Postoperative Complications of Total Joint Arthroplasty in Obese Patients Stratified by BMI

Abstract

Background: High body mass index (BMI) is associated with significant complications in patients undergoing total joint arthroplasty. Many studies have evaluated this trend, but few have looked at the rates of complications based on BMI as a continuous variable. The purpose of this study was to stratify obese patients into 3 BMI categories and evaluate their rates of complications and gauge whether transitioning from higher to lower BMI category lowers complication.

Methods: Patients undergoing primary total joint arthroplasty were selected from the National Surgical Quality Improvement Program database from 2008-2015 and arranged into 3 groups based on BMI: O1 (BMI 30-34.9 kg/m²), O2 (BMI 35-39.9 kg/m²), and O3 (BMI >40 kg/m²). Thirty-day complications were recorded and evaluated utilizing univariate and multivariate analyses stratified by BMI.

Results: A total of 268,663 patients were identified. Patients with a BMI >30 kg/m² had more infectious and medical complications compared with nonobese patients. Furthermore, there were increased complications as the BMI categories increased. Patients with a BMI >40 kg/m² (O3) had longer operating times, length of stay, higher rates of readmissions, reoperations, deep venous thrombosis, renal insufficiency, superficial infections, deep infections, and wound dehiscence. These trends were present when comparing the O2 with O1 category as well.

Conclusion: We have demonstrated increased rates of medical and surgical complications in obese patients. Furthermore, we demonstrated a stepwise increase in complication rates when transitioning to higher BMI groups. Based on our data, we believe that preoperative counseling and interventions to decrease BMI should be explored before offering elective surgery to obese patients.

Keywords: BMI; complications; morbid obesity; obesity; total hip arthroplasty; total knee arthroplasty.