The number of older Americans getting knee replacement surgery more than doubled over the past two decades as an aging population is driven by a desire to stay fit later in life, a study found.
Total knee replacement procedures rose 162 percent from 1991 to 2010 while the number of procedures to repair a previously implanted artificial knee joint, called revision, jumped 106 percent, according to research released in the Journal of the American Medical Association.
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About 600,000 total knee replacement procedures, done to relieve symptoms of severe knee arthritis, are performed each year in the U.S. costing about $9 billion annually, according to the research. About 60 percent of those procedures are paid for by Medicare, the federal government health program for the elderly and disabled, said Peter Cram, the lead study author. The study suggests the success of the surgery may need to be weighed against the increasing costs, he said.
"The growth in knee replacements encapsulates the challenges of controlling spending in the Medicare program," Cram, associate professor of general internal medicine at the University of Iowa Carver College of Medicine in Iowa City, said in a phone interview. "It is an effective surgery."
The public-health issue, Cram said, is that "a procedure that is great in small numbers is financially devastating to the Medicare program and the federal government in the long term. As a patient you want that knee replacement, but from a budgetary standpoint this starts to add up to real dollars."
The first knee replacement surgery was performed in 1968, according to the American Academy of Orthopaedic Surgeons. Improvements in implants and surgical techniques have increased the effectiveness of the procedure.
Researchers in the study looked at 3.27 million Medicare patients who underwent total knee replacement procedures and 318,563 who had revision surgery from 1991, the first year data were available, to 2010.
The number of annual knee replacements rose to 243,802 in 2010, or 62.1 procedures per 10,000 Medicare enrollees, from 93,230 in 1991, or 31.2 procedures per 10,000 Medicare enrollees.
More people may be seeking out the surgery because it is effective at relieving pain and older Americans are staying more active later in life, Cram said.
Fay Lyons, a 69-year-old retiree in Lakewood, N.J., said she had double knee replacement surgery about a month ago. She hoped it would alleviate the grinding pain her arthritis had caused for the last eight to 10 years, she said.
"I couldn't do anything except swing a golf club," she said in a telephone interview. "I couldn't walk for any length of time. I couldn't do anything because it hurt every step I took."
A good friend who had both his knees successfully replaced recommended his doctor and persuaded Lyons to get the procedure as well, she said. She stayed in the hospital for three days, then lived at a rehabilitation center for a week where she received therapy every day. She now sees a physical therapist three times a week. Medicare and supplementary insurance from AARP have helped with costs, Lyons said.
"I wasn't worried about the cost," she said. "I was worried about the pain."
While recovery hurts, Lyons said she can walk farther now and the discomfort declines daily. "The therapy is very painful, but worth it," she said.
Increasing rates of obesity in the U.S., where two-thirds of Americans are considered overweight or obese, may also be contributing to the rise in knee replacements, Cram said. People who are obese are predisposed to arthritis, he said.
The study also showed that the number of people needing a follow-up knee replacement increased to 19,871 from 9,650 during the two decades while the time patients stayed in the hospital post-surgery dropped to 3.5 days from 7.9 days. About 10 percent of people who have knee replacement surgery may go on to need a revision procedure, Cram said.
Sending people home sooner after surgery may not save money over time if people must be readmitted for another procedure because of complications, he said.
By 2030, the demand for knee replacements may be as high as 3.48 million a year in the U.S., said Joseph Zuckerman, chairman of the Department of Orthopaedic Surgery at New York University Langone Medical Center, in an editorial accompanying today's study. Having hospitals managing all aspects of a patient's care from pre-surgical doctor visits to after care once a patient returns home may help reduce the costs, he said.
"People want to be active," Zuckerman said in a telephone interview. "As you get older, you're no longer accepting of a sedentary lifestyle or a quality of life that's diminished."