Newly designed computer controlled knee-ankle-foot orthosis (Intelligent 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.

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Commonly Used Types and Recent Development of Ankle-Foot Orthosis: A Narrative Review

Healthcare ◽

10.3390/healthcare9081046 ◽

2021 ◽

Vol 9 (8) ◽

pp. 1046

Author(s):

Yoo Jin Choo ◽

Min Cheol Chang

Keyword(s):

Stance Phase ◽

Narrative Review ◽

Foot Drop ◽

Ankle Foot Orthosis ◽

Physical Conditions ◽

Heel Contact ◽

Foot Problems ◽

Kenaf Composites ◽

Foot Orthosis ◽

Ankle And Foot

(1) Background: ankle-foot orthosis (AFO) is the most commonly prescribed orthosis to patients with foot drop, and ankle and foot problems. In this study, we aimed to review the commonly used types of AFO and introduce the recent development of AFO. (2) Methods: narrative review. (3) Results: AFO prevents the foot from being dragged, provides a clearance between the foot and the ground in the swinging phase of gait, and maintains a stable posture by allowing heel contact with the ground during the stance phase. In clinical practice, the most commonly used AFO include plastic AFO, walking boot, UD-Flex, and carbon fiber AFO. In addition, for compensating the demerits of these conventional AFOs, new types of AFOs, including AF Servo, TurboMed, three-dimensionally printed AFO, and AFO made from kenaf composites, were developed. (4) Conclusions: we think that our review can guide clinicians in selecting and prescribing the appropriate AFO for each patient in accordance with their specific physical conditions.

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Design of a Novel Variable Stiffness Active Ankle Foot Orthosis Using Permanent Magnets for Drop Foot Assistance

Volume 10: 44th Mechanisms and Robotics Conference (MR) ◽

10.1115/detc2020-22742 ◽

2020 ◽

Author(s):

Abhinaba Basu ◽

Sri Sadhan Jujjavarapu ◽

Ehsan T. Esfahani

Keyword(s):

Stance Phase ◽

Gait Cycle ◽

Permanent Magnets ◽

Variable Stiffness ◽

Drop Foot ◽

Healthy Individuals ◽

Ankle Foot Orthosis ◽

Impact Forces ◽

The Impact ◽

Foot Orthosis

Abstract In this paper, we present the design of a novel variable stiffness ankle-foot orthosis for correcting the drop-foot condition. The proposed mechanism controls the position of permanent magnets to provide torque and stiffness assistance to the patients suffering from drop foot. A publicly available gait dataset of 20 healthy individuals is used to extract the stiffness and torque requirements of a gait cycle and the information is used to evaluate the foot orthosis. It is shown that the proposed foot orthosis can provide appropriate torque and stiffness assistance to the ankle joint during the swing and the stance phase respectively. Moreover, the spring-like nature of the repelling magnets reduces the impact forces on the patient’s joints.

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Evaluation of gait symmetry in poliomyelitis subjects: Comparison of a conventional knee–ankle–foot orthosis and a new powered knee–ankle–foot orthosis

Prosthetics and Orthotics International ◽

10.1177/0309364615596063 ◽

2016 ◽

Vol 40 (6) ◽

pp. 689-695 ◽

Cited By ~ 3

Author(s):

Mokhtar Arazpour ◽

Fardin Ahmadi ◽

Mahmood Bahramizadeh ◽

Mohammad Samadian ◽

Mohammad Ebrahim Mousavi ◽

...

Keyword(s):

Knee Flexion ◽

Stance Phase ◽

Swing Phase ◽

Step Width ◽

Gait Symmetry ◽

Ankle Foot Orthosis ◽

Swing Time ◽

Locked Knee ◽

Stance Time ◽

Foot Orthosis

Background:Compared to able-bodied subjects, subjects with post-polio syndrome and poliomyelitis demonstrate a preference for weight-bearing on the non-paretic limb, causing gait asymmetry.Objectives:The purpose of this study was to evaluate the gait symmetry of the poliomyelitis subjects when ambulating with either a drop-locked knee–ankle–foot orthosis or a newly developed powered knee–ankle–foot orthosis.Study design:Quasi experimental study.Methods:Seven subjects with poliomyelitis who routinely wore conventional knee–ankle–foot orthoses participated in this study and received training to enable them to ambulate with the powered knee–ankle–foot orthosis on level ground, prior to gait analysis.Results:There were no significant differences in the gait symmetry index of step length ( p = 0.085), stance time ( p = 0.082), double-limb support time ( p = 0.929), or speed of walking ( p = 0.325) between the two test conditions. However, using the new powered knee–ankle–foot orthosis improved the symmetry index in step width ( p = 0.037), swing time ( p = 0.014), stance phase percentage ( p = 0.008), and knee flexion during swing phase ( p ⩽ 0.001) compared to wearing the drop-locked knee–ankle–foot orthosis.Conclusion:The use of a powered knee–ankle–foot orthosis for ambulation by poliomyelitis subjects affects gait symmetry in the base of support, swing time, stance phase percentage, and knee flexion during swing phase.Clinical relevanceA new powered knee–ankle–foot orthosis can improve gait symmetry for poliomyelitis subjects by influencing step width, swing time, stance time percentage, and knee flexion during swing phase when compared to ambulating with a drop-locked knee–ankle–foot orthosis.

