An articulated ankle–foot orthosis with adjustable plantarflexion resistance, dorsiflexion resistance and alignment: A pilot study on mechanical properties and effects on stroke hemiparetic gait

Kobayashi, Toshiki; Orendurff, Michael S.; Hunt, Grace; Lincoln, Lucas; Gao, Fan; LeCursi, Nicholas; Foreman, K. Bo

doi:10.1016/j.medengphy.2017.02.012

Cited by 43 publications

(35 citation statements)

References 13 publications

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“…Many different types of AFO are available for different biomechanical and clinical purposes. They can generally be classified into two categories as articulated [10] and [11] and nonarticulated [12] and [13]. Articulated AFOs contain mechanical joints at the ankle section that allow or limit the range of ankle motion in the sagittal plane.…”

Section: Introductionmentioning

confidence: 99%

A Novel Dorsal Trimline Approach for Passive-Dynamic Ankle-Foot Orthoses

Sürmen¹,

Akalan²,

Fetvaci³

et al. 2018

SV-JME

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An ankle-foot orthosis (AFO) is an externally applied assistive device that encompasses the lower leg, ankle, and foot of the human body. In the current one-piece passive-dynamic AFO design, the trimming process is performed from lateral and medial parts of the ankle to ensure desired rotational displacement (hereafter referred to as Design I). In most cases, stress concentrations occurring over the trimmed regions during walking can cause permanent damage to the AFO. In this study, to reduce the stress concentration and ensure a homogeneous stress distribution, a new trimming approach is presented, in which the trim zones were transferred from lateral and medial to dorsal (hereafter referred to as Design II). Finite element analyses of the Designs I and II models were carried out. Displacement and von Mises stress values for both models under the same loading and boundary conditions were obtained. Maximum displacement values were 8.51 mm and 9.05 mm for Design I and Design II, respectively. Maximum stress values were 15.19 MPa and 6.70 MPa for Design I and Design II, respectively. For the similar range of motion of ankle joint, the novel design produced less stress and more homogeneous stress distribution than the currently used design, thus indicating that Design II would be more resistant to plastic deformation than Design I.

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Section: Introductionmentioning

confidence: 99%

A Novel Dorsal Trimline Approach for Passive-Dynamic Ankle-Foot Orthoses

Sürmen¹,

Akalan²,

Fetvaci³

et al. 2018

SV-JME

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“…; H.E. Ploeger et al (2011) (Ploeger et al, 2012 Toshiki Kobayashi et al (2017) (T. Kobayashi et al, 2011); A. Leardini et al (2014) (Leardini et al, 2014 6.…”

Section: Discussionmentioning

confidence: 99%

“…The energy cost of walking, which is often defined as the normalized net oxygen cost of walking, is calculated by dividing the net oxygen consumption by speed and body mass (Bregman et al, 2012). Subsequently, the data of gait performance and the biomechanical effect on the patients extracted from the three-dimensional (3D) eight-camera VICON motion capture system were processed using Visual3D (C-motion, Germantown, MD, USA) or/and Excel (Toshiki Kobayashi et al, 2017).…”

Section: Study Characteristicsmentioning

confidence: 99%

The Categories of AFO and Its Effect on Patients With Foot Impair: A Systemic Review

