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Talks and Poster Presentations (with Proceedings-Entry):

W. Auzinger, I. Reichl, H. Schmiedmayer, E. Weinmüller:
"Knee joint kinematics: comparison of two optimization models with respect to data noise";
Talk: GAMM Jahrestagung 2011, Graz (invited); 2011-04-18 - 2011-04-21; in: "Proceedings of the GAMM 82nd Annual Scientific Conference, Graz, Austria, April 18-21, 2011", 11 (2011), ISSN: 1617-7061; 111 pages.



English abstract:
Kinematic analysis of the human knee joint assists surgical interventions or prosthesis design and relies on an appropriate axis definition. Additionally to the existence of several alternative axes definitions, large deviations between observers applying the same definition occur. Definitions relying on anatomical landmarks may be replaced or assisted by a functional axes computation based on the kinematic analysis of a well-defined type of movement, thus, reducing
observer dependence. Kinematic constraints reducing the number of degrees of freedom (DOFs) are expected to compensate for measurement errors and noise present especially in skin-marker based movement analysis, thus, increasing the reproducibility of joint angles. One approach already successfully applied by several groups approximates the healthy human knee joint as a compound hinge joint with minimal varus/valgus rotation most of them involving a maybe unphysiological orthogonality constraint. This contribution compares the effect of a model with and without orthogonality constraint on the obtained joint rotation angles. For this purpose, knee joint motion is simulated to generate kinematic data with normally distributed noise of varying size. For small noise the unconstrained model provides more accurate results, whereas for noise typical for skin fixed markers, this is the case for the constrained model. This can be attributed to the shape of the objective function of the unconstrained model near its minimum.

Keywords:
knee joint kinematics optimization


"Official" electronic version of the publication (accessed through its Digital Object Identifier - DOI)
http://dx.doi.org/10.1002/pamm.201110047


Created from the Publication Database of the Vienna University of Technology.