Objective:To investigate the perioperative total blood loss of robot-assisted total knee arthroplasty (TKA).Methods:A total of 60 patients with knee osteoarthritis who underwent initial unilateral TKA in Peking Union Medical College Hospital from February to June 2022 were retrospectively analyzed. According to whether they received robot-assisted surgery, they were divided into robot-assisted group and traditional surgery group. In the robot-assisted group, there were 32 patients, including 6 males and 26 females, aged 70.22±5.88 years (range, 57 to 79 years). Left side 14 cases, right side 18 cases; grade of Kellgren-Lawrence: 1 case of grade Ⅱ, 14 cases of grade Ⅲ, 17 cases of grade Ⅳ. In the traditional surgery group, there were 28 patients, including 5 males and 23 females, aged 68.61±6.79 years (range, 57 to 87 years). Left side 16 cases, right side 12 cases; grade of Kellgren-Lawrence: 2 cases of grade Ⅱ, 12 cases of grade Ⅲ, 14 cases of grade Ⅳ. There was no significant difference in baseline data between the two groups ( P>0.05). Postoperative hemoglobin, hematocrit, and their decreased values were recorded in the two groups, and perioperative range of motion (ROM) of knee and Hospital for Special Surgery (HSS) scores were compared between the two groups. Results:All patients successfully completed the surgery and were followed up, with a follow-up time of 9.93±0.83 months (range, 8-11 months) in the robotic-assisted group and 9.59±0.97 months (range, 8-11 months) in the traditional surgery group. The application time of tourniquet in the robot-assisted group was 96.19±10.21 min, which was higher than that in the traditional surgery group (62.68±16.54 min), and the difference was statistically significant ( t=9.57, P<0.001). The total perioperative blood loss in the robot-assisted group was 534.59(411.85, 859.26) ml, which was higher than 411.32(313.42, 613.52) ml in the traditional surgery group, and the difference was statistically significant ( Z=-2.37, P=0.018). There were no significant differences in hemoglobin or hematocrit between the two groups at day 1 and 3 after surgery ( P>0.05). The hemoglobin decrease value in the robotic-assisted group was 19.63±9.73 g/L, which was greater than 14.71±5.84 g/L in the traditional surgery group, and the difference was statistically significant ( t=2.40, P=0.020). The decrease value of hematocrit in the robot-assisted group was 5.77%±3.14%, which was greater than 4.09%±1.57% in the traditional operation group ( t=2.56, P=0.013). At the last follow-up, knee ROM of the two groups were 123.03°±5.91° and 125.82°±6.59°, respectively, which were higher than the preoperative values of 95.69°±11.64° and 90.29°±23.08°. Postoperative HSS scores were 89.50±4.19 points and 90.70±4.34 points, which were higher than 62.58±10.52 points and 61.09±12.66 points before operation, the differences were statistically significant ( P<0.05), and there was no significant difference between groups ( P>0.05). There were 6 cases of postoperative deep vein thrombosis of the lower extremities in the robot-assisted group and 2 cases in the traditional surgery group, and the difference was not statistically significant (χ 2=0.88, P=0.348). Conclusion:Compared with traditional TKA, robotic-assisted TKA increased perioperative blood loss, and there was no difference in postoperative knee function between the two groups.