Obesity and hip replacement­—men and women are different

People who are obese are more likely to have hip osteoarthritis, and so more likely to need hip replacement. Unfortunately, they’re also at higher risk for surgical complications—especially women, new research shows.

SEX DISCRIMINATION
The study focused on 2,186 people who had undergone total hip replacement. The researchers examined whether the main complications—deep infection, hip dislocation, and need for re-operation (revision surgery)—were more likely to occur in obese individuals, defined as people who have a body mass index (BMI) of 30 or higher. (BMI is a measure of weight relative to height.)
The investigators also compared functional outcomes and overall satisfaction with the surgery among those who were obese versus those who were not.

As a group, the obese individuals were younger and their pre-surgery functional status was slightly worse than that of the non-obese people. The functional status differences were more pronounced between obese and non-obese women. Overall, the type of hip implant and surgical technique used and the rehabilitation program followed did not differ between the obese and non-obese individuals. On average, the obese persons’ surgeries took a little longer.

EXCESS WEIGHT is HARDER ON WOMEN
In general, being obese raised the risk of infection and hip dislocation, but the impact was greater in women than in men. For example, the infection rate was about 41?2 times higher in the obese group overall, but 16 times higher when obese women were compared with non-obese women. (Obesity didn’t seem to affect the men’s risk.) Similarly, the hip dislocation rate was about 21?2 times higher in the obese group overall but three times higher in obese women compared with non-obese women. Revision surgery was twice as common in the obese group.

Five years after surgery, 81% of the non-obese group had good-to-excellent hip function, versus 70% of the obese group. Overall, 86% of the non-obese group and 82% of the obese group said they were satisfied with the result of their surgery.

When women were considered separately, 77% of those who were not obese had good-to-excellent function, versus 58% of those who were obese. And 86% of non-obese women were satisfied with the result of their surgery, versus 77% of obese women.

The researchers suggest that doctors should make obese women aware of their greater risk of complications, and that participating in a weight-loss program before surgery might improve their outcome.