Effect of AFO Design on Walking after Stroke: Impact of Ankle Plantar Flexion Contracture

This study was conducted to compare the effects of three ankle-foot orthosis (AFO) designs on walking after stroke and determine whether an ankle plantar flexion contracture impacts response to the AFOs. A total of 30 individuals, ranging from 6–215 months post-stroke, were tested in four conditions: shoes only (SH), dorsi-assist/dorsi-stop AFO (DA-DS), plantar stop/free dorsiflexion AFO (PS), and rigid AFO (Rigid). Kinematics, kinetics, and electromyographic (EMG) activity were recorded from the hemiparetic lower extremity while participants walked at a self-selected pace. Gait parameters were compared between conditions and between participants with and without a moderate ankle plantar flexion contracture. All AFOs increased ankle dorsiflexion in swing and early stance. Anterior tibialis EMG was reduced only in the PS AFO. Both PS and Rigid AFOs restricted ankle plantar flexion and increased knee flexion in loading. Peak ankle dorsiflexion in stance and soleus EMG intensity were greatest in the PS AFO. The Rigid AFO tended to restrict dorsiflexion in stance and knee flexion in swing only in participants without a plantar flexion contracture. Individuals without a contracture benefit from an AFO that permits dorsiflexion mobility in stance and those with quadriceps weakness may more easily tolerate an AFO with plantar flexion mobility in loading.

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Use of a Static Adjustable Ankle-Foot Orthosis Following Tibial Nerve Block to Reduce Plantar-Flexion Contracture in an Individual With Brain Injury

Physical Therapy ◽

10.1093/ptj/82.11.1087 ◽

2002 ◽

Vol 82 (11) ◽

pp. 1087-1097 ◽

Cited By ~ 11

Author(s):

Sarah Blanton ◽

Samuel P Grissom ◽

Lisa Riolo

Keyword(s):

Brain Injury ◽

Physical Therapy ◽

Nerve Block ◽

Tibial Nerve ◽

Plantar Flexion ◽

Flexion Contracture ◽

Ankle Foot Orthosis ◽

Flexion Contractures ◽

Ankle Plantar Flexion ◽

Foot Orthosis

Abstract Background and Purpose. Ankle plantar-flexion contractures are a common complication of brain injuries and can lead to secondary limitations in mobility. Case Description. The patient was a 44-year-old woman with left hemiplegia following a right frontal arteriovenous malformation resection. She had a left ankle plantar-flexion contracture of −31 degrees from neutral. After a tibial nerve block, an adjustable ankle-foot orthosis was applied 23 hours a day for 27 days. Adjustments of the orthosis were made as the contracture was reduced. The patient received physical therapy during the 27-day period for functional mobility activities and stretching the plantar flexors outside of the orthosis. Outcomes. The patient's dorsiflexion passive range of motion increased from −31 degrees to +10 degrees. Discussion. The application of an adjustable ankle-foot orthosis following a tibial nerve block, as an addition to a physical therapy regimen of stretching and mobility training, may reduce plantar-flexion contractures in patients with brain injury.

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Effects of plantar flexion resistive moment generated by an ankle-foot orthosis with an oil damper on the gait of stroke patients: a pilot study

Prosthetics and Orthotics International ◽

10.1177/0309364612460266 ◽

2012 ◽

Vol 37 (3) ◽

pp. 212-221 ◽

Cited By ~ 15

Author(s):

Sumiko Yamamoto ◽

Naoki Tomokiyo ◽

Tadashi Yasui ◽

Toshikazu Kawaguchi

Keyword(s):

