scholarly journals Development of an Active Ankle Foot Orthosis to Prevent Foot Drop and Toe Drag in Hemiplegic Patients: A Preliminary Study

2011 ◽  
Vol 8 (3-4) ◽  
pp. 377-384 ◽  
Author(s):  
Jungyoon Kim ◽  
Sungjae Hwang ◽  
Ryanghee Sohn ◽  
Younghee Lee ◽  
Youngho Kim
Keyword(s):  
Ankle Joint ◽  
Three Dimensional ◽  
Swing Phase ◽  
Foot Drop ◽  
Initial Contact ◽  
Ankle Foot Orthosis ◽  
Series Elastic Actuator ◽  
Spatial Parameters ◽  
Preliminary Study ◽  
Foot Orthosis

We developed an active ankle-foot orthosis (AAFO) that controls dorsiflexion/plantarflexion of the ankle joint to prevent foot drop and toe drag during hemiplegic walking. To prevent foot slap after initial contact, the ankle joint must remain active to minimize forefoot collision against the ground. During late stance, the ankle joint must also remain active to provide toe clearance and to aid with push-off. We implemented a series elastic actuator in our AAFO to induce ankle dorsiflexion/plantarflexion. The activator was controlled by signals from force sensing register (FSR) sensors that detected gait events. Three dimensional gait analyses were performed for three hemiplegic patients under three different gait conditions: gait without AFO (NAFO), gait with a conventional hinged AFO that did not control the ankle joint (HAFO), and gait with the newly-developed AFO (AAFO). Our results demonstrate that our newly-developed AAFO not only prevents foot drop by inducing plantarflexion during loading response, but also prevents toe drag by facilitating plantarflexion during pre-swing and dorsiflexion during swing phase, leading to improvement in most temporal-spatial parameters. However, only three hemiplegic patients were included in this gait analysis. Studies including more subjects will be required to evaluate the functionality of our newly developed AAFO.

scholarly journals EFFECT OF KINETIC RETURN ANKLE FOOT ORTHOSIS IN PATIENT WITH INCOMPLETE SPINAL CORD INJURY: CHANGES OF THE GAIT PATTERN. A CASE REPORT

2016 ◽  
Vol 2 (101) ◽  
pp. 8-16
Author(s):  
Margot Bergmann ◽  
Mari Alvela ◽  
Priit Eelmäe ◽  
Doris Vahtrik ◽  
Helena Gapeyeva
Keyword(s):  
Spinal Cord ◽  
Knee Joint ◽  
Ankle Joint ◽  
Gait Pattern ◽  
Swing Phase ◽  
Initial Contact ◽  
Ankle Foot Orthosis ◽  
Foot Progression Angle ◽  
Cord Injury ◽  
Foot Orthosis

Background. The variety of orthotics available induces a purpose for estimation of their influence of functional mobility for individual needs in people with incomplete spinal cord injuries (ISCI). The aim of the study was to investigate the effect of the use of kinetic return ankle foot orthosis (KRAFO) on gait pattern in case of ISCI. Methods. Ankle and knee joint kinematic and kinetic characteristics during gait with and without KRAFO were studied in a 34-year-old man with ISCI (fracture v.C5) using 3D motion analysis system (Vicon Motion Systems Ltd., UK) including two dynamographic platforms (AMTI, USA). Ankle and knee joint angles at initial contact and mid-stance, ankle dorsiflexion and foot progression angle in swing phase and ankle joint push-off values in stance phase were analysed. Results. An excessive dorsiflexion in right ankle joint at initial contact, in mid-stance and in swing-phase occurred when walking without the orthosis, which decreased (105, 57 and 73%, respectively, p < .01) with the use of KRAFO. Orthoses use evoked the decrease (77%, p < .01) in peak foot progression angle. Ankle joint peak push- off power was low without the use of KRAFO and decreased even more (28%, p < .05) with the use of orthosis. Decreases of knee joint flexion angle at initial contact and in mid-stance (29 and 23%, respectively) with the use of KRAFO were not significant as compared to gait without orthosis. Conclusions. Walking with KRAFO improved ankle and knee joint stability, providing a decrease in ankle kinematic characteristics but ankle joint push-off power did not change. Further studies are needed to compare the effect of KRAFO in comparison with other orthoses on gait pattern in case of ISCI in accordance with the patient- centric approach for rehabilitation process management.

