In clinical practice, motion analysis can be challenging due to lack of space. Therefore, we propose a method of using one-way frontal video that can be executed easily in a small area. As it has been suggested that gait analysis using one-way frontal video can be used to analyze dynamic changes to knee joint alignment, the purpose of this research was to evaluate this method of motion analysis and examine the accuracy of this technique compared with that of a 3D motion analysis system. Twelve healthy subjects wearing optical reflective markers participated in this gait analysis study that involved the simultaneous use of one-way frontal video and a 3D motion analysis system. The femoral tibial angle (FTA) and the distance between the lower limb mechanical axis and the center of the knee joint were analyzed. The mean absolute error (MAE) of the results from the one-way frontal video and the 3D motion analysis system was calculated and the accuracy of the one-way frontal video method was evaluated. As a result, the patterns of change in knee alignment index obtained from the one-way frontal video all qualitatively matched those observed using the 3D motion analysis system. The MAE was 0.8 degrees in the FTA and the distance between the lower limb mechanical axis and the center of the knee joint was 2.5 mm. The MAE of knee joint alignment was sufficiently small compared to the alignment change associated with abnormal motion in patients with osteoarthritis. Therefore, the evaluation of knee joint alignment using the one-way frontal video method offers sufficient levels of accuracy to be used in diagnoses of abnormal movement.

Keywords

Frontal video, Gait analysis, Knee joint alignment, Femoral tibial angle, Lower limb mechanical axis

Paper information

Kensaku KAWAKAMI, Takahiko NAKAMURA, Katsumi HAMA, Koichi KOBAYASHI, Makoto SAKAMOTO, “Evaluation of dynamic knee joint alignment using a one-way frontal video method”, Journal of Biomechanical Science and Engineering, Vol.15, No.2 (2020), p.19-00616. doi:10.1299/jbse.19-00616. Final Version Released on July 15, 2020, Advance Publication Released on May 26, 2020.

The action of the forearm is to transfer force and torque across the elbow and wrist, resulting in axial rotation at the distal and proximal radioulnar joints, called pronation and supination. Pronation and supination are important functions as they allow many kinds of activities of daily living. Three-dimensional (3D) motion analysis of pronation and supination is essential for a better understating of the biomechanics of the forearm to describe the physiological range of motion and optimize clinical options for disorders of the forearm. Although numerous in vitro studies have contributed to gain insights into the forearm pronation and supination, in vivo investigations are still limited. In this study, three-dimensional (3D) motion of the distal radioulnar joint (DRUJ) during forearm pronation and supination was analyzed in vivo using biplanar radiography and 3D models of the ulna and radius. Twelve healthy subjects (6 men and 6 women) were recruited for the study. Each subject's right forearm (dominant hand) underwent a computed tomography (CT) scan to create 3D surface models of the ulna and radius. Each subject was imaged using a calibrated biplanar radiographic system at 90° pronation, 45° pronation, neutral, 45° supination, and 90° supination while the elbow was in extension or flexion. The 3D positions of the radius and ulna were obtained using a 2D-to-3D image registration method. The relative translations of the radius in the radioulnar, dorsopalmar, and proximodistal directions and the relative rotations of the radius about the radioulnar, dorsopalmar, and proximodistal axes were evaluated with respect to the ulna during pronation and supination. In general, the radius translated towards the ulnar side throughout forearm rotation, and moved towards the palmar side as pronation increased and moved dorsally as supination increased, and was positioned proximally during pronation and distally during supination. The rotation of the radius was dominant about the proximodistal axis. These kinematic variables were affected by elbow position and sex of the subject. The current findings regarding the 3D kinematics of the DRUJ during forearm pronation and supination may contribute to further understanding of the physiological biomechanics of the upper limb.

Keywords

Biomechanics, Forearm, Distal radioulnar joint, In vivo kinematics, Image matching

Paper information

Kiyoko KAZAMA, Koichi KOBAYASHI, Makoto SAKAMOTO, “In vivo three-dimensional analysis of distal radioulnar joint kinematics during forearm pronation-supination”, Journal of Biomechanical Science and Engineering, Vol.11, No.1 (2016), p.15-00364. doi:10.1299/jbse.15-00364. Final Version Released on June 17, 2016, Advance Publication Released on Fegruary 26, 2016.

The range of motion (ROM) resulting from total hip arthroplasty (THA) depends on the relative orientation of the femoral and acetabular components, and malpositioning of components is a possible cause of several complications. The purpose of this study was to validate a 3-dimensional (3D) lower extremity alignment assessment system (3D LAAS) for the measurement of alignment of natural and implanted hip joints and implant position with respect to the target bone with the subject in a standing position. Sawbone femur and pelvis and femoral and acetabular components of a total hip arthroplasty system were used. Three spherical markers were attached to each sawbone and each component to define the local coordinate system. Outlines of the 3D bone models and component computer-aided design models were projected onto extracted contours of the femur, pelvis, and implants in calibrated frontal and oblique X-ray images. The 3D position of each model was recovered by minimizing the differences between projected outlines and contours. Mean absolute errors were less than 1.27 ± 0.79 mm and 0.99 ± 0.52° for femur and pelvis, 1.64 ± 0.66 mm and 1.54 ± 0.39° for femoral and acetabular components, 1.58 ± 0.29 mm and 1.75 ± 0.69° for femur and femoral component, and 1.51 ± 0.49 mm and 1.24 ± 0.14° for pelvis and acetabular component, indicating that the 3D LAAS is applicable to measure the alignment of natural and implanted hip joints and implant position after THA.

Keywords

Biomechanics, Hip joint, Alignment, Total hip arthroplasty, Image registration

Paper information

Koichi KOBAYASHI, Shin KAI, Makoto SAKAMOTO, Yuji TANABE, Kunihiko TOKUNAGA, Izumi MINATO, Takashi SATO and Yoshio KOGA, “Image registration method for assessing 3D hip alignment and implant position during standing posture”, Journal of Biomechanical Science and Engineering, Vol.9, No.2 (2014), p.13-00162. doi:10.1299/jbse.13-00162. Final Version Released on December 15, 2014, Advance Publication Released on June 30, 2014.

The purpose of the present study is to develop a direct and accurate method for measuring knee kinematics by using single-plane fluoroscopy. The study was carried out on a human cadaver femur. Computed tomography (CT) scan data of the femur was taken in order to construct 3D bone volume model of the femur. The femur was placed on an acrylic holder that was attached to a micromanipulator. The femur was rotated about in each orthogonal axis of the micromanipulator over a range of ±2°in 1°increments and then translated along each orthogonal axis over a range of ±2 mm in 1-mm increments. The 3-dimensional (3D) position of the femur (in other words, the 6 degree-of-freedom (DOF) parameters) was recovered by matching the digitally reconstructed radiographs (DRRs) generated from the 3D volume model of the femur and single-plane fluoroscopic images taken from the 25 positions generated by using the micromanipulator. The root-mean-square error (RMSE) of the overall rotation parameters was within 1.4°. For the translation parameters RMSE took its maximal value of 7.8 mm in the out-of-plane direction. This indicates that the present method has potential for clinical application.

Keywords

Biomechanics, Knee Kinematics, Image Registration, Orthopaedics

Paper information

Koichi KOBAYASHI, Ken-ichi ODAGAWA, Makoto SAKAMOTO and Yuji TANABE, “Accuracy of Single Plane X-Ray Image-Based Technique for Assessment of Knee Kinematics”, Journal of Biomechanical Science and Engineering, Vol. 4, No. 2 (2009), pp.192-200 . doi:10.1299/jbse.4.192