Abstract
Introduction
Perioperative optimization efforts have improved outcomes following primary total knee arthroplasty (TKA). However, morbidly obese patients continue to have increased rates of complications. The purpose of this study was to assess if rates of early complications after TKA have similarly improved for both morbidly obese and non-morbidly obese patients.
Methods
Elective, primary TKA patients from 2011–2018 were identified in the National Surgical Quality Improvement Program database. Patients were stratified by body mass index (BMI) <40 kg/m2 and ≥40 kg/m2. Thirty-day rates of infectious complications, readmissions, and reoperation were assessed. Trends in these endpoints over the study period were compared between BMI groups utilizing odds ratios (OR) and multivariate analyses.
Results
In total, 314,719 patients underwent TKA and 46,386 (15%) had BMI ≥40 kg/m2. From 2011–2018, the reoperation rate significantly improved from 1.2% to 1.0% (OR: 0.6 [0.6–0.7]) for patients with BMI <40 kg/m2, as did rates of readmission (4.5% to 2.9%, OR: 0.8 [0.7–0.99]). Patients with BMI ≥40 kg/m2 also had a significant decrease in the rate of readmission over the study period (4.9% to 3.3%, OR: 0.6 [0.5–0.8]); however, the rate of reoperation did not significantly change (1.4% to 1.4%, OR: 1.0 [0.6–1.6]). Significant improvements were not observed for infectious complications over time for either group. However, patients with BMI ≥40 kg/m2 consistently had increased risk of both deep infection from 2014–2018 (2014 OR: 2.2 [1.4–3.4], 2018: 2.2 [1.6–3.0]) and wound complications from 2011–2018 (2011 OR: 1.7 [1.2–2.6], 2018 OR: 2.0 [1.7–2.4]) compared to non-morbidly obese patients.
Conclusion
Although readmission rates significantly decreased for all patients, improvements in reoperation rates observed in non-morbidly obese patients were not experienced by the morbidly obese – resulting in a widening of the complication gap between these cohorts. Care improvements have not lowered the differential risk of infectious complications compared to non-morbidly obese.
