A retrospective study comparing a single surgeon's experience on manual versus robot-assisted total hip arthroplasty after the learning curve of the latter procedure - a Cohort Study.

BACKGROUND: Robot-assisted total hip arthroplasty (THA) has the potential of improving cup positioning. However, there is an associated learning curve with robot. This study aimed to determine one surgeon's learning curve with robot-assisted THA and whether robot could achieve similar accuracy in cup positioning as manual THA. METHODS: The first 100 robot-assisted THA operated by one experienced surgeon on manual THA was respectively reviewed. The operating time and robotic complications were recorded to calculate the learning curve through cumulative summation analysis. The demographics, operating time, cup positioning, leg length discrepancy, hip offset, robotic complications and hip Harris score between proficient robot-assisted THA and manual THA in the same period were also compared. RESULTS: The average operating time of robot-assisted THA was 95.92+/-15.64 minutes, ranging from 68 to 145 minutes. Robot-assisted THA was associated with a learning curve of 14 cases for operating time. The duration of acetabular registration and cup implantation between two phases (1-14 and 15-100 case) had significant differences. There were 92% proficient robot-assisted THA and 82% manual THA respectively locating within the Lewinnek's safe zone. The variation of inclinations in proficient robot-assisted THA was significantly less than that in manual THA. CONCLUSION: In the surgeon's series, it took 14 cases' learning curve to be proficient in robot-assisted THA. In the proficiency phase, robot had an advantage in cup positioning than manual technique.