scholarly journals An Improved Smart Ankle Foot Othosis Design Using Dual Fluid Power Cylinders

2010 ◽  
Vol 4 (2) ◽  
Author(s):  
Ricky Mehta ◽  
Eric L. Rohrs ◽  
Katarina F. Lipat ◽  
Evan C. Reed ◽  
Manish Paliwal
Keyword(s):  
Hydraulic Cylinder ◽  
Metatarsal Head ◽  
Foot Drop ◽  
Heel Strike ◽  
Neutral Position ◽  
Foot Orthoses ◽  
Ankle Foot Orthosis ◽  
Plantar Surface ◽  
Ankle Foot Orthoses ◽  
Foot Orthosis

To design a smart ankle-foot orthosis (SAFO) that improves upon current ankle-foot orthoses used to treat steppage gait. Current ankle-foot orthoses are subjected to significant stresses on the ankle region of the structure, causing discomfort and the possible failure of the AFO. Although these AFOs have a constant stiffness, they do not reduce the occurrence of slap foot, where the foot slaps on the ground rather than gradually lowering it. The SAFO is an active ankle-foot orthosis that allows the user’s foot to follow a normal gait cycle. It is designed to reduce stress at the ankle by allowing for movement of the foot beyond a 90 deg angle for plantarflexion. The hinged ankle-foot orthosis is incorporated with a novel dual hydraulic-cylinder system, two tension springs, and force sensitive resistors. The force sensors are placed at the hallux, first metatarsal head, fifth metatarsal base, and heel. The foot movement actuation follows the force applied to the plantar surface of the foot during gait. The sensor outputs are fed to a signal processor and control interface to coordinate the motor actuation with the forces exerted by the user. The motor turns the screw attached to the hydraulic cylinders, which, thereby, control the orifice size by moving a plate in the cylinder, thus, changing the resistance. The cylinder filled with air will be pressurized during the lean phase, as the orifices will be closed and will provide power just as a spring would during the heel-off phase. After the heel strike, the resistance of the fluid-filled cylinder is decreased to slowly lower the foot. Once the foot is flat, the resistance of the fluid-filled cylinder is increased to keep the foot in a position to allow for toe clearance. During the heel-off event, the air-filled cylinder will assist the user with the power to push off. When toe-off occurs, the fluid-filled cylinder will decrease the resistance to allow the tension springs to bring the foot back to neutral position. To power the motor and sensors, a rechargeable battery pack is placed in a waist bag. The SAFO’s flexible design uses a novel combination of hydraulic-pneumatic cylinders to prevent foot drop, and restore the user’s sense of normalcy by providing late stance plantarflexion and a return to neutral position in early swing phase.

The effect of custom carbon ankle-foot orthosis alignment on roll-over shape and center of pressure velocity

2020 ◽  
pp. 030936462097140
Author(s):  
Elizabeth Russell Esposito ◽  
Mitchell D Ruble ◽  
Andrea J Ikeda ◽  
Jason M Wilken
Keyword(s):  
Lower Limb ◽  
Sagittal Plane ◽  
Center Of Pressure ◽  
Heel Strike ◽  
Control Group ◽  
Foot Orthoses ◽  
Ankle Foot Orthosis ◽  
Ankle Foot Orthoses ◽  
Foot Orthosis ◽  
Center Of Pressure Velocity

Background: Maintaining an optimal rolling of the foot over the ground is thought to increase the stability and efficiency of pathologic gait. Ankle-foot orthoses are often prescribed to improve gait mechanics in individuals with lower extremity injuries; however, their design may compromise how the foot rolls over the ground. Objectives: The aim of this study was to investigate the effects of the sagittal plane ankle-foot orthosis alignment on roll-over shape and center of pressure velocity in individuals with lower limb reconstructions. Study design: Randomized cross-over study with a control group comparison. Methods: In total, 12 individuals with lower limb reconstruction who used a custom carbon ankle-foot orthosis and 12 uninjured controls underwent gait analysis. Ankle-foot orthosis users were tested in their clinically-provided ankle-foot orthosis alignment, with an alignment that was 3° more plantarflexed, and with an alignment that was 3° more dorsiflexed. Components of roll-over shape and center of pressure velocity were calculated from heel strike on the ankle-foot orthosis limb to contralateral heel strike. Results: Roll-over shape radius was not affected by 3° changes to alignment and was not significantly different from controls. Aligning the ankle-foot orthosis in more dorsiflexion than clinically provided resulted in a smaller peak center of pressure velocity that occurred later in stance. Conclusion: Individuals using custom carbon ankle-foot orthoses can accommodate 3° alterations in the dorsiflexion or plantarflexion alignment.

