Design of a Mass-Manufacturable Passive Prosthetic Foot

Abstract A lack of affordable energy storage and return (ESR) prosthetic feet leads many amputees in low- and middle-income countries (LMIC) to use feet with biomechanical performance inappropriate for their activity levels. To create better options, the GEAR Lab at MIT developed the LLTE design framework, which systematically designs ESR feet to enable replication of able-bodied gait. LLTE-optimized foot prototypes have been tested in a long-term field trial in India and in gait labs in the United States. The feet demonstrated robustness to use for activities of daily living in India, and as good or better biomechanical performance and user satisfaction compared to commercial carbon fiber feet sold in the United States. However, these prototypes were not designed to be commercial products, but rather to demonstrate the viability of the LLTE design framework. This work translates these costly proof-of-concept prototypes to affordable commercial products by making the foot mass-manufacturable and improving user satisfaction via aesthetics, coronal compliance, and a sandal toe. The keel is revised to be compatible with injection molding manufacturing constraints. It is then encased in a polyurethane foam overmold with a ruggedized sole that resembles a biological foot. Commercialization of this foot will offer amputees an affordable ESR option with improved biomechanical performance over currently available options.