Can intraoperative kinematic analysis predict postoperative kinematics following total knee arthroplasty? A preliminary study

The preliminary study analyzed the relationship between intraoperative navigation-based kinematics and postoperative 2-dimensional/3-dimensional (2D/3D) image registration-based kinematics in total knee arthroplasty (TKA). Six knees in 5 patients were analyzed. All TKA procedures were performed using an image-free knee navigation system. Tibial internal rotation was assessed by intraoperative knee kinematics. At 1 year after surgery, tibial internal rotation was evaluated using a 2D/3D image registration technique under loaded and unloaded conditions. The correlation between intraoperative and postoperative data for the tibial internal rotation angle at 10° increments of knee flexion was then assessed. Difference in the knee flexion angle between the intraoperative and postoperative evaluations was adjusted to account for the sagittal cutting angle of the distal femur and proximal tibia. A correlation was found between the intraoperative and postoperative data for loaded knee flexion with this adjustment (Pearson’s r = 0.725, p = 0.012). However, intraoperative kinematics was not significantly correlated with postoperative kinematics in the absence of loading. Larger adequately powered prospective studies are now needed to confirm our preliminary finding that postoperative loaded kinematics can be predicted by intraoperative evaluation.