Application of Carbon Fiber Ankle Foot Orthoses to Enhance Gait Outcomes for Individuals with Neurologic Gait Dysfunction

Background: Different types of ankle-foot orthoses are commonly used following lower limb surgery in children with bilateral spastic cerebral palsy. After three-dimensional gait analysis 1 year postoperatively, many children are recommended continued use of ankle-foot orthoses. Objectives: Our aims were to quantify the impact of ankle-foot orthoses on gait 1 year postoperatively and evaluate predictors for clinically important improvement. Study design: Prospective cohort study. Methods: A total of 34 ambulating children with bilateral cerebral palsy, with mean age 11 years (range 6–17), comprising 12 girls and 22 boys, were measured with three-dimensional gait analysis preoperatively (barefoot) and 1 year postoperatively (barefoot and with ankle-foot orthoses). Outcome was evaluated using gait profile score, key kinematic, kinetic and temporal–spatial variables in paired sample comparisons. Logistic regression was used to evaluate predictors for clinically important improvement with orthoses (⩾1.6° change in gait profile score). Results: Walking barefoot 1 year postoperatively, major improvements were seen in gait profile score and key variables. With ankle-foot orthoses, there were significantly improved step length and velocity, additional moderate reduction/improvement in gait profile score and knee moments and decreased stance ankle dorsiflexion compared to barefoot. Children using ground reaction ankle-foot orthoses ( n = 14) decreased stance knee flexion from 13.9° walking barefoot to 8.2° with orthoses. High gait profile score and more gait dysfunction preoperatively were significant predictors of clinically important improvement walking with orthoses. Conclusion: The results indicate improved gait function walking with ankle-foot orthoses versus barefoot 1 year after lower limb surgery. Stronger impact of ankle-foot orthoses was found in children with more pronounced gait dysfunction preoperatively. Clinical relevance The 1-year postoperative three-dimensional gait analysis is a useful method to assess treatment outcome after lower limb surgery in children with bilateral cerebral palsy and could also guide clinicians whether further treatment with ankle-foot orthoses is indicated, using clinically important differences as thresholds to evaluate their impact on gait.

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Carbon Fiber Based Twisted and Coiled Artificial Muscles (TCAMs) for Powered Ankle-Foot Orthoses (AFO)

Journal of Biomechanical Engineering ◽

10.1115/1.4051927 ◽

2021 ◽

Author(s):

Parth Kotak ◽

Jason Wilken ◽

Kirsten Anderson ◽

Caterina Lamuta

Keyword(s):

Carbon Fiber ◽

Low Cost ◽

Input Voltage ◽

Input Power ◽

Artificial Muscles ◽

Specific Work ◽

Foot Orthoses ◽

Ankle Foot Orthoses ◽

Low Cost Manufacturing

Abstract Ankle foot orthoses (AFOs) control the position and motion of the ankle, compensate for weakness, and correct deformities. AFOs can be classified as passive or powered. Powered AFOs overcome the limitations of passive AFOs by adapting their performance to meet a variety of requirements. However, the actuators currently used to power AFOs are typically heavy, bulky, expensive, or limited to laboratory settings. Thus, there is a strong need for lightweight, inexpensive, and flexible actuators for powering AFOs. In this technical brief, Carbon Fiber/Silicone Rubber (CF/SR) Twisted and Coiled Artificial Muscles (TCAMs) are proposed as novel actuators for powered AFOs. CF/SR TCAMs can lift up to 12,600 times their weight with an input power of only 0.025 W cm-1 and are fabricated from inexpensive materials through a low-cost manufacturing process. Additionally, they can provide a specific work of 758 J kg-1 when an input voltage of 1.64 V cm-1 is applied. A mechanical characterization of CF/SR TCAMs in terms of length/tension, tension/velocity, and active-passive length/tension is presented, and results are compared with the performance of skeletal muscles. A gait analysis demonstrates that CF/SR TCAMs can provide the performance required to supplement lower limb musculature and replicate the gait cycle of a healthy subject. Therefore, the preliminary results provided in this brief are a stepping stone for a dynamic AFO powered by CF/SR TCAMs.

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Manufacturing and analysis of carbon fiber knee ankle foot orthosis

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i4.17315 ◽

2018 ◽

Vol 7 (4) ◽

pp. 2236 ◽

Cited By ~ 5

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.

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Selective Laser Sintered Versus Carbon Fiber Passive-Dynamic Ankle-Foot Orthoses: A Comparison of Patient Walking Performance

Journal of Biomechanical Engineering ◽

10.1115/1.4027755 ◽

2014 ◽

Vol 136 (9) ◽

Cited By ~ 17

Author(s):

Nicole G. Harper ◽

Elizabeth M. Russell ◽

Jason M. Wilken ◽

Richard R. Neptune

Keyword(s):

Mechanical Properties ◽

Carbon Fiber ◽

Lower Limb ◽

Selective Laser Sintering ◽

Foot Orthoses ◽

Gait Performance ◽

Ankle Foot Orthoses ◽

Subject Specific ◽

Walking Performance ◽

Design Characteristics

Selective laser sintering (SLS) is a well-suited additive manufacturing technique for generating subject-specific passive-dynamic ankle-foot orthoses (PD-AFOs). However, the mechanical properties of SLS PD-AFOs may differ from those of commonly prescribed carbon fiber (CF) PD-AFOs. Therefore, the goal of this study was to determine if biomechanical measures during gait differ between CF and stiffness-matched SLS PD-AFOs. Subject-specific SLS PD-AFOs were manufactured for ten subjects with unilateral lower-limb impairments. Minimal differences in gait performance occurred when subjects used the SLS versus CF PD-AFOs. These results support the use of SLS PD-AFOs to study the effects of altering design characteristics on gait performance.

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Comparing Plantarflexor Power and Function using Carbon Fiber Versus Traditional Thermoplastic Ankle Foot Orthoses: Case Series

Clinical Research on Foot & Ankle ◽

10.4172/2329-910x.1000168 ◽

2015 ◽

Vol 03 (01) ◽

Author(s):

Mary K Hastings

Keyword(s):

Carbon Fiber ◽

Case Series ◽

Foot Orthoses ◽

Ankle Foot Orthoses ◽

And Function

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

Journal of NeuroEngineering and Rehabilitation ◽

10.1186/s12984-021-00890-8 ◽

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.

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