Learning curve associated with robotic arm–assisted unicompartmental knee arthroplasty — A prospective cohort study

Abstract

Aims: The primary aim of this study was to determine the surgical team’s learning curve for introducing robotic arm–assisted unicompartmental knee arthroplasty (UKA) into routine surgical practice. The secondary objective was to compare accuracy of implant positioning in conventional jig-based UKA versus robotic arm–assisted UKA. Methods: This prospective single-surgeon cohort study included 25 consecutive conventional jig-based UKAs compared with 25 consecutive robotic arm–assisted UKAs for medial compartmental knee osteoarthritis. Patients undergoing conventional UKA and robotic arm–assisted UKA were well-matched for baseline characteristics including mean age, mean body mass index, sex, and preoperative deformity. Surrogate measures of the learning curve were prospectively collected. These included operating times, accuracy of implant positioning, limb alignment, and postoperative complications. Results: Robotic arm–assisted UKA was associated with a learning curve of 10 cases for operating time. Cumulative robotic experience did not affect accuracy of implant positioning, posterior tibial slope, native joint line preservation, and postoperative limb alignment. Robotic arm–assisted UKA improved accuracy of femoral and tibial implant positioning with no additional risk of postoperative complications compared to conventional jig-based UKA. Conclusion: Robotic arm–assisted UKA has a short learning curve. The learning curve does not affect the components positioning and postoperative lower limb alignment.