Plantar Flexion ◽

Reaction Force ◽

Three Dimensional ◽

Chronic Phase ◽

Cross Sectional Study ◽

Cross Sectional ◽

Ankle Foot Orthosis ◽

Paretic Limb ◽

Gait Parameters ◽

Foot Orthosis

Background: An ankle-foot orthosis with an oil damper was previously developed to assist the first rocker function during gait, but the effects of the amount of resistive moment generated on gait have not been clarified. Objectives: To measure the amount of resistive moment generated by the ankle-foot orthosis with an oil damper during gait and determine its effect on the gait of patients with stroke. Study Design: Preliminary cross-sectional study. Methods: The gait of four patients with stroke in the chronic phase was measured in four conditions: without an ankle-foot orthosis and with the ankle-foot orthosis with an oil damper generating three different amounts of resistive moment. Measurements were taken with a three-dimensional motion analysis system and a specially designed device to determine the resistive moment. Results: The resistive moment was observed in the former half in stance of the paretic limb, and its magnitude was less than 10 N m. Some gait parameters related to terminal stance and preswing were affected by the amount of resistive moment. The forward component of floor reaction force and the shank vertical angle showed peak values when the patients reported feeling most comfortable during gait. Conclusion: Although the resistive moment generated by the ankle-foot orthosis with an oil damper was small, it was sufficient to alter gait. Clinical relevance To maximize the effectiveness of ankle-foot orthoses, it is necessary to know the effects of resistive moment on the gait of patients with stroke. The ankle-foot orthosis with an oil damper assists the first rocker function in gait and also affects the gait in a later phase in stance. The peak values of some gait parameters coincided with patients reporting gait to be most comfortable. It is important to know that ankle-foot orthosis with an oil damper assistance in the first rocker alters the weight acceptance on the paretic limb and affects the gait parameters related to propulsion ability in stance.

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Does Gait with an Ankle Foot Orthosis Improve or Compromise Minimum Foot Clearance?

Sensors ◽

10.3390/s21238089 ◽

2021 ◽

Vol 21 (23) ◽

pp. 8089

Author(s):

Pedro Fonseca ◽

Leandro Machado ◽

Manoela Vieira Sousa ◽

Ricardo Sebastião ◽

Filipa Sousa ◽

...

Keyword(s):

Plantar Flexion ◽

Lower Limbs ◽

Passive Mode ◽

Compensatory Mechanisms ◽

Ankle Foot Orthosis ◽

Foot Clearance ◽

All Speeds ◽

Hip Flexion ◽

Ankle Plantar Flexion ◽

Foot Orthosis

The purpose of this study was to investigate if the use of an ankle foot orthosis in passive mode (without actuation) could modify minimum foot clearance, and if there are any compensatory mechanisms to enable these changes during treadmill gait at a constant speed. Eight participants walked on an instrumented treadmill without and with an ankle foot orthosis on the dominant limb at speeds of 0.8, 1.2, and 1.6 km/h. For each gait cycle, the minimum foot clearance and some gait linear kinematic parameters were calculated by an inertial motion capture system. Additionally, maximum hip and knee flexion and maximum ankle plantar flexion were calculated. There were no significant differences in the minimum foot clearance between gait conditions and lower limbs. However, differences were found in the swing, stance and step times between gait conditions, as well as between limbs during gait with orthosis (p < 0.05). An increase in hip flexion during gait with orthosis was observed for all speeds, and different ankle ranges of motion were observed according to speed (p < 0.05). Thus, the use of an ankle foot orthosis in passive mode does not significantly hinder minimum foot clearance, but can change gait linear and angular parameters in non-pathological individuals.

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

Journal of Applied Biomechanics ◽

10.1123/jab.2014-0046 ◽

2014 ◽

Vol 30 (6) ◽

pp. 728-731 ◽

Cited By ~ 9

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.

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

Gait & Posture ◽

10.1016/j.gaitpost.2020.06.029 ◽

2020 ◽

Vol 81 ◽

pp. 27-32 ◽

Cited By ~ 2

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

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Stiffness control in posterior-type plastic ankle-foot orthoses: Effect of ankle trimline Part 2: Orthosis characteristics and orthosis/patient matching

Prosthetics and Orthotics International ◽

10.3109/03093649609164431 ◽

1996 ◽

Vol 20 (2) ◽

pp. 132-137 ◽

Cited By ~ 39

Author(s):

T. Sumiya ◽

Y. Suzuki ◽

T. Kasahara

Keyword(s):

Plantar Flexion ◽

Measuring Device ◽

Ankle Foot Orthosis ◽

Maximum Resistance ◽

Severe Spasticity ◽

Ankle Foot Orthoses ◽

Final Adjustment ◽

Flexion Strength ◽

Foot Orthosis ◽

Selection Of

The hingeless plastic ankle-foot orthosis (AFO) changes stiffness largely depending on how much plastic is trimmed around the ankle. To support proper selection of the orthosis and final adjustment of the orthotic stiffness, the correlation between the posterior upright width and the resistance to dorsi- and plantar flexion movements was measured in 30 posterior-type plastic AFOs. The posterior upright width was varied by regularly trimming around the ankle in nine stages. The resistance to dorsi- and plantar flexion movements was measured by bending the plastic AFOs 15d` with the measuring device described in Part 1. All the plastic AFOs decreased in their resistance to both movements in proportion to the reduction of the posterior upright width. The maximum resistance to plantar flexion movement was about 28 Nm, which was strong enough to assist dorsiflexion in patients with severe spasticity. On the other hand, the maximum resistance to dorsiflexion movement measured was about 10 Nm, which was insufficient to stabilise the ankle in patients who lacked in plantar flexion strength. These findings suggested that this type of plastic AFO should be prescribed for patients who predominantly require dorsiflexion assist, and that the orthotic stiffness could be finally adjusted by trimming to exactly meet individual requirements.

