A Depth Camera-Based Evaluation Method for Total Knee Arthroplasty (TKA) Simulation: Cross-Sectional Angle Measurement of 3D Printed Knee Joint

With the aging of our society, there has been a surge in the prevalence of degenerative arthritis among individuals in their 50 s, leading to an elevated demand for total knee arthroplasty. Consequently, there is a growing need for a surgical simulation system that can enhance surgical satisfaction and assist surgeons improving their proficiency with patient-specific surgical plans. However, there are currently limited methods available to evaluate whether the knee joint amputation performed after surgical simulation aligns with the surgical plan. In this study, we propose a system that can instantly calculate the knee joint's cutting angle and evaluate outcomes in the surgical simulation using a depth camera. In order to reduce the inherent measurement errors of the depth camera, we investigated error levels associated with specimen color, object distance, and illumination conditions. Subsequently, we devised a measurement environment that would effectively mitigate these errors. Following this, we produced specimens with varying areas and shapes to evaluate the accuracy of the angle measurement algorithm through error comparison by angle. Finally, we conducted angle measurements on the mimetic bone that was cut, replicating the surgical simulation procedure, and verified that the angle of the cutting surface could be measured with an error margin of around one degree.