Annual case volume is a risk factor for 30-day unplanned readmission after open reduction and internal fixation of acetabular fractures

Abstract

BackgroundSurgical fixation of acetabular fractures is technically challenging, and quality of reduction directly correlates to patient outcomes. Considering the difficulty of open reduction and internal fixation (ORIF), increased case volumes may improve patient outcomes. No studies have investigated case volume as a risk factor for readmission after acetabular fracture ORIF. The present study sought to answer the question of whether annual case volume is a risk factor for 30-day unplanned readmission after acetabular fracture ORIF, if there is an identifiable threshold number of cases most predictive of a readmission, and if differences exist between reasons for readmission between high and low-volume centers. HypothesisInstitutions with a lower annual case volume will have a higher incidence of 30-day unplanned readmissions. Materials and methodsThe national readmissions database (NRD) was queried for acetabular fractures that underwent ORIF during 2016. Comorbid conditions were summed, and annual hospital case volume was identified. A receiver operating characteristic (ROC) curve was generated and the Youden index identified threshold case volume most predictive of a 30-day readmission. A multivariable logistic regression was performed with 30-day readmission as the dependent variable and case volume below the threshold an independent variable. ResultsA total of 3,407 cases were included with a median age of 43. The 30-day readmission for this cohort was 6.5% (220/3407). ROC curve analysis identified 22 annual cases as the threshold value most predictive of 30-day readmission. Multivariable logistic regression identified age (Odds Ratio (OR)=1.01, p=0.005), number of comorbidities (OR=1.35, p<0.0001), and ≤22 cases (OR=1.50, p=0.006) as statistically significant risk factors for 30-day readmission. The most common reason for readmission at both high and low-volume centers was surgical site infection. DiscussionAnnual case volume is a statistically significant predictor of 30-day readmission after acetabular fracture ORIF. Performing ≤22 acetabular ORIFs places patients at greater risk for a readmission. Patients at low-volume centers may be predisposed to readmission, and it is paramount to optimize patients prior to discharge, and have appropriate surgeon and hospital resources to treat these complex injuries. Level of evidenceIII, Cross-sectional study.