scholarly journals An anterior ankle-foot orthosis improves walking economy in Charcot–Marie–Tooth type 1A patients

2013 ◽  
Vol 38 (5) ◽  
pp. 387-392 ◽  
Author(s):  
Federica Menotti ◽  
Luca Laudani ◽  
Antonello Damiani ◽  
Teresa Mignogna ◽  
Andrea Macaluso
Keyword(s):  
Energy Cost ◽  
Foot Drop ◽  
Foot Orthoses ◽  
Charcot Marie Tooth ◽  
Ankle Foot Orthosis ◽  
Ankle Foot Orthoses ◽  
Tooth Type ◽  
Walking Economy ◽  
Foot Orthosis ◽  
Walking Energy Cost

Background: Ankle-foot orthoses are commonly prescribed in Charcot–Marie–Tooth type 1A disease to improve quality of walking and reduce the risk of falling due to the foot drop. Objectives: This study aimed at assessing the effect of an anterior ankle-foot orthosis on walking economy in a group of Charcot–Marie–Tooth type 1A patients. Study design: Within-group comparisons. Methods: 7 Charcot–Marie–Tooth type 1A patients (four women and three men; 37 ± 11 years; age range = 22–53 years) were asked to walk on a circuit at their self-selected speeds (‘slow’, ‘comfortable’ and ‘fast’) in two walking conditions: (1) with shoes only and (2) with Taloelast® anterior elastic ankle-foot orthoses. Speed of walking and metabolic cost of walking energy cost per unit of distance were assessed at the three self-selected speeds of walking for both walking conditions. Results: Speed of walking at the three self-selected speeds did not differ between shoes only and anterior elastic ankle-foot orthoses, whereas walking energy cost per unit of distance at comfortable speed was lower in patients using anterior elastic ankle-foot orthoses with respect to shoes only (2.39 ± 0.22 vs 2.70 ± 0.19 J kg−1 m−1; P < 0.05). Conclusions: In Charcot–Marie–Tooth type 1A patients, the use of anterior elastic ankle-foot orthoses improved walking economy by reducing the energy cost of walking per unit of distance, thus reflecting a lower level of metabolic effort and improved mechanical efficiency in comparison with shoes only. Clinical relevance From a practical perspective, Charcot–Marie–Tooth type 1A patients with anterior elastic ankle-foot orthoses can walk for a longer duration with a lower level of physical effort. Improvements in walking economy due to ankle-foot orthoses are likely a consequence of the reduction in steppage gait.

Influence of modified solid ankle-foot orthosis to be used with and without shoe on dynamic balance and gait characteristic in asymptomatic people

2012 ◽  
Vol 37 (2) ◽  
pp. 145-151
Author(s):  
Mina Arvin ◽  
Mojtaba Kamyab ◽  
Vahideh Moradi ◽  
Behnam Hajiaghaei ◽  
Nader Maroufi
Keyword(s):  
Reaction Force ◽  
Center Of Gravity ◽  
Neutral Position ◽  
Foot Orthoses ◽  
Balance Performance ◽  
Ankle Foot Orthosis ◽  
Sit To Stand ◽  
Gait Characteristic ◽  
Ankle Foot Orthoses ◽  
Foot Orthosis

