An Integrative Computational Design Workflow and Validation Methodology for 3D-Printed Personalized Orthopedic Devices: Case Study of a Wrist–Hand Orthosis (WHO)

Abstract

Additive manufacturing (AM) technologies enable the production of customized and personalized medical devices that facilitate users’ comfort and rehabilitation requirements according to their individual conditions. The concept of a tailor-made orthopedic device addresses the accelerated recovery and comfort of the patient through the utilization of personalized rehabilitation equipment. Direct modeling, with an increasing number of approaches and prototypes, has provided many successful results until now. The modeling procedure for 3D-printed orthoses has emerged as the execution of steady and continuous tasks with several design selection criteria, such as cutting, thickening the surface, and engraving the shell of the orthosis. This publication takes into consideration the aforementioned criteria and proposes the creation of a holistic methodology and automated computational design process for the customization of orthotic assistive devices, considering aspects such as material properties, manufacturing limitations, recycling, and patients’ requirements. This proposal leads to the designing and manufacturing of a wrist orthopedic device based on reverse engineering, Design for AM (DfAM), and Design for Recycling (DfR) principles. The proposed methodology can be adjusted for different limbs. A dual-material approach was attained utilizing rigid, mechanically enhanced feedstock material and soft elastic material with reduced skin irritation risks to achieve both mechanical requirements and adequate cushioning for user comfort during rehabilitation. Recyclable thermoplastic matrices were selected, which also allow for the option to create washable devices for product life extension. Then, 3D scanning procedures were implemented to acquire the initial anatomic measurements for the design of the WHO and ensure and assess the dimensional accuracy of the final product. Physical mechanical testing was implemented to evaluate the WHO’s mechanical behavior and verify its functionality during basic wrist movements. The extracted dimensional data for the two main orthosis components that indicated approximately 50% and 25% of the tolerance values, respectively, were within the range (−0.1 mm, 0.1 mm).

The Influence of Thermoplastic Composite Recycling on the Additive Manufacturing Process and In-Use Phase as Candidate Materials for Wearable Devices Applications

“…Moreover, iron MNPs have also been investigated as additives for 3D-printed magnets and soft-robotics applications [ 26 ]. Concerning the wrist hand orthosis parts [ 27 ], TX1501 was chosen as a potential matrix, incorporating cCFs [ 28 , 29 ] to improve the mechanical properties of the final manufactured products. In addition, the 3D printing of thermoplastic composite filaments with CFs have been extensively investigated in multiple industrial sectors, such as aerospace, defense and automotive, due to their mechanical and thermal properties [ 30 ].…”

Innovative Approaches to 3D Printing of PA12 Forearm Orthoses: A Comprehensive Analysis of Mechanical Properties and Production Efficiency

“…The orientation of the 3D model alignment in the working chamber of the 3D printer significantly affects strength parameters such as tensile strength, flexural strength, and impact strength. In order to verify the necessary mechanical parameters of the orthosis, strength analysis should be carried out based on the data obtained [109,110], e.g., in Ansys 2023 R2 software, in order to investigate the occurring stresses in relation to the biomechanics of the forearm. The best solution is to tilt the 3D models in the working chamber of the machine.…”

“…One solution is to control the filling density of the working chamber to a maximum of 10%. The strength tests carried out for five different orientations can be used to develop a material model for static strength analyses [109,110]. Further development directions may be directed at studying the impact of the mechanical properties of 3D-printed forearm orthoses subjected to finishing treatments such as dyeing, mechanical polishing, and chemical smoothing.…”