Osteoarthritis, also called degenerative joint disease, is the most common type of arthritis. It is associated with a breakdown of cartilage in joints and can occur in almost any joint in the body. It most commonly occurs in the weight bearing joints of the hips, knees, and spine. It can also affect the fingers, thumb, neck, and large toe. It usually does not affect other joints unless previous injury or excessive stress is involved.

Cartilage is a firm, rubbery material that covers the ends of bones in normal joints. Its main function is to reduce friction in the joints and serve as a "shock absorber." The shock-absorbing quality of normal cartilage comes from its ability to change shape when compressed (flattened or pressed together).

Osteoarthritis causes the cartilage in a joint to become stiff and lose its elasticity, making it more susceptible to damage. Over time, the cartilage may wear away in some areas, greatly decreasing its ability to act as a shock absorber. As the cartilage deteriorates, tendons and ligaments stretch, causing pain. If the condition worsens, the bones could rub against each other.

Who Gets Osteoarthritis?
Osteoarthritis affects nearly 21 million Americans. The chance of developing the disease increases with age. Most people over age 60 have osteoarthritis to some degree, but its severity varies. Even people in their 20s and 30s can get osteoarthritis. In people over 50, more women than men get osteoarthritis.

What Are the Symptoms of Osteoarthritis?
Symptoms of osteoarthritis most often develop gradually and include:
* Joint aching and soreness, especially with movement.
* Pain after overuse or after long periods of inactivity.
* Bony enlargements in the middle and end joints of the fingers (which may or may not be painful).
* Joint swelling and joint fluid accumulation.

What Causes Osteoarthritis?
There are several factors that increase a person's chances of developing osteoarthritis. These include: heredity, obesity, injury, and/or joint overuse.

How Is Osteoarthritis Diagnosed?
The diagnosis of osteoarthritis is based on a combination of the following factors: your description of symptoms; the location and pattern of pain; and certain findings during a physical exam. Your doctor may use X-rays to help confirm the diagnosis and rule out other types of arthritis. X-rays show how much joint damage has occurred. If fluid has accumulated in the joints, your doctor may remove some fluid from the joint (called joint aspiration) and examine it under a microscope to rule out other diseases. While there is no blood test to diagnose osteoarthritis, some blood tests may be helpful to rule out other types of arthritis.

How Is Osteoarthritis Treated?
Osteoarthritis is usually treated by medications, exercise, application of heat or cold to the painful joint, use of supportive devices such as crutches or canes, and weight control. Surgery may be helpful to relieve pain when other treatment options have not been effective. The goals of treatment are to accomplish the following: decrease joint pain and stiffness; improve joint mobility and stability;and/or increase your ability to do daily activities. The type of treatment prescribed will depend on several factors including the person's age, activities, occupation, overall health, medical history, and severity of the condition.

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