Balanced Foot Dorsiflexion Requires a Coordinated Activity of the Tibialis Anterior and the Extensor Digitorum Longus: A Musculoskeletal Modelling Study

Equinus and equinovarus foot deviations (EVFD) are the most frequent lower limb acquired deformities in stroke survivors. We analysed the contribution that the tibialis anterior (TA), extensor digitorum longus (EDL) and plantarflexor muscles play in EVFD via a biomechanical musculoskeletal model of...

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Main Authors: Carlo Albino Frigo, Andrea Merlo, Cristina Brambilla, Davide Mazzoli
Format: Article
Language:English
Published: MDPI AG 2023-07-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/13/13/7984
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author Carlo Albino Frigo
Andrea Merlo
Cristina Brambilla
Davide Mazzoli
author_facet Carlo Albino Frigo
Andrea Merlo
Cristina Brambilla
Davide Mazzoli
author_sort Carlo Albino Frigo
collection DOAJ
description Equinus and equinovarus foot deviations (EVFD) are the most frequent lower limb acquired deformities in stroke survivors. We analysed the contribution that the tibialis anterior (TA), extensor digitorum longus (EDL) and plantarflexor muscles play in EVFD via a biomechanical musculoskeletal model of the ankle–foot complex. Our model was composed of 28 bones (connected by either revolute joints or bone surface contacts), 15 ligaments (modelled as non-linear springs), and 10 muscles, modelled as force actuators. Different combinations of muscle contractions were also simulated. Our results demonstrate that, compared to the condition when the foot is suspended off the ground, the contraction of the TA alone produces dorsiflexion (from −18° to 0°) and a greater supination/inversion (from 12° to 30°). The EDL alone produces dorsiflexion (from −18° to −6°), forefoot pronation (25°) and calcaneal eversion (5.6°). Only TA and EDL synergistic action can lead the foot to dorsiflexion suitable for most daily life activities (≥20°) without any deviation in the frontal plane. When pathological contractures of the plantarflexor muscles were simulated, foot deformities reproducing EVFD were obtained. These results can be relevant for clinical applications, highlighting the importance of EDL assessment, which may help to design appropriate functional surgery and plan targeted rehabilitation treatments.
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spelling doaj.art-5e93cfc7ffd1496485351d8c25a442f42023-11-18T16:14:17ZengMDPI AGApplied Sciences2076-34172023-07-011313798410.3390/app13137984Balanced Foot Dorsiflexion Requires a Coordinated Activity of the Tibialis Anterior and the Extensor Digitorum Longus: A Musculoskeletal Modelling StudyCarlo Albino Frigo0Andrea Merlo1Cristina Brambilla2Davide Mazzoli3Department of Electronics, Information and Bioengineering, Politecnico di Milano, 20156 Milan, ItalyGait and Motion Analysis Laboratory, Sol et Salus Hospital, 47922 Rimini, ItalySTIIMA, Italian Council of National Research (CNR), 23900 Lecco, ItalyGait and Motion Analysis Laboratory, Sol et Salus Hospital, 47922 Rimini, ItalyEquinus and equinovarus foot deviations (EVFD) are the most frequent lower limb acquired deformities in stroke survivors. We analysed the contribution that the tibialis anterior (TA), extensor digitorum longus (EDL) and plantarflexor muscles play in EVFD via a biomechanical musculoskeletal model of the ankle–foot complex. Our model was composed of 28 bones (connected by either revolute joints or bone surface contacts), 15 ligaments (modelled as non-linear springs), and 10 muscles, modelled as force actuators. Different combinations of muscle contractions were also simulated. Our results demonstrate that, compared to the condition when the foot is suspended off the ground, the contraction of the TA alone produces dorsiflexion (from −18° to 0°) and a greater supination/inversion (from 12° to 30°). The EDL alone produces dorsiflexion (from −18° to −6°), forefoot pronation (25°) and calcaneal eversion (5.6°). Only TA and EDL synergistic action can lead the foot to dorsiflexion suitable for most daily life activities (≥20°) without any deviation in the frontal plane. When pathological contractures of the plantarflexor muscles were simulated, foot deformities reproducing EVFD were obtained. These results can be relevant for clinical applications, highlighting the importance of EDL assessment, which may help to design appropriate functional surgery and plan targeted rehabilitation treatments.https://www.mdpi.com/2076-3417/13/13/7984dorsiflexionmusculoskeletal modellingtibialis anteriorextensor digitorum longusequinus foot deviationrehabilitation
spellingShingle Carlo Albino Frigo
Andrea Merlo
Cristina Brambilla
Davide Mazzoli
Balanced Foot Dorsiflexion Requires a Coordinated Activity of the Tibialis Anterior and the Extensor Digitorum Longus: A Musculoskeletal Modelling Study
Applied Sciences
dorsiflexion
musculoskeletal modelling
tibialis anterior
extensor digitorum longus
equinus foot deviation
rehabilitation
title Balanced Foot Dorsiflexion Requires a Coordinated Activity of the Tibialis Anterior and the Extensor Digitorum Longus: A Musculoskeletal Modelling Study
title_full Balanced Foot Dorsiflexion Requires a Coordinated Activity of the Tibialis Anterior and the Extensor Digitorum Longus: A Musculoskeletal Modelling Study
title_fullStr Balanced Foot Dorsiflexion Requires a Coordinated Activity of the Tibialis Anterior and the Extensor Digitorum Longus: A Musculoskeletal Modelling Study
title_full_unstemmed Balanced Foot Dorsiflexion Requires a Coordinated Activity of the Tibialis Anterior and the Extensor Digitorum Longus: A Musculoskeletal Modelling Study
title_short Balanced Foot Dorsiflexion Requires a Coordinated Activity of the Tibialis Anterior and the Extensor Digitorum Longus: A Musculoskeletal Modelling Study
title_sort balanced foot dorsiflexion requires a coordinated activity of the tibialis anterior and the extensor digitorum longus a musculoskeletal modelling study
topic dorsiflexion
musculoskeletal modelling
tibialis anterior
extensor digitorum longus
equinus foot deviation
rehabilitation
url https://www.mdpi.com/2076-3417/13/13/7984
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