Development and Comprehensive Evaluation of 3D-Printed Prosthetic Feet: Modeling, Testing and a Pilot Gait Study

Background/Objectives: The modern prosthetic foot market is characterized by a pronounced polarization between affordable but low-function devices and high-performance yet costly composite prostheses. The aim of this study was to develop and comprehensively evaluate cost-effective, functional prosthetic feet manufactured by fused deposition modeling (FDM). Methods: An iterative design methodology was employed, combining finite element analysis to optimize the biomechanical response of the device, the incorporation of user-specific requirements and experimental validation. Two TPU 95A-based 3D-printed prosthetic foot designs were designed and developed, and their strength and functional characteristics were assessed numerically under the ISO 22675:2024 normative loading cycle. Bench-top mechanical tests were conducted on the fabricated prototypes. Functional performance was evaluated by a transtibial amputee using an inertial motion capture system to analyze gait kinematics. Results: The results demonstrated that both designs operate predominantly within the elastic range with an adequate safety margin. The pilot feasibility gait assessment indicated feasibility and plausibility within the tested protocol and participant for both prototypes. Conclusions: The developed TPU 95A-based FDM prosthetic feet demonstrated promising structural integrity and functional feasibility, supporting the potential of low-cost additive manufacturing as a viable approach for producing affordable prosthetic feet. Further studies with larger participant cohorts and extended testing are needed to confirm clinical applicability and long-term performance.