Design and Initial Validation of a Multiple Degree-of-Freedom Joint for an Ankle-Foot Orthosis

2021 ◽  
Author(s):  
Toby Elery ◽  
Emma Reznick ◽  
Staci Shearin ◽  
Karen McCain ◽  
Robert D. Gregg
Keyword(s):  
Lower Limb ◽  
Knee Flexion ◽  
Degree Of Freedom ◽  
The Novel ◽  
Ankle Foot Orthosis ◽  
Initial Validation ◽  
Lower Limb Muscles ◽  
Walking Speeds ◽  
Novel Design ◽  
Foot Orthosis

Abstract This paper presents the novel design of a Multi-Degree-Of-Freedom joint (M-DOF) for an Ankle-Foot Orthosis (AFO) that aims to improve upon the commercially available Double Action Joint (DAJ). The M-DOF is designed to maintain the functionality of the DAJ, while increasing dorsiflexion stiffness and introducing inversion/eversion. This increase in range of motion is designed to produce greater engagement from lower limb muscles during gait. The M-DOF was experimentally validated with one able-bodied and one stroke subject. Across walking speeds, the M-DOF AFO minimally affected the able-bodied subject's joint kinematics. The stroke subject's ankle dorsiflexion/plantarflexion and knee flexion were not heavily altered when wearing the M-DOF AFO, compared to the DAJ AFO. The new DOF allowed by the M-DOF AFO increased the inversion/eversion of the ankle by ~3°, without introducing any new compensations compared to their gait with the DAJ AFO.

scholarly journals Gait evaluation of new powered knee–ankle–foot orthosis in able-bodied persons: A pilot study

2013 ◽  
Vol 38 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Mokhtar Arazpour ◽  
Fardin Ahmadi ◽  
Monireh Ahmadi Bani ◽  
Stephen William Hutchins ◽  
Mahmood Bahramizadeh ◽  
...  
Keyword(s):  
Pilot Study ◽  
Lower Limb ◽  
Knee Flexion ◽  
Healthy Subjects ◽  
Step Length ◽  
Normal Walking ◽  
Limb Weakness ◽  
Ankle Foot Orthosis ◽  
Lower Limb Weakness ◽  
Foot Orthosis

Background: Knee–ankle–foot orthoses are utilized for walking by patients with lower limb weakness. However, they may be rejected by patients due to the lack of knee flexion available when using them for walking activities. Aim: The aim of this study was to perform a pilot study investigating the effect of a new powered knee–ankle–foot orthosis on walking in healthy persons before testing with patients with lower limb weakness. Methods: Walking evaluation was performed on five healthy subjects (mean age: 26 ± 5.6 years). Walking trials were randomly performed in three test conditions: normal walking without an orthosis, walking with a conventional knee–ankle–foot orthosis unilaterally, and also with a new powered knee–ankle–foot orthosis applied to the same leg. Results: The means of walking speed, cadence, and knee flexion during swing and step length were all decreased. Compensatory motions were increased by both orthoses compared to normal walking. More knee flexion was observed in both swing and stance phases when walking with the powered knee–ankle–foot orthosis compared to the conventional knee–ankle–foot orthosis. Conclusion: The results demonstrated the potential of a powered orthosis in providing improvements in gait parameters compared to a conventional device in healthy subjects but are yet untested in subjects with lower limb weakness. Clinical relevance The results of this study demonstrated that a powered knee–ankle–foot orthosis could lock the knee during stance and provide active knee flexion during swing to potentially reduce the tripping during ambulation.

Defining the Mechanical Properties of a Spring-hinged Ankle Foot Orthosis to Assess its Potential Use in Children With Spastic Cerebral Palsy

2014 ◽  
Vol 30 (6) ◽  
pp. 728-731 ◽  
Author(s):  
Yvette L. Kerkum ◽  
Merel-Anne Brehm ◽  
Annemieke I. Buizer ◽  
Josien C. van den Noort ◽  
Jules G. Becher ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cerebral Palsy ◽  
Knee Flexion ◽  
Spastic Cerebral Palsy ◽  
Gait Performance ◽  
Ankle Foot Orthosis ◽  
The Moment ◽  
Potential Use ◽  
Foot Orthosis ◽  
Walking Energy Cost

A rigid ventral shelf ankle foot orthosis (AFO) may improve gait in children with spastic cerebral palsy (SCP) whose gait is characterized by excessive knee flexion in stance. However, these AFOs can also impede ankle range of motion (ROM) and thereby inhibit push-off power. A more spring-like AFO can enhance push-off and may potentially reduce walking energy cost. The recent development of an adjustable spring-hinged AFO now allows adjustment of AFO stiffness, enabling tuning toward optimal gait performance. This study aims to quantify the mechanical properties of this spring-hinged AFO for each of its springs and settings. Using an AFO stiffness tester, two AFO hinges and their accompanying springs were measured. The springs showed a stiffness range of 0.01−1.82 N·m·deg−1. The moment-threshold increased with increasing stiffness (1.13–12.1 N·m), while ROM decreased (4.91–16.5°). Energy was returned by all springs (11.5–116.3 J). These results suggest that the two stiffest available springs should improve joint kinematics and enhance push-off in children with SCP walking with excessive knee flexion.