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Development of a Dynamic Knee Actuator for a KAFO Using Superelastic Alloys

Volume 3: Biomedical and Biotechnology Engineering ◽

10.1115/imece2014-40431 ◽

2014 ◽

Cited By ~ 3

Author(s):

Feng Tian ◽

Mohamed Samir Hefzy ◽

Mohammad Elahinia

Keyword(s):

Knee Joint ◽

Gait Cycle ◽

Swing Phase ◽

Walking Ability ◽

Knee Motion ◽

Walking Gait ◽

Ankle Foot Orthosis ◽

Stance Control ◽

In Series ◽

Foot Orthosis

A knee-ankle-foot orthosis (KAFO), which covers the knee, ankle and foot, can mitigate abnormal walking pattern caused by weak quadriceps. Several types of KAFOs are currently available in the market: passive KAFOs, stance-control KAFOs and dynamic KAFOs. In passive KAFOs, the knee joint keeps being locked during standing and walking, and can be unlocked manually to allow free rotation for sitting. Stance-control KAFOs (SCKAFOs) allow free knee motion during swing phase when the braced leg is unloaded. Dynamic KAFOs are able to reproduce normal walking ability throughout whole gait cycle. This research is directed at using superelastic alloys to develop a dynamic knee actuator that can be mounted on a traditional passive KAFO. The actuator stiffness can match that of a normal knee joint during the walking gait cycle. This proposed knee actuator utilizes a storing-releasing energy method to apply functional compensation to the knee joint, controlling the knee joint during both stance and swing phases. Fundamentally, the knee actuator is composed of two distinct parts which are connected with the thigh and shank segments, respectively. There are two superelastic actuators that are housed within these two parts and activated independently. Each actuator is developed by combining a superelastic rod and a rotary spring in series. When neither actuator is engaged, the knee joint is allowed to rotate freely. The stance actuator works only in the stance phase and the swing actuator is active for the swing phase. The conceptual design of the knee actuator is verified using numerical simulation and a prototype is developed through additive manufacturing for confirming the concept.

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Analysis of body-device interface forces in the sagittal plane for patients wearing ankle-foot orthoses

Prosthetics and Orthotics International ◽

10.3109/03093649909071615 ◽

1999 ◽

Vol 23 (1) ◽

pp. 75-81 ◽

Cited By ~ 11

Author(s):

B. McHugh

Keyword(s):

Stance Phase ◽

Muscle Power ◽

Sagittal Plane ◽

Swing Phase ◽

The Body ◽

Loss Of Function ◽

Ankle Foot Orthosis ◽

Ankle Foot Orthoses ◽

Foot Orthosis ◽

Interface Forces

An ankle-foot orthosis (AFO) is employed principally to treat musculoskeletal disorders of the ankle and/or subtalar joints although, occasionally, it may be prescribed to provide stance phase control of the knee. In order to function satisfactorily, an AFO must apply appropriate forces to the lower leg in a manner which does not cause local tissue damage or discomfort. Equally the leg will apply forces to the AFO which it must be capable of withstanding without breakage or loss of function. Thus it is useful to know where the body-device interface forces act during walking and to be able to estimate their magnitudes. This is not well understood and has not been satisfactorily documented. This paper explains the force actions between the AFO and the leg, in the sagittal plane, where there is absence of muscle power. Furthermore, it explores the possibility of estimating the magnitudes of these forces. It is found that the forces are greatest when orthotic assistance is needed to compensate for plantar flexor insufficiency in late stance phase. On the other hand, where the AFO is used to support the foot, in the absence of dorsiflexion power in swing phase, the forces are relatively small. Understanding these force levels is relevant to the design of the AFO in terms of choice and use of materials and components.

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The influence of a powered knee–ankle–foot orthosis on walking in poliomyelitis subjects: A pilot study

Prosthetics and Orthotics International ◽

10.1177/0309364615592703 ◽

2015 ◽

Vol 40 (3) ◽

pp. 377-383 ◽

Cited By ~ 7

Author(s):

Mokhtar Arazpour ◽

Alireza Moradi ◽

Mohammad Samadian ◽

Mahmood Bahramizadeh ◽

Mahmoud Joghtaei ◽

...

