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Skigen JT, Koller CA, Nigro L, Reisman DS, McKee Z, Pinhey SR, Henderson A, Wilken JM, Arch ES. Customized passive-dynamic ankle-foot orthoses can improve walking economy and speed for many individuals post-stroke. J Neuroeng Rehabil 2024; 21:126. [PMID: 39069629 DOI: 10.1186/s12984-024-01425-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 07/17/2024] [Indexed: 07/30/2024] Open
Abstract
BACKGROUND Passive-dynamic ankle-foot orthoses (PD-AFOs) are often prescribed to address plantar flexor weakness during gait, which is commonly observed after stroke. However, limited evidence is available to inform the prescription guidelines of PD-AFO bending stiffness. This study assessed the extent to which PD-AFOs customized to match an individual's level of plantar flexor weakness influence walking function, as compared to No AFO and their standard of care (SOC) AFO. METHODS Mechanical cost-of-transport, self-selected walking speed, and key biomechanical variables were measured while individuals greater than six months post-stroke walked with No AFO, with their SOC AFO, and with a stiffness-customized PD-AFO. Outcomes were compared across these conditions using a repeated measures ANOVA or Friedman test (depending on normality) for group-level analysis and simulation modeling analysis for individual-level analysis. RESULTS Twenty participants completed study activities. Mechanical cost-of-transport and self-selected walking speed improved with the stiffness-customized PD-AFOs compared to No AFO and SOC AFO. However, this did not result in a consistent improvement in other biomechanical variables toward typical values. In line with the heterogeneous nature of the post-stroke population, the response to the PD-AFO was highly variable. CONCLUSIONS Stiffness-customized PD-AFOs can improve the mechanical cost-of-transport and self-selected walking speed in many individuals post-stroke, as compared to No AFO and participants' standard of care AFO. This work provides initial efficacy data for stiffness-customized PD-AFOs in individuals post-stroke and lays the foundation for future studies to enable consistently effective prescription of PD-AFOs for patients post-stroke in clinical practice. TRIAL REGISTRATION NCT04619043.
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Affiliation(s)
- Jacob T Skigen
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
| | - Corey A Koller
- Biomechanics and Movement Science Interdisciplinary Program, University of Delaware, Newark, DE, USA
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Luke Nigro
- Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - Darcy S Reisman
- Biomechanics and Movement Science Interdisciplinary Program, University of Delaware, Newark, DE, USA
- Department of Physical Therapy, University of Delaware, Newark, DE, USA
| | - Zahra McKee
- Biomechanics and Movement Science Interdisciplinary Program, University of Delaware, Newark, DE, USA
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Shay R Pinhey
- Biomechanics and Movement Science Interdisciplinary Program, University of Delaware, Newark, DE, USA
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Adrienne Henderson
- Biomechanics and Movement Science Interdisciplinary Program, University of Delaware, Newark, DE, USA
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Jason M Wilken
- Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA, USA
| | - Elisa S Arch
- Biomechanics and Movement Science Interdisciplinary Program, University of Delaware, Newark, DE, USA.
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA.
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Fallahtafti F, Samson K, Salamifar Z, Johanning J, Pipinos I, Myers SA. Enhancing walking performance in patients with peripheral arterial disease: An intervention with ankle-foot orthosis. Int J Cardiol 2024; 407:131992. [PMID: 38527630 DOI: 10.1016/j.ijcard.2024.131992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 03/20/2024] [Accepted: 03/22/2024] [Indexed: 03/27/2024]
Abstract
Lower extremity peripheral artery disease (PAD) is a cardiovascular condition manifesting from narrowed or blocked arteries supplying the legs. Gait is impaired in patients with PAD. Recent evidence suggests that walking with carbon fiber ankle foot orthoses (AFOs) can improve patient mobility and delay claudication time. This study aimed to employ advanced biomechanical gait analysis to evaluate the impact of AFO intervention on gait performance among patients with PAD. Patients with claudication had hip, knee, and ankle joint kinetics and kinematics assessed using a cross-over intervention design. Participants walked over the force platforms with and without AFOs while kinematic data was recorded with motion analysis cameras. Kinetics and kinematics were combined to quantify torques and powers during the stance period of the gait cycle. The AFOs effectively reduced the excessive ankle plantar flexion and knee extension angles, bringing the patients' joint motions closer to those observed in healthy individuals. After 3 months of the AFO intervention, the hip range of motion decreased, likely due to changes occurring within the ankle chain. With the assistance of the AFOs, the biological power generation required from the ankle and hip during the push-off phase of walking decreased. Wearing AFOs resulted in increased knee flexor torque during the loading response phase of the gait. Based on this study, AFOs may allow patients with PAD to maintain or improve gait performance. More investigation is needed to fully understand and improve the potential benefits of ankle assistive devices.
