<p>Osteoarthritis (OA) is the most common form of arthritis in the United States, affecting an estimated 21 million adults. OA begins with the breakdown of joint cartilage, resulting in pain and stiffness.  OA commonly affects the joints of the fingers, knees, hips, and spine. Other joints affected less frequently include the wrists, elbows, shoulders, and ankles. When OA is found in a less-frequently affected joint, there is usually a history of injury or unusual stress to that joint.</p>
<p>Work-related repetitive injury and physical trauma may contribute to the development of OA. For example, if you have a strenuous job that requires repetitive bending, kneeling, or squatting, you may be at high risk for OA of the knee.</p>
<p>What are the symptoms of osteoarthritis?</p>
<p>The most common symptoms of OA include: </p>
<p>•	Steady or intermittent pain in a joint.<br />
•	Stiffness after periods of inactivity, such as sleeping or sitting.<br />
•	Swelling or tenderness in 1 or more joints.<br />
•	Crunching feeling or sound of bone rubbing on bone (called crepitus) when the joint is used. </p>
<p>OA usually comes on slowly. Early in the disease, joints may ache after physical work or exercise. If you are experiencing symptoms such as joint pain and stiffness, see a doctor to find out if you have OA.</p>
<p>Where do symptoms of osteoarthritis typically appear?</p>
<p>Although OA can occur in any joint, most often it occurs in the following areas:</p>
<p>•	Fingers. OA of the fingers is often hereditary, meaning it runs in families. Fingers may ache or be stiff and numb. The base of the thumb joint is commonly affected. Fingers can become enlarged and gnarled. Small, bony knobs (called Heberden's nodes) may also appear on the end joints of the fingers. Similar knobs (called Bouchard's nodes) can appear on the middle joints of the fingers. More women than men have OA of their fingers. Women become especially susceptible to OA after menopause.<br />
•	Knees. Because knees are primary weight-bearing joints, they are very commonly affected by OA. They may be stiff, swollen, and painful, making it hard to walk, climb, and get in and out of chairs and bathtubs.<br />
•	Hip. OA in the hip can cause pain, stiffness, and severe disability. In addition to your hip, you may feel the pain in your groin, inner thigh, or knees. This can lead to difficulty moving, bending, and walking.<br />
•	Spine. OA of the spine can cause stiffness and pain in the neck or in the lower back, as well as weakness or numbness in your arms or legs.</p>
