What is OsteoArthritis?

Osteoarthritis, the most common form of arthritis, may affect any joint including fingers, hips, knees, lower back and feet. While women often show symptoms of osteoarthritis earlier, men and women are equally likely to develop the condition's characteristic breakdown of joint cartilage.

Osteoarthritis is a common, progressive joint disorder characterized by a deterioration of the articular cartilage and reactive new bone formation in the subchondral and juxtaarticular regions. Although the name implies an inflammation, this process is probably not primarily inflammatory; therefore, it can more accurately be called degenerative joint disease.

Who is affected by osteoarthritis?

Osteoarthritis occurs throughout the world and in all population groups. Osteoarthritis is equally common in men and women, but women tend to develop symptoms earlier. It is estimated that 70% to 90% of people older than age 75 are affected by osteoarthritis.

Osteoarthritis is the most common form of arthritis, and a major reason people become disabled and dependent on others as they get older.

In the general population, many people have osteoarthritis that is evident on X-rays, although not all of these people have symptoms. As seen on X-rays:
-30% have osteoarthritis in the hands. -21% have osteoarthritis in the feet. -3% have osteoarthritis in the knees and hips.
Of people older than 60, 17% of men and 30% of women have symptoms of osteoarthritis.
Of people older than 65:
-Almost all people have osteoarthritis in the hands.
-33% have osteoarthritis in the knee.

Although age itself is not a cause of osteoarthritis, the chances of getting it increase significantly as people get older. Up to 33% of people in the United States older than 18 report symptoms of arthritis or chronic joint pain.

Risk factors

The exact causes of osteoarthritis are unclear, but these factors increase your risk:

Being 45 years old or older
Being female
Having certain hereditary conditions, including defective cartilage and malformed joints
Having joint injuries caused by physical activity or sports
Being obese
Having diseases that change the normal structure and function of cartilage, such as rheumatoid arthritis, hemochromatosis, gout or pseudogout
Having weak thigh (quadriceps) muscles, which may lead you to develop osteoarthritis in your knees

Signs and symptoms of OsteoArthritis

Osteoarthritis often develops slowly, and some people may not experience any signs or symptoms. However, osteoarthritis can cause the following signs and symptoms:

Pain in a joint during or after use, or after a period of inactivity
Discomfort in a joint before or during a change in the weather
Swelling and stiffness in a joint, particularly after using it
Bony lumps on the middle or end joints of your fingers or the base of your thumb
Loss of joint flexibility

The acute pain of early osteoarthritis often tends to fade within a year of its appearance, but it may return if you overuse the affected joint - this is especially true of fingers affected by osteoarthritis.

Areas osteoarthritis typically affects include:

Fingers. Bony knobs called nodes can enlarge your finger joints, creating a gnarled appearance. Early in the course of the disease, your joints may feel painful or stiff and numb. Eventually, the pain often subsides, leaving just bony nodes that affect the mobility of the joints at the end of your fingers. These nodes tend to run in families and affect more women than men.
Spine. Slow deterioration of disks between the bones along your spine can lead to back and neck pain and stiffness.
Weight-bearing joints. The parts of your body that bear the majority of your weight - your hips, knees and feet - are more susceptible to osteoarthritis. As cartilage slowly deteriorates over the years, you can develop chronic pain or varying amounts of discomfort when you stand and walk. Swelling also may occur, especially in your knees.

Unless you've been injured or placed unusual stress on a joint, it's uncommon for osteoarthritis to affect your jaw, shoulder, elbows, wrists or ankles.

Causes of OsteoArthritis

With osteoarthritis the problem lies in the cartilage that cushions the ends of bones in your joints. Over time, the cartilage deteriorates, and its smooth surface roughens. Eventually, if the cartilage wears down completely, you may be left with bone rubbing on bone - causing the ends of your bones to become damaged and your joints to become painful. The exact cause of osteoarthritis isn't known. Researchers suspect that it's a combination of factors, including being overweight, the aging process, joint injury or stress, heredity, and muscle weakness.

Some scientists believe the cartilage damage may be due to a mechanical stress that results in an imbalance of enzymes released from the cartilage cells or from the lining of the joint. When balanced, these enzymes allow for the natural breakdown and regeneration of cartilage. But too much of the enzymes can cause the joint cartilage to break down faster than it's rebuilt. The exact cause of this enzyme imbalance is unclear.

Your body goes to work repairing the damage, but the repairs may be inadequate, resulting instead in growth of new bone along the sides of the existing bone, which produces prominent lumps, most noticeable on hands and feet. Each of the steps in this repair process produces pain. The pain and tenderness over the bony lumps may be most marked early in the course of the disease and less evident later on.

Osteoarthritis commonly occurs in the fingers, neck or lower back. Hips and knees also are frequently affected because they bear most of your weight. You can have chronic pain or varying amounts of discomfort when you stand and walk. Swelling also may occur, especially in your knees.

Prevention of Osteoarthritis

You can take steps to help prevent the development of osteoarthritis or to help prevent the progression of this condition. These steps include:

Weight control. Maintaining a healthy weight may be the single most important thing you can do to prevent osteoarthritis.4 Being overweight puts extra strain on the joints, particularly the large weight-bearing joints such as the knees, the hips, and the balls of the feet. It is estimated that every 1 lb of body weight means at least 3 lb of stress at the knee joint, and even more at the hip joint. That would mean that losing just 5 lb would take at least 15 lb of stress off your knees. Extra weight may also alter the normal structure of the joint and increase the risk for osteoarthritis. Lose unhealthy weight to prevent or lessen joint damage and decrease the stress on osteoarthritic joints.
Injury prevention. Protect your joints from serious injury or repeated minor injuries to decrease your risk of damaging cartilage. Repeated minor injuries include those from job-related activities such as frequent or constant kneeling, squatting, or other postures that place stress on the knee joint.
Exercise can help reduce joint pain and stiffness. Light- to moderate-intensity physical activity may prevent a decline in, and may even restore, health and function.7 However, some people with osteoarthritis may be reluctant to exercise because of joint pain after activity. You can take various steps to help relieve pain, such as heat and cold therapy or taking pain relievers, which may make it easier for you to exercise and stay active. Choose partial– or non–weight-bearing exercise, such as bicycling, swimming, or water exercise.

Research shows that even modest weight loss combined with exercise is more effective in decreasing pain and restoring function than either weight loss or exercise alone.

Young adults who have significant knee injuries have an increased risk of future osteoarthritis. Prevention of joint injuries during youth depends in good part on the use of proper sports equipment and on playing under safe playing conditions.9 A young person who has a serious knee injury can limit further damage by using a brace to stabilize the knee joint and by changing the way he or she does high-impact exercise.

A physical therapist or athletic trainer can help advise you on returning to activities after an injury.

Dr. Emmanuel - Providing services in orthopedic surgery to the area of Culver City, Los Angeles and Beveraly Hills, California (CA).