FRIDAY, March 24 (HealthDay News) -- Demand for total knee and hip replacement in the United States is expected to increase so much by 2030 that there may not be enough orthopedic surgeons to handle the workload, a new study warns.

The study projected that the number of first-time total knee replacements would soar by 673 percent, to 3.48 million, by 2030, while the number of first-time total hip replacements would increase by 174 percent to 572,000. Partial joint replacements are projected to increase by 54 percent in the next 25 years.

The findings were to be presented Friday at the American Academy of Orthopaedic Surgeons annual meeting, in Chicago.

The study also projected that total knee and hip revision joint replacement (repair or replacement of an artificial joint) surgeries will double by 2015. Currently, hip revisions are done more often than knee revisions, but that will likely change by 2007.

"There's definitely going to be a huge need for more orthopedic surgeons. If the massive expected demand for total joint replacement is not planned for before 2030, patients may end up waiting a long time for a new hip or knee," study author Steven M. Kurtz, director of the Philadelphia office of the engineering and scientific consulting firm Exponent Inc., said in a prepared statement.

One reason for the anticipated boost in joint replacement is increased patient acceptance.

"There are few procedures that return as much quality of life as joint replacement," said Kurtz, who is also research associate professor at Drexel University's School of Biomedical Engineering in Philadelphia.

Other factors influencing the demand for joint replacement include: an aging population with arthritis; increasing rates of obesity, which puts added stress on the knee and hip joints; and the fact that more baby boomers are remaining physically active later in life, which also affects the knees and hips.

Along with more surgeons, the growing demand for joint replacements also requires more economic resources and improved longevity of artificial joints, Kurtz said.

More information

The U.S. National Institute of Arthritis and Musculoskeletal and Skin Diseases has more about joint replacement.