Knee surgery study suggests doctors' old theory about patients' weight is wrong

(WYTV) — Each year, nearly 60,000 Americans injure their meniscus, the cartilage that sits between your knee and shin bone. But before determining a course of action, some doctors may have asked their patients to step on a scale to see how much they weigh.

A torn meniscus is the most common reason for knee surgery in the U.S., and some doctors assume that the heavier a patient is, the more knee strain there is, and the more likely repair surgery will ultimately fail.

According to a study by the Ohio State University Wexner Medical Center based on body mass index (BMI), that theory doesn't entirely prove true.

"When we looked at the results, patients who had a higher BMI — and we defined a higher BMI as greater than 25 — did not have an increased failure rate compared to those who had a low BMI," said Dr. David Flanigan with the Ohio State Wexner Medical Center.

The university study followed more than 400 patients for two years after meniscus surgery. The doctors found no difference in patient success rate if they had a BMI under 25 or up to 35.

They now say a patient's weight shouldn't be a major factor in deciding if meniscus surgery is appropriate.

In fact, repairing rather than removing the meniscus can actually prevent arthritis from creeping into that knee down the road.

"Trying to save that meniscus saves that cushion, prevents some of [those] arthritic changes down the road within their knee and can be very beneficial for them," Flanigan said.

However, it’s unclear whether more severe obesity contributes to the failure of meniscal repair surgery since 90% of the monitored patients had BMIs under 35.