scholarly journals Effects of the degree of freedom and assistance characteristics of powered ankle-foot orthoses on gait stability

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242000
Author(s):  
Ho Seon Choi ◽  
Yoon Su Baek
Keyword(s):  
Subtalar Joint ◽  
Center Of Pressure ◽  
Pearson Correlation ◽  
Critical Role ◽  
Angular Acceleration ◽  
Degree Of Freedom ◽  
Measurement Unit ◽  
Foot Orthoses ◽  
Gait Stability ◽  
Ankle Foot Orthoses

We studied the use of powered ankle-foot orthoses (PAFOs) and walking stability of the wearers, focusing on the ankle joint, which is known to play a critical role in gait stability. Recognizing that the subtalar joint is an important modulator of walking stability, we conducted the walking experiment on a treadmill by applying varying assistance techniques to the 2-degree-of-freedom (DOF) PAFO, which has the subtalar joint as the rotating axis, and the commonly used 1-DOF PAFO. The participants were 8 healthy men (mean±SD: height, 174.8±7.1 cm; weight, 69.8±6.5 kg; and age, 29.1±4.8 years) with no history of gait abnormality. Center of pressure (COP) was measured with an in-shoe pressure sensor, and stability was estimated on the basis of the angular acceleration measured with the inertial measurement unit attached to the trunk. The experimental results of the 2-DOF PAFO, with or without assistance, showed a significantly higher stability than those of the 1-DOF PAFO (up to 23.78%, p<0.0326). With the 1-DOF PAFO, the stability deteriorated with the increase in the degree of assistance provided. With the 2-DOF PAFO, this tendency was not observed. Thus, the importance of the subtalar joint was proven using PAFOs. The mean position analysis of the COP during the stance phase confirmed that the COP highly correlated with stability (Pearson correlation coefficient: −0.6607). Thus, we conclude that only the 2-DOF PAFO can maintain walking stability, regardless of the assistance characteristics, by preserving the COP in the medial position through eversion. Awareness regarding the role of the subtalar joint is necessary during the manufacture or use of PAFOs, as lack of awareness could lead to the degradation of the wearer’s gait stability, regardless of effective assistance, and deteriorate the fundamental functionality of PAFO.

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 Effects of Hinged versus Floor-Reaction Ankle-Foot Orthoses on Standing Stability and Sit-to-Stand Performance in Children with Spastic Diplegic Cerebral Palsy

2022 ◽  
Vol 19 (1) ◽  
pp. 542
Author(s):  
Yu-Lin Wang ◽  
Wen-Chou Chi ◽  
Chiung-Ling Chen ◽  
Cheng-Hsieh Yang ◽  
Ya-Ling Teng ◽  
...  
Keyword(s):  
Cerebral Palsy ◽  
Repeated Measures ◽  
Center Of Pressure ◽  
Reaction Force ◽  
Vertical Direction ◽  
Foot Orthoses ◽  
Maximal Velocity ◽  
Repeated Measures Design ◽  
Sit To Stand ◽  
Ankle Foot Orthoses

Hinged ankle-foot orthoses (HAFOs) and floor reaction ankle-foot orthoses (FRAFOs) are frequently prescribed to improve gait performance in children with spastic diplegic cerebral palsy (CP). No study has investigated the effects of FRAFO on sit-to-stand (STS) performance nor scrutinized differences between the application of HAFOs and FRAFOs on postural control. This study compared the effects of HAFOs and FRAFOs on standing stability and STS performance in children with spastic diplegic CP. Nine children with spastic diplegic CP participated in this crossover repeated-measures design research. Kinematic and kinetic data were collected during static standing and STS performance using 3-D motion analysis and force plates. Wilcoxon signed ranks test was used to compare the differences in standing stability and STS performance between wearing HAFOs and FRAFOs. The results showed that during static standing, all center of pressure (COP) parameters (maximal anteroposterior/mediolateral displacement, maximal velocity, and sway area) were not significantly different between FRAFOs and HAFOs. During STS, the floor reaction force in the vertical direction was significantly higher with FRAFOs than with HAFOs (p = 0.018). There were no significant differences in the range of motion in the trunk, knee, and ankle, the maximal velocity of COP forward displacement, completion time, and the force of hip, knee, and ankle joints between the two orthoses. The results suggest both FRAFOs and HAFOs have a similar effect on standing stability, while FRAFOs may benefit STS performance more compared to HAFOs.

Anatomical Origin of Forefoot Varus Malalignment

2012 ◽  
Vol 102 (5) ◽  
pp. 390-395 ◽  
Author(s):  
Rebecca S. Lufler ◽  
T. M. Hoagland ◽  
Jingbo Niu ◽  
K. Douglas Gross
Keyword(s):  
Soft Tissue ◽  
Confidence Interval ◽  
Subtalar Joint ◽  
Pearson Correlation ◽  
Foot Orthoses ◽  
Pearson Correlation Coefficient ◽  
Varus Malalignment ◽  
Clinical Methods ◽  
Forefoot Varus ◽  
The Relationship