Ankle–foot orthosis with dorsiflexion resistance using spring-cam mechanism increases knee flexion in the swing phase during walking in stroke patients with hemiplegia

2020 ◽  
Vol 81 ◽  
pp. 27-32 ◽  
Author(s):  
Yusuke Sekiguchi ◽  
Dai Owaki ◽  
Keita Honda ◽  
Kenichiro Fukushi ◽  
Noriyoshi Hiroi ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Swing Phase ◽  
Stroke Patients ◽  
Ankle Foot Orthosis ◽  
Cam Mechanism ◽  
Foot Orthosis

scholarly journals Newly designed computer controlled knee-ankle-foot orthosis (Intelligent Orthosis)

1998 ◽  
Vol 22 (3) ◽  
pp. 230-239 ◽  
Author(s):  
T. Suga ◽  
O. Kameyama ◽  
R. Ogawa ◽  
M. Matsuura ◽  
H. Oka
Keyword(s):  
Lower Limb ◽  
Stance Phase ◽  
Gait Cycle ◽  
Normal Subjects ◽  
Swing Phase ◽  
Ankle Foot Orthosis ◽  
Normal Gait ◽  
Heel Contact ◽  
Computer Controlled ◽  
Foot Orthosis

The authors have developed a knee-ankle-foot orthosis with a joint unit that controls knee movements using a microcomputer (Intelligent Orthosis). The Intelligent Orthosis was applied to normal subjects and patients, and gait analysis was performed. In the gait cycle, the ratio of the stance phase to the swing phase was less in gait with the knee locked using a knee-ankle-foot orthosis than in gait without an orthosis or gait with the knee controlled by a microcomputer. The ratio of the stance phase to the swing phase between controlled gait and normal gait was similar. For normal subjects the activity of the tibialis anterior was markedly increased from the heel-off phase to the swing phase in locked gait. The muscle activities of the lower limb were lower in controlled force in locked gait showed spikes immediately after heel-contact in the vertical at heel-contact in the sagittal to locked gait, gait with the Intelligent Orthosis is smooth and close to normal gait from the viewpoint of biomechanics. Even in patients with muscle weakness of the quadriceps, control of the knee joint using the Intelligent Orthosis resulted in a more smooth gait with low muscle discharge.

scholarly journals Control Reference Parameter for Stance Assistance Using a Passive Controlled Ankle Foot Orthosis—A Preliminary Study

2019 ◽  
Vol 9 (20) ◽  
pp. 4416 ◽  
Author(s):  
Dimas Adiputra ◽  
Mohd Azizi Abdul Rahman ◽  
Ubaidillah ◽  
Saiful Amri Mazlan ◽  
Nurhazimah Nazmi ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Standard Error ◽  
Walking Speed ◽  
Parameters Estimation ◽  
Ankle Foot Orthosis ◽  
Preliminary Study ◽  
Reference Parameters ◽  
Walking Speeds ◽  
Foot Orthosis

This paper aims to present a preliminary study of control reference parameters for stance assistance among different subjects and walking speeds using a passive-controlled ankle foot orthosis. Four young male able-bodied subjects with varying body mass indexes (23.842 ± 4.827) walked in three walking speeds of 1, 3, and 5 km/h. Two control references, average ankle torque (aMa), and ankle angular velocity (aω), which can be implemented using a magnetorheological brake, were measured. Regression analysis was conducted to identify suitable control references in the three different phases of the stance. The results showed that aω has greater correlation (p) with body mass index and walking speed compared to aMa in the whole stance phase (p1(aω) = 0.666 > p1(aMa) = 0.560, p2(aω) = 0.837 > p2(aMa) = 0.277, and p3(aω) = 0.839 > p3(aMa) = 0.369). The estimation standard error (Se) of the aMa was found to be generally higher than of aω (Se1(aMa) = 2.251 > Se1(aω) = 0.786, Se2(aMa) = 1.236 > Se2(aω) = 0.231, Se3(aMa) = 0.696 < Se3(aω) = 0.755). Future studies should perform aω estimation based on body mass index and walking speed, as suggested by the higher correlation and lower standard error as compared to aMa. The number of subjects and walking speed scenarios should also be increased to reduce the standard error of control reference parameters estimation.

Preliminary Evaluation of a Knee-Ankle-Foot Orthosis for the Emulation of Transfemoral Prosthesis Socket Loads

2011 ◽  
Author(s):  
James A. Dawley ◽  
Andrew M. Romanazzi ◽  
Kevin B. Fite
Keyword(s):  
Lower Limb ◽  
Myoelectric Control ◽  
Preliminary Evaluation ◽  
Residual Limb ◽  
Direct Control ◽  
Ankle Foot Orthosis ◽  
Prosthetic Limbs ◽  
Transfemoral Prosthesis ◽  
Socket Interface ◽  
Foot Orthosis

Control of prosthetic limbs using myoelectric muscle potentials from the wearer’s residual limb enables direct control of artificial limb behavior. The typical approach entails the integration of surface electromyogram (sEMG) electrodes within the inner wall of the socket interface, located to target specific superficial muscles in the amputee’s residual limb. While myoelectric upper-limb control is commonplace in prosthetic practice, its use in lower-extremity devices has been slow to follow suit. Various research efforts have studied approaches to implementing myoelectric control of artificial leg behavior [1–4], but the need for myoelectric control in lower-limb prostheses has been limited by the lack of commercial prototypes with the capability of net power generation.

scholarly journals Novel design for a dynamic ankle foot orthosis with motion feedback used for training in patients with hemiplegic gait: a pilot study

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Chih-Chao Hsu ◽  
Yin-Kai Huang ◽  
Jiunn-Horng Kang ◽  
Yi-Feng Ko ◽  
Chia-Wei Liu ◽  
...  
Keyword(s):  
Pilot Study ◽  
Ankle Foot Orthosis ◽  
Hemiplegic Gait ◽  
Novel Design ◽  
Foot Orthosis
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