Simulation Based Design of a Pediatric-Sized Hydraulic Ankle-Foot Orthosis

2016 ◽  
Author(s):  
Brett Cullen Neubauer ◽  
William K. Durfee
Keyword(s):  
Performance Metrics ◽  
Preliminary Design ◽  
Ankle Foot Orthosis ◽  
Simulation Based Design ◽  
Simulation Based ◽  
Ankle Foot Orthoses ◽  
Computer Controlled ◽  
Optimal Stiffness ◽  
Foot Orthosis ◽  
Gait Impairments

Cerebral palsy can cause gait impairments in children that require the prescription of passive ankle-foot orthoses. This project aims to develop a pediatric-sized hydraulic active ankle-foot orthosis with computer-controlled stiffness. The orthosis will allow a clinician to investigate a range of AFO stiffnesses while collecting gait performance metrics to determine the optimal stiffness value for the AFO prescription. The ankle-foot orthosis uses hydraulic technology to generate the large required torques in a light, compact package. The preliminary design uses additive manufacturing to further reduce the weight of the manifolds on the medial and lateral sides of the ankle. The simulation prototype of the design illustrated that the orthosis should be capable of generating 91 Nm of ankle torque and a maximum angular velocity of 483 °/sec. The device will be a valuable resource in the clinic, saving time and resources in the AFO prescription process while improving the healthcare of the patient.

Actuation Timing Strategies for a Portable Powered Ankle Foot Orthosis

2011 ◽  
Author(s):  
Emily A. Morris ◽  
K. Alex Shorter ◽  
Yifan Li ◽  
Elizabeth T. Hsiao-Wecksler ◽  
Geza F. Kogler ◽  
...  
Keyword(s):  
State Estimation ◽  
Event Detection ◽  
Cross Correlation ◽  
State Information ◽  
Ankle Foot Orthosis ◽  
Ankle Foot Orthoses ◽  
Timing Strategies ◽  
Future Work ◽  
Foot Orthosis ◽  
Gait Impairments

Ankle-foot orthoses (AFOs) are used to assist persons with lower-limb neuromuscular impairments. We have developed the portable powered AFO (PPAFO). This device uses a bidirectional pneumatic actuator powered by a CO2 bottle to provide dorsiflexor and plantarflexor torque assistance. The PPAFO operates tether-free, allowing for use outside of the laboratory. This system has been tested on one impaired and multiple healthy subjects. Timing of the assistance provided by the PPAFO has been determined by: 1) direct event detection using sensor feedback with threshold triggers, and 2) state estimation in which gait events are estimated using a cross-correlation based algorithm. Direct event detection, while simple to implement, can be unreliable for subjects with certain gait impairments. State estimation, while more complicated to implement, provides access to state information that cannot be directly measured by the AFO, which allows for greater flexibility in assistance timing. Current hardware limitations and future work are also discussed.

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

1996 ◽  
Vol 20 (2) ◽  
pp. 132-137 ◽  
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.

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.

Content analysis of child user and carer perspectives of ankle–foot orthoses

2020 ◽  
pp. 030936462095290
Author(s):  
David Lahoud ◽  
Christine HE Teng ◽  
Erez Nusem ◽  
Joshua Burns ◽  
Cara Wrigley ◽  
...  
Keyword(s):  
Content Analysis ◽  
User Experience ◽  
Secondary Data ◽  
Foot Orthoses ◽  
Ankle Foot Orthosis ◽  
Online Platforms ◽  
Ankle Foot Orthoses ◽  
Data Points ◽  
Negative Feelings ◽  
Foot Orthosis

Background: The evaluation of ankle–foot orthoses is primarily focused on biomechanical performance, with comparatively less studies pertaining to users’ quality of life and experiential factors. Objectives: To investigate how child users regard acquisition and use of ankle–foot orthoses through the perspectives of child users, parents/carers and practitioners. Study design: Inductive content analysis of secondary data. Methods: Child user and parent/carer perspectives, as communicated by them and by practitioners, were collected from online platforms and formal publications. Data and themes were analysed through an inductive approach. Investigator triangulation was used to increase trustworthiness and reduce bias. Results: We found and analysed 223 data points from 30 informal online platforms and 15 formal publications. These data clustered into five key themes relating to user experience with ankle–foot orthoses, including materials, structure, aesthetics, service and impact. Child users had mixed opinions about ankle–foot orthoses, reporting satisfaction with the functional improvements resulting from ankle–foot orthosis wear, while noting negative feelings from the experience of acquiring and using the device. Conclusion: This research suggests that considering the five themes in ankle–foot orthosis provision could improve the child user experience, inform future ankle–foot orthosis design, and improve clinical outcomes.

