Design and Additive Manufacturing of a Transfemoral Prosthetic Socket

Abstract

Traditional manufacturing of transfemoral (TF) prosthetic sockets relies on labour-intensive casting and lamination processes that are costly, time-consuming, and difficult to standardise. As additive manufacturing (AM) technologies-particularly fused deposition modelling (FDM)-continue to advance in affordability and reliability, they present an opportunity to streamline prosthetic production while enabling greater repeatability, digital control, and accessibility. This study addresses the need for a more efficient and cost-effective alternative by designing and manufacturing a TF prosthetic socket specifically for AM and evaluating its structural performance against regulatory loading requirements. A patient-specific socket geometry was obtained by 3D scanning an existing TF socket and processing the resulting mesh in MeshMixer before generating two design variants in SOLIDWORKS. Each design underwent linear static finite element analysis (FEA) to identify critical stress regions and compare relative structural performance under ISO 10328 loading condition P5. Based on these simulations, a final design was selected for fabrication. Sockets were manufactured using FDM with polyethylene terephthalate glycol (PETG) filament, chosen for its favourable printability and availability. The final PETG sockets were subjected to ultimate static strength testing in accordance with ISO 10328 P5 [I] using a uniaxial testing machine. Only PETG specimens were tested. The PETG sockets successfully exceeded the ultimate test force of the P5 [I] loading condition. One specimen was loaded to failure, which occurred at 7.2 kN through a brittle fracture at the distal end. The fracture propagated along and across layer lines, indicating strong interlayer adhesion. Additional sockets were loaded to 5 kN-beyond the ISO 10328 requirement-to avoid equipment damage, and no visible deformation or structural compromise was observed. The failure location and fracture propagation pattern corresponded qualitatively with the high-stress regions predicted by FEA, demonstrating that the simulations were effective as a comparative design tool. Overall, the findings demonstrate that PETG is a suitable material for FDM-manufactured TF prosthetic sockets and is capable of meeting the ultimate static strength requirement specified by ISO 10328 P5 [I]. While the results confirm the viability of PETG sockets under static loading, further testing-including cyclic loading and additional ISO 10328 requirements-is necessary to establish full regulatory compliance. Nevertheless, the successful performance of PETG, combined with its printability and widespread availability, highlights its potential for producing accessible, low-cost, and digitally manufactured TF prosthetic sockets.