Application of the Superelastic NiTi Spring in Ankle Foot Orthosis (AFO) to Create Normal Ankle Joint Behavior
Hinge-based Ankle Foot Orthosis (HAFO) is one of the most common non-surgical solutions for the foot drop. In conventional HAFOs, the ankle joint is almost locked, and plantar flexion is restricted due to the high stiffness of the hinge mechanism. This often leads to a rigid walking gate cycle, poor...
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| Format: | Article |
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MDPI AG
2017-12-01
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| Series: | Bioengineering |
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| Online Access: | https://www.mdpi.com/2306-5354/4/4/95 |
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| author | Amirhesam Amerinatanzi Hashem Zamanian Narges Shayesteh Moghaddam Ahmadreza Jahadakbar Mohammad Elahinia |
| author_facet | Amirhesam Amerinatanzi Hashem Zamanian Narges Shayesteh Moghaddam Ahmadreza Jahadakbar Mohammad Elahinia |
| author_sort | Amirhesam Amerinatanzi |
| collection | DOAJ |
| description | Hinge-based Ankle Foot Orthosis (HAFO) is one of the most common non-surgical solutions for the foot drop. In conventional HAFOs, the ankle joint is almost locked, and plantar flexion is restricted due to the high stiffness of the hinge mechanism. This often leads to a rigid walking gate cycle, poor muscle activity, and muscle atrophy. Since the ankle torque-angle loop has a non-linear profile, the use of a superelastic NiTi spring within the hinge, due to its nonlinear behavior, could recreate a close-to-normal stiffness of the normal ankle joint, which, in turn, could create a more natural walk. The focus of this study is to evaluate the performance of a superelastic NiTi spring versus a conventional Stainless Steel spring in a hinge mechanism of a custom-fit HAFO. To this aim, a custom-fit HAFO was fabricated via the fast casting technique. Then, motion analysis was performed for two healthy subjects (Case I and Case II): (i) subjects with bare foot; (ii) subjects wearing a conventional HAFO with no spring; (iii) subjects wearing a conventional Stainless Steel-based HAFO; and (iv) subjects wearing a NiTi spring-based HAFO. The data related to the ankle angle and the amount of moment applied to the ankle during walking were recorded using Cortex software and used for the evaluations. Finally, Finite Element Analysis (FEA) was performed to evaluate the safety of the designed HAFO. The NiTi spring offers a higher range of motion (7.9 versus 4.14 degree) and an increased level of moment (0.55 versus 0.36 N·m/kg). Furthermore, a NiTi spring offers an ankle torque-angle loop closer to that of the healthy subjects. |
| first_indexed | 2024-03-12T07:19:53Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 2306-5354 |
| language | English |
| last_indexed | 2024-03-12T07:19:53Z |
| publishDate | 2017-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Bioengineering |
| spelling | doaj.art-16ee1de849fe43079fc521557fd4cf5b2023-09-02T22:28:02ZengMDPI AGBioengineering2306-53542017-12-01449510.3390/bioengineering4040095bioengineering4040095Application of the Superelastic NiTi Spring in Ankle Foot Orthosis (AFO) to Create Normal Ankle Joint BehaviorAmirhesam Amerinatanzi0Hashem Zamanian1Narges Shayesteh Moghaddam2Ahmadreza Jahadakbar3Mohammad Elahinia4Dynamics and Smart Systems Laboratory, Mechanical, Industrial and Manufacturing Engineering Department, The University of Toledo, Toledo, OH 43606, USADynamics and Smart Systems Laboratory, Mechanical, Industrial and Manufacturing Engineering Department, The University of Toledo, Toledo, OH 43606, USADynamics and Smart Systems Laboratory, Mechanical, Industrial and Manufacturing Engineering Department, The University of Toledo, Toledo, OH 43606, USADynamics and Smart Systems Laboratory, Mechanical, Industrial and Manufacturing Engineering Department, The University of Toledo, Toledo, OH 43606, USADynamics and Smart Systems Laboratory, Mechanical, Industrial and Manufacturing Engineering Department, The University of Toledo, Toledo, OH 43606, USAHinge-based Ankle Foot Orthosis (HAFO) is one of the most common non-surgical solutions for the foot drop. In conventional HAFOs, the ankle joint is almost locked, and plantar flexion is restricted due to the high stiffness of the hinge mechanism. This often leads to a rigid walking gate cycle, poor muscle activity, and muscle atrophy. Since the ankle torque-angle loop has a non-linear profile, the use of a superelastic NiTi spring within the hinge, due to its nonlinear behavior, could recreate a close-to-normal stiffness of the normal ankle joint, which, in turn, could create a more natural walk. The focus of this study is to evaluate the performance of a superelastic NiTi spring versus a conventional Stainless Steel spring in a hinge mechanism of a custom-fit HAFO. To this aim, a custom-fit HAFO was fabricated via the fast casting technique. Then, motion analysis was performed for two healthy subjects (Case I and Case II): (i) subjects with bare foot; (ii) subjects wearing a conventional HAFO with no spring; (iii) subjects wearing a conventional Stainless Steel-based HAFO; and (iv) subjects wearing a NiTi spring-based HAFO. The data related to the ankle angle and the amount of moment applied to the ankle during walking were recorded using Cortex software and used for the evaluations. Finally, Finite Element Analysis (FEA) was performed to evaluate the safety of the designed HAFO. The NiTi spring offers a higher range of motion (7.9 versus 4.14 degree) and an increased level of moment (0.55 versus 0.36 N·m/kg). Furthermore, a NiTi spring offers an ankle torque-angle loop closer to that of the healthy subjects.https://www.mdpi.com/2306-5354/4/4/95superelastic NiTi springAnkle Foot Orthosis (AFO)normal ankle joint behavior |
| spellingShingle | Amirhesam Amerinatanzi Hashem Zamanian Narges Shayesteh Moghaddam Ahmadreza Jahadakbar Mohammad Elahinia Application of the Superelastic NiTi Spring in Ankle Foot Orthosis (AFO) to Create Normal Ankle Joint Behavior Bioengineering superelastic NiTi spring Ankle Foot Orthosis (AFO) normal ankle joint behavior |
| title | Application of the Superelastic NiTi Spring in Ankle Foot Orthosis (AFO) to Create Normal Ankle Joint Behavior |
| title_full | Application of the Superelastic NiTi Spring in Ankle Foot Orthosis (AFO) to Create Normal Ankle Joint Behavior |
| title_fullStr | Application of the Superelastic NiTi Spring in Ankle Foot Orthosis (AFO) to Create Normal Ankle Joint Behavior |
| title_full_unstemmed | Application of the Superelastic NiTi Spring in Ankle Foot Orthosis (AFO) to Create Normal Ankle Joint Behavior |
| title_short | Application of the Superelastic NiTi Spring in Ankle Foot Orthosis (AFO) to Create Normal Ankle Joint Behavior |
| title_sort | application of the superelastic niti spring in ankle foot orthosis afo to create normal ankle joint behavior |
| topic | superelastic NiTi spring Ankle Foot Orthosis (AFO) normal ankle joint behavior |
| url | https://www.mdpi.com/2306-5354/4/4/95 |
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