Are Morbidly Obese Patients Equally Benefitting From Care Improvements in Total Hip Arthroplasty?

Morbidly obese patients have increased rates of complications following primary total hip arthroplasty (THA) and it is not clear whether improvements in THA care pathways are equally benefitting these patients. The purpose of this study is to assess if reductions in complications have similarly improved for both morbidly obese and non-morbidly obese patients after THA.

Patients undergoing primary THA between 2011 and 2019 were identified in the American College of Surgeons National Surgical Quality Improvement Program database. Patients were stratified by body mass index (BMI) <40 and ≥40 kg/m². Thirty-day rates of infectious complications, readmissions, reoperation, and any complication were assessed. Trends in complications were compared utilizing odds ratios and multivariate analyses.

In total, 234,334 patients underwent THA and 16,979 (7.8%) had BMI ≥40 kg/m². Patients with BMI ≥40 kg/m² were at significantly higher odds for readmission, reoperation, and infectious complications. Odds for any complication were lower for morbidly obese patients in 2011, not different from 2012 to 2014, and higher from 2015 to 2019 compared to lower BMI patients. Odds for any non-transfusion complication were higher for morbidly obese patients and there was no improvement for either group over the study period. There were improvements in rates of readmission and reoperation for patients with BMI <40 kg/m² and readmission for BMI >40 kg/m².

Odds for readmission and reoperation for non-morbidly obese patients and readmission for morbidly obese patients improved from 2011 to 2019. Reductions in transfusions are largely responsible for improvements in overall complication rates. Although morbidly obese patients remain at higher risk for complications, there does not appear to be a growing disparity in outcomes between morbidly obese and non-morbidly obese patients.