Disorders of the Joints

A joint is the point at which two or more bones meet. It is made up of the bones and muscles brought together at the joint, the ligaments (which connect bone to bone), the tendons (which connect muscle to bone), the bursae (which cushion the joint), and cartilage. The cartilage permits smooth movement of the joint and acts as a shock absorber between the bones. The entire joint is enclosed in a fibrous capsule with a special lining (the synovium) that produces fluid to reduce friction within the joint. Inflammation of or damage to any of these components affects the entire joint. This section describes some common problems that can affect the joints.

Osteoarthritis
Arthritis is a general term that refers to inflammation of one or more joints. There are more than 100 arthritic disorders. Osteoarthritis, which most people refer to as simply arthritis, is a chronic joint disease that affects many middleaged and older Americans. Osteoarthritis that has no obvious cause is called primary arthritis. Osteoarthritis that results from damage to the cartilage that covers the ends of the bones in a joint is called secondary arthritis. Injury and obesity are two factors that may be involved in the development of osteoarthritis. Heredity may also be a factor.

The symptoms of osteoarthritis include pain, tenderness, swelling, redness, and loss of motion or strength in the affected joint or joints. The pain tends to worsen toward the end of the day. In some people the joint may make cracking sounds when it is in motion. In osteoarthritis, joint cartilage gradually wears away, allowing adjoining bones to rub against each other. Painful outgrowths of bone (spurs) also may develop. Although symptoms usually do not appear until middle age, they can begin as early as between ages 20 and 30. Among adults under age 55, men and women are affected equally; after age 55, the incidence of osteoarthritis is higher in women. Joints in the hips, knees, spine, big toe, and fingers are most commonly affected.

Osteoarthritis is diagnosed based on your symptoms and the results of a physical examination. X rays usually are taken to confirm the diagnosis. There is no cure for osteoarthritis. Your doctor probably will prescribe a nonsteroidal anti-inflammatory drug to relieve symptoms. Severe episodes of inflammation
may be treated by injecting a corticosteroid drug directly into the affected joint. Massage, heat treatments, and warm baths may help relieve symptoms. Regular, gentle exercise (such as walking or swimming) will help your joints stay flexible. Maintaining a healthy weight (search healthy weight for more info) will reduce the strain on your joints. For some people doctors may recommend joint replacement.

Rheumatoid Arthritis
Rheumatoid arthritis is a chronic autoimmune disease in which the immune system attacks the synovial tissue, the membrane that lines the joints. It is the second most common form of arthritis and usually appears between ages 20 and 40. Although the cause of rheumatoid arthritis is unknown, there is a genetic component: if a close relative is affected, you are more likely to develop the disease. There is no known cure.

In rheumatoid arthritis, the fluid that lubricates the joints contains irritating chemicals that attack and damage the surfaces of the joints. The inflamed membrane swells and thickens, causing a wearing away of the joint cartilage, which leads to erosion of the bone and weakening of supporting tendons, ligaments, and muscles. The small joints in the hands, wrists, feet, ankles, and neck are most frequently affected, but the hips and the knees also can be affected. In most cases, more than one joint is affected and usually the same joints are affected on both sides, such as both hands.

Rheumatoid arthritis alternates between periods during which symptoms are present and periods with no symptoms. These periods can vary in length. When the disease is active, it causes redness, warmth, swelling, tenderness, pain, and stiffness in the affected joints. The severity of symptoms can vary from person to person. The joint damage resulting from the disease is not reversible; in advanced cases, the joints can become deformed.

A diagnosis of rheumatoid arthritis is based on the symptoms and an examination of the joints. The doctor also can use X rays to detect damage—such as erosion of cartilage and bone—in the affected joints. A blood test also may be performed to check for a specific protein (an antibody called rheumatoid factor) that is present in most people who have rheumatoid arthritis.

