Design and feasibility testing of an automated custom finger orthosis for virtual therapy.

Abstract

Background: 3D printing has revolutionized orthoses manufacturing in assistive technologies, enabling development of custom-fitted orthoses in under 24 hours. Physician-engineer collaboration is essential to addressing the mechanical complexities of automated orthoses design. Single-step manufacturing of these devices is necessary for simplistic and translational technologies.

Purpose: This work proposes a novel automated program, application programing interface, to design a custom single-finger orthosis using only basic biometric data (body weight, height, and age) as input to enable fully virtual rehabilitation.

Study design: Feasibility study, cross-sectional design, and survey study.

Methods: Customization without body scans streamlines programming and enables gross estimate of hand orthosis size. Computer-aided design models are automatically generated using the Automated Custom Finger Orthoses system that was created using several macros with SolidWorks and Visual Basic Editor. A military database was used for the biometric data for the program to establish a relationship between finger size and biometric data. Survey data were taken from 10 human healthy participants (six male and four female, aged between 18 and 60) using Likert scales to check fitness of 3D-printed soft index finger orthosis part.

Results: Computer-aided design models were successfully created using the application programing interface using military database, the models were 3D-printed and fitted on subjects. The fitness of the device varies significantly under the current parameters. Eight of the 10 test devices fit their test subjects with overall average offsets of 7.00 mm, 6.14 mm, and 8.89 mm for DIP (L1), PIP (L2), and MCP joints (L3 offset), respectively and the subjects were fully donned. The biasing of current data toward male subjects results in slightly better fit accuracy in males than in females.

Conclusions: Anthropometric studies can aid in discerning fundamental ratios for orthoses design, allowing for custom-fitted designs and manufacturing with ease and efficiency.