Complications after hip replacement surgery tend to be more common among patients who are obese, especially women, a study suggests.

Researchers in Switzerland conducted a study of patients who had total hip replacements to see if there were any differences in how obese men and women fared.

"Because our study revealed increased complications among obese women, we suggest that surgeons counsel this group of patients so that they are made aware of this fact," the study's authors concluded in the March issue of Arthritis Care & Research.

"In addition, participating in a weight-loss program prior to surgery might be beneficial for such patients."

Dr. Anne Lübbeke of the Geneva University Hospital looked at infections, dislocation and redoing the replacement as well as quality of life, satisfaction and general health five years after the surgery.

Among the 635 hip replacements in non-obese patients and 183 in obese patients, obese women showed a higher incidence of complication and less satisfaction.

People who are obese are known to be at higher risk for infection because of longer operating times and diabetes, but these factors did not explain why the women had poorer results, the researchers said.

More osteoarthritis

Sex differences such as body fat distribution and metabolic response might be involved, the study's authors said.

Dislocations might be more common in obese women with less peripheral muscle strength and they fare more poorly in functional terms because of other factors like a higher incidence of osteoarthritis, they added.

In Canada, 46 per cent of people who had a joint replacement in 2003-2004 were defined as obese, with a body mass index of 30 or higher, according to the Canadian Institute for Health Information's annual report.

Obesity is linked to an increased risk of osteoarthritis, the most common diagnosis in joint replacement surgery.