Gait analysis of patients with knee osteoarthritis by using elevation angle: confirmation of the planar law and analysis of angular difference in the approximate plane. - Yuki Ishikawa; Qi An; Junki Nakagawa; Hiroyuki Oka; Tetsuro Yasui; Michio Tojima; Haruhi Inokuchi; Nobuhiko Haga; Hiroshi Yamakawa; Yusuke Tamura; Atsushi Yamashita; Hajime Asama (Adv. Robotics, 2017)