 Tourniquets are still widely used in total knee arthroplasty, but are associated with several adverse effects. Most of previous studies did not randomize the participants so the baseline difference of the patients might have influenced the outcome. Therefore, investigators conducted a randomized controlled trial, in which all the patients received staged bilateral TKA with two different durations of tourniquet use. Investigators aimed to quantify the effect of tourniquet use on reducing blood loss and to evaluate the impact of tourniquet use on functional and clinical outcome. 