Beräkning av rotationscentrum för knä-och höftled. : En kinematisk modell för kroppens rörelse baserad på experimentell data.

Sammanfattning: This report is part of a Bachelor’s degree corresponding to 15 credits at the Royal Institute of Technology, Stockholm. The work has been carried out by Max Wikander, author of the report, supervised by Lanie Gutierrez-Farewik and Erik Dijkstra. Gait analysis includes measurement, characterization and assessment of human movement and is used to assess kinematic or other abnormalities during gait. Center of rotation and the axis of rotation of a joint are fundamental parameters in motion analysis. However, the ability to create individualized analysis is limited by the lack of accuracy when these parameters are calculated. Therefore, the ability to improve and innovate methodology used to calculate the joint center of rotation is evaluated. A number of movements including gait was examined using infrared technology at Karolinska University Hospital in Stockholm. During the measurements self-constructed clusters of markers were used. This report presents the results and analysis of these measurements. Kinematic models to describe the knee and hip motion and compute the center of rotation of these joints are formulated and evaluated.The models are partly based on the literature study performed in the beginning of the project. To begin with, a model adapted to movement with a static center of rotation is formulated. The static model is then developed to be applicable in the case of a moving center of rotation. Both models are applied to the measurements conducted. A three-dimensional model is briefly described and is considered suitable for further development of the project. The results show that the models are applicable to various movements including gait. A comparison with the software currently used at Karolinska University Hospital indicates that the model adapted to plane motion provides reasonable results. However, no assessment of the model’s precision can be made as this would require some form of medical imaging or invasive techniques.