Despite advancements in 3D-printed wrist splints, prior studies often overlook the combined effects of loading directions, mass retention levels, materials, and splint lengths, limiting insights into optimal designs that balance structural integrity with functional usability. The study evaluates the mechanical and functional performance of three-dimensional (3D)-printed topology-optimized wrist splints. The methodology includes wrist scanning, 3D modelling, mesh validation and convergence study, and topology optimization with mass retention levels of 50%, 60%, 70% and 100%. Four loading directions of flexion, extension, radial and ulnar deviations were simulated in ANSYS Mechanical to determine maximum stress, deformation and Factor of Safety (FOS) of the wrist splint model. Additionally, different materials (Polylactic Acid (PLA), Acrylonitrile Butadiene Styrene (ABS), Polycarbonate (PC) and Nylon) and splint lengths were investigated to identify the optimal configuration. Flexion was identified as the critical loading direction, which yielded the highest stress and deformation. PLA models demonstrated lowest stress and deformation, with a FOS of 5.39 and above, as compared to other materials regardless of mass retention levels. The 70% topology-optimized medium-length splint (173.4 mm) demonstrated consistent mechanical performance, with a maximum stress of 7.51 MPa, deformation of 0.52 mm, and FOS of 7.58. The wrist splint was fabricated using PLA and evaluated through Range of Motion (ROM) and Jebsen-Taylor Hand Function Test (JTHFT). The topology-optimized splint achieved ROM values of 10° to 13° in flexion and extension, and 5°-10° in ulnar and radial deviation. JTHFT results indicated that optimized splints provided sufficient flexibility for daily and modern activities. Overall, the study provides practical guidelines for topology optimization, splint length, material selection and functional performance for 3D-printed wrist splint. This approach offers advantages over prior works by integrating multi-directional finite element analysis with functional testing, yielding practical guidelines for customizable splints that reduce mass while enhancing safety and patient comfort compared to traditional casts or single-parameter optimizations.
Yuen et al. (Thu,) studied this question.