Moderate/severe GR: To identify potential kinematic patterns correlating with the severity of knee hyperextension, two groups of severity were formed according to the maximum knee hyperextension in stance phase of gait. The first group (moderate GR) included patients with less severe knee hyperextension of 5 to 15. The second group(severe GR) represented patients with a severe recurvatum gait of more than 15 knee hyperextension during stance phase