Intra-Articular Injection of Bupivacaine and Adrenaline Reduces Intraoperative and Postoperative Blood Loss in Total Knee Arthroplasty: A Retrospective Case-Control Study

<b>Objective</b>: To evaluate the effect of preoperative intra-articular injection of bupivacaine and adrenaline (BAD) on blood loss and postoperative hemoglobin levels in primary total knee replacement. <b>Methods</b>: We retrospectively assessed 38 consecutive patients who underwent primary total knee arthroplasty at our institution between 2018 and 2019, as performed by two chief orthopedic surgeons. The study group included 22 patients who received an intra-articular injection of 40 mL solution of BAD 0.25% preoperatively. The control group included 16 patients who did not receive the BAD injection preoperatively. Both groups received an IV tranexamic acid (TXA) 1 g treatment prior to the first incision. The posterior capsule and soft tissues were infiltrated after femoral chamfer cuts with a 60 mL BAD solution in both groups. Blood loss was evaluated in all patients by measuring the volume collected in the suction container before the first irrigation and prior to cementation. Additional assessments included the volume of blood drained during the first 24 h postoperatively, as well as changes in hemoglobin levels (delta hemoglobin) 24 h after surgery and at hospital discharge. <b>Results</b>: The study and the control groups were similar in age, sex, demographics, and comorbidities. The mean patient age was 71.4 ± 6.5 in the injected group and 70.6 ± 7.5 in the control group. The volume of blood suctioned during surgery was significantly lower in the study group compared to the control group (201 ± 84.3 mL vs. 261.25 ± 83.3 mL; <i>p</i> = 0.04). Similarly, the amount of blood drained within the first 24 h postoperatively was also reduced in the study group (204.3 ± 91.1 mL vs. 363.44 ± 131.9 mL; <i>p</i> = 0.0001). Ultimately, the decrease in hemoglobin levels from baseline to discharge was less pronounced in the study group compared to the control group (1.7 ± 0.9 g/dL vs. 2.44 ± 1.3 g/dL; <i>p</i> = 0.038). <b>Conclusions:</b> Intra-articular injection of 40 mL bupivacaine and 0.25% adrenaline solution before skin incision may reduce intraoperative and postoperative blood loss among patients undergoing total knee arthroplasty.