Comparative risk stratification for prediction of early postoperative morbidity and mortality after open fixation of periarticular lower extremity fractures.

Introduction: The identification of patients at higher risk of early postoperative adverse events has implications for quality improvement, preoperative medical optimization, and cost reduction through bundled payments. The purpose of the present study was to develop points-based risk stratification systems for predicting 30-day adverse events (AEs) and mortality after open fixation of periarticular hip, knee, and ankle fractures. Methods: Query of the NSQIP database yielded 65,529 patients who underwent periarticular lower extremity repair from 2010 to 2019. To generate our risk stratification systems, 60% of patients were randomly analyzed with multivariable regression plus bootstrap modeling to identify independent risk factors for early AE or mortality. A nomogram analysis was then conducted to assign scores for each risk factor. To validate our models, the systems were tested for predictive ability using the remaining 40% of patients. Results: In total, 13,212 patients (20.2%) experienced any AE and 3613 patients (5.5%) mortality within 30 days of fracture fixation. Patients were assigned points for the following in both risk stratification systems: fracture type, male gender, age, functional dependence, anemia, pulmonary disease, congestive heart failure, and end-stage renal disease. Corticosteroid use, hypertension, and insulin-dependent diabetes were additional predictors for only AEs. The AE and mortality models had maximum scores of 27 and 17 points, and Harrell C statistics of 0.66 and 0.75, respectively. The estimated risk of developing early AE ranged from 3.4 to 79.5% and mortality from 0.08 to 54.4%. Conclusion: Fracture type and preoperative characteristics can be used in the prediction of early AE or mortality following open fixation of periarticular lower extremity fractures, with a marked disparity in estimated risks depending on the number of risk factors possessed by a patient. Level of Evidence: Therapeutic IV.