Development of modular wrist, hand and finger orthesis by additive manufacturing

Paloma Hohmann Poier,Gabriel Chemin Rosenmann,Maria Gabriela Reis Carvalho,José Aguiomar Foggiatto,Leandra Ulbricht,Rodrigo Pulido Arce

doi:10.33448/rsd-v10i15.22707

Abstract

Additive Manufacturing (AM) has been considered an innovative technology for the development of orthoses. Even so, the use of AM, utilizing low cost rigid and flexible material which can be used in different ways by the same user, to produce a modular orthosis has yet to be explored. Purpose: Develop a modular wrist, hand and finger orthosis that can be utilized as a functional or static orthosis, depending on the therapeutic objective. This being produced by low cost Additive Manufacturing, through a single anatomy acquisition process. Approach: Firstly, requirements for modularization and development were defined in a team with occupational therapists and mechanical engineers, After indirect anatomy acquisition of a volunteer, without disabilities, two parts of the same orthosis were modeled, one flexible (functional) and the other rigid (static). These were printed on PLA (rigid part) and flexible TPU (functional part) with an Open Source printer. In addition, fastening strips were also made in flexible TPU. Findings: Three parts of which make up the modular orthosis were produced. This can be used in two different ways; one being to maintain the static posture of the wrist, hand and fingers and the other to provide functionality of the hands, but with the correct positioning of the wrist and thumb. Originality: Even with low-cost material and an open source machine, it was possible to generate an innovative proposal with the use of AM as the orthosis manufacturing process.

Highlights

Additive manufacturing (AM) has been recognized as a modern process for the manufacture of customized assistive technology devices, such as orthoses for upper limbs (Chen, Jin, Wensman, & Shih, 2016; Fernandez-Vicente, Chust, & Conejero, 2017; Palousek, Rosicky, Koutny, Stoklásek, & Navrat, 2013; Paterson, Bibb, Campbell, & Bingham, 2015)
Using only the functional part made of flexible material, correct thumb positioning and extended wrist stabilization were observed (Figure xa) The inclusion of material reinforcement in the region of the wrist joint was sufficient to limit the flexion movement
The modular orthosis developed presents innovative elements regarding the different options of use and the application of low cost flexible 3D printing

Summary

Introduction

Additive manufacturing (AM) has been recognized as a modern process for the manufacture of customized assistive technology devices, such as orthoses for upper limbs (Chen, Jin, Wensman, & Shih, 2016; Fernandez-Vicente, Chust, & Conejero, 2017; Palousek, Rosicky, Koutny, Stoklásek, & Navrat, 2013; Paterson, Bibb, Campbell, & Bingham, 2015). The fabrication process allows for the use of different materials and substantial changes in originally developed projects (Paterson et al, 2014; Poier et al, 2021). The upper limb orthoses made by AM, as reported in the literature, are of the static type, for limb immobilization, constructed with rigid materials such as ABS (Palousek et al, 2014; Kim and Jeong, 2015) or PLA (Rosenmann et al, 2018; Blaya et al, 2018). The devices are used alternately, according to a rehabilitation protocol

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