New Knees on the Rise

When medications and exercise no longer give arthritis patients the relief they need, surgery may be the next option. A total joint replacement can free patients from pain, giving them the mobility to live a normal life.

The number of total knee replacement surgeries has more than doubled in the last decade, according to a recent study.

The leading cause of knee replacement surgeries continues to be joint damage caused by osteoarthritis.

Get treated for osteoarthritis to prevent joint damage.

Elena Losina, Ph.D., of Brigham and Women's Hospital and lead investigator of the study, and colleagues wanted to find out how many Americans are living with total knee replacements.

They found that more than 4.5 million Americans - or 4.7 percent of Americans over the age of 50 - have at least one knee replacement.

These rates are more than the national rates for rheumatoid arthritis and congestive heart failure.

Osteoarthritis is still the main reason for total knee replacement.

"The number of total knee replacements is growing drastically," says Dr. Losina.

The high number of people living with knee replacements may lead to increases in the number of revisions and complications. However, these findings may help in preparing for the coming challenges associated with the growing numbers of knee replacement patients.

The study suggests that doctors and policy makers should be thinking about capacity for follow-up care, the costs of health care, and access to treatment.

Using data from a variety of sources - including the National Health Interview Survey, the Multicenter Osteoarthritis Study, and the Osteoarthritis Initiative - the researchers also found that rates of both osteoarthritis and total knee replacement are higher in women.

The results show that 4.8 percent of women between 60 and 69 years of age have had at least one knee replaced. In comparison, 4.1 percent of men between 60 and 69 years of age have one knee replacement.

Similarly, 7.1 percent of men and 8.2 percent of women between 70 and 79 years of age have at least one knee replacement.

Ten percent of men and women over the age of 80 have had at least one knee replaced.

This study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases.

The results were presented at the 2012 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS). As such, the findings have yet to be peer-reviewed.