Does BMI affect perioperative complications following total knee and hip arthroplasty?

Background: Orthopedic surgeons are reluctant to perform total knee (TKA) or hip (THA) arthroplasty on patients with high body mass index (BMI). Recent studies are conflicting regarding the risk of obesity on perioperative complications. Our study investigates the effect of BMI on perioperative complications in patients undergoing TKA and THA using a national risk-adjusted database. Methods: A retrospective analysis was performed using the 2005-2007 American College of Surgeons-National Surgical Quality Improvement Program ACS-NSQIP dataset. Inclusion criteria were patients between 18 and 90 y of age who underwent TKA or THA. Patients were stratified into five BMI categories: normal, overweight, obese class I, obese class II, and morbidly obese. Demographic characteristics, length of stay, co-morbidities, and complication rates were compared across the BMI categories. Results: A total of 1731 patients met the inclusion criteria, with 66% and 34% undergoing TKA and THA, respectively. A majority were female (60%) and >60 y (70%) in age. Of the patients who underwent TKA, 90% were either overweight or obese, compared with 77% in those undergoing THA. The overall preoperative comorbidity rate was 73%. The complication and mortality rates were 7% and 0.4%, respectively. When stratifying perioperative complications by BMI categories, no differences existed in the rates of infection (P = 0.368), respiratory (P = 0.073), cardiac (P = 0.381), renal (P = 0.558), and systemic (P = 0.216) complications. Conclusions: Our study demonstrates no statistical difference in perioperative complication rates in patients undergoing TKA or THA across BMI categories. Performing TKA or THA on patients with high BMI may increase mobility leading to improved quality of life.