The effect of changing plantarflexion resistive moment of an articulated ankle–foot orthosis on ankle and knee joint angles and moments while walking in patients post stroke

As rehabilitation for post-stroke hemiplegic patients has become widely accepted practice, there has been an increase in patients who are more difficult to treat. In the prescription rationale of orthoses for hemiplegics, the knee-ankle-foot orthosis (KAFO) for the lower limb has generally been underestimated because of its inhibitory effect on the normal walking pattern and also its interference with gait training. The authors had an experience of 28 hemiplegics with severe physical impairments who were fitted with a convertible plastic KAFO. Among these patients, there were 11 cases in which the KAFO was replaced by an ankle-foot orthosis (AFO) within 1.5 to 8 months (average 4 months) following initial prescription when they were able to control their knee actively. Ambulatory capability in these patients was superior to that of the remaining KAFO group. The Barthel index of the AFO group patients was higher than the KAFO group (p<0.01). However neither age, sex, severity of hemiplegia, starting time of rehabilitation following onset of stroke, time of fitting with the orthosis, nor the functional recovery stage were critical factors between the two groups, only the incidence of major complications affected ambulatory capability.

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A Soft Wearable Robotic Ankle-Foot-Orthosis for Post-Stroke Patients

IEEE Robotics and Automation Letters ◽

10.1109/lra.2019.2908491 ◽

2019 ◽

Vol 4 (3) ◽

pp. 2547-2552 ◽

Cited By ~ 17

Author(s):

Junghan Kwon ◽

Ji-Hong Park ◽

Subyeong Ku ◽

YeongHyeon Jeong ◽

Nam-Jong Paik ◽

...

Keyword(s):

Stroke Patients ◽

Ankle Foot Orthosis ◽

Post Stroke ◽

Foot Orthosis

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Kinematic Design and Evaluation of a Six-Bar Knee-Ankle-Foot Orthosis

Journal of Engineering and Science in Medical Diagnostics and Therapy ◽

10.1115/1.4046474 ◽

2020 ◽

Vol 3 (2) ◽

Author(s):

Shramana Ghosh ◽

Nina P. Robson ◽

J. Michael McCarthy

Keyword(s):

Knee Joint ◽

Motion Capture ◽

Performance Optimization ◽

Design Procedure ◽

Motion Capture Data ◽

Ankle Foot Orthosis ◽

Kinematic Design ◽

Computational Synthesis ◽

Kinematic Evaluation ◽

Foot Orthosis

Abstract This paper presents a new two-step design procedure and preliminary kinematic evaluation of a novel, passive, six-bar knee-ankle-foot orthosis (KAFO). The kinematic design and preliminary kinematic gait analysis of the KAFO are based on motion capture data from a single healthy male subject. Preliminary kinematic evaluation shows that the designed passive KAFO is capable of supporting flexion and extension of the knee joint during stance and swing phases of walking. The two-step design procedure for the KAFO consists of (1) computational synthesis based on user's motion data and (2) performance optimization. In the computational synthesis step, first the lower leg (knee-ankle-foot) of the subject is approximated as a 2R kinematic chain and its target trajectories are specified from motion capture data. Six-bar linkages are synthesized to coordinate the angular movements of knee and ankle joints of the 2R chain at 11 accuracy points. The first step of the design procedure yields 332 six-bar KAFO design candidates. This is followed by a performance optimization step in which the KAFO design candidates are optimally modified to satisfy specified constraints on end-effector trajectory and shape. This two-step process yields an optimally designed passive six-bar KAFO that shows promising kinematic results at the knee joint of the user during walking. The preliminary prototype manufactured is cost effective, easy to operate, and suitably demonstrates the feasibility of the proposed concept.

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Robotic Knee Orthosis for Hemiplegic Patients to Prevent Falls During Walking Rehabilitation

Volume 3: Biomedical and Biotechnology Engineering ◽

10.1115/imece2019-10382 ◽

2019 ◽

Author(s):

Ryuji Tsuzuki ◽

Taku Itami ◽

Ken’ichi Yano ◽

Takaaki Aoki ◽

Yutaka Nishimoto

Keyword(s):

Control System ◽

Knee Joint ◽

Healthy Subject ◽

Center Of Gravity ◽

Ankle Foot Orthosis ◽

Walking Rehabilitation ◽

Knee Orthosis ◽

Foot Orthosis

Abstract Walking disturbance is one of the dysfunctions caused by stroke. In walking rehabilitation, it is common to shift to an ankle-foot-orthosis after using a knee-ankle-foot-orthosis for patients with stroke. However, there exist such danger of falling due to knee bending. The purpose of this research is to develop a robotic knee orthosis for hemiplegic patients to prevent falls. The equipment prevents falling by locking the knee joint when knee bending occurs. We analyzed the falling motion according to knee bending and designed the control system focusing on the result that the speed of the center of gravity in the traveling direction becomes zero. In the experiments, we demonstrated the effectiveness of the proposed method by reproducing the knee bending during walking of a healthy subject. As the result, it was demonstrated that the device was operating before the knee bending occurs and it was possible to prevent falls.

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