scholarly journals A Portable Ankle-Foot Rehabilitation Orthosis Powered by Electric Motor

2015 ◽  
Vol 9 (1) ◽  
pp. 982-991 ◽  
Author(s):  
Yang Bai ◽  
Xueshan Gao ◽  
Jun Zhao ◽  
Fei Jin ◽  
Fuquan Dai ◽  
...  
Keyword(s):  
Ankle Joint ◽  
Electric Motor ◽  
Plantar Flexion ◽  
Structure Design ◽  
Foot Drop ◽  
Installation Space ◽  
Joint Movement ◽  
Loop Control ◽  
Ankle Foot Orthosis ◽  
Foot Orthosis

Powered ankle-foot orthosis can not only prevent foot-drop and assist patients’ walking but also improve the ankle joint movement for patients with dysfunction caused by the various injuries and nervous system diseases. Common ankle rehabilitation devices limit the ankle injury patients’ rehabilitation training within fixed places, so a portable powered ankle-foot orthosis is presented in this paper to enable the patients to continue their work normally with the treatment. The orthosis employs electric motor drive mode to provide ankle dorsiflexion and plantar flexion assistance during patient’s walking. First, the ankle-foot dynamics model is established and the gait is analyzed for the powered ankle-foot orthosis system. Then, a new mechanical structure including wearing parts, analogous ankle joint and transmission is described. For the small installation space between the instep and the knee, the compact transmission mechanism has been given more attention and the finite element method is adopted to optimize the key structure after the force analysis. In addition, the closed-loop control system is chosen for the orthosis position and speed control. At last, wearing and movement experiments on the prototype are carried out, which validates the stability and rationality of the structure design and the effectiveness of the motion control. It has great significance in promoting patient's rehabilitation to help them return to the society.

Immediate-term effects of use of an ankle–foot orthosis with an oil damper on the gait of stroke patients when walking without the device

2014 ◽  
Vol 39 (2) ◽  
pp. 140-149 ◽  
Author(s):  
Sumiko Yamamoto ◽  
Setsuro Ibayashi ◽  
Masako Fuchi ◽  
Tadashi Yasui
Keyword(s):  
Ankle Joint ◽  
Three Dimensional ◽  
Chronic Phase ◽  
Therapeutic Effects ◽  
Stroke Patients ◽  
Joint Power ◽  
Ankle Foot Orthosis ◽  
Natural Movement ◽  
Analysis System ◽  
Foot Orthosis

Background:An ankle–foot orthosis using an oil damper is designed to enable natural movement of the ankle joint. Wearing an ankle–foot orthosis using an oil damper has been demonstrated to assist the first rocker in stroke patients, but its effect on their gait when not wearing it is unclear.Objectives:To determine the effect of use of ankle–foot orthosis using an oil damper on the gait of stroke patients with hemiparesis when not wearing the ankle–foot orthosis.Study design:Crossover study.Methods:The gait of eight stroke patients in the chronic phase when not wearing an ankle–foot orthosis was measured, using a three-dimensional motion analysis system, before using the ankle–foot orthosis using an oil damper and then without and with using the ankle–foot orthosis using an oil damper after 3 weeks of use. Differences in gait were compared between the three measurement conditions.Results:Use of ankle–foot orthosis using an oil damper significantly decreased preswing time and significantly increased the positive ankle joint power in stance when not wearing the ankle–foot orthosis using an oil damper.Conclusions:These changes indicate the promising therapeutic effects of ankle–foot orthosis using an oil damper use and suggest the ankle–foot orthosis using an oil damper’s potential as a therapeutic device.Clinical relevanceAfter 3 weeks of use of an ankle–foot orthosis using an oil damper, which assists the first rocker, the gait of stroke patients in the chronic phase when not wearing the ankle–foot orthosis using an oil damper was improved. Preswing time was significantly decreased and positive ankle joint power was significantly increased. The ankle–foot orthosis using an oil damper, which assists the first rocker function with natural movement of the ankle joint during gait, has the potential to improve the gait of stroke patients after immediate-term use.