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Affiliation(s)
- Farahnaz Fallahtafti
- Department of Biomechanics, University of Nebraska at Omaha, 6160 University Drive South, Omaha, NE 68182, USA.
| | - Kaeli Samson
- Department of Biostatistics, University of Nebraska Medical Center, 984375 Nebraska Medical Center, Omaha, NE 68198-4375, USA
| | - Zahra Salamifar
- Department of Biomechanics, University of Nebraska at Omaha, 6160 University Drive South, Omaha, NE 68182, USA
| | - Jason Johanning
- Department of Surgery, University of Nebraska Medical Center, Omaha, NE 68105, USA; Department of Surgery and VA Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA
| | - Iraklis Pipinos
- Department of Surgery, University of Nebraska Medical Center, Omaha, NE 68105, USA; Department of Surgery and VA Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA
| | - Sara A Myers
- Department of Biomechanics, University of Nebraska at Omaha, 6160 University Drive South, Omaha, NE 68182, USA; Department of Surgery and VA Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA.
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Feng J, Weiss J, Thompson A, Meeker JE. Passive Dynamic Ankle Foot Orthoses Use in Civilian Patients with Arthritic Conditions of the Foot and Ankle. FOOT & ANKLE ORTHOPAEDICS 2023; 8:24730114231157734. [PMID: 36937807 PMCID: PMC10014983 DOI: 10.1177/24730114231157734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Background Nonsurgical interventions such as bracing with ankle foot orthoses (AFOs) aim to assist, restore, and redirect weightbearing forces to address difficulty with mobilization. We identified a custom carbon fiber passive dynamic ankle foot orthosis (PDAFO) that was designed to meet the needs of military combat veterans. We sought to evaluate the off-loading properties of one model of PDAFO (ExoSym) in a civilian population. Methods Civilian patients 18 years or older were prescribed a PDAFO by a single surgeon. Pedobarographic data were obtained using the Tekscan F-Scan system. With the insole, participants were instructed to walk at a self-selected pace along a 20 m walkway under 3 conditions: (1) insole placed in between the brace and foot (over); (2) insole placed between the brace and insole of the shoe (under); (3) without the brace, the insole was placed in between the foot and insole of the shoe in both limbs (without).For assessment, forefoot and heel areas were evaluated with respect to maximal force, force*time integral (FTI), maximal contact area, maximal contact pressure, pressure*time integral (PTI), center of force (COF) excursion. Results Six patients with arthritic foot and ankle conditions completed pedobarographic assessment for analysis. The brace reduced forefoot maximal force and contact pressures by 66% and 49%, respectively (538 ± 236 to 185 ± 130 N [P < .001], and 99 ± 38 to 50 ± 24 P < .002). Additionally, participants were observed to load the forefoot portion of the brace with double the maximum contact pressures compared to the unbraced foot (204 ± 57 to 99 ± 38 kPa, P < .001). Conclusion The results of this study showed that the PDAFO unloaded substantial force and pressure experienced by the forefoot. Participants loaded the brace to a greater extent than when going unbraced. ADAFO can provide measurable pressure relief for patients with arthritic conditions. Level of Evidence Level IV, case series.
