3 degrees of freedom ankle prosthesis

An ankle prosthesis or orthosis comprising

• a tibia portion,
• two upper foot parts to perform inversion and eversion movements 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 support 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 first pistons, wherein the at least one dorsiflexion member stores energy during dorsiflexion of the ankle prosthesis or orthosis toward a user's leg during walking, and returns the stored energy during plantarflexion as the ankle prosthesis or orthosis moves away from the user's leg toward the support surface, and
• two second pistons, wherein the two second pistons connect rear parts of the two upper foot parts with rear parts of the two lower foot parts, wherein each second piston includes a heel member located therein, wherein a pressure is exerted on the heel member by a downward movement of the respective second piston, and the heel member allows inversion and eversion of the ankle prosthesis or orthosis to be performed.