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Immediate Effects of the Dorsiflexion Angle of Hinged Ankle-foot Orthosis on the Spatiotemporal Gait Parameters of Children With Spastic Cerebral Palsy

10.21203/rs.3.rs-581906/v1 ◽

2021 ◽

Author(s):

IlHyun Son ◽

GyuChang Lee

Keyword(s):

Cerebral Palsy ◽

Stride Length ◽

Step Length ◽

Gait Velocity ◽

Spastic Cerebral Palsy ◽

Spastic Diplegia ◽

Ankle Foot Orthosis ◽

Gait Parameters ◽

Children With Cerebral Palsy ◽

Foot Orthosis

Abstract Background: It has been reported the effects of a hinged ankle-foot orthosis on the gait ability of children with cerebral palsy. However, no studies investigated the effects of the dorsiflexion angle of the hinged ankle-foot orthosis on the spatiotemporal gait parameters of children with cerebral palsy. This study aimed to investigate the immediate effects of a 10° dorsiflexion inducing ankle-foot orthosis the spatiotemporal gait parameters of children with spastic diplegia compared to barefoot and a hinged ankle-foot orthosis.Methods: This study was cross-over design. 10 children with spastic diplegia were walked with barefoot, a hinged ankle-foot orthosis, and a 10° dorsiflexion inducing ankle-foot orthosis. GAITRite was used to collect the spatiotemporal gait parameters including gait velocity, cadence, step length, stride length, single leg support, and double leg support. Results: It showed that a 10° dorsiflexion inducing ankle-foot orthosis significantly improved the gait velocity, cadence, step length, stride length, single leg support, and double leg support than barefoot and a hinged ankle-foot orthosis (p<.05). Conclusion: The results of this study implied that a 10° dorsiflexion inducing ankle-foot orthosis could improve the gait ability of children with spastic diplegia more than barefoot or a hinged ankle-foot orthosis. High quality future studies will need to examine the effects of hinged ankle-foot orthosis on gait ability according to dorsiflexion angles.

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The effect of a knee ankle foot orthosis incorporating an active knee mechanism on gait of a person with poliomyelitis

Prosthetics and Orthotics International ◽

10.1177/0309364612469140 ◽

2013 ◽

Vol 37 (5) ◽

pp. 411-414 ◽

Cited By ~ 20

Author(s):

Mokhtar Arazpour ◽

Ahmad Chitsazan ◽

Monireh Ahmadi Bani ◽

Gholamreza Rouhi ◽

Farhad Tabatabai Ghomshe ◽

...

Keyword(s):

Knee Flexion ◽

Walking Speed ◽

Horizontal Displacement ◽

Step Length ◽

Knee Extension ◽

Knee Joints ◽

Ankle Foot Orthosis ◽

Stance Control ◽

Control Knee ◽

Foot Orthosis

Background: The aim of this case study was to identify the effect of a powered stance control knee ankle foot orthosis on the kinematics and temporospatial parameters of walking by a person with poliomyelitis when compared to a knee ankle foot orthosis. Case description and methods: A knee ankle foot orthosis was initially manufactured by incorporating drop lock knee joints and custom molded ankle foot orthoses and fitted to a person with poliomyelitis. The orthosis was then adapted by adding electrically activated powered knee joints to provide knee extension torque during stance and also flexion torque in swing phase. Lower limb kinematic and kinetic data plus data for temporospatial parameters were acquired from three test walks using each orthosis. Findings and outcomes: Walking speed, step length, and vertical and horizontal displacement of the pelvis decreased when walking with the powered stance control knee ankle foot orthosis compared to the knee ankle foot orthosis. When using the powered stance control knee ankle foot orthosis, the knee flexion achieved during swing and also the overall pattern of walking more closely matched that of normal human walking. The reduced walking speed may have caused the smaller compensatory motions detected when the powered stance control knee ankle foot orthosis was used. Conclusion: The new powered SCKAFO facilitated controlled knee flexion and extension during ambulation for a volunteer poliomyelitis person. Clinical relevance The powered stance control knee ankle foot orthosis has the potential to improve knee joint kinematics in persons with poliomyelitis when ambulating.