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Affiliation(s)
- Jing Feng
- Motion Analysis Center, Shriners
Hospitals for Children, Portland, OR, USA
| | - Jason Weiss
- Department of Orthopaedics and
Rehabilitation, Oregon Health & Science University, Portland, OR, USA
| | - Austin Thompson
- Department of Orthopaedics and
Rehabilitation, Oregon Health & Science University, Portland, OR, USA
| | - James E. Meeker
- Department of Orthopaedics and
Rehabilitation, Oregon Health & Science University, Portland, OR, USA
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Nigro L, Arch E. Comparison of Existing Methods for Characterizing Bi-Linear Natural Ankle Quasi-Stiffness. J Biomech Eng 2022; 144:1141606. [PMID: 35698872 DOI: 10.1115/1.4054798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Indexed: 11/08/2022]
Abstract
Natural ankle quasi-stiffness (NAS) is a mechanical property of the ankle joint during motion. NAS has been historically calculated as the average slope (linear regression) of the net ankle moment vs. ankle angle during discrete phases of stance. However, recent work has shown that NAS is nonlinear during stance. Specifically, during the loading phase (~10-60% of stance), plantarflexion moment increases at an accelerating rate compared to dorsiflexion angle. Updated models have been developed to better capture this inherent nonlinearity. One type of model is called bi-linear NAS (BL-NAS) divides the loading phase of stance into two sub-phases, called early loading (EL) and late loading (LL) NAS. Two papers, written by Crenna & Frigo in 2011 and Shamaei et al. in 2013, outline different BL-NAS models. Both models fit measured data better (lower RMSE) than standard single linear NAS (SL-NAS) models, but have not been widely adopted, possibly because of methodological discrepancies and lack of applicability to physical devices at the time. This paper compares these existing BL-NAS models and translate those findings to possible orthotic device designs. Results showed that both BL-NAS models had lower RMSE than SL-NAS, EL-NAS was not significantly different across walking speeds, and LL-NAS increased significantly at faster walking speeds. These improved NAS models better approximate natural human movement than commonly used SL-NAS models, and provide a basis to design ankle-foot devices with multiple stiffness properties to emulate and facilitate natural human motion.
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Affiliation(s)
- Luke Nigro
- Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - Elisa Arch
- Department of Kinesiology & Applied Physiology, University of Delaware, Newark, DE, USA; Biomechanics & Movement Science Interdisciplinary Program, University of Delaware, Newark, DE, USA
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Yamamoto S, Motojima N, Kobayashi Y, Osada Y, Tanaka S, Daryabor A. Ankle-foot orthosis with an oil damper versus nonarticulated ankle-foot orthosis in the gait of patients with subacute stroke: a randomized controlled trial. J Neuroeng Rehabil 2022; 19:50. [PMID: 35619141 PMCID: PMC9137172 DOI: 10.1186/s12984-022-01027-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/16/2022] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Gait improvement in patients with stroke has been examined in terms of use or non-use of an ankle-foot orthosis (AFO), but the effects of different kinds of AFOs remain unclear. In this study, the effect on gait of using an AFO with an oil damper (AFO-OD), which has plantarflexion stiffness without dorsiflexion resistance, was compared with a nonarticulated AFO, which has both dorsiflexion and plantarflexion stiffness, in a randomized controlled trial. METHODS Forty-one patients (31 men, 10 women; mean age 58.4 ± 11.3 years) in the subacute phase of stroke were randomly allocated to two groups to undergo gait training for 1 h daily over 2 weeks by physiotherapists while wearing an AFO-OD or a nonarticulated AFO. A motion capture system was utilized to measure shod gait without orthosis at baseline and after training with the allocated AFO. Data analysis focused on the joint kinematics and kinetics, spatial and temporal parameters, ground reaction force, and shank-to-vertical angle. Unpaired t-test or Mann-Whitney U test was performed to clarify the difference in gait with an AFO between the two AFO groups after training, with a significance level of p = 0.05. RESULTS Thirty-six patients completed the study (17 in the AFO-OD group and 19 in the nonarticulated AFO group). The ankle joint was more dorsiflexed in single stance (p = 0.008, effect size r = 0.46) and peak ankle power absorption was larger in stance (p = 0.007, r = 0.55) in the AFO-OD group compared with the nonarticulated AFO group. Peak power absorption varied among patients in the AFO-OD group. Increased dorsiflexion angles were also found at initial contact (p = 0.008, r = 1.51), pre-swing (p = 0.045, r = 0.91), and the swing phase (p = 0.045, r = 0.91) in the AFO-OD group. There was no difference in peak plantarflexion moment, ankle power generation, spatial or temporal parameters, ground reaction force, or shank-to-vertical angle between the two groups. CONCLUSIONS The results of this study showed that an AFO with plantarflexion stiffness but without dorsiflexion resistance produced greater improvement in ankle joint kinematics and kinetics compared with the nonarticulated AFO, but the results of peak power absorption varied greatly among patients. Trial registration UMIN000028126, Registered 1 August 2017, https://upload.umin.ac.jp/cgi-bin/icdr/ctr_menu_form_reg.cgi?recptno=R000032197.
