Higher Comorbidities are Correlated With Readmission Following Arthroplasty for Femoral Neck Fracture

Background: A desire to control cost and improve patient outcomes following arthroplasty led to the introduction of the Center for Medicare and Medicaid Service Comprehensive Care for Joint Replacement Program. Hemi and total hip arthroplasty for femoral neck fracture has been shown to have worse outcomes than those for osteoarthritis. However, little has been studied about the effect of comorbidities on costs associated with arthroplasty for femoral neck fracture. This study investigates how the number of comorbidities influence 90-day outcomes and cost following hemi or total hip arthroplasty for displaced femoral neck fracture in patients covered by the Comprehensive Care for Joint Replacement bundle. Methods: We reviewed all Medicare hip fracture patients undergoing hemi or total hip arthroplasty at our institution between April 2016 and November 2020. Basic demographic and perioperative information was collected. The primary outcome was hospital readmission within 90 days. The data set captured 90-day readmission to any institution, not just within our system. Secondary outcomes included 90-day reoperation and outpatient complications. Multiple logistic regression was used to examine the influence of number of comorbidities on the primary and secondary outcomes while controlling for other variables. Results: The cohort comprised 378 patients (72% female), mean age 82 (±9) years, mean body mass index 23.4 (±4.7) kg/m². For every additional comorbidity, the odds of related readmission without reoperation increased by 1.261 (95% confidence interval [1.055-1.507], P = .011). Odds of reoperation and odds of outpatient complication did not show statistical significance with the available numbers. Conclusions: Increasing preoperative comorbidities results in a higher odd of readmission within 90 days following arthroplasty for femoral neck fracture in this Medicare population.