scholarly journals Gastrocnemius operating length with ankle foot orthoses in cerebral palsy

2016 ◽  
Vol 41 (3) ◽  
pp. 274-285 ◽  
Author(s):  
Hwan Choi ◽  
Tishya Anne Leong Wren ◽  
Katherine Muterspaugh Steele
Keyword(s):  
Cerebral Palsy ◽  
Classification System ◽  
Daily Life ◽  
System Level ◽  
Foot Orthoses ◽  
Functional Classification ◽  
Ankle Foot Orthosis ◽  
Ankle Foot Orthoses ◽  
Children With Cerebral Palsy ◽  
Foot Orthosis

Background:Many individuals with cerebral palsy wear ankle foot orthoses during daily life. Orthoses influence joint motion, but how they impact muscle remains unclear. In particular, the gastrocnemius is commonly stiff in cerebral palsy. Understanding whether orthoses stretch or shorten this muscle during daily life may inform orthosis design and rehabilitation.Objectives:This study investigated the impact of different ankle foot orthoses on gastrocnemius operating length during walking in children with cerebral palsy.Study design:Case series, within subject comparison of gastrocnemius operating length while walking barefoot and with two types of ankle foot orthoses.Methods:We performed gait analyses for 11 children with cerebral palsy. Each child was fit with two types of orthoses: a dynamic ankle foot orthosis (Cascade dynamic ankle foot orthosis) and an adjustable dynamic response ankle foot orthosis (Ultraflex ankle foot orthosis). Musculoskeletal modeling was used to quantify gastrocnemius musculotendon operating length and velocity with each orthosis.Results:Walking with ankle foot orthoses could stretch the gastrocnemius more than barefoot walking for some individuals; however, there was significant variability between participants and orthoses. At least one type of orthosis stretched the gastrocnemius during walking for 4/6 and 3/5 of the Gross Motor Functional Classification System Level I and III participants, respectively. AFOs also reduced peak gastrocnemius lengthening velocity compared to barefoot walking for some participants, with greater reductions among the Gross Motor Functional Classification System Level III participants. Changes in gastrocnemius operating length and lengthening velocity were related to changes in ankle and knee kinematics during gait.Conclusion:Ankle foot orthoses impact gastrocnemius operating length during walking and, with proper design, may assist with stretching tight muscles in daily life.Clinical relevanceDetermining whether ankle foot orthoses stretch tight muscles can inform future orthotic design and potentially provide a platform for integrating therapy into daily life. However, stretching tight muscles must be balanced with other goals of orthoses such as improving gait and preventing bone deformities.

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

2007 ◽  
Vol 31 (1) ◽  
pp. 76-87 ◽  
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.

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

2012 ◽  
Vol 37 (2) ◽  
pp. 95-107 ◽  
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.

scholarly journals A new structural concept in moulded fixed ankle foot orthoses and comparison of the bending stiffness of four constructions

2004 ◽  
Vol 28 (1) ◽  
pp. 44-48 ◽  
Author(s):  
R. E. Major ◽  
P. J. Hewart ◽  
A. M. Macdonald
Keyword(s):  
Carbon Fibre ◽  
Gait Cycle ◽  
Test Procedure ◽  
The Other ◽  
Foot Orthoses ◽  
Mechanical Stiffness ◽  
Ankle Foot Orthosis ◽  
Ankle Foot Orthoses ◽  
Structural Concept ◽  
Foot Orthosis

