An Adjustable Semi-Customized Design Methodology to Promote Mass Customization of Arm–Wrist Orthotic Devices: A Pathway to Cost-Effective Mass Customization

Abstract Orthoses are effective rehabilitation devices that provide support, protection, comfort, and deformity correction, playing a vital role in improving recovery and functional outcomes. Because of substantial individual anatomical variations, higher customization levels are critical for optimal fit and comfort. However, this typically increases cost and production time. To promote mass customization by reducing time and cost while maintaining satisfactory fit, this study proposes an adjustable semi-customized design methodology and develops 12 modular arm–wrist orthoses assembled with adjustable connectors. Analyses and experiments were conducted to evaluate connector adjustability and validate the overall fitting performance. Connector experiments confirmed their ability to achieve the required adjustability range, with deformation between −9.2 mm and +10.5 mm accommodating intracluster variations. Computational analyses demonstrated that the semi-customized designs conform effectively to target surfaces through adjustment. Approximately 75% of surface regions exhibited a normal distance below 1.5 mm between target and orthosis after adjustment, indicating successful adaptation—especially considering the conventional 2–5 mm padding allowance. Furthermore, the fitting experiment yielded positive participant feedback, confirming the satisfactory performance of the adjustable semi-customized designs. The proposed methodology thus provides a promising solution to mitigate the excessive time and cost of orthotic manufacturing while maintaining fit quality, contributing to time-efficient and cost-effective mass customization of orthotic devices.