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Affiliation(s)
- Sumiko Yamamoto
- Graduate School, International University of Health & Welfare, 4-1-26 Akasaka, Minato-ku, Tokyo, 107-8402 Japan
| | - Naoyuki Motojima
- Showa University School of Nursing and Rehabilitation Science, 1865 Tohkaichibacho, Midoriku, Yokohama, Kanagawa 226-8555 Japan
| | - Yosuke Kobayashi
- Nakaizu Rehabilitation Center, 1523-108 Hiekawa, Izu, Shizuoka 410-2507 Japan
| | - Yuji Osada
- Department of Health and Welfare, Tokushima Bunri University, Nishihamahoji-180, Yamashirocho, Tokushima, 770-8514 Japan
| | - Souji Tanaka
- Saiseikai Higashikanagawa Rehabilitation Hospital, 1-13-10 Nishikanagawa, Kanagawa-ku, Yokohama, Kanagawa 221-0822 Japan
| | - Aliyeh Daryabor
- School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Velenjak St., Shahid Chamran Highway, Tehran, Iran
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Rogati G, Caravaggi P, Leardini A. Design principles, manufacturing and evaluation techniques of custom dynamic ankle-foot orthoses: a review study. J Foot Ankle Res 2022; 15:38. [PMID: 35585544 PMCID: PMC9118871 DOI: 10.1186/s13047-022-00547-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 05/10/2022] [Indexed: 11/10/2022] Open
Abstract
Ankle-Foot Orthoses (AFO) can be prescribed to allow drop-foot patients to restore a quasi-normal gait pattern. Standard off-the-shelf AFOs are cost-effective solutions to treat most patients with foot and ankle weakness, but these devices have several limitations, especially in terms of comfort. Therefore, custom AFOs are increasingly adopted to address drop-foot when standard solutions are not adequate. While the solid ones are the most common type of AFO, providing full stability and strong resistance to ankle plantarflexion, passive dynamic AFOs (PD-AFOs) represent the ideal solution for patients with less severe ankle weakness. PD-AFOs have a flexible calf shell, which can bend during the stance phase of walking and absorb energy that can be released to support the limb in the push-off phase. The aim of this review is to assess the state-of-the-art and identify the current limitations of PD-AFOs. An extensive literature review was performed in Google Scholar to identify all studies on custom PD-AFOs. Only those papers reporting on custom PD-AFOs were included in the review. Non peer-reviewed papers, abstract shorter than three pages, lecture notes and thesis dissertations were excluded from the analysis. Particular attention was given to the customization principles and the mechanical and functional tests. For each topic, the main results from all relevant papers are reported and summarized herein. There were 75 papers that corresponded to the search criteria. These were grouped according to the following macro-topics: 16 focusing on scanning technologies and geometry acquisition; 14 on customization criteria; 19 on production techniques; 16 on mechanical testing, and 33 on functional testing. According to the present review, design and production of custom PD-AFOs are becoming increasingly feasible due to advancements in 3D scanning techniques and additive manufacturing. In general, custom PD-AFOs were shown to provide better comfort and improved spatio-temporal parameters with respect to standard solutions. However, no customization principle to adapt PD-AFO stiffness to the patient's degree of ankle impairment or mechanical/functional demand has thus far been proposed.
