Application of high-precision 3D laser scanning in the kinematics of the knee joint post total knee arthroplasty

BackgroundThe number of patients with knee osteoarthritis in China is gradually growing due to the aging society.ObjectiveTo examine the accuracy of two-dimensional and three-dimensional image matching technology equipped with a high-precision 3D laser scanner in kinematics measurement after knee arthroplasty.MethodThe artificial knee joint model fitted with a knee prosthesis was positioned beneath a single-plane X-ray fluoroscope, and the lateral contour of the prosthesis was retrieved through the lateral radiograph of the knee prosthesis. A three-dimensional image of the prosthesis was acquired by a high-precision 3D laser scanner. The three images were manually rotated and repositioned to correspond with the lateral contour to acquire the 3D spatial position of the femoral prosthesis relative to the tibial prosthesis. The coordinates of the thighbone relative to the tibia in the three-dimensional spatial position were measured by the laser scanner and used as the true position of thighbone. The error of the measured position relative to the actual position was compared to determine the accuracy of the measurement.ResultsThe errors of movement and rotation in different angles of the femoral prosthesis relative to the tibial prosthesis in the coronal, horizontal, and sagittal planes were measured using respective 2D and 3D image matching techniques and a 3D laser scanner; a paired <i>t</i>-test was performed for the comparison; and there were no statistically significant differences in the errors of movement and rotation in each angle across different dimensions.ConclusionThe application of 2D and 3D image matching techniques with a high-precision 3D laser scanner can accurately measure the knee kinematic patterns of patients after knee arthroplasty, thereby enhancing the design of the prosthesis and surgical expertise, thus enhancing the postoperative life quality of patients.