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A Model to Predict the Effect of Ankle Joint Misalignment on Calf Band Movement in Ankle-Foot Orthoses

Prosthetics and Orthotics International ◽

10.1080/03093640600983873 ◽

2007 ◽

Vol 31 (1) ◽

pp. 76-87 ◽

Cited By ~ 10

Author(s):

Stefania Fatone ◽

Andrew H. Hansen

Keyword(s):

Ankle Joint ◽

Walking Speed ◽

Sagittal Plane ◽

Plantar Flexion ◽

Dimensional Model ◽

Ankle Foot Orthosis ◽

Ankle Joints ◽

Ankle Foot Orthoses ◽

Foot Orthosis ◽

Anterior Posterior

Accurate alignment of anatomical and mechanical joint axes is one of the major biomechanical principles pertaining to articulated orthoses, yet knowledge of the potential effects of axis misalignment is limited. The purpose of this project was to model the effects of systematic linear (proximal-distal and anterior-posterior) misalignments of single axis mechanical ankle joints in an ankle-foot orthosis (AFO) in order to determine the degree and direction of calf band travel that would occur over a functional range of motion. Sagittal plane misalignments of the ankle joint centres of an AFO were simulated using a simple two-dimensional model for both a range of ankle angles and a typical able-bodied ankle kinematic curve for self-selected normal walking speed. The model assumed that no movement occurred between the foot and the foot-plate of the AFO. The model predicted that for anterior (positive horizontal) misalignments, dorsiflexion movements would cause the calf band to travel proximally (i.e., up the leg) and plantar flexion movements would cause the calf band to travel distally (i.e., down the leg). The opposite was predicted for posterior (negative horizontal) misalignments. Proximal (positive vertical) misalignments would cause only distal movements of the calf band while distal (negative vertical) misalignments would cause only proximal movements of the calf band. Anterior-posterior misalignments were found to have a much larger effect on the amount of calf band travel than proximal-distal misalignments.

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The effect of tuning ankle foot orthoses–footwear combination on the gait parameters of children with cerebral palsy

Prosthetics and Orthotics International ◽

10.1177/0309364612450706 ◽

2012 ◽

Vol 37 (2) ◽

pp. 95-107 ◽

Cited By ~ 30

Author(s):

Nicola Eddison ◽

Nachiappan Chockalingam

Keyword(s):

Cerebral Palsy ◽

Foot Orthoses ◽

Ankle Foot Orthosis ◽

Gait Parameters ◽

Ankle Foot Orthoses ◽

Children With Cerebral Palsy ◽

Within Subjects ◽

Kinetics Of ◽

Kinematics And Kinetics ◽

Foot Orthosis

Background:There are a wide variety of ankle foot orthoses used in clinical practice which are characterised by their design, the material used and the stiffness of that material. Changing any of these three components will alter the effect of the ankle foot orthosis on gait.Objectives:The purpose of this article is to provide an overview on the available research on ankle foot orthosis–footwear combination tuning on the gait characteristics of children with cerebral palsy through a structured review.Study Design:Literature review.Methods:A thorough search of previous studies published in English was conducted within all major databases using relevant phrases without any limits for the dates. These searches were then supplemented by tracking all key references from the appropriate articles identified including hand searching of published books where relevant.Results:To date, there are 947 papers in the literature pertaining to the study of ankle foot orthosis. Of these, 153 investigated the use of ankle foot orthosis for children with cerebral palsy. All the studies included in this review were of a within-subjects design and the evidence levels were generally low.Conclusions:The overall results suggested that ankle foot orthosis–footwear combination tuning has the potential to improve the kinematics and kinetics of gait in children with cerebral palsy. However, the review highlights a lack of well-designed and adequately powered studies.Clinical relevanceWhile the research described in this article indicates an improvement in the gait of children with cerebral palsy following tuning of their ankle foot orthosis–footwear combination, there is still a paucity of research with quantitative data on the effects of kinematics and kinetics of ankle foot orthosis–footwear combination tuning, comparing untuned ankle foot orthosis–footwear combinations with tuned ankle foot orthosis–footwear combination. Furthermore, current research does not identify the effect of tuning on energy efficiency.

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