INTRODUCTION. The main goal of this study was to estimate the influence of knee arthroplasty on angular changes of knee movement in three planes. Angular values changes in the knee joints and spatio-temporal parameters were studied. MATERIAL AND METHODS. The three-dimensional analysis of locomotion was carried out with 20 subjects after total knee replacement aged 40-70, using Vicon system. The examination took place 6 months after arthroplasty. The results were represented at the background of biomechanical gait parameters of 30 healthy people aged 50-70. RESULTS. Studies on the locomotion were carried out in the Laboratory of Biokinetics, Chair of Anthropomotorics, Academy of Physical Education in Kraków. Increased external rotation in knee joints and flexion contracture of the joint in stance phase was proved. Double support phase was lengthened but cadence was decreased.