Patient-specific design of passive prosthetic leg for transtibial amputee: analysis between two different designs

Abstract

Amputee patients are usually utilized prosthetic leg for daily activities such as walking, climbing, and running. However, the current prosthetic leg that available from the market often associated with poor comfortability due to its conventional way of socket manufacturing. Therefore, this research aims to build custom-made passive transtibial prosthetic legs and to evaluate the aspects of biomechanical analysis. Methods: The residual leg of a subject was scanned using the Sense three-dimensional scanner. By referring to scanned residual leg model, two design of prosthetic legs which are the low-cost solid ankle cushion heel (SACH) foot (D1), and the high-cost flex foot (D2), were developed by using computer aided software (CAD), SolidWorks and Meshmixer. Each of the components were then meshed with triangle edge length of 5 mm in 3-Matic software. Marc.Mentat software was used to simulate the midstance phase of a gait cycle where an axial load of 350 N was applied. Results: The overall maximum stress of the D1 (190.2 MPa) was higher than D2 (38.47 MPa). In addition, socket and pylon in D1 showed tendency to yield because the maximum stress is higher than yield stress of respective materials. In displacement analysis, D2 showed higher overall displacement than D1 because the flex foot has higher flexibility. Conclusion: From overall result, prosthetic leg of D2 is better in biomechanical strength as compared with the D1 because it can withstand the loading from subject's weight without showing any sign of yield.