Osteoarthritis -- It's the most common form of arthritis, affecting more than 21 million people in the U.S., and it's one of the most frequent causes of disability among adults.
By age 65, more than half of the population has X-ray evidence of osteoarthritis (OA) in at least one joint, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases. In addition, OA accounts for most hip and knee replacements.
"Osteoarthritis is a highly debilitating and painful condition suffered by millions of people," states Marc C. Hochberg, M.D., M.P.H., head of the Division of Rheumatology and Clinical Immunology at the University of Maryland Medical Center and a professor of medicine at the University of Maryland School of Medicine.
OA, or degenerative joint disease, is characterized by the breakdown of the joint's cartilage. Cartilage is the slippery tissue that covers the ends of bones in a joint. When the cartilage breaks down, it causes bones to rub against each other, resulting in pain and loss of movement. Over time, the joint may lose its normal shape. In addition, bone spurs may grow on the edges of the joint. Pieces of bone or cartilage can break off and float inside the joint space, causing more pain and damage.
OA most often occurs in people over 45, but some younger people get it from a joint injury. Both men and women get the disease, but after age 50, women are more commonly affected. OA most often occurs in the hands, hips, knees, neck and spine.
Many factors can cause or lead to osteoarthritis including heredity, obesity, joint injury, and overuse of certain joints.
Genetics often play a key role. According to Hochberg, genetic factors account for about half of OA in the hands and hips and a smaller percentage of OA in the knees.
So who is most likely to get OA? Hochberg says higher-risk groups would include those with a parent or older sibling affected by OA, or a person with a congenital or developmental disease of the hip, knee or lower limb.
"Frequently OA runs in families and affects multiple family members," said Danuta. Bujak, Ph.D., FNP, instructor of medicine at the University of Maryland School of Medicine (Division of Rheumatology and Clinical Immunology).
In fact, The University of Maryland Medical Center is part of an international research network that has launched the largest study ever to find the genetic susceptibility for OA.
"Finding a genetic basis for the disease will open up whole new possibilities for finding effective treatments and even preventive measures for this condition," said Hochberg, who is the principal investigator of the study.
Besides genetics there are other risk factors, such as participation in sports such as football, baseball and soccer.
Hochberg says that people involved in sports that involve high-intensity, acute, direct joint impact from contact with other players, playing surfaces or equipment do have an increased risk of OA. Football is a good example.
"Sports that involve both repetitive joint impact and twisting also have an increased risk of OA, such as soccer and baseball pitching," he said.
Much of OA in men can also be attributed to occupational activities, particularly jobs requiring kneeling or squatting, along with heavy lifting.
In addition, Bujak points out that people often sustain injuries in the course of regular exercise because they are not using the proper techniques and are not warming up. "Imagine all those people who are constantly exercising, running on cement and pavement, not wearing proper shoes. They are getting injured. Once you have a torn cartilage it precipitates the process of OA," she said.
Weight also plays an important role. "People who are obese (overweight) have great problems with weight-bearing joints (hips and knees). If they lose weight and can control it, they will have a lesser degree of OA then people who do not," said Bujak.
Usually, doctors will try to use non-medication treatments first, and then progress to drugs if necessary. It all depends on the severity of the disease, said Bujak.
"If someone has a mild form of OA, first we use heat, ice and rest," said Bujak. "Then we start them on physical therapy because what really accelerates the destruction of the joint (like the knee) is poor muscle tone. We can also use Tylenol, some acupuncture and myofacial release. When the pain becomes more severe, we go to medication."
Hochberg said non-drug therapies are fundamental to the overall treatment approach, and should focus on:
There are many different medications used to treat OA, including:
Hochberg says several steps can be taken to prevent or delay the onset of OA:
By Michelle W. Murray
University of Maryland Medical System Web Site Writer