Simultaneous Bilateral Primary Total Knee Arthroplasty With TXA and Restrictive Transfusion Protocols: Still a 1 in 5 Risk of Allogeneic Transfusion.

Background: Historically, there was up to a 60% risk of blood transfusion for patients undergoing simultaneous bilateral total knee arthroplasty (SBTKA). As such, the goal of this study was to analyze the rate and risk factors for allogeneic blood transfusions in patients undergoing SBTKA with tranexamic acid (TXA).

Methods: We retrospectively identified 475 patients who underwent SBTKA with a double dose TXA regimen at a single institution from 2016 to 2019. Mean age was 65 years. Two hundred fifty-seven patients (54%) were female. Mean body mass index was 30 kg/m. Drains were utilized in 143 patients (30%). Mean preoperative hemoglobin (Hgb) was 13.7 g/dL. Multivariate logistic regression analysis adjusting for age ≥70 years, sex, body mass index, drain use, and preoperative Hgb of <12.5 g/dL was utilized to identify risk factors for transfusion.

Results: One hundred six patients (22%) received an allogeneic transfusion, including 28 patients (6%) who received ≥2 units. Multivariate analysis showed that preoperative Hgb <12.5 (OR = 3.99, P < .0001), female sex (OR = 2.34, P = .002), and drain use (OR = 2.13, P = .004) were risk factors for transfusion. Forty-two patients (42/83, 51%) with a preoperative Hgb <12.5 received a transfusion compared with 64 patients (64/392, 16%) with a Hgb ≥12.5 (P < .001).

Conclusion: Patients undergoing SBTKA with contemporary blood management still have a 1 in 5 rate of allogeneic transfusion. Drain use independently increases transfusion risk by 2-fold and should be avoided. Patients with a preoperative Hgb <12.5 have a transfusion rate of 50% and, as such, should either not undergo SBTKA or have extensive perioperative blood optimization.