The Effect of Bariatric Surgery on Complication Risk Following Total Hip Arthroplasty in Patients with Morbid Obesity

BACKGROUND: Obesity is an independent risk factor for complications following total hip arthroplasty (THA). Preoperative bariatric surgery to facilitate weight loss has been used to reduce complication risk, but its effectiveness remains unclear. The purpose of this study was to evaluate the impact of bariatric surgery on the risk of surgical complications in patients with morbid obesity undergoing THA. METHODS: A population-based, retrospective cohort study was conducted using administrative data from Ontario, Canada. All adults undergoing primary elective THA from 2002 to 2023 were subclassified according to the presence of morbid obesity (body mass index [BMI], ≥40 kg/m2) and whether they had undergone prior bariatric surgery. The primary outcome was a composite of major surgical complications within 1 year, including revision arthroplasty, periprosthetic fracture, periprosthetic joint infection (PJI), and dislocation. Secondary outcomes were 30-day hospital readmission and length of stay. Multivariable logistic regression adjusted for demographic, medical, and surgical factors was used. RESULTS: A total of 148,977 patients who underwent THA were identified, including 10,287 patients (6.9%) with morbid obesity and 637 patients (0.4%) who had undergone prior bariatric surgery. Patients who had undergone bariatric surgery had the highest risk of major surgical complications, particularly PJI. Even among patients who achieved a BMI of <40 kg/m2 following bariatric surgery, there was a higher risk of major complications (odds ratio [OR], 1.84 [95% confidence interval (CI), 1.16 to 2.94]) and PJI (OR, 3.36 [95% CI, 1.48 to 7.63]) compared with patients with a similar BMI who had not undergone prior bariatric surgery. Prior bariatric surgery did not reduce revision risk, including in patients achieving a BMI of <40 kg/m2 (p = 0.077). All bariatric and morbidly obese cohorts demonstrated higher 30-day readmission rates. CONCLUSIONS: Prior bariatric surgery did not significantly reduce major surgical complications or infection risk following THA. Our findings suggest that THA should not be routinely delayed for bariatric surgery to reduce postoperative complications. Alternative strategies for obesity management and perioperative risk mitigation warrant further investigation. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.