Design of an Automated Device to Measure Sagittal Plane Stiffness of an Articulated Ankle-Foot Orthosis

2010 ◽  
Vol 34 (4) ◽  
pp. 439-448 ◽  
Author(s):  
Toshiki Kobayashi ◽  
Aaron k. L. Leung ◽  
Yasushi Akazawa ◽  
Hisashi Naito ◽  
Masao Tanaka ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Range Of Motion ◽  
Fatigue Testing ◽  
Sagittal Plane ◽  
Testing Machine ◽  
Ankle Foot Orthosis ◽  
Resistive Torque ◽  
Angular Velocities ◽  
Rotary Plate ◽  
Foot Orthosis

The purpose of this study was to design a new automated stiffness measurement device which could perform a simultaneous measurement of both dorsi- and plantarflexion angles and the corresponding resistive torque around the rotational centre of an articulated ankle-foot orthosis (AAFO). This was achieved by controlling angular velocities and range of motion in the sagittal plane. The device consisted of a hydraulic servo fatigue testing machine, a torque meter, a potentiometer, a rotary plate and an upright supporter to enable an AAFO to be attached to the device via a surrogate shank. The accuracy of the device in reproducing the range of motion and angular velocity was within 4% and 1% respectively in the range of motion of 30&dG (15&dG plantarflexion to 15&dG dorsiflexion) at the angular velocity of 10&dG /s, while that in the measurement of AAFO torque was within 8% at the 0&dG position. The device should prove useful to assist an orthotist or a manufacturer to quantify the stiffness of an AAFO and inform its clinical use.

Design of a manual device to measure ankle joint stiffness and range of motion

2011 ◽  
Vol 35 (4) ◽  
pp. 478-481 ◽  
Author(s):  
Toshiki Kobayashi ◽  
Aaron KL Leung ◽  
Stephen W Hutchins
Keyword(s):  
Range Of Motion ◽  
Ankle Joint ◽  
High Reliability ◽  
Intraclass Correlation ◽  
Joint Stiffness ◽  
Technical Note ◽  
Steering Wheel ◽  
Ankle Foot Orthosis ◽  
Resistive Torque ◽  
Rotary Plate

Background and Aim: Ankle joint stiffness and its range of motion (ROM) are commonly assessed to determine the appropriate mechanical characteristics required in an effective ankle-foot orthosis (AFO) prescription. The aim of this technical note is to present the design of a manual device that enables their convenient measurement in the clinical setting and to demonstrate its reliability.Technique: The manual device was designed with a torquemeter, a potentiometer, a steering wheel, a rotary plate, and a foot plate. The measurement of resistive torque at 0° (neutral), 5° (dorsiflexion) and 10° (dorsiflexion) ankle angular positions demonstrated the high reliability of the device with Intraclass Correlation Coefficient (ICC) (1,k) values over 0.97.Discussion: Quantitative measurement of ankle joint stiffness and ROM by this manual device would provide objective information that could potentially assist AFO prescriptions. A future study should investigate how to incorporate the measurement obtained from the device into the prescription of an AFO.

scholarly journals Effectiveness of an ankle–foot orthosis on walking in patients with stroke: a systematic review and meta-analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yoo Jin Choo ◽  
Min Cheol Chang
Keyword(s):  
Stride Length ◽  
Walking Speed ◽  
Sagittal Plane ◽  
Meta Analysis ◽  
Step Length ◽  
Stride Time ◽  
Plane Angle ◽  
Ankle Foot Orthosis ◽  
Biomechanical Parameters ◽  
Foot Orthosis

