While more Americans than ever are having their knees and joints replaced, a new study has found that the likelihood of having the procedure may be influenced not just by medical need, but also by where you live, or even the color of your skin.
White men on Medicare, for example, have knee replacements at more than twice the rate of black men on Medicare — despite the fact that blacks are more likely than whites to suffer from osteoarthritis, a prime contributor to joint damage.
In the Tampa Bay area, seniors of all races get these surgeries at a rate similar to the national average. But Medicare recipients in Fort Myers had their hips and knees replaced at far higher rates than average, while rates in Miami were way below average.
The report, released this month by the Dartmouth Institute for Health Policy & Clinical Practice, raises questions about whether some people are suffering unnecessarily, while others are costing Medicare unnecessarily.
"We have a right to be concerned about both underuse and overuse," said Dr. David Goodman, one of the report's authors and co-director of the Dartmouth Atlas Project, which studies how medical care is used in the United States.
Geographic variations may be influenced by the supply of surgeons in a particular area, or physician preference.
When it comes to race, however, researchers and doctors suggest more subtle factors come into play. History, pain tolerance, even whether one knows anybody who has had the surgery could all be factors in a phenomenon that experts say needs more investigation.
St. Petersburg orthopedic surgeon Koco Eaton wasn't at all surprised by the findings.
"African-American men of a certain age have known pain in their lifetimes," he said. "They've endured segregation. … As a group, their tolerance of pain may be a lot different."
He says his 74-year-old African-American father, Harold Eaton, is a good example.
"He has horrible X-rays in which his knees are completely bone on bone," yet refuses to have joint replacement.
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More than 700,000 knee and hip replacements are performed each year in United States. The procedures have increased dramatically as Americans have become older and heavier, placing more strain on their joints.
The Dartmouth report examined joint replacements among Medicare recipients over age 65. Between 2000-01 and 2005-06, the rate of hip replacements increased by 15 percent and knee replacements increased by 48 percent.
Rates vary wildly. Lincoln, Neb., had the highest knee replacement rates (15.7 per 1,000 Medicare beneficiaries), while Manhattan had the lowest (4.0).
In Florida, Fort Myers had the highest knee replacement rate (12.1), while Miami — just 150 miles away — had the lowest (5.2).
The Dartmouth report suggests physicians in some regions are just more likely to recommend joint replacements. Some areas may have an abundance of orthopedic surgeons, or doctors who want to make more money, Goodman said.
And the racial disparities might also explain some of the geographic differences. Miami's low rate is intriguing, given that the region generally has higher-than-average Medicare spending. But Miami's high minority population might account at least in part for the relatively few joint replacements there.
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The racial data are far from complete. The Dartmouth group didn't have enough information to know what's happening with Hispanics, for instance.
But what is known so far is striking, even after adjusting for income and access to care.
Overall, black people are far less likely than other groups to have the surgeries, and the difference is starkest among men. Nationally, 4.8 out of every 1,000 white male Medicare recipients had a knee replaced in 2005-06, the most recent year for which data are available. But just 1.8 of every 1,000 black male recipients had the procedure.
Dr. Richard Roetzheim, who has studied health disparities at the University of South Florida for the past 20 years and also is co-leader of the new Center for Equal Health, said most of the studies to date have used data such as Medicare claims, which don't provide a full picture.
"That can't speak to the issues of patients' own beliefs, how trusting they are, what kinds of discussions led up to the decision to have joint replacement," he said.
But past research has provided a few clues. Some research has found that white patients are more likely to know somebody who has had joint replacement surgery.
Another study reported that black male veterans with knee pain were more likely than white male veterans to use over-the-counter medications and to cut down on regular activities, rather than seek a doctor's help — regardless of ability to pay.
Another factor, particularly among older people, is history. The Tuskegee experiment, in which hundreds of poor black sharecroppers with syphilis were denied medication for in the name of science, is a touchstone many cite.
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Carolyn Johnson, a 56-year-old African-American woman from Clearwater, illustrates some of the trends researchers are examining.
She has had pain in her knees for more than 10 years. But she never considered knee replacement surgery. She didn't know anybody who had had it, and she didn't know much about it.
She kept popping Motrin. But once the pain became too intense, she started looking for another answer. Around that time, she also learned a co-worker — an African-American man — had his knees replaced and was very satisfied.
Eaton replaced both of Johnson's knees on Monday. Her path to his operating room doesn't surprise him.
"Most of our business is through word of mouth," he said.
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Goodman said solving the problem of both too many and too few joint replacements will take work from both patients and doctors to make sure people fully understand the potential risks and benefits before going under the knife.
"But that's a more complicated process than most orthopedic surgeons have time for," Goodman said. "Part of that is there is a reluctance on the part of many surgeons to give up their autonomy and their traditional roles of recommending to patients."
Which means more patients might follow Johnson's example and ask a lot of questions, both of doctors and acquaintances, and really examine whether this is the best course for them.
"Once I got educated about it, I knew it was something I wanted to do," Johnson said.
"I can't wait to get back to exercising," she said. "And I promised my grandchildren I would take them to the beach."
Richard Martin can be reached at email@example.com or (727) 893-8330.