Erratum to: Comparative Analysis of Length of Stay and Inpatient Costs for Orthopedic Surgery Patients Treated with IV Acetaminophen and IV Opioids vs. IV Opioids Alone for Post-Operative Pain. Issue 9 (September 2016) - Hansen, Ryan; Pham, An; Strassels, Scott; Balaban, Stela; Wan, George