This is kind of cool, we guess: a new study from Dartmouth shows that Manhattanites are the most likely people in the country to make it past 65 without needing a knee replacement. Obesity is the number one reason why knee and hip joints wear out, which constantly walking city folk usually aren't plagued with. According to the Hospital for Special Surgery, only 4 in 1,000 Medicaid patients in NYC needed knee replacements in 2006, compared with 15.7 per 1,000 in Lincoln, Nebraska, which was actually rated the best city for women to live in for their health—now presumably excluding the knees.