Rat kinematic gait analysis : exploring novel experimental and computational analysis tools

Osteoarthritis is a disease which can affect most joints in the body. Osteoarthritis of the knee is the most common. This disease has been studied intensively but its effect on the gait kinematics is not always well understood. This thesis will focus on studying gait kinematics of rats to be able to determine the effect of OA. Marker-based techniques with external markers and optic cameras have been widely used.This has, however, several disadvantages, such as movement of the markers on the skin, difficulties in tracking the joints, etc. As a possible solution, X-ray-based techniques have recently been introduced. For this technique, both marker-based and markerless approached have been studies. Marker-based tracking is based on the 3D localisation of small radio opaque markers and using these positions to computed rigid body matrix of each bone. Markerless tracking is based on the registration of 3D models of the bones on the 2D radiographic images, and this can be performed automatically. Markerless techniques are emerging and several softwares are presented to perform kinematic analysis of bones without using markers. Optimisation of marker implementation when using the marker-based technique was studied and we foudn that the best way to implant the markers is close to the bone and along the length of the bone. This appeared to be less easy for the femur. For markerless tracking, contrast of the image is important for the registration algorithms to perform. The contrast at different camera parameters has been computed and within this thesis and the best parameters have been determined. Contrast can always be improved by post-processing the images. Furthermore, as this was the first time this technique was applied within the research groups involved in this thesis, we screened different procedures for performing both marker-based and markerless tracking of joint (femur and tibia) movement, and summarized their advantages and disadvantages. Finally, protocols to follow for future experiments have been provided.