3 degrees of freedom ankle prosthesis

An ankle prosthesis or orthosis comprising

• a tibia portion,
• two upper foot parts to perform an inversion and eversion of the ankle prosthesis or orthosis, wherein the tibia portion is positioned between the two upper foot parts, and connected with the two upper foot parts at right and left sides of the tibia portion by means of connecting members, and
• two lower foot parts, wherein the two lower foot parts are positioned parallel to each other, wherein the ankle prosthesis or orthosis is in contact with a surface, comprising
• two first pistons, wherein the two first pistons are positioned parallel to each other at a predetermined distance at a middle of the two lower foot parts and comprise at least one dorsiflexion member, wherein the at least one dorsiflexion member stores kinetic energy during a movement of the ankle prosthesis or orthosis and releases the kinetic energy during push-off, wherein
• a tibia connecting member is connected by a piston connecting member, wherein the tibia connecting member connects the tibia portion with the two first pistons, wherein the tibia connecting member is disposed between the two identical first pistons, wherein a stored energy is in the at least one dorsiflexion member with a bending movement of an ankle towards a leg during walking, and the stored energy is returned back with a plantar flexion as the ankle moves away from the leg and towards the surface, and
• a second piston, wherein the second piston connects rear parts of the two upper foot parts with rear parts of the two lower foot parts, wherein a heel member is located inside the second piston,
• wherein a pressure is exerted on the heel member by a downward movement of the second piston, and the heel member allows the inversion and eversion of the ankle prosthesis or orthosis.