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Affiliation(s)
- Giulia Rogati
- Movement Analysis Laboratory, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy
| | - Paolo Caravaggi
- Movement Analysis Laboratory, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy
| | - Alberto Leardini
- Movement Analysis Laboratory, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy
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Shen G. Strategies for Improving Text Reading Ability Based on Human-Computer Interaction in Artificial Intelligence. Front Psychol 2022; 13:853066. [PMID: 35360634 PMCID: PMC8963353 DOI: 10.3389/fpsyg.2022.853066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 02/09/2022] [Indexed: 12/03/2022] Open
Abstract
In order to improve text reading ability, a human-computer interaction method based on artificial intelligence (AI) human-computer interaction is proposed. Firstly, the design of the AI human-computer interaction model is constructed, which includes the Stanford Question Answering Dataset (SQuAD) and the designed baseline model. There are three components: the coding layer is based on a cyclic neural network (recurrent neural network [RNN] encoder layer), which aims to encode the problem and text into a hidden state; the interaction layer is used to integrate problems and text representation; the output layer connects two independent soft Max layers after a fully connected layer, one is used to obtain the starting position of the answer in the text and the other is used to obtain the ending position. In the interaction layer of the model, this manuscript uses hierarchical attention and aggregation mechanism to improve text coding. The traditional model interaction layer has a simple structure, which leads to weak relevance between text and problems, and poor understanding ability of the model. Finally, the self-attention model is used to further enhance the feature representation of text. The experimental results show that the improved model in this manuscript is compared with the public AI human-computer interaction reading comprehension model. According to the data in the table, the accuracy of the model in this manuscript is better than that of the baseline model, in which the exact match (EM) value is increased by 1.4% and the F1 value is increased by 2.7%. However, compared with improvement point 2, the EM and F1 values of the model have decreased by 0.7%. It shows that the output layer has a certain impact on the effect of the model, and the improvement and optimization of the output layer can also improve the performance of the model. It is proved that AI human-computer interaction can effectively improve text reading ability.
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Affiliation(s)
- Guorong Shen
- School of Foreign Languages, Henan University of Technology, Zhengzhou, China
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8
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Understanding the effects of quantitatively prescribing passive-dynamic ankle-foot orthosis bending stiffness for individuals after stroke. Prosthet Orthot Int 2021; 45:313-321. [PMID: 33840749 DOI: 10.1097/pxr.0000000000000012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 11/17/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND Passive-dynamic ankle-foot orthosis (PD-AFO) bending stiffness, which assists plantar flexor function, can be prescribed to improve poststroke gait. However, outcomes with PD-AFOs are variable likely because of improper personalization. We implemented a prescription model that objectively personalizes PD-AFO bending stiffness based on each individual's level of plantar flexor weakness (quantitatively prescribed PD-AFO). OBJECTIVES To evaluate whether a quantitatively prescribed PD-AFO improves peak paretic plantar flexion moment compared with the original AFO for individuals after stroke and to examine the immediate effects of wearing a quantitatively prescribed PD-AFO. STUDY DESIGN This is a repeated-measures study. METHODS PD-AFO bending stiffness was personalized for 10 individuals after stroke through the previously developed prescription model. Participants underwent an instrumented gait analysis while wearing their original AFO and the quantitatively prescribed PD-AFO. RESULTS Participants' peak paretic plantar flexion moment significantly increased while wearing the quantitatively prescribed PD-AFO compared with the original AFO. In addition, participants showed different levels of improvements in a series of other key biomechanical and walking performance parameters with PD-AFO use. Some participants showed improvements in all parameters, whereas others showed moderate to no improvements. CONCLUSIONS Quantitatively prescribed PD-AFO bending stiffness resulted in inconsistent improvements in biomechanical and walking performance parameters, which warrants further investigation. Future work should investigate whether more consistent benefits are seen with faster walking speeds and longer-term PD-AFO use. In addition, future work should conduct larger-scale studies that aim to understand and optimize orthosis-patient matching for all AFO designs/characteristics.
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Hedrick EA, Stanhope SJ, Takahashi KZ. The foot and ankle structures reveal emergent properties analogous to passive springs during human walking. PLoS One 2019; 14:e0218047. [PMID: 31173623 PMCID: PMC6555524 DOI: 10.1371/journal.pone.0218047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 05/24/2019] [Indexed: 01/19/2023] Open
Abstract
An objective understanding of human foot and ankle function can drive innovations of bio-inspired wearable devices. Specifically, knowledge regarding how mechanical force and work are produced within the human foot-ankle structures can help determine what type of materials or components are required to engineer devices. In this study, we characterized the combined functions of the foot and ankle structures during walking by synthesizing the total force, displacement, and work profiles from structures distal to the shank. Eleven healthy adults walked at four scaled speeds. We quantified the ground reaction force and center-of-pressure displacement in the shank’s coordinate system during stance phase and the total mechanical work done by these structures. This comprehensive analysis revealed emergent properties of foot-ankle structures that are analogous to passive springs: these structures compressed and recoiled along the longitudinal axis of the shank, and performed near zero or negative net mechanical work across a range of walking speeds. Moreover, the subject-to-subject variability in peak force, total displacement, and work were well explained by three simple factors: body height, mass, and walking speed. We created a regression-based model of stance phase mechanics that can inform the design and customization of wearable devices that may have biomimetic or non-biomimetic structures.