A three-dimensional model to assess the effect of ankle joint axis misalignments in ankle–foot orthoses

2014 ◽  
Vol 40 (2) ◽  
pp. 240-246 ◽  
Author(s):  
Stefania Fatone ◽  
William Brett Johnson ◽  
Kerice Tucker
Keyword(s):  
Ankle Joint ◽  
Three Dimensional ◽  
Foot Orthoses ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Ankle Foot Orthosis ◽  
Joint Axis ◽  
Ankle Foot Orthoses ◽  
Foot Orthosis

Background: Misalignment of an articulated ankle–foot orthosis joint axis with the anatomic joint axis may lead to discomfort, alterations in gait, and tissue damage. Theoretical, two-dimensional models describe the consequences of misalignments, but cannot capture the three-dimensional behavior of ankle–foot orthosis use. Objectives: The purpose of this project was to develop a model to describe the effects of ankle–foot orthosis ankle joint misalignment in three dimensions. Study design: Computational simulation. Methods: Three-dimensional scans of a leg and ankle–foot orthosis were incorporated into a link segment model where the ankle–foot orthosis joint axis could be misaligned with the anatomic ankle joint axis. The leg/ankle–foot orthosis interface was modeled as a network of nodes connected by springs to estimate interface pressure. Motion between the leg and ankle–foot orthosis was calculated as the ankle joint moved through a gait cycle. Results: While the three-dimensional model corroborated predictions of the previously published two-dimensional model that misalignments in the anterior -posterior direction would result in greater relative motion compared to misalignments in the proximal -distal direction, it provided greater insight showing that misalignments have asymmetrical effects. Conclusions: The three-dimensional model has been incorporated into a freely available computer program to assist others in understanding the consequences of joint misalignments. Clinical relevance Models and simulations can be used to gain insight into functioning of systems of interest. We have developed a three-dimensional model to assess the effect of ankle joint axis misalignments in ankle–foot orthoses. The model has been incorporated into a freely available computer program to assist understanding of trainees and others interested in orthotics.

scholarly journals A New Ankle Foot Orthosis for Running

2009 ◽  
Vol 33 (3) ◽  
pp. 192-197 ◽  
Author(s):  
David Bishop ◽  
Allan Moore ◽  
Naveen Chandrashekar
Keyword(s):  
Range Of Motion ◽  
Peroneal Nerve ◽  
Knee Injuries ◽  
Swing Phase ◽  
The Body ◽  
Foot Drop ◽  
Ankle Foot Orthosis ◽  
Ankle Inversion ◽  
Ankle Eversion ◽  
Foot Orthosis

Traumatic knee injuries in automobile accidents and sports often lead to damage of the peroneal nerve. A lack of control of muscles innervated by the peroneal nerve due to this damage, results in the inability to dorsiflex and evert the foot and to extend the toes. This condition is commonly known as foot drop. Foot drop reduces the stability in the body while walking and running and may also cause injury due to lack of foot clearance during the swing phase of the gait. Traditionally, an ankle foot orthosis (AFO), comprised of a moulded sheet of plastic that conforms around the posterior calf and distally contains all or part of the calcaneous as well as the plantar foot, is used to treat foot drop. The intent of this orthosis is to dorsiflex the foot to provide clearance during the swing phase of walking and running. Traditional AFO results in increased pressures due to a decrease in dorsiflexion range of motion at the ankle and make the orthosis increasingly uncomfortable to wear. Several other existing designs of foot drop AFO suffer from similar inadequacies. To address these issues, a new AFO was developed. The device was successfully used by one person with foot drop without issues for more than one year. This new design conforms to the lower anterior shin and dorsum of the foot using dorsiassist Tamarack ankle joints to allow for greater plantar and dorsiflexion range of motion. While still limiting ankle inversion it does allow for more ankle eversion. This orthosis can be discretely worn inside shoes due to its smaller size, and can be worn for a longer period of time without discomfort.

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