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The purpose of this study was to compare three-dimensional (3D) kinematic measurements from single-plane radiographic projections using bone models created from magnetic resonance imaging (MRI) and computed tomography (CT). MRI is attractive because there is no ionizing radiation, but geometric field distortion and poor bone contrast degrade model fidelity(More)
Kneeling is an important function of the knee for many activities of daily living. In this study, we evaluated the in vivo kinematics of kneeling after total knee arthroplasty (TKA) using radiographic based image-matching techniques. Kneeling from 90 to 120 degrees of knee flexion produced a posterior femoral rollback after both cruciate-retaining and(More)
In order to obtain high reproducibility and sensitivity in the evaluation of joint space in osteoarthritic knees, we used new equipment, and established an anteroposterior weight-bearing radiograph with both knees in semiflexion taking into account our investigation of the posterior slope angle. We compared our method with the Rosenberg method, and the(More)
OBJECT Mechanical stress has been considered one of the important factors in ossification of the spinal ligaments. According to previous clinical and in vitro studies, the accumulation of tensile stress to these ligaments may be responsible for ligament ossification. To elucidate the relationship between such mechanical stress and the development of(More)
Dynamic knee kinematics were analyzed for normal knees in three activities, including two different types of maximum knee flexion. Continuous X-ray images of kneel, squat, and stair climb motions were taken using a large flat panel detector. CT-derived bone models were used for model registration-based 3D kinematic measurement. Three-dimensional joint(More)
Femoral condyle geometry was evaluated in 30 normal and 30 varus knees using magnetic resonance imaging. In the sagittal view, the distal part of the medial condyle was deformed in the varus knees, but there was no significant difference in the posterior part of the medial condyle between the normal and varus knees. In the transverse view, the(More)
Objective evaluation of surgical skills is essential for an arthroscopic training system. We asked whether a quantitative assessment of arthroscopic skills using scores, time to completion, instrument tip trajectory data, and force data was valid. We presumed more experienced surgeons would perform better on a simulated arthroscopic procedure than novices,(More)
Patellar tracking and femoral condylar geometry in deep knee flexion were evaluated using magnetic resonance imaging. The patellar tilting angle, patellar shift, and patellar anteroposterior translation from 0 degrees to 135 degrees flexion were measured. The depth of the femoral condylar articular surface and the curvature of the femoral condylar articular(More)
Appropriate tension of the posterior cruciate ligament, which often is tight in deep flexion, is difficult to achieve after posterior cruciate ligament retaining total knee arthroplasty. Kinematics and maximum flexion after partial release of the posterior cruciate ligament were evaluated in this study. A partial release improved the maximum flexion angle(More)
Application of adenosine triphosphate (ATP) induced a depolarizing response in bullfrog sympathetic ganglion cells, which was associated with a decrease in membrane conductance. This depolarizing response was also produced by application of ADP, but not by adenosine, cyclic-AMP or cyclic-GMP. Suramin, an antagonist for the P2-purinoceptor, suppressed the(More)