AbstractWe conducted a meta-analysis to investigate the effectiveness of ankle–foot orthosis (AFO) use in improving gait biomechanical parameters such as walking speed, mobility, and kinematics in patients with stroke with gait disturbance. We searched the MEDLINE (Medical Literature Analysis and Retrieval System Online), CINAHL (Cumulative Index to Nursing and Allied Health Literature), Cochrane, Embase, and Scopus databases and retrieved studies published until June 2021. Experimental and prospective studies were included that evaluated biomechanics or kinematic parameters with or without AFO in patients with stroke. We analyzed gait biomechanical parameters, including walking speed, mobility, balance, and kinematic variables, in studies involving patients with and without AFO use. The criteria of the Cochrane Handbook for Systematic Reviews of Interventions were used to evaluate the methodological quality of the studies, and the level of evidence was evaluated using the Research Pyramid model. Funnel plot analysis and Egger’s test were performed to confirm publication bias. A total of 19 studies including 434 participants that reported on the immediate or short-term effectiveness of AFO use were included in the analysis. Significant improvements in walking speed (standardized mean difference [SMD], 0.50; 95% CI 0.34–0.66; P < 0.00001; I2, 0%), cadence (SMD, 0.42; 95% CI 0.22–0.62; P < 0.0001; I2, 0%), step length (SMD, 0.41; 95% CI 0.18–0.63; P = 0.0003; I2, 2%), stride length (SMD, 0.43; 95% CI 0.15–0.71; P = 0.003; I2, 7%), Timed up-and-go test (SMD, − 0.30; 95% CI − 0.54 to − 0.07; P = 0.01; I2, 0%), functional ambulation category (FAC) score (SMD, 1.61; 95% CI 1.19–2.02; P < 0.00001; I2, 0%), ankle sagittal plane angle at initial contact (SMD, 0.66; 95% CI 0.34–0.98; P < 0.0001; I2, 0%), and knee sagittal plane angle at toe-off (SMD, 0.39; 95% CI 0.04–0.73; P = 0.03; I2, 46%) were observed when the patients wore AFOs. Stride time, body sway, and hip sagittal plane angle at toe-off were not significantly improved (p = 0.74, p = 0.07, p = 0.07, respectively). Among these results, the FAC score showed the most significant improvement, and stride time showed the lowest improvement. AFO improves walking speed, cadence, step length, and stride length, particularly in patients with stroke. AFO is considered beneficial in enhancing gait stability and ambulatory ability.

Biomechanical Comparison of a New Dynamic Ankle Orthosis to a Standard Ankle-Foot Orthosis During Walking

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Chloe L. Chung ◽  
Denis J. DiAngelo ◽  
Douglas W. Powell ◽  
Max R. Paquette
Keyword(s):  
Angular Velocity ◽  
Cartilage Damage ◽  
Three Dimensional ◽  
Frontal Plane ◽  
Ankle Injuries ◽  
Ankle Motion ◽  
Ankle Foot Orthosis ◽  
Plantar Pressures ◽  
Biomechanical Comparison ◽  
Foot Orthosis

Abstract Patients who sustain irreversible cartilage damage or joint instability from ankle injuries are likely to develop ankle osteoarthritis (OA). A dynamic ankle orthosis (DAO) was recently designed with the intent to offload the foot and ankle using a distractive force, allowing more natural sagittal and frontal plane ankle motion during gait. To evaluate its efficacy, this study compared ankle joint kinematics and plantar pressures among the DAO, standard double upright ankle-foot orthosis (DUAFO), and a nonorthosis control (CON) condition in healthy adults during walking. Ten healthy subjects (26 ± 3.8 yr; 69.6 ± 12.7 kg; and 1.69 ± 0.07 m) walked on a treadmill at 1.4 m/s in three orthosis conditions: CON, DAO, and DUAFO. Ankle kinematics were assessed using a three-dimensional (3D) motion capture system and in-shoe plantar pressures were measured for seven areas of the foot. DAO reduced hallux peak plantar pressures (PPs) compared to CON and DUAFO. PPs under toes 2–5 were smaller in DAO than DUAFO, but greater in DUAFO compared to CON. Early stance peak plantarflexion (PF) angular velocity was smaller in DAO compared to CON and DUAFO. Eversion (EV) ROM was much smaller in DUAFO compared to CON and DAO. Early stance peak eversion angular velocity was smaller in DAO and much smaller in DUAFO compared to CON. This study demonstrates the capacity of the DAO to provide offloading during ambulation without greatly affecting kinematic parameters including frontal plane ankle motion compared to CON. Future work will assess the effectiveness of the DAO in a clinical osteoarthritic population.

scholarly journals The effect of floor reaction ankle foot orthosis on postural control in children with spastic cerebral palsy

2011 ◽  
Vol 36 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Mahmood Bahramizadeh ◽  
Mohammad Ebrahim Mousavi ◽  
Mehdi Rassafiani ◽  
Gholamreza Aminian ◽  
Ismail Ebrahimi ◽  
...  
Keyword(s):  
Cerebral Palsy ◽  
Postural Control ◽  
Sagittal Plane ◽  
Standing Position ◽  
Force Platform ◽  
Spastic Cerebral Palsy ◽  
Phase Plate ◽  
Ankle Foot Orthosis ◽  
Objective Evidence ◽  
Foot Orthosis

