Patients who lost weight after knee-replacement surgery had much better results in terms of pain, function and activity levels than those who maintained or gained weight, the researchers found.
But in both knee- and hip-replacement patients, weight gain was associated with poorer outcomes, according to the study, which was presented at this month’s annual meeting of the American Academy of Orthopaedic Surgeons in New Orleans.
“Based on our findings, as physicians, we should convey to our patients the importance of maintaining good health and an appropriate weight, and we should help them in any way we can to achieve this goal,” said Dr. Geoffrey Westrich, senior investigator and director of research in adult reconstruction and joint replacement at the Hospital for Special Surgery in New York City.
Researchers looked at body-mass index (BMI) changes in the two years after nearly 7,000 patients received hip or knee replacements. BMI is a measure of body fat based on height and weight.
No change in BMI was seen in 84 percent of hip patients and 74 percent of knee patients. People who were obese before joint-replacement surgery were more likely to lose weight than those who were overweight or normal weight.