Treatment of rheumatoid arthritis is similar to the treatment of osteoarthritis. If treatment with nonsteroidal anti-inflammatory drugs is not effective, the doctor may prescribe other medications, including gold compounds such as auranofin and aurothioglucose, and oral corticosteroids such as prednisolone and triamcinolone. The doctor also may prescribe antirheumatic drugs such as hydroxychloroquine and penicillamine. In severe cases, medications such as azathioprine, cyclophosphamide, cyclosporine, and methotrexate sometimes are prescribed to suppress the inappropriate immune response.

For most people with rheumatoid arthritis, regular exercise can help maintain flexibility and strength in the joints. Your doctor can recommend suitable exercises and also may recommend that you work with a physical therapist to maintain or restore movement in your joints. For some people, surgery to remove the affected joint lining (a procedure called synovectomy) may provide relief. For severely damaged joints, a total joint replacement can reduce pain and restore movement, allowing a person to return to an active life.

Joint Replacement Because of engineering and medical advances, surgeons can now replace certain joints and restore their normal function. Joint replacement (called arthroplasty) has been used on the ankles, hands, wrists, and toes, but it is most often performed on the knee and the hip. With total joint replacement, the bone ends and cartilage are replaced with metal and plastic joint components. The metal component is inserted into the canal inside each long bone involved, while the plastic part covers or receives the metal “bone ends” as a cartilagelike cushion, where bone meets bone. The joint components are usually attached to the bone tissue with an acrylic cement.

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In hip replacement surgery, the end of the femur is replaced with a metal ball, and a plastic cup is cemented into the pelvis where the acetabulum (pelvic socket) would normally receive the end of the femur. In many patients, particularly younger ones, the plastic cup is not cemented into place to give time (with limited activity) for the natural bone to grow and attach to it. In the knee, damaged bone ends are replaced with metal ends covered with plastic that can permit the same range of motion as a normal knee joint.

Joint replacement surgery lasts approximately 2 to 4 hours and requires a lengthy, structured recuperation period. The amount of recovery time required in the hospital depends on the nature of the surgery, your overall health, and whether you have any complications (such as infection, joint dislocation, or blood clots). You may be walking with support within a day of surgery, and you will start physical therapy immediately. You will probably be hospitalized for about a week, although full recovery can take up to 6 months. It is vital to maintain an appropriate exercise and stretching program after the surgery to keep your new joint in good working order. Although replacement joints usually last at least 20 years, younger and more active patients may need to undergo revision surgery (surgery to repair or replace the artificial joint). Joint replacement surgery has an excellent success rate.

Gout
Gout is a metabolic disorder that results from high levels of uric acid (a waste product of cell metabolism) in the blood. The condition can lead to joint inflammation, deposits of uric acid in and around the joints, reduced kidney function, and sometimes the development of kidney stones.

Gout is nine times more common in men than in women. Risk factors for gout include obesity, moderate to heavy alcohol consumption, high blood pressure, and kidney disorders. Certain drugs (such as aspirin) can worsen gout, and certain diseases that affect kidney function (such as diabetes and sickle-cell disease) can be a factor. Acute attacks of gout can be brought on by dehydration, joint injury, fever, large meals, high alcohol intake, stress, or recent surgery. Certain foods, such as shellfish, sardines, and organ meats, also may trigger attacks.

The small joint at the base of the big toe is the most common location for an acute gout attack. Other joints affected may include the ankles, knees, wrists, fingers, and elbows. An acute gout attack often begins at night, with severe pain and sometimes a fever. The attack may subside in several hours or several days but usually recurs at irregular intervals.

The symptoms alone usually are sufficient to diagnose gout, but your doctor can confirm the diagnosis by examining your blood for elevated uric acid levels and your joint fluid for signs of uric acid crystals.

Future attacks can be prevented by increasing fluid consumption (at least eight 8-ounce glasses every day), losing weight, reducing alcohol intake, modifying your diet, and taking nonsteroidal anti-inflammatory drugs (such as ibuprofen) to relieve the pain and inflammation and medications (such as allopurinol or probenecid) to lower blood levels of uric acid.