Comparison of a manual walking platform and the CatWalk gait analysis system in a rat osteoarthritis model

Background. Effects of osteoarthritis (OA) are observed in experimental animal models using different gait analysis systems. Objectives. The aim of this study was to determine whether the Noldus CatWalk XT v. 10.9 gait analysis sys-tem (CatWalk) device can be used effectively in a chemically induced rat OA model and to reveal the strengths and weaknesses of the system compared to manual gait analysis. Materials and methods. Ten Wistar rats were run on a manual walking platform as well as on the CatWalk and the basal values were recorded. For OA induction, monosodium iodoacetate (MIA) was injected into the left knee of all rats under anesthesia. After a period of 4 weeks for OA development, the rats were again run on both the manual and CatWalk gait platforms. For manual gait analysis, the stride length, paw print width and paw print length were measured on both knees. In addition to these parameters, the average run speed, run duration, maximum contact intensity, paw print area, mean stance, and swing speed were measured on the left knee (affected knee) using the CatWalk device. Results. Significant differences were observed in the stride width (p = 0.0272), left stride length (p = 0.0344), and left paw print length (p = 0.0233) recorded before and after OA via the manual walking platform. For CatWalk, a significant difference was detected in the left knee's average run speed (p = 0.0010), maximum contact intensity (p = 0.0155), paw print length (p = 0.0058), paw print width (p = 0.0324), and swing speed (p = 0.0066) based on data obtained before and after OA. Conclusions. The CatWalk gait analysis system is suitable for the evaluation of OA rat models and related interventions. It also provides additional parameters compared to the manual system and minimizes human-related variation.