Development of a 3D Fluoroscopy Method and its Integration with Stereophotogrammetry to Study the Effects of Soft Tissue Artifacts on the Calculated Mechanical Variables of the Knee During Functional Activities
Date Issued
2010
Date
2010
Author(s)
Tsai, Tsung-Yuan
Abstract
Accurate measurement of the three-dimensional (3D) rigid body and surface kinematics of the natural and implanted knee is essential for many clinical applications. Skin marker-based stereophotogrammetry has been widely used in the in vivo, non-invasive measurement of 3D joint kinematics. However, the measured poses of body segments are subject to errors called soft tissue artifacts (STA). Existing techniques are limited either in their accuracy or lack of more realistic experimental evaluation of the measurement errors. The purposes of the study were to develop a volumetric model-based 2D-to-3D registration method, called the weighted edge-matching score (WEMS) method, for measuring accurate natural and implanted knee kinematics with single-plane fluoroscopy; to assess the 3D movement of skin markers relative to the underlying bones in normal subjects during functional activities; to access the effects of STA on the calculated joint variables at the knee in normal subjects during stair-ascent (SA); to quantify the STA and their effects on the calculated variables of the knee in patients with total knee replacements (TKR) during sit-to-stand (STS); and to validate the performance and effectiveness of global optimization method (GOM) with an appropriate kinematic model for compensating the STA for in vivo knee kinematics of normal, anterior cruciate ligament deficient (ACLD) and TKR subjects during functional activities. The precision of the WEMS method has been determined experimentally with cadaver knee and TKR. With the help of integrated 3D fluoroscopy method and stereophotogrammetry, considerable STA of normal and TKR subjects, during SA and STS respectively, were found and which led to significant differences of measured biomechanical variables of the knee. Compensating the effects of STA with GOM showed that the mean values of root mean squared error (RMSE) over all functional activities of all kinds of subjects were in the order of 3-6 mm for measurement of knee joint translations and about 3˚ for knee joint rotations. These findings suggested that GOM would be helpful for compensating STA in human motion analysis for basic research and clinical applications.
Subjects
knee
kinematics
kinetics
motion analysis
fluoroscopy
soft tissue artifacts
functional activities
Type
thesis
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