Feng

Song

2017

Physical Activity and Health

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There are a lot of ailments that would lead to foot impair. For instance, cerebral palsy (CP), stroke, multiple sclerosis (MS), hemiplegia, duchenne muscular dystrophy (DMD) and so on. With the further deterioration of these diseases, gait would become imbalanced and then it may contribute to high risk of fall incidence. Thus, it is urgent to invent a tool to adjust the foot impair. Most of the previous studies had found that the ankle-foot orthoses (AFO) has a significant effect to overcome the foot impair. Studies that investigated the ankle-foot orthoses (AFO) and its effect on patients with foot impair are various and abundant. Nevertheless, there are a little studies that integrated the categories of AFO and its specific effect on patients with foot impair. It is important to integrate the categories of AFO and its specific effect on patients with foot impair because the previous studies had proved that different designs of AFO have different mechanical properties and these would affect outcomes in a way. The purpose of this paper is to review and integrate the published studies on the categories of AFO and its effect on patients with foot impair and thereby offer better guidelines and suggestions for prescriptions and future studies. The publication of all papers about the categories of AFO and its effect on patients with foot impair were obtained from Science Direct(SD), Google Scholar and other peer reviewed journals that were published in English. The keywords used for searching were "AFO," "material," "foot impair," and "systemic review." There were total 8647 studies regarding these keywords, and 37 studies were eligible to be selected in this research: 2 studies on systemic review, 35 studies on the materials and categories of AFO and its effect on patients with foot impair. Most previous studies had found that the effect of AFO is related to mechanical properties of AFO and disease characteristics. Therefore, this review could provide researchers with more systemic and detailed information about the categories of AFO and its effect on patients with foot impair and promote synthesis of literature.

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“…The reported control of the mechanical properties of an AFO, such as bending stiffness, damping stiffness, and assistive torque, showed both fixed and adaptive output references. It could be clearly observed that the fixed output reference worked with a flexible rigid AFO [18,64] and an AFO with only mechanical actuators, such as an oil damper [69] and a spring [32,73]. The adaptive output reference could be observed from those works that utilized electrical actuators such as an MR device [41,49,56], SEA [54,75], and a pneumatic system [53].…”

Section: Output Reference: Fixed Versus Adaptivementioning

confidence: 99%

“…Moreover, combinations of two or more springs can be used to add more variations of joint stiffness [72]. For instance, one spring was located at the front and one at the back of the foot, as shown in a study by Kobayashi [73]. Thus, it can be used to optimize the mechanical properties of an AFO for the individual gait treatment of post-stroke patients [74].…”

Section: Damping Stiffness Controlmentioning

confidence: 99%

A Review on the Control of the Mechanical Properties of Ankle Foot Orthosis for Gait Assistance

et al. 2019

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In the past decade, advanced technologies in robotics have been explored to enhance the rehabilitation of post-stroke patients. Previous works have shown that gait assistance for post-stroke patients can be provided through the use of robotics technology in ancillary equipment, such as Ankle Foot Orthosis (AFO). An AFO is usually used to assist patients with spasticity or foot drop problems. There are several types of AFOs, depending on the flexibility of the joint, such as rigid, flexible rigid, and articulated AFOs. A rigid AFO has a fixed joint, and a flexible rigid AFO has a more flexible joint, while the articulated AFO has a freely rotating ankle joint, where the mechanical properties of the AFO are more controllable compared to the other two types of AFOs. This paper reviews the control of the mechanical properties of existing AFOs for gait assistance in post-stroke patients. Several aspects that affect the control of the mechanical properties of an AFO, such as the controller input, number of gait phases, controller output reference, and controller performance evaluation are discussed and compared. Thus, this paper will be of interest to AFO researchers or developers who would like to design their own AFOs with the most suitable mechanical properties based on their application. The controller input and the number of gait phases are discussed first. Then, the discussion moves forward to the methods of estimating the controller output reference, which is the main focus of this study. Based on the estimation method, the gait control strategies can be classified into subject-oriented estimations and phase-oriented estimations. Finally, suggestions for future studies are addressed, one of which is the application of the adaptive controller output reference to maximize the benefits of the AFO to users.

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An articulated ankle–foot orthosis with adjustable plantarflexion resistance, dorsiflexion resistance and alignment: A pilot study on mechanical properties and effects on stroke hemiparetic gait

Cited by 43 publications

References 13 publications

A Novel Dorsal Trimline Approach for Passive-Dynamic Ankle-Foot Orthoses

A Novel Dorsal Trimline Approach for Passive-Dynamic Ankle-Foot Orthoses

The Categories of AFO and Its Effect on Patients With Foot Impair: A Systemic Review

A Review on the Control of the Mechanical Properties of Ankle Foot Orthosis for Gait Assistance

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