Skinny New Yorkers keep their knees

Crain's New York Business—May 30, 2010   

Manhattanites are the most likely people in the nation to make it past age 65 without getting a knee replaced, a Dartmouth study recently found.

That could be because its residents avoid getting fat, a top reason why knee and hip joints wear out with age.

“Obesity is the most influential factor in needing a knee replacement,” said Stephen Lyman, Ph.D., director of epidemiology and biostatistics at Hospital for Special Surgery. "Manhattan residents tend not to be obese."

Though the island is loaded with expert orthopedic surgeons and home to renowned centers like Hospital for Special Surgery, only four Manhattan Medicare patients per 1,000 had knee replacements. That's compared to a high of 15.7 patients per 1,000 in Lincoln, Neb.

But in New York City, Dr. Lyman is convinced obesity is the deciding factor, with weight-conscious Manhattanites' joints less likely to crumble.

Still, he says, that does not explain why his hospital is not drawing throngs of heftier knee surgery patients from the outer boroughs, where obesity rates are far higher.

Dr. Lyman says he agrees with the study's conclusion that physicians may be bad-mouthing the operation, particularly those working in areas that serve mostly minorities. The study found joint replacement surgeries in general were less frequent in hospitals in minority neighborhoods.

"It can be a word-of-mouth thing, one patient has a bad experience, and it gets around," which he says is unfortunate for outer-borough New Yorkers with access to top centers. "Knee replacement is one of the best bangs for your buck when it comes to surgery."

“It could be a matter of educating referring physicians there that this is a highly effective surgery,” he said.

The Dartmouth study found similar geographic disparities for hip replacements, also possibly related to obesity rates.

Read the full story at crainsnewyork.com.