NEW YORK (Reuters Health) – Both hip and knee arthritis are common among older adults, but the need for hip replacements seems to far exceed that for knee replacements, new research suggests.

In a study of nearly 7,600 Spanish adults age 60 and older, researchers found that 7 percent had hip osteoarthritis, while 12 percent had osteoarthritis of the knee. Osteoarthritis refers to the common “wear-and-tear” form of arthritis, in which cartilage in the joints gradually breaks down, leading to symptoms like pain and stiffness.

Both hip and knee arthritis were more common in women than men, with the difference being particularly apparent when it came to the knees: 15 percent of women had knee arthritis versus fewer than 9 percent of men.

But while knee arthritis was generally more common than hip arthritis, the latter condition was much more likely to need surgery, the researchers report in the Archives of Internal Medicine.

Of study participants with hip arthritis, 53 percent of women and 38 percent of men were candidates for a total hip replacement, according to the investigators. In contrast, only 18 percent of women and 12 percent of men with knee arthritis were deemed to be candidates for a total knee replacement.

Dr. Jose M. Quintana, of the Hospital de Galdakao in Spain, led the study.

Quintana’s team reached their conclusions after surveying 7,577 adults between the ages of 60 and 90. Those who reported potential symptoms of knee or hip arthritis were then examined by an orthopedic surgeon to confirm a diagnosis and to judge whether a total hip or total knee replacement might be appropriate.

In judging whether surgery was a good option, the researchers considered factors like how much pain and how many physical limitations a patient had, as well as his or her overall health.

In the end, Quintana’s team found, joint replacement was far more often an appropriate treatment for hip arthritis than it was for knee arthritis.

The choice of whether to have joint replacement surgery is, of course, an individual one, depending on a person’s own symptoms and general health, the researchers note.

The current findings, Quintana and his colleagues write, serve more as a way to help health systems plan for the “growing health problem” of hip and knee arthritis, and their “costly medical interventions.”

SOURCE: Archives of Internal Medicine, July 28, 2008.