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OSTEOARTHRITIS OVERVIEW — Osteoarthritis (OA) is the most common type of arthritis. In OA, the cartilage in the joints (which covers the ends of the bones and allows free movement between them) becomes worn down. In addition to the cartilage thinning out, bone spurs can also form around the edges of the joint (figure 1). Some people have joint changes related to OA but do not have pain or other problems. In other people, OA does cause symptoms such as pain, stiffness, reduced joint motion, or changes in the shape of affected joints. Although OA can affect almost any joint, it most commonly affects the hands, knees, hips, feet, and spine.
OA is a chronic condition that has a variable outcome depending on which joint is affected. However, it is not necessarily progressive, and there are several measures that can relieve symptoms and reduce the risk of OA getting worse. Getting an official diagnosis of OA is the first step in ensuring appropriate treatment.
This article reviews the symptoms and diagnosis of OA. Treatment of OA is discussed separately. (See "Patient education: Osteoarthritis treatment (Beyond the Basics)".)
OSTEOARTHRITIS RISK FACTORS — A number of factors can increase the risk of developing osteoarthritis (OA); most people with OA have one or more of these factors.
Age — Advancing age is one of the strongest risk factors for OA. The condition rarely occurs in people younger than 40 years of age, but at least 80 percent of people over the age of 55 years have some X-ray evidence of the disorder. However, not all people with arthritis on an X-ray have pain or other joint problems.
Sex — For unknown reasons, females are two to three times more likely than males to develop OA and are more likely to have pain if it does develop.
Obesity — People who are overweight or obese are at higher risk of developing OA. Losing weight may reduce this risk.
Genetic factors — An increasing number of common genetic variations have been found to increase a person's risk of knee, hip, and hand OA. In addition, genetic factors contribute to the shape and alignment of a person's joints, which affects the risk of OA. If you have a parent or sibling who has (or had) OA, your risk is also increased.
Occupation — OA of the knee has been linked to certain occupations that require frequent squatting and kneeling, including dock work, shipyard work, mining, and carpentry.
OA of the hip has been linked to farm work, construction work, and other activities that require heavy lifting, prolonged standing, or walking several miles each day.
Injury — Substantial joint injury or trauma to a specific joint increases the risk of OA in that joint in the future.
Competitive sports — The risk of OA is increased in people who participate competitively in certain sports that predispose to joint injury. This includes wrestling, boxing, pitching in baseball, cycling, gymnastics, soccer, and football; by contrast, noncompetitive running does not appear to increase the risk of OA.
OSTEOARTHRITIS SYMPTOMS — The symptoms of osteoarthritis (OA) usually begin after age 40 and can vary considerably from one person to another. OA most commonly affects the fingers, feet, knees, hip, and spine. OA less commonly affects the elbow, wrist, shoulder, and ankle.
Pain — The main symptom of OA is joint pain that is worse with activity and relieved by rest. In severe cases, the pain may also occur at rest or at night. The pain usually occurs over or near the affected joint; however, in some cases, the pain may be referred to other areas. For example, a person with OA of the hip may feel pain in the lower thigh or at the knee, and a person with knee OA may have knee pain that extends into the upper shin.
Stiffness — Morning stiffness is a common symptom of OA. This stiffness usually resolves well within 30 minutes of rising, but it may recur throughout the day after periods of inactivity. Some people note a change in symptoms related to the weather, particularly more joint pain and stiffness in cold, damp, or low-pressure weather.
Swelling (effusion) — OA may cause a type of joint swelling called an effusion, which results from the accumulation of excess fluid in the joint.
Crackling or grating sensation (crepitus) — Movement of a joint affected by OA may cause a crackling or grating sensation called "crepitus." This sensation likely occurs because of roughening of the normally smooth surfaces inside the joint.
Changes in joint shape — Change in joint shape can be a prominent symptom when small joints in the hands (such as the joints in the fingers or at the base of the thumbs) are affected.
OA often causes outgrowths of bone called bone spurs or "osteophytes" (figure 1). These bony growths can be felt under the skin near the joints and typically grow larger over time. They can contribute to visible swelling, especially in the joints of the hands and feet.
