Accuracy of tibial component positioning in the robotic arm assisted versus conventional unicompartmental knee arthroplasty

Background: Our study aims to determine the planned accuracy of the tibial component placement in robotic arm assisted unicompartmental knee arthroplasty (UKA) versus the conventional jig based UKA of the initial cases done in India for the first time with this particular robotic system. Materials & Methods: Study group 1 consisted of patients who underwent robotic arm (MAKO, Stryker, USA) assisted UKA. Group 2 consists of patients who underwent a standard conventional jig based (Oxford knee, Biomet, UK). Post-operative radiographs were taken to determine the Tibial Implant position and orientation which were compared to their preoperative plan respectively by two independent observers. The mean error value was obtained for both study groups respectively and compared to determine the accuracy of the post-operative tibial implant placement. Results: In the Robotic arm assisted UKA, the deviation of post-operative varus angle from preoperative planned angle was about 0.43° and post-operative Tibial slope alignment differed from preoperative plan was 0.41°. In the Conventional UKA group post-operative varus angle differed from preoperative planned angle by about 2.12° and post-operative Tibial slope alignment deviation from preoperative plan was 2.47°. Conclusions: Robotic arm assisted system was more accurate compared to the conventional jig-based technique in achieving the planned orientation and alignment of the tibial implant in the initial learning phase of this particular Robotic System used for the first time in India. Mesh terms: partial knee replacement, robotic assisted surgery.