Comparison of Hemoglobin Trends in Robotic-Assisted Versus Conventional Total Knee Arthroplasty: A Retrospective Cohort Study

Abstract Background: Total knee arthroplasty (TKA) is a common procedure for managing end-stage knee osteoarthritis. Robotic-assisted TKA has been introduced to enhance surgical precision and outcomes. This study aims to compare perioperative hemoglobin (Hb) trends between robotic-assisted and conventional TKA, with a focus on differences between unilateral and bilateral procedures. Methods: We conducted a retrospective analysis of patients who underwent TKA, categorized into robotic-assisted and conventional groups. Subgroup analyses were performed for unilateral and bilateral procedures. Preoperative and postoperative Hb levels on Days 1, 2, and 3 were recorded. The mean Hb drop from preoperative levels to postoperative Day 3 (POD3) was calculated for each group. Statistical analyses, including independent t-tests and ANOVA, were used to compare Hb drops between the groups. Results: The study included 184 patients: 37 in the robotic-assisted group and 147 in the conventional group. The mean Hb drop from preoperative to POD3 was 2.56 ± 0.99 g/dL in the robotic-assisted group and 2.41 ± 1.12 g/dL in the conventional group (p = 0.428). In subgroup analyses, the mean Hb drop was 2.60 ± 1.00 g/dL for unilateral robotic-assisted TKA, 2.50 ± 0.98 g/dL for bilateral robotic-assisted TKA, 2.35 ± 1.10 g/dL for unilateral conventional TKA, and 2.50 ± 1.15 g/dL for bilateral conventional TKA. No statistically significant differences were found between unilateral and bilateral procedures within each group. Conclusion: Robotic-assisted TKA does not significantly reduce perioperative blood loss compared to conventional TKA, regardless of whether the procedure is unilateral or bilateral. Both approaches result in comparable Hb trends postoperatively. Bilateral TKR induces a greater cumulative Hb drop than unilateral TKR, with significant recovery beginning on POD 3. Further prospective studies with larger sample sizes are warranted to validate these findings and explore other potential benefits of robotic assistance in TKA.