One third of people getting knee replacements don't need them

A knee replacement is a decidedly unpleasant event. From the hassle of getting the surgery to the three-month recovery to the possibility of catching an infection while you're in the hospital, nothing aside from a possible balloon or flower delivery is very fun.

But knee surgery isn't something we do for fun. It's something we do because we think its the treatment we need — but it turns out, in a high number of cases, even that isn't true.

A new paper finds that one-third of knee replacements are performed on patients who don't fit the criteria for being a good knee replacement candidate. These are people who might have their problem solved by a less invasive treatment — but instead are undergoing a major surgery.

Knee replacements are a booming area of surgery right now. The annual volume of knee replacements among Medicare patients grew by 161 percent between 1991 and 2010.

It's an intensive surgery. Researchers have developed certain criteria for knee replacements that largely have to do with the intensity of symptoms and a history of prior treatment that hasn't totally solved the problem.

The best candidates for full knee replacement, research shows, are those who have intense symptoms and are over 55. But a lot of people who didn't fit those criteria got the procedure anyway.

Researchers Daniel Riddle, William Jiranek and Curtis Hayes looked at a sample of 175 recent knee replacement patients to see if they met the criteria for undergoing the surgery. They found that 34.5 percent did not: most of that group had symptoms milder than the ones that medical literature suggests should prompt a knee replacement.

"Many patients struggle with the decision to undergo [knee replacement] surgery," the authors write in their new paper. "The rate of [knee replacements] was determined to be inappropriate than we expected."

It's easy to brush off smaller incidents of unnecessary medicine — an unwarranted blood draw at the doctor's office or an extra MRI — as small inconveniences. But a knee replacement is no small inconvenience — and the incredibly high rate of inappropriate procedures drives home the point that unnecessary care can actually harm patients in significant ways.

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