Economic impact of Comorbidities in Total Ankle Arthroplasty and Ankle Arthrodesis.

ABSTRACT Background: The demand for total ankle arthroplasty (TAA) and ankle arthrodesis surgery is increasing. Findings from other orthopaedic populations suggest an increasing comorbidity burden among those planned for surgery, however, data on TAA and ankle arthrodesis is limited. The goal of this study is to study the comorbidity burden for TAA and ankle arthrodesis. Hypothesis: Comorbidity burden is associated with higher resource utilization for both TAA and ankle arthrodesis. Patients and Methods: This retrospective cohort study utilized data from the nationwide Premier Healthcare Database (2006-2016) which contains inpatient claims on N=10,085 ankle arthrodesis and N=4,977 TAA procedures. Patients were categorized into Deyo-Charlson comorbidity index (DCCI) groups. Outcomes were cost of hospitalization, length of stay (LOS), total opioid utilization, discharge to a skilled nursing facility (SNF), and 30-day readmission. Mixed-effects models estimated associations between DCCI and outcomes. We report odds ratios (OR, or % change for continuous outcomes) and 95% confidence intervals (CI). Results: In the TAA group, 67.9% of patients were in DCCI category 0 while 22.4%, 6.6%, and 3.1% were in the 1, 2, and >2 DCCI categories, respectively. This was 61.3%, 18.1%, 9.8% and 10.9% in the ankle arthrodesis group. The most common comorbidities were obesity, diabetes mellitus, and chronic pulmonary disease. Particularly in the ankle arthrodesis group, the proportion of patients with comorbidities has increased over time. After adjustment for relevant covariates, patients in the DCCI group >2 (compared to ‘0’) were associated with stepwise effects of up to 77.1% (CI 70.9%; 83.6%) longer length of stay and up to 48.5% (CI 44.0%; 53.2%) higher cost of hospitalization. Discussions: Comorbidity burden is increasing among patients undergoing ankle arthrodesis where it is associated with significantly increased resource utilization. Our data demonstrate the potential impact of patient selection, which may be crucial in optimizing preoperative status. Level of Evidence: III