There are many reasons why a rigid ankle foot orthosis (AFO) may be prescribed. In some cases it is desirable that the rigidity is sufficient to maintain a constant ankle position throughout the gait cycle. There is a need to determine a design of cosmetic, lightweight AFO that provides the necessary stiffness whilst being acceptable to the patient, encouraging continued wear with the resultant benefits. This paper describes an investigation of AFO resistance to dorsiflexion, comparing the stiffness of an AFO with forward trim lines, two designs of reinforced AFOs and an AFO with forward trim lines and an external ankle strap. One reinforced AFO had corrugations moulded in the polypropylene around the ankle, the other had carbon fibre inserts attached to the inside of the polypropylene. The emphasis was on testing the mechanical stiffness of the four AFO designs: the test procedure did not mimic the patterns of AFO loading during gait. Each design was tested in the same manner by the same examiner. The AFO with forward trimlines and an ankle strap displayed similar stiffness to the carbon fibre reinforced AFO and both were stiffer than the other two designs.

scholarly journals Manufacturing and analysis of carbon fiber knee ankle foot orthosis

2018 ◽  
Vol 7 (4) ◽  
pp. 2236 ◽  
Author(s):  
Ayad M. Takhakh ◽  
Saif M. Abbas
Keyword(s):  
Mechanical Properties ◽  
Spinal Cord ◽  
Carbon Fiber ◽  
Tensile Tests ◽  
Foot Orthoses ◽  
Well Control ◽  
Ankle Foot Orthosis ◽  
Cord Injury ◽  
Ankle Foot Orthoses ◽  
Foot Orthosis

Knee ankle foot orthoses (KAFOs) are used by paraplegia patients with low level spinal cord injury and having well control of the stem muscles. Four layers of carbon fiber with C- orthocryl lamination resin are used for manufacturing the knee ankle foot orthoses in this work. The mechanical properties of most of the components materials were estimated with the aid of fatigue and tensile test machines. Results of the tensile tests showed that the mechanical properties: yield stress, ultimate strength and modulus of elasticity were 92MPa, 105.7MPa and 2GPa respectively. The value of amidst pressure between the patient limb and the manufactured KAFO was measured using (F-socket) Mat scan sensor and these values of pressure were (663kPa) and (316kPa) for the thigh and calf regions respectively. 

Comparison of ankle–foot orthoses with plantar flexion stop and plantar flexion resistance in the gait of stroke patients: A randomized controlled trial

2018 ◽  
Vol 42 (5) ◽  
pp. 544-553 ◽  
Author(s):  
Sumiko Yamamoto ◽  
Souji Tanaka ◽  
Naoyuki Motojima
Keyword(s):  
Controlled Trial ◽  
Plantar Flexion ◽  
Upper Body ◽  
Foot Orthoses ◽  
Stroke Patients ◽  
Subacute Phase ◽  
Ankle Foot Orthosis ◽  
Randomized Controlled ◽  
Ankle Foot Orthoses ◽  
Foot Orthosis

Background: The effect of plantar flexion resistance of ankle–foot orthoses on the ankle and knee joints is well known, but its effect on the hip joint and upper body movement during the gait of stroke patients remains unclear. Objectives: To compare the effect of an ankle–foot orthosis with plantar flexion stop and an ankle–foot orthosis with plantar flexion resistance on the gait of stroke patients in the subacute phase. Study design: Randomized controlled trial. Methods: A total of 42 stroke patients (mean age = 59.9 ± 10.9 years, 36 men and 4 women) in the subacute phase were randomized to each ankle–foot orthosis group in a parallel controlled trial with no blinding. Patients received gait training from physiotherapists using the specified ankle–foot orthosis for 2 weeks. Shod gait without an ankle–foot orthosis before training and gait with an ankle–foot orthosis after training were measured by three-dimensional motion analysis. Results: A total of 20 patients were analyzed in each group. Significant differences were found in pelvic and thoracic tilt angles between the two groups. Compared with the gait without an ankle–foot orthosis, the pelvis showed forward tilt when patients walked with an ankle–foot orthosis with plantar flexion stop, and the thorax showed decreased forward tilt when the patients walked with an ankle–foot orthosis with plantar flexion resistance. Conclusion: The difference in ankle–foot orthosis function in sagittal plantar flexion resistance affected the alignment of the upper body and the pelvis during the gait of stroke patients in the subacute phase. Clinical relevance Maintaining upright posture is important in gait rehabilitation. The findings of this study suggest that the ankle–foot orthosis with plantar flexion resistance facilitated better alignment of the upper body and pelvis during the gait of stroke patients in subacute phase. This type of ankle–foot orthosis could be beneficial for patients with malalignment of the upper body and pelvis.

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