Develop remote orthotic fabrication workflow using 3D modeling and 3D printing technology for carpometacarpal osteoarthritis.

BACKGROUND

Carpometacarpal (CMC) osteoarthritis often requires orthotic intervention to reduce pain and improve function. Traditional orthosis fabrication typically demands in-person clinical visits, which can be a barrier to care.

PURPOSE: To develop and validate a fully remote workflow for fabricating custom orthoses using mobile 3D scanning, web-based assessment, and 3D printing technologies for patients with CMC osteoarthritis.

STUDY

DESIGN

Pilot validation study.

METHODS

A five-step workflow was created: (1) a web-based application ("Hand Scan") for assessing pain, sensory function, and range of motion; (2) mobile 3D hand scanning using smartphone cameras, with scans processed in Agisoft Metashape; (3) digital joint repositioning using finite element analysis software; (4) orthosis design using parametric modeling; and (5) fabrication using 3D printing with Orfit's low-temperature polycaprolactone filament. Five patients with CMC osteoarthritis were recruited. The application's usability was tested via cognitive interviews. Mobile scanning accuracy was validated against high-precision photogrammetry, and surface deviations of the 3D-printed orthoses were compared with traditional thermoplastic models.

RESULTS

The Hand Scan app demonstrated strong content validity. Mobile scans showed a mean absolute deviation of 0.93 mm (SD = 0.61 mm). Joint repositioning yielded a mean deviation of 0.87 mm. The 3D-printed orthoses demonstrated a better fit than thermoplastic models, with a mean surface deviation of 0.95 mm compared to 1.96 mm. The maximum deviation was 3.17 mm for 3D-printed and 5.81 mm for traditional orthoses.

CONCLUSIONS

This remote orthotic fabrication workflow is accurate, feasible, and clinically applicable. It supports personalized orthosis design while reducing the need for in-person visits. The workflow has strong potential for telehealth and remote hand therapy services.