Between 2000 and 2009 demographics, comorbidity, complications, and 30-day mortality following same-day BTKA (SBTKA) in two high-volume institutions were obtained. Two 5-year periods were created to facilitate trend analysis. The percentage of SBTKA decreased by 36.2% in the latter period. A decline in mean age reflected mainly by a 50% decrease in patients >75 years was observed. The average LOS decreased (5.7 vs. 4.5 days). Overall, selected patients were healthier in the second period. The prevalence of CAD and obesity decreased, whereas hypercholesteremia increased. The overall complication rate decreased by 55.5%; reduction in cardiac adverse events and acute posthemorrhagic anemia was observed. The rate of PE and 30-day mortality was unchanged with time. A need for more selective preoperative screening for potential candidates of SBTKAs is indicated.