OSTEOARTHRITIS DIAGNOSIS — There is no single sign, symptom, or test that can diagnose osteoarthritis (OA). Instead, the diagnosis is based on several factors, including the person's age, history, and symptoms.
For example, knee OA can usually be diagnosed in a person over the age of 50 years if the following are present:
●Pain predominantly when weight-bearing and moving the knee
●Early morning stiffness lasting for just a short time (less than 30 minutes)
●A crackling or grating sensation in the knee when going up and down stairs
●Hard bony enlargement of the knees
OA does not cause inflammation (ie, the joint is not warm to the touch). The symptoms of OA generally vary from day to day but change only slowly over years and may level off or even improve at some point.
Similar symptoms to the above can affect other joints, such as the hands and the hips. As the hip joint is deep inside the body, bony enlargement of this joint is not visible, whereas bony enlargement of finger joints is easy to see. Laboratory tests and imaging studies (such as X-rays) are sometimes done if OA is suspected, particularly if the person's symptoms are atypical, but these tests are not always required to diagnose OA.
Laboratory tests — Laboratory tests may be used to rule out other diseases if a health care provider suspects that something else may be causing symptoms.
Imaging tests — Imaging is not a routine part of making a diagnosis. It can be helpful when there is lack of clarity around a source of joint pain other than OA. However, imaging tests are required prior to joint replacement surgery to help stage and guide the procedure.
Other types of imaging, such as ultrasound and magnetic resonance imaging (MRI), are not necessary to make a diagnosis but may be used if the diagnosis is uncertain.
COURSE OF OSTEOARTHRITIS — The course of osteoarthritis (OA) varies greatly between people and depending on which joint is affected. For example, pain and functional restriction due to OA of the hip is most likely to worsen slowly over time, whereas OA affecting the finger joints often causes intermittent pain and stiffness while it is developing, but only minimal symptoms later on. In people whose pain and joint stiffness worsens over time, there is usually intermittent worsening (ie, periods when symptoms get worse followed by periods of stabilization).
Some people with OA are able to function almost normally despite pain, while others may have difficulty with even simple tasks as a result of pain. Exercise can help decrease pain and improve quality of life. (See "Patient education: Arthritis and exercise (Beyond the Basics)".)
OSTEOARTHRITIS TREATMENT — The treatment of osteoarthritis (OA) is discussed in a separate topic review. (See "Patient education: Osteoarthritis treatment (Beyond the Basics)".)
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient education: Osteoarthritis (The Basics)
Patient education: Hip replacement (The Basics)
Patient education: Physical activity for people with arthritis (The Basics)
Patient education: Meniscal tear (The Basics)
Patient education: Paget disease of bone (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Patient education: Osteoarthritis treatment (Beyond the Basics)
Patient education: Gout (Beyond the Basics)
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Patient guidelines for weight-resistance training in osteoarthritis
Epidemiology and risk factors for osteoarthritis
Overview of surgical therapy of knee and hip osteoarthritis
Clinical manifestations and diagnosis of osteoarthritis
Management of knee osteoarthritis
Overview of the management of osteoarthritis
The following organizations also provide reliable health information.
●National Library of Medicine
(www.medlineplus.gov/arthritis.html, available in Spanish)
●National Institute of Arthritis and Musculoskeletal and Skin Diseases
(301) 496-8188
(www.niams.nih.gov/health-topics/arthritis)
●National Institute on Aging
(www.nia.nih.gov/health/osteoarthritis, available in Spanish)
●American College of Rheumatology
(404) 633-3777
(www.rheumatology.org/I-Am-A/Patient-Caregiver)
●The Arthritis Foundation
(800) 283-7800
●My Joint Pain
●Versus Arthritis
(www.versusarthritis.org/about-arthritis/conditions/osteoarthritis-of-the-knee/)
ACKNOWLEDGMENT — The editorial staff at UpToDate would like to acknowledge Kenneth Kalunian, MD, who contributed to an earlier version of this topic review.
