Is Preoperative Weight Reduction in Patients Who Have Body Mass Index ≥ 40 Associated with Lower Complication Rates After Primary Total Hip Arthroplasty?

Overview

abstract

INTRODUCTION: Given the heightened risk of postoperative complications associated with obesity, delaying total hip arthroplasty (THA) in patients who have a body mass index (BMI) > 40 to maximize pre-operative weight loss has been advocated by professional societies and orthopaedic surgeons. While the benefits of this strategy are not well understood, previous studies have suggested that a 5% reduction in weight or BMI may be associated with reduced complications after THA. METHODS: We identified 613 patients who underwent primary THA in a single institution during a 7-year period, and who had a BMI > 40 recorded 9 to 12 months prior to surgery. Subjects were stratified into three cohorts based on whether their baseline BMI decreased by > 5% (147 patients, 24%), was unchanged (+/-5%) (336 patients, 55%), or increased by > 5% (130 patients, 21%) on the day of surgery. The frequency of 90-day Hip Society and Centers for Medicare & Medicaid Services (CMS) complications was compared between these cohorts. There were significant baseline differences between the cohorts with respect to baseline American Society of Anesthesiologists Class (P < 0.001) and hemoglobin A1C (P = 0.011), which were accounted for in a multivariate regression analysis. RESULTS: In univariate analysis, there was a lower incidence of readmission (P = 0.025) and total complications (P = 0.005) in the increased BMI cohort. The overall complication rate was 18.4% in the decreased BMI cohort, 17.6% in the unchanged cohort, and 6.2% in the increased cohort. However, multivariable regression analysis controlling for potential confounders did not find that preoperative change in BMI was associated with differences in 90-day complications between cohorts (P > 0.05). CONCLUSION: Patients who have a BMI > 40 and achieved a clinically significant (> 5%) BMI reduction prior to THA did not have a lower risk of 90-day complications or readmissions. Thus, delaying THA in these patients to encourage weight loss may result in restricting access to a beneficial surgery without an appreciable safety benefit.