MODELING AND GAIT EVALUATION OF ASYMMETRICAL-KEEL FOOT PROSTHESIS

The paper documents a new concept in prosthetic foot design, It is bas ed on the capacity of a flexible keel to allow a greater medio-lateral function than previously available. The heel has a complex curvature consisting of a medially concave shape that joins the mid-foot, There a hump acting as a leaf-spring ends at the metatarsal break, with an i nwardly curved toe extremity, These curvatures contribute to increased medio-lateral control at heel-strike and propulsion for weight transf er and push-off. Results from finite-element modelling indicate that t he asymmetrically shaped keel is at least twice as active in storing e nergy compared with a completely symmetrical one. A preliminary gait s tudy is carried out for a 24-year-old below-knee amputee fitted with t he new design, the SPACE foot and a dynamic elastic response foot with a symmetrical keel, With the SPACE foot, there is a 14% increase in w alking speed combined with a reduction in the phasic asymmetries, The absolute difference between the initial and terminal double support is 1.4% for the asymmetrical keel design compared with 4.4% for the symm etrical keel foot prosthesis. The peak ankle power generation burst in dicates that the SPACE foot behaves as a dynamic elastic response foot .