain.
Effective use of an opioid analgesic as a component in the therapeutic
strategy for osteoarthritis requires regular monitoring of outcomes and
techniques to optimize the therapy (including dose titration and side-effect
management).
Intra-Articular Agents
Various intra-articular therapeutic modalities have been used in the treatment
of osteoarthritis. Corticosteroids and hyaluronic acid are the most commonly
used agents for intra-articular injection.
Topical Agents
Patients with osteoarthritis commonly use topical agents such as menthol,
other liniments, and rubbing alcohol to reduce their pain. There have
been some trials showing the efficacy of capsaicin (an enzyme in hot peppers)
in osteoarthritis. Capsaicin might be useful in patients who can tolerate
the burning side effect of the treatment; it should be applied to the
affected joint four times per day. It may cause mild local irritation.
Adjuvant Analgesics
Adjuvant analgesics are drugs with a primary indication other than pain,
but are used to relieve some painful conditions. Use of these drugs has
been recommended for some patients with osteoarthritis pain.
Several adjuvant drugs or drug classes have been used for the management
of chronic joint pain. Drug classes used for this indication include multipurpose
analgesics, such as the antidepressants.
Antidepressant Drugs. Antidepressants
are widely used to manage chronic pain. The pain-relieving effect of these
drugs is not dependent on their antidepressant activity, although effective
treatment of accompanying depression can contribute to a good outcome.
The usually effective dose is often lower than the dose required to treat
depression, and pain relieve typically occurs within a week.
Recent research and clinical experience suggest that antidepressants are
not always effective for osteoarthritis pain, but that serotonergic-noradrenergic
(SNRI) agents and tricyclics are the most consistently beneficial.
Though serious side effects are uncommon at the doses typically administered
for pain, they can occur, in some patients, even at low doses. The SNRIs
and the serotonin-selective reuptake inhibitors (SSRIs) are better tolerated
than the tricyclics. Heart problems have been reported with the tricyclics,
though this is very uncommon. Patients with significant heart disease
should not be treated with a tricyclic.
| Multipurpose Analgesics |
Antidepressants
Tricyclics |
amitriptyline, desipramine, imipramine, nortriptyline, doxepin |
Serotonin-noradrenergic
and
serotonin-selective reuptake
inhibitors (SNRIs and SSRIs) |
paroxetine, citalopram, duloxetine, venlafaxine |
| α2-Adrenergic Agonists |
clonidine, tizanidine |
| Corticosteroids |
dexamethasone, prednisone |
| Topical Analgesics |
capsaicin, local anesthetics (creams/patches) |
Nondrug Treatments for Osteoarthritis
Nonpharmacologic measures are important in treating osteoarthritis.
Muscle strengthening, occupational therapy, and rest are important.
The goals of nonpharmacologic management of osteoarthritis are to control
pain, reduce joint stiffness, limit joint damage, and improve function
and quality of life.
Several other physical therapy modalities commonly used include acupuncture, heat or cold, transcutaneous electrical nerve stimulation (TENS), mobilization or manipulation, and massage. The research regarding these therapies is limited, but they can be integrated with other pharmacological and non-pharmacological approaches.
Exercise for Patients with Osteoarthritis
Patients with osteoarthritis are encouraged to include all three types—flexibility
exercise (i.e., range-of-motion exercises), strengthening exercise,
and aerobic exercise—in their routines. Flexibility exercises
should be performed every day; strengthening exercises should been performed
2 to 3 times per week on alternate days; and aerobic exercise should
be performed for 30 to 45 minutes at least 3 to 4 times per week. At
a minimum, all individuals should be encouraged to participate in the
minimum level of physical activity recommended by the U.S. Surgeon General—at
least 30 minutes of moderate physical activity on most days of the week.
Regular joint motion and weight bearing exercises are beneficial to
both cartilage and muscle. Inactivity leads to articular cartilage atrophy
and weakening of the muscles and ligaments surrounding the joint, thus
destabilizing it. All patients with osteoarthritis should exercise in
order to build muscle strength and endurance, to improve flexibility
and joint motion, and to improve aerobic activity. Exercise may be the
single most important intervention for osteoarthritis.
People with osteoarthritis who are highly debilitated, or who have
difficulty maintaining minimum levels of physical activity, should see
a physical therapist and/or occupational therapist. These therapists
can evaluate and reduce impairments in range of motion, flexibility,
strength, and endurance and can instruct the patient in joint-protection
strategies. Physical therapy and occupational therapy are important
in treating patients with functional limitations.
Surgery should not be used as only a last resort, because it can be
critical in restoring joint function and alleviating pain. A delay in
surgery can lead to advanced muscle weakness and functional loss, leading
to further deconditioning and joint damage. Patients who undergo total
hip and knee replacement before severe functional loss have been shown
to have better outcomes than those treated later in the disease. The
American Pain Society (2002) recommends considering surgery when pain
and functional limitations prevent the minimum amount of activity recommended
by the U.S. Surgeon General (30 minutes of exercise on most days of
the week).
