In an accompanying editorial in BMJ, Karl Michaëlsson, a professor of medical epidemiology and senior consultant in orthopaedic surgery at Uppsala University, in Sweden, says these findings suggest “one dislocation or revision would be prevented in every 100 or so patients if they switched from a low volume to high volume surgeon.”

Although higher risks of complications were seen with low surgeon volume, a surgeon’s overall experience (measured in years of practice) did not appear to be a factor. “We were surprised, but it was interesting to see that experience was not necessarily the driver of lower complications,” Dr. Ravi explains. “It really suggests that it is the act of performing the surgery over and over again, and doing so in the recent past.”

This data is a little easier to come by in Canada, where there is a universal system of healthcare and provincial administrative databases. But Dr. Ravi says this kind of information is accessible in other regions in North America and Europe, and he believes there’s a value in other centers using the method employed in this study to determine the level of surgeon volume at which the complication rate declines.

“The number 35 in our study is just something that came out of the data,” Dr. Ravi explains. “What I would love to see is people using the technique for their area and health care providers, trying to actually pinpoint what the specific threshold or cutoff for volume is in their region.”

The finance website NerdWallet – which “hire[s] nerds to analyze complex decisions” – did something similar recently in the U.S., after the Centers for Medicare & Medicaid Services released large amounts of physician data to the public in early April. NerdWallet crunched the numbers on more than 3,400 orthopaedic surgeons and came up with 50 as the number of hip surgeries a surgeon should perform per year to be considered “high volume.”

Dr. Michaëlsson says the methods used to determine the surgeon volume threshold in the Canadian study are certainly more precise than methods used previously, but he thinks more research still is needed on this topic. “My view is that recommendations should not be based on a single study. We have to repeat this study design in other settings and we will see if can end up with a similar surgeon volume,” he explains.

But Dr. Ravi says for now, he believes his findings suggest patients should feel comfortable asking about an individual surgeon’s track record instead of simply looking at how many procedures are done annually at a particular hospital.

“Patients should feel empowered to ask how many procedures surgeons have done in the last year and see if those numbers are reassuring to them. You don’t necessarily need someone who does 200 or 300 a year, but our study suggests that it might be less than ideal to go to someone who only does a few a year,” he says.