Compared to other forms of arthritis, osteoarthritis usually produces relatively mild symptoms. And in many people, the disease is silent. That is, while X-rays may show some signs of osteoarthritis, the changes may not produce pain or discomfort for decades, if ever.
“The connection between the osteoarthritis changes that show up on X-rays and the pain and discomfort you actually feel is tenuous at best. There are thousands of people walking around with a substantial degree of osteoarthritis who feel no discomfort at all,” says New York physician W. Nagler, M.D.
Millions of people do have pain and discomfort from OA. Women are twice as likely as men to develop this disease. Most often, symptoms begin after the age 40, but OA can strike earlier if your joints have been injured.
OA causes a deep, aching pain in one or more joints, especially those that bear weight, such as the hips, knees, and feet. The disease can also settle in the spine. Another place for OA to target is the hands, causing knobby enlargements of the finger joints and pain at the base of the thumb.
In OA, the smooth cushions of cartilage at the ends of the bones become pitted and frayed. In time, the cartilage may completely wear away, leaving the end of the bones unprotected. The bones also begin to grow and thicken in the joint, producing little bony spurs or osteophytes, that can get in the way of normal movements and cause pain. Eventually, the joint begins to work like a rusted hinge rather than a well oiled one.
Doctors used to think of OA as a wear and tear disease. They assumed that, with age, cartilage inevitably wore thin, like the tread on a pair of tires after many miles of use. But modern researchers say it’s unfair to blame age alone for OA. Normal joints do wear some with age, but generally to a much lesser degree than previously injured or over-stressed joints.
So what causes OA? It may be an insult to the joints when we’re young that sets off a gradual process that causes the symptoms to appear years later. Or years of repeated out-of-the-ordinary demands on a joint that may eventually lead to OA. OA is more common in the toes of ballet dancers, for example, because they spend so much time on their toes. Similarly, basketball players tend to develop OA in their knees, while miners and loggers get it in the spine, probably from lifting heavy loads and improper work positions.
“Development of OA can often be traced to abnormal or increased stress on a joint,” writes Dr. Bland in Running and Fit News, the newsletter of the American Running and Fitness Association. That is, when a joint is continually stressed, it can become injured, and possibly OA can develop.” People who are overweight are more likely to develop OA, studies show.
Phases of Osteoarthritis
Osteoarthritis is a degenerative process that worsens with time. If neglected, this potentially crippling condition quietly progresses without obvious symptoms.
It starts with some type of uncorrected trauma to the joint. A slip or a fall. A car accident. Smaller, less obvious repetitive injuries can also start this process. The “first phase” of OA is revealed as a loss of normal joint movement or function. Other joints and tissues often compensate, starting a chain reaction of health problems.
Left uncorrected, the body responds by depositing calcium onto the affected joint surfaces, ligaments and connective tissue. This “second phase” of OA is the result of the body’s attempt to stabilize and “splint” the malfunctioning joint. As with high blood pressure or cancer, pain or other obvious symptoms are often absent until the problem advances. Unaware of the serious damage that is occurring, many allow their problem to worsen.