Remimazolam is an ultra-short acting benzodiazepine agonist which is used widely for general anesthesia and sedation. Remimazolam has several advantages. Remimazolam is rapidly metabolized by tissue esterase that it does not accumulate even after infusion for long periods of time. The presence of reversal agents (flumazenil) is also advantageous. Also, hemodynamic stability compared to propofol gives clinicians preference to use for geriatric anesthesia. However, the study on the effect of remimazolam compared to propofol on postoperative delirium have not been carried out. The purpose of the study is to compare the incidence of postoperative delirium and recovery profile in elderly patients undergoing orthopedic surgery using either remimazolam or propofol.