Abstract: Objective To investigate the clinical efficacy and learning curve of robot-assisted total knee arthroplasty(TKA)by retrospectively analyzing the operation time and imaging data of TKA procedures performed with the "Skywalker" robot. Methods A total of 25 robotic-assisted TKA procedures performed by the same surgical group were retrospectively analyzed. The operation time was analyzed using the cumulative sum analysis(CUSUM)method to plot the learning curve, based on which the learning curve was divided into two stages. The operation time, bleeding volume, hospital days, hip-knee-ankle angle and other imaging data, and clinical scores of the two stages were compared. Results The CUSUM analysis revealed the maximum turning point of the learning curve at 13 cases. Based on this, the learning curve was divided into two stages: the learning improvement stage and the mastery stage. There were no significant differences in general data, postoperative hip-knee-ankle angle and other imaging data, HSS scores, knee ROM and FSJ-12 scores between the two stages(P>0.05). However, in the mastery stage, the overall operation time decreased by 23 min, the spatial positioning time decreased by 4.4 min, the optical target installation decreased by 5.0 min; the time to position the lower limb force line and joint surface alignment reduced by 2.9 min and 5.2 min, respectively, and the robotic arm osteotomy operation time reduced by 14.1 min. Conclusion The learning curve of robot-assisted TKA is precisely profiled by CUSUM analysis, indicating that operators need to perform at least 13 surgical cases to master the technique. The learning curve of robot-assisted TKA is short, and the clinical results are satisfactory.

Key words: Robotics, Total knee arthroplasty, Learning curve, Clinical outcome, Imaging measurement