Unconscious bias may make some doctors less likely to recommend knee replacement surgery to women than to men, a new study suggests.
Canadian researchers found that when they sent two knee arthritis patients — one woman and one man — to 71 Ontario doctors, twice as many physicians recommended knee replacement surgery to the man as to the woman.
This was despite the fact that both patients were identical in the severity of their knee arthritis and reported the same symptoms, such as morning knee stiffness and difficulty climbing stairs. Both also told the doctors they’d failed to improve with physical therapy, pain medication or cortisone injections.
The findings suggest that many doctors harbor an unwitting bias against recommending knee replacement to women, the researchers report in the Canadian Medical Association Journal.
“I’d be shocked if this were a case of overt discrimination,” said senior researcher Dr. James Wright of the University of Toronto and the Hospital for Sick Children.
Instead, he said, doctors, like everyone else, have preconceptions about different groups of people that can unconsciously affect their decisions.
Wright said that many doctors may, for example, believe that women with arthritis do not benefit from knee replacement as much as men do — based on their own experience or from what other doctors have told them.
There are studies showing that, compared with men, women tend to have the surgery when their arthritis is at a more advanced stage. This fact may explain why women, as a group, tend to fare more poorly than men after knee replacement.
For the current study, Wright and his colleagues recruited two patients with moderate knee arthritis and coached them in how to present their symptoms so that their cases would be identical.
The doctors — 38 family physicians and 33 orthopedic surgeons — knew that they would be seeing patients who were part of the study, but did not know which patients they were. Nor did they know the purpose of the study was to see how a patient’s sex affected medical decision-making.
Overall, Wright’s team found, 67 percent of the doctors recommended knee replacement surgery to the male patient, while only 33 percent recommended it to the woman.
What’s more, 42 percent of doctors recommended surgery to the man but not the woman, while just 8 percent suggested the procedure for the woman but not the man.
Both male and female doctors more often recommended surgery to the male patient.
While the study was small and a first of its kind, Wright said, the hope is that it will get doctors thinking about whether they harbor biases that affect their clinical judgment.
For women with knee arthritis, he said, the findings suggest they should “be more assertive” in asking about knee replacement, if they are interested in it. If they are not satisfied with their doctor’s evaluation, Wright noted, they can always seek a second opinion.
