Structural Performance Assessment of FUPRO Grace Foot

The structural safety qualification of medical devices such as trans-tibial prosthetic foot for regulatory compliance is performed in vitro as per international standards. This study attempts application of in silico analysis-driven approach for prosthetic foot design verification before attempting pilot production and in vitro qualification tests as per regulatory requirements. This procedure reduces the time and cost involved in developing and qualifying a batch of trans-tibial prosthetic feet prototypes. This paper presents the structural performance assessment of the FUPRO Grace Foot, a trans-tibial prosthetic foot, which is now commercialized in India by M/s FUPRO Innovation Pvt Limited. The study starts with a modal analysis of the device to determine the mode shapes and frequencies. Subsequently, the study reports static structural analysis of the device for forefoot and heel configurations. Finally, the study verifies the finite element model by in vitro tests of a batch of the Grace Foot as per the international standard, ISO 22675. The in silico modelling approach was verified by custom made fixtures, test systems and standard experimental protocols. The in silico results show a close correlation with in vitro results, which implies that the modelling approach can be used for the analysis-driven design of safe and effective trans-tibial prosthetic devices. Also, the FUPRO grace foot qualified for the in vitro cyclic endurance test, which implies the device is structurally safe.