Osteoarthritis, sometimes referred to as degenerative joint disease, is the most widespread form of arthritis which mostly affects the hands and the weight-bearing joints such as the hips, knees and spine. Osteoarthritis is a joint disease that mostly affects cartilage which is the slippery tissue that covers the ends of the bones in a joint. Healthy cartilage reduces friction between two bones gliding over or moving over each other, it reduces stress on the ends of the bones forming the joint by absorbing compressive forces created by physical movement, which is a cushion-like affect at the ends of the bones. In osteoarthritis, the surface layer of the cartilage covering the bone breaks down and wears away leaving the ends of the bones at the joint rubbing against each other. Eventually this process leads to the ends of the bones thickening, scarring and forming bone cysts near the joint line. Both the cartilage and bone respond by growing bone spurs, the membrane of tissue surrounding the joint and adjacent ligaments become swollen and painful. Actually the cartilage breakdown is not the cause of pain as cartilage has no sensory innervation.
Osteoarthritis is one of the most frequent causes of physical disability among adults. More than 20 million people in the United States have the disease. By 2030, 20 percent of Americans, about 70 million people, will be 65 years of age or older and will be at risk for osteoarthritis. Some younger people who have sustained joint trauma from incidents such as sports, recreation or auto accidents, may also develop osteoarthritis, but it mostly occurs in older people. In fact, more than half of the population age 65 or older would show x-ray evidence of osteoarthritis in at least one joint. Before age 45, more men than women have osteoarthritis, whereas after age 45, it is more common in women and more common in black women than Caucasian women.
Aging alone does not cause osteoarthritis. Other presumed causal factors include obesity, injury or overuse, diabetes and genetics. In a recent study conducted by investigators from the National Institute on Aging/NIH and John Hopkins Center on Aging and Health, the researchers wanted to determine whether female patients with osteoarthritis in their lower extremities were more prone to developing mobility limitations than women who did not have the disease. Their analysis included 199 women with lower extremity osteoarthritis who had no difficulty with mobility tasks at the beginning of the study and 140 women without osteoarthritis in the knee or hip, all of whom were between 70 and 79 years old. Patients were evaluated as to their osteoarthritis status, the presence of pain, knee strength, knee torque, and their level of mobility at 18, 36, and 72 months following the initial evaluation.
The results showed that even though more women with osteoarthritis reported using arthritis medications, a greater proportion reported having pain most days and greater pain severity while walking and climbing stairs compared to women with no osteoarthritis. Also 26% of the women with osteoarthritis were obese compared to 11% of the women without the disease, and an additional 40% were overweight. Overall, the two groups were similar with regard to knee strength and torque, the women with osteoarthritis were about 2.5 times more likely to develop difficulty in both lower extremity mobility and activities of daily living than those who did not have osteoarthritis. Greater knee strength reduced the risk of developing difficulty performing daily activities whether or not the women had osteoarthritis, and greater knee torque had the same effect, although it did not reduce the risk for lower extremity difficulty.
In another recent study, a group of 439 people 60 and older with knee osteoarthritis and self-reported disability took part in an 18 month exercise program consisting of walking and resistive strength training for the lower extremities. The findings were significant because they show that exercise over a long period of time is safe as well as beneficial for older adults with knee osteoarthritis. The results showed a modest but consistent improvement in pain relief, disability, and physical performance compared to the control group. The results were published in the January 1, 1997 issue of the Journal of the American Medical Association.
For the older adult with osteoarthritis, the benefits of prevention, early detection, early lifestyle changes, and interventions raise an interesting question. If elderly fitness screens and personalized exercise programs were performed as regularly as sports screens for the young athlete, could the need for joint replacement surgeries be reduced?