Several robotics of TKA has been introduced for improving outcomes. As with all new technology, the new system is associated with a learning curve. Therefore, the aim of this study is to determine the learning curve necessary to minimize the operative time and to evaluate the alignment accuracy when using advanced active robotic (AR) TKA (AR-TKA).
In AR TKA, advanced active robotic technology refers to the use of a robot for planning and bone preparation by a milling tool under surgeon guidance and control. Operative times, implant and limb alignment were evaluated. Sixty patients were classified into 6 groups according to the day of surgery. The differences among 6 groups were analyzed to assess learning curves for operative time, implant alignment and lower leg alignment. The cumulative summation analysis(CUSUM) was performed for learning curve assessment.
AR-TKA was associated with a learning curve of more than 40 cases for operative time (p<0.001). After 40 cases, the operative time was significantly decreased by approximately 15-20 minutes. The precision of implant positioning and lower limb alignment showed no learning curve. An average deviation for the coronal planes of the femoral and tibial implants from the preoperative plan was observed less than 1.0°. Limb alignment showed a mean deviation of 1.6° towards varus postoperatively compared to the intraoperative plan. The inflection point of CUSUM analysis was found as 39 cases from the initial case.
Active Robotic total knee arthroplasty is associated with a learning curve of 39 cases for operative time. There was no learning curve-associated component position. These findings suggest that a high degree of accuracy with regards to implant position and lower limb alignment can be achieved with advanced active robot regardless of the learning curve.