A study reveals bariatric surgery performed on morbidly obese people prior to hip or knee replacement can reduce in-hospital and 90-day post-operative complications.

According to the researchers from Hospital for Special Surgery, this will improve the patient’s health, but does not reduce the risk of needing a revision surgery. The study was presented at the American Academy of Orthopedic Surgeons Annual Meeting in New York.

The findings suggest morbidly obese patients, who had bariatric surgery, were 75 percent less likely to have in-hospital complications from a total hip replacement and 31 percent less likely to have in-hospital complications for a total knee replacement. "With our data, I think we can say with confidence that bariatric surgery prior to total joint replacement is not a harmful recommendation," said lead study author Alexander McLawhorn.

"As an orthopedic surgeon, you are not going to compromise your joint replacement outcome if you advise a morbidly obese patient to seek an opinion from a bariatric surgeon,” McLawhorn added.

Morbid obesity (a body mass index greater than or equal to 40 kg/m2) is associated with poor post-operative outcomes after total knee arthroplasty (TKA) and total hip arthroplasty (THA) including increased risk for revision surgery, postoperative infection and medical complications.

There were 2,636 patients, who underwent a total knee replacement, and 792 patients, who underwent a total hip replacement after bariatric surgery. The researchers then used propensity score matching to build control groups of morbidly obese patients receiving total hips and knees without prior or subsequent bariatric surgery.

The statistical analyses showed that bariatric surgery lowered the comorbidity burden of patients prior to total joint replacement. Morbidly obese patients, who had bariatric surgery, had lower rates of in-hospital complications for total hip replacement and for total knee replacement.

However, bariatric surgery did not lower the risk of having a revision surgery or the risk for a hip dislocation.