Comparison of the Unipolar Electrocautery and the Bipolar Sealer in Reducing Blood Loss in Total Knee Arthroplasty: A Prospective, Randomized, Noninferiority Study.

Background: This was a noninferiority trial to evaluate blood loss during total knee arthroplasty (TKA) when using the unipolar electrocautery system compared to the saline coupled bipolar sealer system in primary TKA.

Methods: One hundred sixty-four patients were randomly assigned by a 1:1 ratio to either the unipolar electrocautery system (N = 82) or bipolar sealer system (N = 82). Inclusion criteria included patients scheduled for primary unilateral TKA, preoperative hemoglobin ≥11 mg/dL, preoperative platelet count ≥150,000, age >18 years, and patient willing to complete all study-related procedures. The primary efficacy outcome was estimated blood loss on morning of postoperative day. Secondary efficacy outcomes were comparison between the preoperative hemoglobin and postoperative day 1 hemoglobin, and allogeneic blood transfusions. Additionally, the study collected objective and functional outcomes using the postoperative 2011 Knee Society Score.

Results: The unipolar electrocautery system was not found to be less efficacious than the bipolar sealer system. Mean blood loss for the unipolar electrocautery system was 1062.0 cubic centimeters (cc) (95% confidence limit for the mean: 985.2, 1138.7), and for the bipolar sealer system was 929.4 cc (95% confidence limit for the mean: 841.9, 1016.8). The mean difference in blood loss was 132.6 cc, below the margin of inferiority set at 200 cc. Additionally, there was no difference in patient outcomes as measured by the Knee Society Score.

Conclusions: The safety, efficacy, and outcomes profile of the unipolar electrocautery system compared to the bipolar sealer system were similar. Use of the bipolar sealer system significantly increases surgical cost without any added benefits.