Background: Children with cerebral palsy (CP) often demonstrate postural control difficulties. Orthotic management may assist in improving postural control in these children.Objective: The purpose of this investigation was to examine the influence of floor reaction ankle foot orthosis (FRAFO) on postural flexion called the crouch position in children with CP.Study Design: Quasi-experimental.Methods: Eight children with spastic diplegic CP and eight matched typically developing children participated in this study. Postural control of children with CP was assessed in a static standing position on a force platform with/without a FRAFO. The parameters used were centre of pressure (CoP) measures, calculated from force platform signals including the standard deviation (SD) of excursion; phase plate portrait and SD of velocity in anteroposterior (AP) and mediolateral (ML) directions.Results: The maximum knee extension was statistically significant in children with CP when barefoot compared to wearing braced footwear ( p < 0.05, t = 10.01). AP and ML displacement, AP velocity and AP phase plate portrait of CoP were not statistically significant between children with CP with/without a FRAFO ( p < 0.05).Conclusion: FRAFO can improve the alignment of the knee, but may not be helpful in improving postural control in children with CP in a short time period.Clinical relevanceThis article will provide objective evidence about the effect of FRAFO on the postural control in children with CP. Therapists can use FRAFO to effectively decrease the knee joint angle in the sagittal plane in children with spastic CP, but cannot use it to improve the postural control.

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.

scholarly journals Mechanistic insights into the modulatory role of the mechanoreflex on central hemodynamics using passive leg movement in humans

2018 ◽  
Vol 125 (2) ◽  
pp. 545-552 ◽  
Author(s):  
Nicholas T. Kruse ◽  
William E. Hughes ◽  
Darren P. Casey
Keyword(s):  
Cardiac Output ◽  
Angular Velocity ◽  
Range Of Motion ◽  
Joint Angle ◽  
Feedback Mechanism ◽  
Fascicle Length ◽  
Percent Change ◽  
Muscle Fascicle ◽  
Angular Velocities ◽  
Leg Movement

The aim of this study was to examine the independent contributions of joint range of motion (ROM), muscle fascicle length (MFL), and joint angular velocity on mechanoreceptor-mediated central cardiovascular dynamics using passive leg movement (PLM) in humans. Twelve healthy men (age: 23 ± 2 yr, body mass index: 23.7 kg/m2) performed continuous PLM at various randomized joint angle ROMs (0°–50° vs. 50°–100° vs. 0°–100°) and joint angular velocities (“fast”: 200°/s vs. “slow”: 100°/s). Measures of heart rate (HR), cardiac output (CO), and mean arterial pressure (MAP) were recorded during baseline and during 60 s of PLM. MFL was calculated from muscle architectural measurements of fascicle pennation angle and tissue thickness (Doppler ultrasound). Percent change in MFL increased across the transition of PLM from 0° to 50° (15 ± 3%; P < 0.05) and from 0° to 100° knee flexion (27 ± 4%; P < 0.05). The average peak percent change in HR (increased, approx. +5 ± 2%; P < 0.05), CO (increased, approx. +5 ± 3%; P < 0.05), and MAP (decreased, approx. −2 ± 2%; P < 0.05) were similar between fast versus slow angular velocities when compared against shorter absolute joint ROMs (i.e., 0°–50° and 50°–100°). However, the condition that exhibited the greatest angular velocity in combination with ROM (0°–100° at 200°/s) elicited the greatest increases in HR (+13 ± 2%; P < 0.05) and CO (+12 ± 2%; P < 0.05) compared with all conditions. Additionally, there was a significant relationship between MFL and HR within 0°–100° at 200°/s condition ( r2 = 0.59; P < 0.05). These findings suggest that increasing MFL and joint ROM in combination with increased angular velocity via PLM are important components that activate mechanoreflex-mediated cardioacceleration and increased CO. NEW & NOTEWORTHY The mechanoreflex is an important autonomic feedback mechanism that serves to optimize skeletal muscle perfusion during exercise. The present study sought to explore the mechanistic contributions that initiate the mechanoreflex using passive leg movement (PLM). The novel findings show that progressively increasing joint angle range of motion and muscle fascicle length via PLM, in combination with increased angular velocity, are important components that activate mechanoreflex-mediated cardioacceleration and increase cardiac output in humans.

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.

Characterization of Thigh and Shank Segment Angular Velocity During Jump Landing Tasks Commonly Used to Evaluate Risk for ACL Injury

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Ariel V. Dowling ◽  
Julien Favre ◽  
Thomas P. Andriacchi
Keyword(s):  
Angular Velocity ◽  
Injury Risk ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Acl Injury ◽  
Simple Method ◽  
Jump Landing ◽  
Drop Jumps ◽  
Angular Velocities ◽  
Knee Abduction

