The researchers also wanted to know whether lower-income and minority patients were more likely to undergo joint replacement procedures in hospitals with higher complication rates. In contrast to other studies, they did not find this to be the case. Still, Dr. Drye cautions that physicians and policy makers must continue to closely monitor healthcare disparities among disadvantaged patients. 

So how do patients know which hospitals to choose – and more important, which to avoid – for joint replacement surgery?

“We still don’t have enough quality measures to help patients choose a hospital. This measure provides one important piece of information,” Dr. Drye says. “But patients will want to talk to one or more surgeons about their options and expected results. We are currently working on a hospital measure of how well the surgery improves patients’ ability to function, and through measuring the most important outcomes, we hope to improve care and better inform patient choice.”

Peter Cram, MD, a professor at the University of Toronto and director of the Division of General Internal Medicine at University Health Network and Mt. Sinai Hospitals in Toronto, has been involved in many important studies of comparative outcomes in joint replacement surgery.

“This is a nice study with a good group of investigators who are experienced in using Medicare data. The methodology is sound, clear and transparent,” he says. “One of the great strengths of the study is its length – a three-year period. Every hospital can have a bad week or even a bad year, but in this study, the good hospitals were good for three years and the bad hospitals were bad for three years, and that can be a really important contribution.”

Dr. Cram says one possible limitation of the study is variability in coding schemes (the alphanumeric designations hospitals use to describe procedures and complications), which might account for some of the differences between the best and worst hospitals.

He also notes that hospital measure scores for all U.S. hospitals are available at

“The lesson is the same as for anything else. Do your homework, invest some time and energy, do some reading, get on the Internet and learn everything you can [about your local hospitals],” he says.

Joseph Bosco, MD, associate professor and vice chair of clinical affairs, Department of Orthopaedic Surgery at New York University Langone Medical Center in New York, and an expert on hospital quality issues, takes an even broader view.

“This study reported a fourfold difference in complications following joint replacement across the country. The next step is understanding the causes of these differences and learning what the best performing hospitals do to decrease complications. Once we know what the best performers do, we can apply those principles to the worst performing hospitals, so that the population as a whole benefits,” he says.