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Affiliation(s)
- Erica A. Hedrick
- Department of Biomechanics, University of Nebraska at Omaha, Omaha, NE, United States of America
- * E-mail:
| | - Steven J. Stanhope
- Department of Kinesiology & Applied Physiology, University of Delaware, Newark, DE, United States of America
| | - Kota Z. Takahashi
- Department of Biomechanics, University of Nebraska at Omaha, Omaha, NE, United States of America
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Schmidtbauer KA, Russell Esposito E, Wilken JM. Ankle-foot orthosis alignment affects running mechanics in individuals with lower limb injuries. Prosthet Orthot Int 2019; 43:316-324. [PMID: 30762469 DOI: 10.1177/0309364619826386] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Individuals with severe lower extremity injuries often require ankle-foot orthoses to return to normal activities. Ankle-foot orthoses alignment is a key consideration during the clinical fitting process and may be particularly important during dynamic activities such as running. OBJECTIVE To investigate how 3° changes in sagittal plane ankle-foot orthoses alignment affect running mechanics. STUDY DESIGN Controlled laboratory study. METHODS Twelve participants with unilateral lower limb injury ran overground and lower extremity running mechanics were assessed. Participants wore their passive-dynamic ankle-foot orthoses in three alignments: clinically fit neutral, 3° plantarflexed from clinically fit neutral, and 3° dorsiflexed from clinically fit neutral. RESULTS The 3° changes in sagittal alignment significantly influenced ankle mechanics during running. The plantarflexed alignment significantly decreased the peak ankle plantarflexor moment, peak knee extensor moment, and peak ankle and knee power absorption and generation compared to more dorsiflexed alignments. Alignment also altered footstrike angle, with dorsiflexed alignments associated with a more dorsiflexed footstrike pattern and plantarflexed alignments toward a more plantarflexed footstrike pattern. However, alignment did not influence loading rate. CONCLUSION Small changes in ankle-foot orthoses alignment significantly altered running mechanics, including footstrike angle, and knee extensor moments. Understanding how ankle-foot orthoses design parameters affect running mechanics may aid the development of evidence-based prescription guidelines and improve function for ankle-foot orthoses users who perform high-impact activities. CLINICAL RELEVANCE Understanding how ankle-foot orthoses alignment impacts biomechanics should be a consideration when fitting passive-dynamic devices for higher impact activities, such as running. Individual running styles, including footstrike patterns, may be affected by small changes in alignment.
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Affiliation(s)
- Kelly A Schmidtbauer
- 1 Center for the Intrepid, Brooke Army Medical Center, JBSA Fort Sam Houston, San Antonio, TX, USA.,2 Extremity Trauma and Amputation Center of Excellence.,3 Department of Rehabilitation Medicine, Uniformed Services University, Bethesda, MD, USA
| | - E Russell Esposito
- 1 Center for the Intrepid, Brooke Army Medical Center, JBSA Fort Sam Houston, San Antonio, TX, USA.,2 Extremity Trauma and Amputation Center of Excellence.,3 Department of Rehabilitation Medicine, Uniformed Services University, Bethesda, MD, USA
| | - Jason M Wilken
- 1 Center for the Intrepid, Brooke Army Medical Center, JBSA Fort Sam Houston, San Antonio, TX, USA.,2 Extremity Trauma and Amputation Center of Excellence
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Ielapi A, Lammens N, Van Paepegem W, Forward M, Deckers JP, Vermandel M, De Beule M. A validated computational framework to evaluate the stiffness of 3D printed ankle foot orthoses. Comput Methods Biomech Biomed Engin 2019; 22:880-887. [PMID: 30958030 DOI: 10.1080/10255842.2019.1601712] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The purpose of this study was to create and validate a standardized framework for the evaluation of the ankle stiffness of two designs of 3D printed ankle foot orthoses (AFOs). The creation of four finite element (FE) models allowed patient-specific quantification of the stiffness and stress distribution over their specific range of motion during the second rocker of the gait. Validation was performed by comparing the model outputs with the results obtained from a dedicated experimental setup, which showed an overall good agreement with a maximum relative error of 10.38% in plantarflexion and 10.66% in dorsiflexion. The combination of advanced computer modelling algorithms and 3D printing techniques clearly shows potential to further improve the manufacturing process of AFOs.
