Most of the people affected are 65 or older. Osteoarthritis affects both men and women. Before age 45, more men have the disease. After age 65, women are more likely to develop it, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). Younger people also can develop osteoarthritis, usually from injuries to a joint.

Cartilage is the slippery tissue that covers the ends of bones in a joint, according to the NIAMS. Healthy cartilage allows bones to slip over one another and also absorbs the energy from the moving joint. In osteoarthritis, the cartilage wears away, leaving the bones beneath it to rub together. This rubbing causes pain, swelling, and loss of motion. Tiny bits of bone and cartilage can break off inside the joint area, causing more pain and damage.

Researchers think that a combination of these factors may bring on osteoarthritis. Each person is different, however. In some people, the disease progresses quickly; in some people, the symptoms are more serious, according to the NIAMS. In most cases, osteoarthritis develops slowly. At first, joints may ache after exercising or doing other physical activity. The joints most often affected by osteoarthritis are the hands, knees, hips, and spine.

Osteoarthritis of the hip can lead to severe disability, according to the NIAMS. The condition can limit how much a person can move and bend, making daily activities difficult. A cane or walker can reduce the stress on the hip and medication and exercise can help relieve pain. The doctor may recommend hip replacement if the pain is severe and not relieved by other methods.

An X-ray may not show joint damage early on in the condition. To help diagnose osteoarthritis, the health care provider will also note symptoms and when they appeared, and examine the affected joints. A clinical history that describes the symptoms, and when and how they started, and physical exam are important to make sure symptoms are not caused by another medical condition.

Exercise is one of the best treatments for osteoarthritis, according to NIAMS. Exercise can decrease pain, increase flexibility, help with weight control, and improve cardiovascular fitness. The affected joints also need regular rest, so they are not overexerted. Relaxation techniques or stress reduction can help rest the joints, as can using a cane or splint to take the pressure off them. A person who is overweight or obese should lose weight to reduce the stress on weight-bearing joints. Other non-drug methods of treatment include hot packs or a warm bath or shower; and water therapy in a heated pool. For more severe osteoarthritis, surgery may be needed to replace, resurface, or reposition bones.

All of these medications are commonly used for pain relief in osteoarthritis. Aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) have more side effects than acetaminophen. They can irritate the stomach and occasionally can affect kidney function. NSAIDs called COX-2 inhibitors don't cause stomach irritation, but they may cause other side effects. Hyaluronic acid is used to treat osteoarthritis of the knee. It is injected into the joint to help joint lubrication. Another treatment option is injectable glucocorticoids.

Other suggestions from the Arthritis Foundation: Exercise to strengthen the muscles that surround your joints; use your largest joints and muscles when you lift or carry objects; alternate intense activity with periods of rest to avoid repetitive stress on joints; if you find yourself stationary, change your position regularly to decrease stiffness.