Keyword(s):

Knee Joint ◽

Knee Flexion ◽

Stance Phase ◽

Step Length ◽

Gait Pattern ◽

Swing Phase ◽

Ankle Foot Orthosis ◽

Active Flexion ◽

Locked Knee ◽

Foot Orthosis

Background:Traditionally, the anatomical knee joint is locked in extension when walking with a conventional knee–ankle–foot orthosis. A powered knee–ankle–foot orthosis was developed to provide restriction of knee flexion during stance phase and active flexion and extension of the knee during swing phase of gait.Objective:The purpose of this study was to determine differences of the powered knee–ankle–foot orthosis compared to a locked knee–ankle–foot orthosis in kinematic data and temporospatial parameters during ambulation.Study design:Quasi—experimental design.Methods:Subjects with poliomyelitis (n = 7) volunteered for this study and undertook gait analysis with both the powered and the conventional knee–ankle–foot orthoses. Three trials per orthosis were collected while each subject walked along a 6-m walkway using a calibrated six-camera three-dimensional video-based motion analysis system.Results:Walking with the powered knee–ankle–foot orthosis resulted in a significant reduction in both walking speed and step length (both 18%), but a significant increase in stance phase percentage compared to walking with the conventional knee–ankle–foot orthosis. Cadence was not significantly different between the two test conditions ( p = 0.751). There was significantly higher knee flexion during swing phase and increased hip hiking when using the powered orthosis.Conclusion:The new powered orthosis permitted improved knee joint kinematic for knee–ankle–foot orthosis users while providing knee support in stance and active knee motion in swing in the gait cycle. Therefore, the new powered orthosis provided more natural knee flexion during swing for orthosis users compared to the locked knee–ankle–foot orthosis.Clinical relevanceThis orthosis has the potential to improve knee joint kinematics and gait pattern in poliomyelitis subjects during walking activities.

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The Use of Orthotics in Foot and Ankle Problems in Cerebral Palsy

Foot & Ankle ◽

10.1177/107110078400400407 ◽

1984 ◽

Vol 4 (4) ◽

pp. 195-200 ◽

Cited By ~ 19

Author(s):

Robert K. Rosenthal

Keyword(s):

Cerebral Palsy ◽

Gait Analysis ◽

Stance Phase ◽

Specific Problem ◽

Swing Phase ◽

Foot Orthoses ◽

Foot And Ankle ◽

Ankle Foot Orthosis ◽

Control Dynamic ◽

Foot Orthosis

The molded polypropylene orthosis offers many advantages in the treatment of foot and ankle problems in cerebral palsy. Numerous balancing, stance phase, and swing phase difficulties are treated with an ankle-foot orthosis with appropriate molding to correct each specific problem. Various foot orthoses can also be used to control dynamic muscle imbalances. Gait analysis has confirmed the merits of these orthoses.

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A Dynamic Knee-Ankle-Foot Orthosis With Superelastic Actuators

Volume 2: Mechanics and Behavior of Active Materials; Structural Health Monitoring; Bioinspired Smart Materials and Systems; Energy Harvesting ◽

10.1115/smasis2013-3044 ◽

2013 ◽

Cited By ~ 2

Author(s):

Feng Tian ◽

Mohammad Elahinia ◽

Mohamed Samir Hefzy

Keyword(s):

Knee Joint ◽

Shape Memory ◽

Conceptual Design ◽

Stance Phase ◽

Gait Cycle ◽

Joint Rotation ◽

Ankle Foot Orthosis ◽

Normal Knee ◽

Actuation System ◽

Foot Orthosis

A knee-ankle-foot orthosis (KAFO) spans the knee, ankle and foot, and assists in the walking motion of those who suffer neuromuscular deficiencies. KAFOs can be classified as passive, semi-dynamic and dynamic. Passive KAFOs lock the knee joint during the whole gait cycle. Semi dynamic KAFOs lock the knee joint during the stance phase. Dynamic KAFOs attempt to reproduce normal knee motions during the whole gait cycle. Two types of dynamic KAFOs have been reported in the literature. The first one is activated by using a pneumatic system, and the second one uses a spring mechanism. Both systems are bulky and controlled through complex control systems that limit their application as assistive devices. The purpose of our research is to develop a dynamic KAFO that is actuated easily by employing shape memory materials. Such an actuation system makes the KAFO lightweight and with a great commercialization potential. The purpose of this paper is to present a conceptual design for the knee actuator of a dynamic KAFO. This actuator uses torsional shape memory rods to match the stiffness of the knee joint of the KAFO with that of a normal knee joint during the walking gait cycle. Joint stiffness is measured by the moment around the joint per degree of joint rotation. The proposed actuator includes two parts that work independently during the two phases of the gait cycle. The first part engages only during the stance phase and the other works only during the swing phase. Each part is developed by combining a superelastic (SE) rod and a rotary spring in series. The conceptual design is verified by simulation. The simulation results show that the proposed knee actuator reproduces the stiffness of the normal knee joint during the whole gait cycle. It is thus possible to develop a novel dynamic KAFO that can provide normal knee stiffness characteristics to assist individuals with quadriceps deficiency.

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