 The purpose of this study is to determine whether topical or intravenous administration of tranexamic acid during unilateral total knee replacement is more effective at reducing bleeding in the first 24 hours following surgery. Tranexamic acid is a synthetic drug that has been shown to reduce blood drain output and the need for blood transfusions in both its topical and intravenous forms and is commonly used in orthopedic surgery. We hypothesize that IV and topical administration of tranexamic acid will be equally good at reducing the loss of blood and the need for transfusion immediately following total knee replacement. 