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Affiliation(s)
- Alessio Ielapi
- a Department of Electronics and Information Systems , Institute Biomedical Technology (IBiTech) - bioMMeda, Ghent University , Gent , Belgium.,b SIM vzw , Zwijnaarde , Belgium
| | - Nicolas Lammens
- c Belgian company, Siemens Industry Software N.V , Leuven , Belgium.,d Department of Materials Science & Engineering , Ghent University , Zwijnaarde , Belgium
| | - Wim Van Paepegem
- d Department of Materials Science & Engineering , Ghent University , Zwijnaarde , Belgium
| | - Malcolm Forward
- e Gait & Movement Analysis Laboratory - Cerebral Palsy Reference Centrum , University Hospital Ghent , Gent , Belgium
| | | | | | - Matthieu De Beule
- a Department of Electronics and Information Systems , Institute Biomedical Technology (IBiTech) - bioMMeda, Ghent University , Gent , Belgium
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Totah D, Menon M, Jones-Hershinow C, Barton K, Gates DH. The impact of ankle-foot orthosis stiffness on gait: A systematic literature review. Gait Posture 2019; 69:101-111. [PMID: 30708092 DOI: 10.1016/j.gaitpost.2019.01.020] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 01/10/2019] [Accepted: 01/13/2019] [Indexed: 02/02/2023]
Abstract
BACKGROUND Ankle-foot orthoses (AFOs) are commonly prescribed to provide ankle support during walking. Current prescription standards provide general guidelines for choosing between AFO types, but are limited in terms of guiding specific design parameter choices. These design parameters affect the ankle stiffness of the AFO. RESEARCH QUESTION The aim of this review was to investigate the impact of AFO stiffness on walking mechanics. METHODS A literature search was conducted using three databases: Pubmed, Engineering Village, and Web of Science. RESULTS After applying the exclusion criteria, 25 of 287 potential articles were included. The included papers tested a range of stiffnesses (0.02-8.17 Nm/deg), a variety of populations (e.g. healthy, post-stroke, cerebral palsy) and various gait outcome measures. Ankle kinematics were the most frequently reported measures and the most consistently affected by stiffness variations. Greater stiffnesses generally resulted in reduced peak ankle plantarflexion, dorsiflexion, and total range of motion, as well as increased dorsiflexion at initial contact. At the knee, a few studies reported increased flexion at initial contact, and decreased peak extension and increased peak flexion during stance when stiffness was increased. Stiffness did not affect hip kinetics and there was low evidence for its effects on hip or pelvis kinematics, ankle and knee kinetics, muscle activity, metabolic cost, ground reaction forces and spatiotemporal parameters. There were no generalizable trends for the impact of stiffness on user preference. SIGNIFICANCE AFO stiffness is a key factor influencing ankle movement. Clear reporting standards for AFO design parameters, as well as additional high quality research is needed with larger sample sizes and different clinical populations to ascertain the true effect of stiffness on gait.
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Affiliation(s)
- Deema Totah
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Meghna Menon
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Kira Barton
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Deanna H Gates
- School of Kinesiology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
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Roelker SA, Bowden MG, Kautz SA, Neptune RR. Paretic propulsion as a measure of walking performance and functional motor recovery post-stroke: A review. Gait Posture 2019; 68:6-14. [PMID: 30408710 PMCID: PMC6657344 DOI: 10.1016/j.gaitpost.2018.10.027] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 09/25/2018] [Accepted: 10/19/2018] [Indexed: 02/02/2023]
Abstract
BACKGROUND Although walking speed is the most common measure of gait performance post-stroke, improved walking speed following rehabilitation does not always indicate the recovery of paretic limb function. Over the last decade, the measure paretic propulsion (Pp, defined as the propulsive impulse generated by the paretic leg divided by the sum of the propulsive impulses of both legs) has been established as a measure of paretic limb output and recently targeted in post-stroke rehabilitation paradigms. However, the literature lacks a detailed synthesis of how paretic propulsion, walking speed, and other biomechanical and neuromuscular measures collectively relate to post-stroke walking performance and motor recovery. OBJECTIVE The aim of this review was to assess factors associated with the ability to generate Pp and identify rehabilitation targets aimed at improving Pp and paretic limb function. METHODS Relevant literature was collected in which paretic propulsion was used to quantify and assess propulsion symmetry and function in hemiparetic gait. RESULTS Paretic leg extension during terminal stance is strongly associated with Pp. Both paretic leg extension and propulsion are related to step length asymmetry, revealing an interaction between spatiotemporal, kinematic and kinetic metrics that underlies hemiparetic walking performance. The importance of plantarflexor function in producing propulsion is highlighted by the association of an independent plantarflexor excitation module with increased Pp. Furthermore, the literature suggests that although current rehabilitation techniques can improve Pp, these improvements depend on the patient's baseline plantarflexor function. SIGNIFICANCE Pp provides a quantitative measure of propulsion symmetry and should be a primary target of post-stroke gait rehabilitation. The current literature suggests rehabilitation techniques that target both plantarflexor function and leg extension may restore paretic limb function and improve gait asymmetries in individuals post stroke.
