Retraction: Comparison of Accuracy of Navigation between Infrared Optical and Electromagnetic Systems

Abstract

Purpose: This study compared the accuracy of mechanical axis measurement between infrared optical and electromagnetic navigation. Materials and Methods: We compared the preoperative mechanical axes of 20 TKAs using both navigation systems. Experimentally, the mechanical axes of the synthetic bone model were compared and the true mechanical axis was determined using the ORTHODOC. Additionally, a surgeon intentionally registered incorrect landmarks and then measured the amount of mechanical axis change in the two navigation methods. Results: Clinically, AxiEM provided greater varus () than Orthopilot (). The mean mechanical axis difference was and a difference greater than in the same patient occurred in 15% of patients. For the synthetic bone, the true mechanical axis was varus , OrthoPilot displayed varus and AxiEM varus . The mechanical axis differences were not significantly different, but OrthoPilot had more reproducibility. When anatomical landmarks were erroneously identified, AxiEM showed a greater change in the mechanical axis. Conclusion: Both navigation systems provided high mechanical axis accuracy and reproducibility under experimental conditions. Infrared optical navigation was more reproducible than electromagnetic navigation. In the clinical setting, there was a disparity of mechanical axis difference greater than in 15% between the two navigation methods in the same patient.