Total joint replacement (called arthroplasty)
provides marked pain relief and functional improvement in the vast majority
of patients with OA. Costs associated with long-term medication, assistive
care, and decreased work productivity may exceed the cost of surgery.
Surgery, especially total joint arthroplasty, has been shown to be a
cost-effective treatment compared with nonsurgical treatments.
Several factors should be considered when determining whether surgery
is indicated for treatment of OA. Pain and function are the primary factors
that should be considered. The physician takes a medical history to assess
other factors including deformity, medical risk, your goals and preferences,
prior non-surgical treatment, and your age. Stiffness, which can easily
be measured, is also evaluated. Imaging studies are also performed, although
changes do not always correlate with pain level or extent of functional
impairment. Neither obesity nor advanced age is a contraindication to
surgery.
Assessment of Pain and Function of the Lower Extremity
- Are you able to walk 1 mile?
- Are you able to walk 6 blocks?
- Do you have pain with every step taken?
- Do you have pain at rest?
- How long have you had pain?
- Are you using pain medication and/or NSAID medication?
- Do medications adequately relieve your pain?
- Do you use a cane, crutch, or walker?
- Do you have difficulty getting in and out of a car?
- Do you have difficulty reaching your feet or putting on shoes?
- Do you have difficulty bending, stooping, or climbing stairs?
- What activities have you stopped due to your arthritis pain?
Reproduced from American Pain Society Guideline for the
Management of Pain in Osteoarthritis, Rheumatoid Arthritis, and Juvenile
Chronic Arthritis, 2002.
How effective is joint replacement?
Joint replacement, is a relatively standard procedure to treat advanced
OA of the hip and knee joints, and can provide pain free and functioning
joints for up to 20 years. With joint replacement, most patients achieve
complete pain relief and major improvement in function.
The outcome for joint replacement depends on the timing of the surgery,
the experience of the surgeon and the hospital with the procedure, and
the patient’s health status before the operation, peri- and postoperative
management, and rehabilitation. One concern is the risk of an inflammatory
response caused by small particles of polyethylene debris from a worn
polyethylene joint. However, joint replacement has an extremely low failure
rate. One study in patients less than 55 years found that 99% of total
knee prostheses survived after 10 years (Duffy et al., 1998). Young, active
patients with OA may have slightly higher failure rates. Because of the
effectiveness and high rate of success, patients should be given this
option when nonsurgical treatment is inadequate, and preferably before
deconditioning becomes severe and difficult to reverse.
Other Surgical Approaches
Resection arthroplasty, the removal of a joint
without replacement with artificial material, is not commonly performed
because results are substantially inferior to results with total joint
replacement. There may be some benefit for patients in whom total joint
replacement has failed.
Arthrodesis is the removal of articular joint
surfaces with fixation of bone ends. Arthrodesis is used in the corpus,
spine and foot, but is used rarely in joints that can be treated with
joint replacement. Following arthrodesis, there is no motion at the prior
joint and the two bones function as one. Arthrodesis is indicated when
functional impairment and pain in a joint is not sufficiently relieved
by nonsurgery treatment. Patients typically achieve complete or nearly
complete pain relief with arthrodesis, which may improve function despite
the loss of motion in the affected joint.
Osteotomy is the cutting or sectioning of bone,
which may be performed to change angular alignment of a joint surface
to relieve diseased areas of weight-bearing stress. It is typically used
for the leg, but may also be beneficial in the hip and knee. Osteotomy
may relieve symptoms and slow the rate of progression in patients with
early OA who are not yet candidates for joint replacement. Pain relief
following osteotomy is inferior to that following total joint replacement.
However, younger patients for whom the longevity of joint replacement
would be in question may benefit considerably from the procedure. Osteotomy
should not be performed in patients with inflammatory arthritis.
Arthroscopic surgery is the insertion of an
endoscope into the joint through a small incision to examine the interior
of a joint. It is frequently used as a diagnostic aid, but is also used
for treating mechanical damage. Arthroscopic lavage and debridement may
be useful in patients who wish to postpone joint replacement. Joint arthroscopy
is used most commonly for the knee, but can be performed in the shoulder,
elbow, wrist, and ankle. It is used less commonly for the hip, subtalar
joint, and smaller joints of the hand.
Exostectomy, the removal of bone, is useful
in patients with OA who have areas of bone prominence that are painful.
Exostectomy may be particularly useful for patients with foot pain that
is aggravated by weight bearing during ambulation.
eMedicine: Osteoarthritis
Medline Plus: Osteoarthritis
AAOS Clinical Guidelines:
Osteoarthritis of the Knee
Article: Exercise for Older Adults with Osteoarthritis Pain (.pdf)
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