Baby Boomers Need New Knees

First appeared in USA Today

A soaring demand for new knees from aging Baby Boomers wanting to dance through Zumba workouts or zip down ski slopes is likely to lead to additional, more costly surgeries, according to a new report.

Boomers' expectations of knee replacements are high; their parents were content to be rid of the pain and to be relatively sedentary, says Elena Losina, lead author of a study to be presented today in San Francisco at the annual conference of the American Academy of Orthopaedic Surgeons. In the analysis, a computer model based on data from the 2009 U.S. Census and the National Health Interview Survey, researchers estimate the number of Americans with total knee replacements and the number of young adults likely to require more surgeries later in life.

More than 620,000 people a year have knee replacement surgery — twice as many as hip implants. More than 4.5 million adults (4.7% of those 50 and older) have had a total knee replacement. Among that group, the researchers say 1.5 million adults are in their 50s and 60s. The demand for knee replacements from ages 45 to 64 has tripled in the past 10 years, to more than 254,000 in 2009, the latest year for which statistics are available.

"The operation has really shifted toward the young," says Losina, co-director of the orthopedics and arthritis center at Brigham and Women's Hospital in Boston. "We're wondering what this snowballing will give us as a nation. Everyone needs to be aware of the pluses and minuses of the surgery. It eliminates pain, but many will have a greater risk of revision if they do the high-intensity sports."

Studies have not been done to determine how long implants will last in people with active lifestyles, but many younger patients seem destined for complications and revision surgeries, the report says. The authors write "among adults who undergo a (total knee replacement), risk of subsequent revision is 14.7% for males, 17.5% for females." Revisions can be required because of loosening, fractures and wear and tear.

Revisions are more costly, complicated and risky, the report notes. They cost about $27,000, compared with the original surgery (about $20,000) and are riskier and more complicated. Most are covered by insurance, according to the American Academy of Orthopaedic Surgeons. Losina says the report will help the nation grasp the "substantial health burden" posed by those with knee replacements. The principal diagnosis is osteoarthritis.

Despite manufacturers' suggestions that some prosthetic joints will last 30-plus years, Losina says there are no studies to support those claims: "Most older people will take their knees (replacements) to the grave. Younger people need to discuss with their surgeons what they can expect in terms of the longevity of the prosthesis and if they should delay having the surgery (to avoid revision)."

The authors call for "increasing efforts" to prevent osteoarthritis — and the subsequent need for knee replacement — by focusing on two key risk factors: obesity and an earlier knee injury, often from playing sports.

"We really don't know how long these devices are going to last in younger, active people," says Patience White, a physician and chief public health officer for the Arthritis Foundation. "Where are these people going to be in 40 years? The surgeries eliminate pain in most people but the better they feel, the more they'll expect of the technology. People need to take care of their knees before taking the easy way out."