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Affiliation(s)
- Sarah A. Roelker
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Mark G. Bowden
- Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, USA.,Division of Physical Therapy, College of Health Professions, Medical University of South Carolina, Charleston, SC, USA,Ralph H. Johnson VA Medical Center, Charleston, SC, USA
| | - Steven A. Kautz
- Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, USA.,Ralph H. Johnson VA Medical Center, Charleston, SC, USA
| | - Richard R. Neptune
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, USA
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Koller C, Arch ES. State of the Prescription Process for Dynamic Ankle-Foot Orthoses. CURRENT PHYSICAL MEDICINE AND REHABILITATION REPORTS 2018. [DOI: 10.1007/s40141-018-0177-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ranz EC, Russell Esposito E, Wilken JM, Neptune RR. The influence of passive-dynamic ankle-foot orthosis bending axis location on gait performance in individuals with lower-limb impairments. Clin Biomech (Bristol, Avon) 2016; 37:13-21. [PMID: 27280325 DOI: 10.1016/j.clinbiomech.2016.05.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 04/28/2016] [Accepted: 05/05/2016] [Indexed: 02/07/2023]
Abstract
BACKGROUND Passive-dynamic ankle-foot orthoses are commonly prescribed to augment impaired ankle muscle function, however their design and prescription are largely qualitative. One design includes a footplate and cuff, and flexible strut connecting the two. During gait, deflection occurs along the strut, with the greatest deflection at a central bending axis. The vertical location of the axis can affect lower extremity biomechanics. The goal of this study was to investigate the influence of bending axis location on gait performance. METHODS For thirteen participants with unilateral ankle muscle weakness, an additive manufacturing framework was used to fabricate passive-dynamic ankle-foot orthosis struts with central and off-center bending axes. Participants walked overground while electromyographic, kinetic and kinematic data were collected for three different bending axes: proximal (high), central (middle) and distal (low), and the participants indicated their order of bending axis preference after testing. Gait measures and preference effect sizes were examined during six regions of the gait cycle. FINDINGS A few differences between bending axes were observed: in the first double-leg support peak plantarflexion angle, peak dorsiflexion moment and positive hip work, in the early single-leg support peak knee extension moment and positive ankle and knee work, and in the late single-leg support gastrocnemius activity and vertical ground reaction force impulse. In addition, preference was strongly related to various gait measures. INTERPRETATION Despite the observed statistical differences, altering bending axis location did not produce large and consistent changes in gait performance. Thus, individual preference and comfort may be more important factors guiding prescription.
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Affiliation(s)
- Ellyn C Ranz
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Elizabeth Russell Esposito
- Center for the Intrepid, Brooke Army Medical Center, JBSA Ft. Sam Houston, TX 78234, USA; Extremity Trauma and Amputation Center of Excellence, USA
| | - Jason M Wilken
- Center for the Intrepid, Brooke Army Medical Center, JBSA Ft. Sam Houston, TX 78234, USA; Extremity Trauma and Amputation Center of Excellence, USA
| | - Richard R Neptune
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
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Passive-Dynamic Ankle-Foot Orthoses with Personalized Bending Stiffness Can Enhance Net Plantarflexor Function for Individuals Poststroke. ACTA ACUST UNITED AC 2016. [DOI: 10.1097/jpo.0000000000000089] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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