Functional Assessment for the Natural Knee Joints in Squat Activity by Simulation of 2D X-Ray Images Based on 3D CT Images

Abstract

In biomechanics of the knee joints, the definition of the cruciate ligament adhesion areas is discussed for the cruciate ligament reconstruction. Effective information can be expected to be fed back to the cruciate ligament reconstruction if accurate movement of the natural knee joints can be analyzed. Therefore, this study performed in vivo six-degree-of-freedom (6-DOF) motion analysis for the natural knee joints with high precision using an image matching technique. The image matching technique was performed determining the strength of correlation between the X-ray images from a single-plane flat panel detector (FPD) and the computational simulated image from three-dimensional gray-scale model reconstructed using computed tomography (CT). Average root mean square errors of this technique were 0.84 mm for the in-plane translation, 0.17 mm for the out-of-plane translation, and 0.29 degrees for the rotation.We report analysis results for the natural knee joints in squat activity using this technique. Subjects were the natural knee joints of four healthy men. We assessed the four items for the motion pattern and the functionality of cruciate ligament. The roll-back motion of subluxation in high-flexion, and the importance of anteromedial (AM) bundle and posterolateral (PL) bundle in the anterior cruciate ligament (ACL) could be confirmed from the results. From these, this highly accurate technique can be expected to become a valuable tool for the medical device development and the diagnostic in field of orthopedics.

Three‐dimensional motion analysis of the patellar component in total knee arthroplasty by the image matching method using image correlations

“…The simulated value A of a voxel at a point ( x , y ) on the project plane was defined by: where α i is a value of a property of interest (e.g., bone mineral density) per unit length for the i th voxel that a virtual x‐ray beam passes through, L i is the length of the i th voxel, and n represents the number of voxels that a virtual x‐ray beam travels through (Fig. ) …”

“…Previously, we developed a unique computer‐assisted image matching procedure to analyze the kinematics of natural and TKA knees by applying an image window‐based analytical method to serial unidirectional x‐ray scans . In this study, we aimed to visualize the patellar component and identify contact points on a 3D model in the TKA patient between the patellofemoral joint components with our analytical method.…”

Bioinspired Knee Joint for a Power-Assist Suit

“…Therefore, the rotational axis is not fixed in a point. According to the definition of the coordination system in [17] (Figure 1), the origin of the femur's rotation in the sagittal plane with respect to the tibia's origin moves as shown in Figure 2 during the standing motion [16]. The vertical axis of this figure shows the displacement of the superior-inferior motion of the rotational axis (positive values denote the superior positions).…”

“…Furthermore, during flexion of the knee joint, the femur normally has a 5-10 degrees' abduction against the tibia, reaching up to 30 degrees during extension in some cases [16]. From the 30-degree flexion to the terminal extension, the femur rotates 5-10 degrees in inner rotation.…”

Improvement of flexion/extension angle range of KneeRobo to replicate involuntary movements

“…3. Using data presented by Shiraishi et al [6][7] on the internal/external rotation angle and abduction/adduction angle during the flexion and extension of a healthy knee joint, we calculated the desired trajectory of Point P to replicate normal knee joint movement in the flexion/extension angle range of 0°-90°. The desired trajectory of Point P is represented by the green line in Fig.…”