Development of a Passive Upper Extremity Orthosis for Amyoplasia
Authors
Raunsbæk, Joakim ; Lund, Jan Nørgaard ; Jensen, Erik Føge
Term
4. semester
Education
Publication year
2017
Submitted on
2017-06-07
Pages
80
Abstract
Personer, der er født med amyoplasi, har ofte nedsat muskelmasse, ledkontrakturer og unaturlige stillinger af arme og ben. Det gør det svært at klare aktiviteter i dagligdagen (ADL). En ortose (en bærbar støtte) kan hjælpe ved at aflaste armen, så der kræves mindre muskelkraft. En passiv ortose bruger fjedre til at modvirke tyngdekraften. Dette studie præsenterer et prototype-design, der ved hjælp af muskel-skelet-modellering (computersimulering af knogler, led og muskler) optimerer fjederstivheder for at balancere armens vægt og samtidig kompensere for overdreven indadrotation i det primære skulderled (glenohumeralleddet). Der blev udviklet en personspecifik muskel-skelet-model til at simulere, hvordan ortosen påvirker bevægelser i ADL. Simulationerne viste, at en biartikulær fjeder (der virker over to led) med en stivhed på 233,33 Nm^-1 kunne sænke den maksimale muskelaktivitet til et niveau, hvor ADL-opgaver potentielt kan udføres.
People born with amyoplasia often have reduced muscle mass, joint contractures, and unusual limb positions, which makes activities of daily living (ADL) difficult. An orthosis (a wearable support) can help by unloading the arm so less muscle force is needed. A passive orthosis uses springs to counteract gravity. This study presents a prototype design that uses musculoskeletal modeling (computer simulations of bones, joints, and muscles) to optimize spring stiffnesses to balance the arm’s weight while compensating for excessive internal rotation of the main shoulder joint (the glenohumeral joint). A subject-specific musculoskeletal model was developed to simulate how the orthosis would affect ADL movements. The simulations showed that a biarticular spring (spanning two joints) with a stiffness of 233.33 Nm^-1 could lower maximal muscle activity to a level at which ADL tasks may be possible.
[This abstract was generated with the help of AI]
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