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Osteoarthritis is a degenerative joint disease. It is the most common type of arthritis, and the percentage of people who have it grows higher with age. An estimated 12.1 percent of the U.S. population (nearly 21 million Americans) age 25 and older have osteoarthritis.
Although osteoarthritis is more common in older people, younger people can develop it - usually as the result of a joint injury, a joint malformation, or a genetic defect in joint cartilage. Both men and women have the disease. Before age 45, more men than women have osteoarthritis; after age 45, it is more common in women. It is also more likely to occur in people who are overweight and in those with jobs that stress particular joints.
Usually, osteoarthritis comes on slowly. Early in the disease, the joints may ache after physical work or exercise. Later on, joint pain may become more persistent. Although osteoarthritis can occur in any joint, most often it affects knees, hips, spine and hands.
Knees: The knees are among the joints most commonly affected by osteoarthritis. Symptoms of knee osteoarthritis include stiffness, swelling, and pain, which make it hard to walk, climb, and get in and out of chairs and bathtubs. Osteoarthritis in the knees can lead to disability.
Hips: The hips are also common sites of osteoarthritis. As with knee osteoarthritis, symptoms of hip osteoarthritis include pain and stiffness of the joint itself. But sometimes pain is felt in the groin, inner thigh, buttocks, or even the knees. Osteoarthritis of the hip may limit moving and bending, making daily activities such as dressing and putting on shoes a challenge.
Spine: Osteoarthritis of the spine may show up as stiffness and pain in the neck or lower back. In some cases, arthritis-related changes in the spine can cause pressure on the nerves where they exit the spinal column, resulting in weakness or numbness of the arms and legs.
Hands: Osteoarthritis of the hands seems to have some hereditary characteristics. If a person has or had osteoarthritis in the hands, his or her children are at greater-than-average risk of having it too. Women are more likely than men to have hand involvement and, for most, it develops after menopause. When osteoarthritis involves the hands, small, bony knobs may appear on the end joints (those closest to the nails) of the fingers. They are called Heberden�s nodes. Similar knobs, called Bouchard's nodes, can appear on the middle joints of the fingers. Fingers can become enlarged and gnarled, and they may ache or be stiff and numb. The base of the thumb joint also is commonly affected by osteoarthritis.
Osteoarthritis can be diagnosed by X-rays or magnetic resonance imaging (MRI).
Osteoarthritis mostly affects cartilage, the hard but slippery tissue that covers the ends of bones where they meet to form a joint. Healthy cartilage allows bones to glide over one another. It also absorbs energy from the shock of physical movement. In osteoarthritis, the surface layer of cartilage breaks down and wears away. This allows bones under the cartilage to rub together, causing pain, swelling, and loss of motion of the joint. Over time, the joint may lose its normal shape. Also, small deposits of bone - called osteophytes or bone spurs - may grow on the edges of the joint. Bits of bone or cartilage can break off and float inside the joint space. This causes more pain and damage.
Rest and relief from stress on joints
Medications for pain and inflammation
Surgeons may replace affected joints with artificial joints called prostheses. These joints can be made from metal alloys, high-density plastic, and ceramic material. Some prostheses are joined to bone surfaces with special cements. Others have porous surfaces and rely on the growth of bone into that surface (a process called biologic fixation) to hold them in place. Artificial joints can last 10 to 15 years or longer. Surgeons choose the design and components of prostheses according to their patient's weight, sex, age, activity level, and other medical conditions.