Background: Ankle-foot orthoses are usually used in combination with footwear. Shoe design can have a significant effect on kinematics of the lower limb joints and line of action of the ground reaction force during walking. But, ankle-foot orthosis–footwear combination is not appropriate for indoor barefoot walking in some Asian cultures. In this study, we have modified a solid ankle-foot orthosis in order to set it in the same position as a solid ankle-foot orthosis–footwear combination. Objective: To investigate the effect of a modified solid ankle-foot orthosis; a solid ankle-foot orthosis which can be locked in different positions on gait and balance performance in comparison with a conventional solid ankle-foot orthosis, a common solid ankle-foot orthosis–shoe combination in asymptomatic adults. Study Design: Cross sectional. Methods: Two standard solid ankle-foot orthoses were manufactured with the ankle joint in neutral position. Then, one of these solid ankle-foot orthoses was modified in order to allow locking in a different alignment. Walk across, limit of stability, and sit-to-stand tests of the balance master system were performed while participants wore the modified solid ankle-foot orthosis aligned in 5°–7° anterior inclination without a shoe and a conventional solid ankle-foot orthosis–shoe combination. Results: There was no significant change in walking speed, step length, and step width with the conventional and modified solid ankle-foot orthoses. In addition, movement velocity and maximum excursion of the center of gravity during the limit of stability test were not different, although the maximal forward excursion of the center of gravity was longer when wearing the modified solid ankle-foot orthosis compared to the conventional solid ankle-foot orthosis–shoe combination ( P = 0.000). Sway velocity of the center of gravity did not change during the sit-to-stand test. Conclusion: The results demonstrated that the modified solid ankle-foot orthosis had the same effects as the conventional solid ankle-foot orthosis–shoe combination on the gait and balance performance of asymptomatic adults. Clinical relevance The findings of the present study can be used as the basis for further investigations on the efficacy of the modified solid ankle-foot orthoses in different neuromuscular populations in order to help people who do not wear shoes at home, as is the custom in some Asian cultures.

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.

836 Custom Fabricated Open Anterior Ankle Foot Orthosis to Promote Early Mobility with Lower Extremity Grafts

2020 ◽  
Vol 41 (Supplement_1) ◽  
pp. S256-S257
Author(s):  
Lisa LePage
Keyword(s):  
Lower Extremity ◽  
Direct Contact ◽  
Weight Bearing ◽  
Heel Strike ◽  
Early Mobility ◽  
Foot Placement ◽  
Ankle Foot Orthosis ◽  
Plantar Surface ◽  
Distal Aspect ◽  
Foot Orthosis

Abstract Introduction Distal lower extremity STSG’s present a challenge with the balance of early mobility and immobilization of the ankle. Traditional commercially available ambulation boots or pre-fabricated orthotics may impose circumferential compression endangering graft integrity. Custom fabricated posterior AFO’s comprised of thermoplastic, scotch cast or fiberglass materials are not recommended for weight-bearing of the lower extremity during mobility/ambulation. What may also hinder promotion of early mobility is having a multitude of injuries or advanced age with decreased ability to adhere to a LE NWB status. An anterior approach to immobilization of the ankle was thought of to free the plantar surface of the foot for weight-bearing. The open concept of the orthosis itself minimizes direct contact with the involved LE graft. This promotes graft integrity during mobility with ankle immobilization. Methods Materials: Thermoplastic material, scissors, strapping, dense adhesive foam, adhesive Velcro and a heat gun. Fabrication: Measure the point of distance between where the desired proximal end of the orthosis would be to the patient’s metatarsal heads on the dorsal aspect of the foot; double it to calculate the amount of material needed. The width of the material should be approx. 3 to 4 inches. Warm material and tri-fold it together reducing width to approx. 1 ½ to 2 inches to increase stability. Shape the folded material into a continuous oval and place on the patient’s distal LE. As the material cools, shape the oval away from the medial/ lateral aspects of the distal LE restricting the points of contact to the anterior most proximal and distal aspect of the desired splint parameters. Remove once cooled and add dense adhesive foam to the 2 points of contact that will rest against the patient. This will allow for a slight area of “give” against the patient during weight-bearing of the LE/foot. Velcro and straps are added to the proximal/distal ends of the oval; heating the adhesive side will imbed the Velcro allowing increased durability with repeated donning/doffing. Results The open construction of this orthosis allows different degrees of weight-bearing eliminating contact with the distal LE STSG. The forefoot and heel are available to weight bear safely within the confines of the open anterior ankle foot orthosis. Conclusions Patients have been trialed with/without an AD with success in the achievement of ankle immobilization with mobility. Weight-bearing instructions that accompany this splint wear is foot placement rather than a normal heel strike cadence to avoid undue pressure at the proximal aspect of the splint on the lower extremity. Applicability of Research to Practice This splint has been successfully utilized for immobilization without compromise to STSG integrity due to the anterior open support it offers the ankle. Perhaps this concept could be applied to other joints to avoid direct contact of the splint with STSG during the initial stages of healing.

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.

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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