en عمومى General پژوهشي Research <p style="text-align: justify;"><strong>Purpose:</strong> This study aimed to investigate excursion changes at the hip, knee, and ankle joints during gait in patients with knee osteoarthritis (KOA) of varying severity.<br> <strong>Methods:</strong> The method of research was causal-comparative (Ex Post Facto). A Vicon motion analysis system with 4 T-Series cameras was used to measure the kinematics variables. Fifteen normal subjects without KOA and thirty patients with KOA participated in this study. According to Kellgren and Lawrence radiologic scale, the patients were divided into three groups of mild (n=10), moderate (n=10), and severe (n=10). Kinematics parameters of gait includes the range of motion (ROM) in all three planes of motion at the hip, knee, and ankle joints during gait, which were calculated by Vicon Nexus 1.8.5 software. All data were extracted by Polygon 3.5.1 and then were analyzed in SPSS20 using 1-way ANOVA test. The level of significance was set at P<0.05.<br> <strong>Results:</strong> There were no significant differences in all kinematics parameters (joint angles) between the healthy and KOA groups (P>0.05). There were significant differences observed between groups of mild, moderate, and severe KOA with healthy one with respect to foot progress angles in the transverse plane, foot eversion/inversion excursion, knee flexion/extension excursion, knee abduction/adduction excursion, hip internal/external rotation excursion, anterior/posterior pelvic tilt, and lateral pelvic tilt (P<0.05).<br> <strong>Conclusion:</strong> The results showed that some ROM parameters in all three planes of motion can estimate the severity of osteoarthritis. Some observed changes in kinematics parameters are due to effects of compensatory mechanisms, and some might be considered as the severity of the osteoarthritis. In addition, osteoarthritis in one joint had strong effects on other joints.</p> Severity of osteoarthritis, Joint excursion, Gait 233 241 http://ptj.uswr.ac.ir/browse.php?a_code=A-10-272-1&slc_lang=en&sid=1 Ali Jalalvand علی جلالوند jalalvand_ali@yahoo.com Yes Department of Physical Education, Faculty of Human Sciences, Hamedan Branch, Islamic Azad University, Hamedan, Iran. Department of Sport Biomechanics, Faculty of Humanities, Islamic Azad University, Hamedan Branch, Hamedan, Iran. Tel: +98 918 9513172, E-mail: jalalvand_ali@yahoo.com Mehrdad Anbarian مهرداد عنبریان mehrdadanbarian36@gmail.com No Department of Sport Biomechanics, Faculty of Sport Sciences, Bu-Ali Sina University, Hamedan, Iran. Shahram Ahanjan شهرام آهنجان drahanjan@yahoo.com No Department of Physical Education, Amirkabir University of Technology, Tehran, Iran. Behrouz Hajiloo بهروز حاجیلو behrouz.hajiloo@yahoo.com No Department of Sport Biomechanics, Faculty of Sport Sciences, Bu-Ali Sina University, Hamedan, Iran. Ali Akbar Tayfe Seyedan علی اکبر طایفه سیدان No Department of Physical Education, Faculty of Human Sciences, Hamedan Branch, Islamic Azad University, Hamedan, Iran.