Before the patients set foot in a doctor's office, they were coached by the researchers in how to describe their knee problem and, if the doctor didn't bring up the subject, to ask, "Do you think I need a new knee?" The point was for the patients to present their conditions as similarly as possible.
About two-thirds of the doctors -- 67% -- recommended total knee replacement surgery (total knee arthroplasty) to the man. Roughly half as many -- 33% -- recommended it to the woman.
"A male patient was twice as likely as a female patient to receive a recommendation for total knee arthroplasty," write the researchers, who included Cornelia Borkhoff, PhD, and James Wright, MD, MPH, of The Hospital for Sick Children in Toronto.
Gender bias on the part of the doctors may explain the results, Borkhoff's team notes.
"Our findings suggest that physicians are prone to the same automatic, unconscious, and ubiquitous social stereotyping that affect all of our behavior," write the researchers. "Acknowledging that a gender bias may affect physicians' decision-making is the first step toward ensuring that women receive complete and equal access to joint arthroplasty."
The data doesn't show whether doctors' gender or age affected the results.
The study appears in the March 11 edition of the Canadian Medical Association Journal.