Abstract
BACKGROUND: All previous studies comparing the blood sparing efficacy oral and intravenous tranexamic acid (TXA) in total knee arthroplasty have involved two or more patient cohorts, outcomes of which may be limited by inter-individual variability in human drug response. The purpose of this study was to evaluate if both oral and intravenous preparations of TXA are equivalent at reducing blood loss in the same patients undergoing staggered bilateral total knee arthroplasty. METHODS: 40 patients undergoing staggered bilateral total knee replacement were recruited. They received 2 g of oral TXA 2 hours preoperatively for the first knee and 1 g of bolus intravenous TXA 15 minutes before skin incision for the second knee. 7 patients were excluded for protocol deviation, leaving 33 participants for the study. The second knee was operated within 5-6 days of the first knee. The primary outcome was reduction in hemoglobin. Equivalence was tested with a two one-sided test (TOST) and a P < 0.05 indicated equivalence between oral and intravenous modes of TXA administration. RESULTS: The mean reduction in hemoglobin was similar between oral and intravenous mode of TXA administration (2.18 and 2.16 g/dl respectively, P<0.0001, equivalence). There was no significant difference in the total hemoglobin loss and total red blood cell volume loss {(104 and 102 g, P=0.86) and (865 and 863 ml, P=0.53) respectively}. CONCLUSION: Oral and intra venous TXA have equal blood sparing properties in patients undergoing staggered bilateral total knee arthroplasty.