The dynamic movements associated with anterior cruciate ligament (ACL) injury during jump landing suggest that limb segment angular velocity can provide important information for understanding the conditions that lead to an injury. Angular velocity measures could provide a quick and simple method of assessing injury risk without the constraints of a laboratory. The objective of this study was to assess the inter-subject variations and the sensitivity of the thigh and shank segment angular velocity in order to determine if these measures could be used to characterize jump landing mechanisms. Additionally, this study tested the correlation between angular velocity and the knee abduction moment. Thirty-six healthy participants (18 male) performed drop jumps with bilateral and unilateral landing. Thigh and shank angular velocities were measured by a wearable inertial-based system, and external knee moments were measured using a marker-based system. Discrete parameters were extracted from the data and compared between systems. For both jumping tasks, the angular velocity curves were well defined movement patterns with high inter-subject similarity in the sagittal plane and moderate to good similarity in the coronal and transverse planes. The angular velocity parameters were also able to detect differences between the two jumping tasks that were consistent across subjects. Furthermore, the coronal angular velocities were significantly correlated with the knee abduction moment (R of 0.28–0.51), which is a strong indicator of ACL injury risk. This study suggested that the thigh and shank angular velocities, which describe the angular dynamics of the movement, should be considered in future studies about ACL injury mechanisms.

Effect of ankle-foot orthosis on level walking in healthy subjects

2019 ◽  
Vol 233 (12) ◽  
pp. 1262-1268
Author(s):  
Mizuki Kato ◽  
Arinori Kamono ◽  
Naomichi Ogihara
Keyword(s):  
Ground Reaction Force ◽  
Healthy Subjects ◽  
Sagittal Plane ◽  
Reaction Force ◽  
Walking Ability ◽  
Vertical Ground Reaction Force ◽  
Walking Gait ◽  
Ankle Foot Orthosis ◽  
Heel Contact ◽  
Foot Orthosis

An ankle-foot orthosis is often prescribed in the rehabilitation of patients with neurological motor disorders such as hemiparesis. However, walking with a unilateral ankle-foot orthosis may not be effectively achieved just by trying to reproduce normal intact walking with a symmetrical gait pattern. Understanding skills to facilitate walking gait with a unilateral ankle-foot orthosis has implications for better rehabilitative interventions to help restore walking ability in patients with stroke. We, therefore, analyzed the kinematics and ground reaction forces of walking with and without an ankle-foot orthosis in healthy subjects to infer the possible skills to facilitate walking gait with a unilateral ankle-foot orthosis. Adult male participants were asked to walk with and without an ankle-foot orthosis across two force platforms set in a wooden walkway, and body kinematics and ground reaction force profiles in the sagittal plane were simultaneously recorded. We found that the forward tilting angle of the trunk at the time of toe-off of the leg with the ankle-foot orthosis was significantly larger than that of the leg without the ankle-foot orthosis, to adaptively compensate for the loss of ankle joint mobility due to the unilateral ankle-foot orthosis. Furthermore, the peak vertical ground reaction force at heel-contact was significantly larger in the leg without the ankle-foot orthosis than in the leg with the ankle-foot orthosis owing to the fact that the stance phase duration of the leg with the ankle-foot orthosis was relatively shorter. Such information may potentially be applied to facilitate walking training in stroke patients wearing a unilateral ankle-foot orthosis.

scholarly journals A Convertible Spinal Orthosis for Controlled Torso Rigidity

2013 ◽  
Vol 10 (1) ◽  
pp. 59-73
Author(s):  
Nicole I. Kern ◽  
Ronald J. Triolo ◽  
Rudi Kobetic ◽  
Musa Audu ◽  
Roger D. Quinn
Keyword(s):  
Range Of Motion ◽  
Free Motion ◽  
Lateral Bending ◽  
Mean Values ◽  
Ankle Foot Orthosis ◽  
Wear Time ◽  
Spinal Orthosis ◽  
Foot Orthosis

A traditional spinal orthosis in conjunction with a hip-knee-ankle-foot orthosis (HKAFO) improves posture in persons with paraplegia during standing and walking. It also limits the wearer's range of motion when worn during other activities, such as vehicle transfer or sitting and reaching for objects. In order to regain full torso flexibility the user would need to remove the spinal orthosis which can be arduous and time consuming. A Convertible Spinal Orthosis (CSO) that allows the user to switch between Locked rigid torso support and Unlocked free motion has been designed, fabricated and tested. It shows promise for increasing functionality, wear time and subject comfort. Analysis of movement has been performed with an able-bodied and a paraplegic subject wearing a rigid spinal orthosis, the CSO in both states, and without any bracing. Configuration state had the most impact on lateral bending. Mean values for the paraplegic subject of 27°, 38°, 48°, and 48° and for the able-bodied subject of 22°, 26°, 48°, and 45° were found for lateral bending of the upper torso relative to the thighs in theRigid,Locked,Unlocked, andNo-Bracestates, respectively.

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