Economic Impact of Comorbidity burden in Total Ankle Arthroplasty and Ankle Arthrodesis

Abstract

Category: Ankle, Ankle Arthritis, Diabetes Introduction/Purpose: 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 lacking. 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 groups with higher scores representing higher comorbidity burden: 0, 1, 2, =3. Outcomes were cost of hospitalization, length of stay (LOS), total opioid utilization (in oral morphine equivalents), discharge to a skilled nursing facility (SNF) and 30-day readmission. Mixed-effects models estimated associations between Deyo-Charlson comorbidity index and outcomes. We report odds ratios (OR, or % change for continuous outcomes) and 95% confidence intervals (CI). Results: In the TAA group, 64.4% of patients were in Deyo-Charlson category 0 while 24.1%, 7.6%, and 3.9% were in the 1, 2, and =3 Deyo-Charlson categories, respectively; this was 50.3%, 23.2%, 12.4% and 14.1% in the ankle arthrodesis group. The most common comorbidities were obesity, diabetes mellitus and chronic pulmonary disease. After adjustment for relevant covariates, patients in the Deyo-Charlson group =3 (compared to ‘0’) were associated with stepwise effects of 77.1% (CI 70.9%;83.6%) longer LOS and 48.5% (CI 44.0%;53.2%) higher cost of hospitalization with higher odds for admission to a SNF (OR=3.12 CI 2.64;3.70), all P<0.0001. Smaller or non-significant effects of comorbidity burden were seen for opioid utilization and 30 day readmission. These effects were also present but less pronounced in TAA patients. Conclusion: Comorbidity burden is particularly 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.