Background: Forefoot varus malalignment is clinically defined as a nonweightbearing inversion of the metatarsal heads relative to a vertical bisection of the calcaneus in subtalar joint neutral. Although often targeted for treatment with foot orthoses, the etiology of forefoot varus malalignment has been debated and may involve an unalterable bony torsion of the talus. Methods: Forty-nine feet from 25 cadavers underwent bilateral measurement of forefoot alignment using adapted clinical methods, followed by dissection and measurement of bony talar torsion. The relationship between forefoot alignment and talar torsion was determined using the Pearson correlation coefficient. Results: Mean ± SD forefoot alignment was −0.9° ± 9.8° (valgus) and bony talar torsion was 32.8° ± 5.3° valgus. There was no association between forefoot alignment and talar torsion (r = 0.18; 95% confidence interval, −0.11 to 0.44; P = .22). Conclusions: These findings may have implications for the treatment of forefoot varus since they suggest that the source of forefoot varus malalignment may be found in an alterable soft-tissue deformity rather than in an unalterable bony torsion of the talus. (J Am Podiatr Med Assoc 102(5): 390–395, 2012)

scholarly journals Individual stiffness optimization of dorsal leaf spring ankle–foot orthoses in people with calf muscle weakness is superior to standard bodyweight-based recommendations

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Niels F. J. Waterval ◽  
Merel-Anne Brehm ◽  
Jaap Harlaar ◽  
Frans Nollet
Keyword(s):  
Muscle Weakness ◽  
Energy Cost ◽  
Activity Level ◽  
Calf Muscle ◽  
Leaf Spring ◽  
Foot Orthoses ◽  
Ankle Foot Orthoses ◽  
The Individual ◽  
Optimal Stiffness ◽  
Walking Energy Cost

Abstract Background In people with calf muscle weakness, the stiffness of dorsal leaf spring ankle–foot orthoses (DLS-AFO) needs to be individualized to maximize its effect on walking. Orthotic suppliers may recommend a certain stiffness based on body weight and activity level. However, it is unknown whether these recommendations are sufficient to yield the optimal stiffness for the individual. Therefore, we assessed whether the stiffness following the supplier’s recommendation of the Carbon Ankle7 (CA7) dorsal leaf matched the experimentally optimized AFO stiffness. Methods Thirty-four persons with calf muscle weakness were included and provided a new DLS-AFO of which the stiffness could be varied by changing the CA7® (Ottobock, Duderstadt, Germany) dorsal leaf. For five different stiffness levels, including the supplier recommended stiffness, gait biomechanics, walking energy cost and speed were assessed. Based on these measures, the individual experimentally optimal AFO stiffness was selected. Results In only 8 of 34 (23%) participants, the supplier recommended stiffness matched the experimentally optimized AFO stiffness, the latter being on average 1.2 ± 1.3 Nm/degree more flexible. The DLS-AFO with an experimentally optimized stiffness resulted in a significantly lower walking energy cost (− 0.21 ± 0.26 J/kg/m, p < 0.001) and a higher speed (+ 0.02 m/s, p = 0.003). Additionally, a larger ankle range of motion (+ 1.3 ± 0.3 degrees, p < 0.001) and higher ankle power (+ 0.16 ± 0.04 W/kg, p < 0.001) were found with the experimentally optimized stiffness compared to the supplier recommended stiffness. Conclusions In people with calf muscle weakness, current supplier’s recommendations for the CA7 stiffness level result in the provision of DLS-AFOs that are too stiff and only achieve 80% of the reduction in energy cost achieved with an individual optimized stiffness. It is recommended to experimentally optimize the CA7 stiffness in people with calf muscle weakness in order to maximize treatment outcomes. Trial registration Nederlands Trial Register 5170. Registration date: May 7th 2015. http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=5170.

State of the Art Review of Knee–Ankle–Foot Orthoses

2015 ◽  
Vol 43 (2) ◽  
pp. 427-441 ◽  
Author(s):  
Feng Tian ◽  
Mohamed Samir Hefzy ◽  
Mohammad Elahinia
Keyword(s):  
State Of The Art ◽  
Foot Orthoses ◽  
Ankle Foot Orthoses

Quantification of gait asymmetry in patients with ankle foot orthoses based on hip–hip cyclograms

2014 ◽  
Vol 34 (1) ◽  
pp. 46-52 ◽  
Author(s):  
Patrik Kutilek ◽  
Vladimir Socha ◽  
Slavka Viteckova ◽  
Zdenek Svoboda
Keyword(s):  
Foot Orthoses ◽  
Ankle Foot Orthoses ◽  
Gait Asymmetry

scholarly journals The Importance of Being Earnest about Shank and Thigh Kinematics Especially When Using Ankle-Foot Orthoses

2010 ◽  
Vol 34 (3) ◽  
pp. 254-269 ◽  
Author(s):  
Elaine Owen
Keyword(s):  
Joint Kinematics ◽  
Foot Orthoses ◽  
Traditional Beliefs ◽  
Vertical Angle ◽  
Gait Biomechanics ◽  
Normal Gait ◽  
Ankle Foot Orthoses ◽  
Pathological Gait ◽  
Kinematics And Kinetics

This paper reviews and summarizes the evidence for important observations of normal and pathological gait and presents an approach to rehabilitation and orthotic management, which is based on the significance of shank and thigh kinematics for standing and gait. It discusses normal gait biomechanics, challenging some traditional beliefs, the interrelationship between segment kinematics, joint kinematics and kinetics and their relationship to orthotic design, alignment and tuning. It proposes a description of four rather than three rockers in gait; a simple categorization of pathological gait based on shank kinematics abnormality; an algorithm for the designing, aligning and tuning of AFO-Footwear Combinations; and an algorithm for determining the sagittal angle of the ankle in an AFO. It reports the results of research on Shank to Vertical Angle alignment of tuned AFO-Footwear Combinations and on the use of ‘point loading’ rocker soles.

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