Purpose: This study aimed at measuring the knee joint angle on the sagittal plane during walking using two-dimensional motion analysis 2DMA) and three-dimensional motion analysis 3DMA) in patients with stroke, as well as investigate the reliability of both systems, the validity of 2DMA related to criteria, and the similarity of the waveforms for knee kinematic pattern between both systems. Methods: Thirteen patients participated in the study. The knee joint and lower leg rotation angles were measured during walking using 2DMA and 3DMA. The inter-day reliability and validity of the maximum and minimum angles of knee flexion were investigated using the intra-class correlation coefficient and Bland-Altman plots. Also confirmed was the similarity of the waveforms for knee kinematic pattern between both systems. Results: The inter-day reliability was high for both systems. A systematic error was found between 2DMA and 3DMA, whereas a high degree of waveform similarity in the knee joint angle for both systems was observed. Conclusions: The results of this study suggest that 2DMA can be a clinically useful tool for knee kinematic analysis during walking, even in patients with stroke.
