Outpatient Versus Inpatient Surgical Fixation of Isolated Ankle Fractures: An Analysis of 90-Day Complications, Readmissions, and Costs

Abstract

Despite increasing interest toward managing isolated ankle fractures in an outpatient setting, evidence of its safety remains largely limited. The 2007 to 2014 Humana Administrative Claims database was queried to identify patients undergoing open reduction internal fixation for unimalleolar, bimalleolar, or trimalleolar isolated closed ankle fractures. Two cohorts (outpatient versus inpatient) were then matched on the basis of age, sex, race, region, fracture type (uni-/bi-/trimalleolar) and Elixhauser Comorbidity Index to control for selection bias. Multivariate regression analyses were performed to report independent impact of outpatient-treated ankle fracture surgery on 90-day complications, readmission, and emergency department visit rates. Independent-samples t test was used to compare global 90-day costs between cohorts. A total of 5317 inpatient-treated and 6941 outpatient-treated closed ankle fractures were included in the final cohort. After matching and multivariate analyses, patients with outpatient ankle fractures, compared with patients with inpatient ankle fractures, had statistically lower rates of pneumonia (2.3% versus 4.0%; p < .001), myocardial infarction (0.9% versus 1.8%; p = .005), acute renal failure (2.2% versus 5.3%; p < .001), urinary tract infections (7.4% versus 12.3%; p < .001), and pressure ulcers (0.9% versus 2.0%; p = .001). Outpatient ankle fractures also had lower rates of 90-day readmissions (9.7% versus 14.1%; p < .001) and emergency department visits (13.8% versus 16.2%; p = .028). Last, overall 90-day costs for outpatient ankle fractures were nearly $9000 lower than costs for inpatient ankle fractures ($12,923 versus $21,866; p < .001). Based on our findings, it appears that outpatient treatment of ankle fractures can be deemed safe and feasible in a select cohort of patients.

Keywords: 90-day outcomes; ankle fractures; complications; costs; inpatient; outpatient.