Cost and safety of inpatient versus outpatient open reduction internal fixation of isolated ankle fractures

BACKGROUND: As health care shifts to value-based models, one strategy within orthopedics has been to transition appropriate cases to outpatient or ambulatory settings to reduce costs; however, there are limited data on the efficacy and safety of this practice for isolated ankle fractures. The purpose of this study was to compare the cost and safety associated with inpatient versus outpatient ankle open reduction internal fixation (ORIF). METHODS: All patients who underwent ORIF of isolated closed ankle fractures at 2 affiliated hospitals between April 2016 and March 2017 were identified retrospectively. Demographic characteristics, including age, gender, comorbidities and injuryspecific variables, were collected. We grouped patients based on whether they underwent ankle ORIF as an inpatient or outpatient. We determined case costing for all patients and analyzed it using multivariate regression analysis. RESULTS: A total of 196 patients (125 inpatient, 71 outpatient) were included for analysis. Inpatients had a significantly longer mean length of stay than outpatients (54.3 h [standard deviation (SD) 36.3 h] v. 7.5 h [SD 1.7 h], p < 0.001). The average cost was significantly higher for the inpatient cohort than the outpatient cohort ($4137 [SD $2285] v. $1834 [SD $421], p < 0.001). There were more unimalleolar ankle fractures in the outpatient group than in the inpatient group (42 [59.2%] v. 41 [32.8%], p < 0.001). Outpatients waited longer for surgery than inpatients (9.6 d [SD 5.6 d] v. 2.0 d [SD 3.3 d], p < 0.001). Fourteen patients (11.2%) in the inpatient group presented to the emergency department or were readmitted to hospital within 30 days of discharge, compared to 5 (7.0%) in the outpatient group (p = 0.3). CONCLUSION: In the treatment of isolated closed ankle fractures, outpatient surgery was associated with a significant reduction in length of hospital stay and overall case cost compared to inpatient surgery, with no significant difference in readmission or reoperation rates. In medically appropriate patients, isolated ankle ORIF can be performed safely in an ambulatory setting and is associated with significant cost savings.