Development and Implementation of Novel Functions for Total Knee Arthroplasty Support System to Improve Usability

In total knee arthroplasty (TKA), osteotomy is performed at a predetermined angle to the mechanical axis that passes through the centers of the hip joint and knee joint. The probability of reoperation increases when an angular error of 3[deg] or more exists in the implanted artificial knee. Hence, accurate implantation in accordance with the mechanical axis is necessary. Tamaki et al. developed a simple TKA support system version 1 (V1) to estimate mechanical axes in a simplified manner by employing a three-axis inertial sensor. However, the V1 the process. In this study, to improve usability, we developed version 2 (V2) that includes a novel function for measuring angular error by free rotation angle and adjusting at any knee position. An experiment for comparing the accuracies of the versions V1 and V2 was conducted. The obtained results indicate that although the operational degrees of freedom were increased, the angular error associated with the estimated mechanical axis is within the acceptable range of 3[deg].