Design and Fabrication of 3D-Printed Splints for Wrist Fractures

Lee, Hao Yuen (2025) Design and Fabrication of 3D-Printed Splints for Wrist Fractures. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

This project focuses on the design, simulation, fabrication, and evaluation of a 3D-printed wrist splint using Finite Element Analysis (FEA) and topology optimization to improve material efficiency and mechanical performance. Wrist fractures often require immobilization treatments such as casting, which can be heavy, uncomfortable, and time-consuming. Additive manufacturing, specifically Fused Deposition Modeling (FDM), was selected for its flexibility, cost-effectiveness, and ability to produce customized orthopedic devices. The methodology involved wrist scanning, 3D modeling, mechanical simulation under both splinted and typical human loading conditions, and application of topology optimization targeting mass retention strategies of 50%, 60%, 70%, and 100%, hand functionality test were conducted with Range of Motion (ROM) test and Jebsen- Taylor Hand Functionality Test (JTHFT). Forces applied included 279.38N for flexion, 157.5N for extension, 213.75N for radial deviation, and 185.63N for ulna deviation. Printing parameters such as infill density of 85%, infill using line pattern, wall thickness of 0.6mm, and layer height of 0.2mm were systematically investigated to balance strength and minimize material usage. Key findings revealed that the optimized wrist splint achieved a 27.4% reduction in mass without compromising structural integrity, achieving factors of safety well above the minimum threshold of 1.5. Simulation results indicated that higher mass retention improved both maximum equivalent stress resistance and reduced deformation with a value of 3.62MPa and 0.20mm respectively. ROM evaluations further validated the designs, showing performance within clinically acceptable ranges of 10-15° of flexion and extension and 5-10° of ulna and radial deviation. Further evaluation on (JTHFT) shows the current design showing performance within range of 3.38s to 24.5s. Compared to previous studies, the current study demonstrated lower deformation and competitive structural performance, highlighting the benefits of topology optimization. In conclusion, this study demonstrates the feasibility and effectiveness of integrating FEA and additive manufacturing in developing lightweight, structurally optimized wrist splints. The optimized splint offers a practical, cost-effective alternative to traditional orthopedic treatments, ensuring patient comfort and faster recovery times through personalized and sustainable fabrication methods