Orthopedic device

1. An orthopedic device for the orthotic or prosthetic provision of a patient, comprising:

a knee joint, the knee joint having a proximal upper part and a distal lower part arranged pivotably thereon;

an ankle joint;

a pivotable foot part, which can be secured distally on the ankle joint;

a shin part arranged between the ankle joint and the knee joint;

wherein the upper part of the knee joint, or a thigh part that is secured thereon and can be fastened to the patient's body, is coupled to the foot part via a force transmission mechanism, which causes a plantar flexion of the foot part when the knee joint is flexed, the force transmission mechanism comprising a hydraulic system, the hydraulic system comprising:

a first unit comprising a first cylinder and a first piston, the first unit being arranged on the upper part or the thigh part, the first piston dividing the first cylinder into a first hydraulic chamber and a second hydraulic chamber;

a second unit comprising a second cylinder and a second piston, the second unit being arranged on the shin part or the foot part, the second piston dividing the second cylinder into a third hydraulic chamber and a fourth hydraulic chamber;

at least one hydraulic line fluidly connecting the first and second units.

2. The orthopedic device as claimed in claim 1 , wherein the force transmission mechanism further comprises a mechanical coupling mechanism that transmits at least one of tensile force and compressive force.

3. The orthopedic device as claimed in claim 2 , wherein the mechanical coupling mechanism is mounted on a first bearing point protruding dorsally or ventrally with respect to a knee axis and is mounted on a second bearing point ventrally or dorsally with respect to an ankle joint axis, wherein the first and second bearing points lie on different sides of a connection line between the knee axis and the ankle joint axis.

4. The orthopedic device as claimed in claim 2 , wherein the mechanical coupling mechanism is designed as an articulated rod or tensioning member.

5. The orthopedic device as claimed in claim 3 , wherein at least the first bearing point is designed to be adjustable.

6. The orthopedic device as claimed in claim 2 , wherein the force transmission mechanism has a control mechanism in order to permit or interrupt a force transmission.

7. The orthopedic device as claimed in claim 6 , wherein the control mechanism is coupled to at least one sensor in order to control a force transmission in accordance with sensor values.

8. The orthopedic device as claimed in claim 1 , wherein the cylinder/piston units are connectable to each other in parallel or crosswise via valves or individually adjustable.

9. The orthopedic device as claimed in claim 8 , wherein a sensor mechanism is provided for detecting at least one of a knee angle (α) and a plantar flexion angle (β), and is connected to a control mechanism for adjusting the valves.

10. The orthopedic device as claimed in claim 1 , wherein the force transmission mechanism blocks a force transmission in the dorsiflexion direction.

11. The orthopedic device as claimed in claim 1 , wherein a maximum dorsiflexion position of the foot part is designed to be variably adjustable.

12. The orthopedic device as claimed in claim 1 , wherein a restoring device is assigned to the foot part in order to effect a dorsiflexion of the foot part.

13. The orthopedic device as claimed in claim 1 , wherein the ankle joint is designed as an elastic joint and exerts a restoring force in the event of an excursion from a starting position.

14. The orthopedic device as claimed in claim 1 , wherein at least one damper, which counteracts a dorsiflexion, is present in the ankle joint.

15. An orthopedic device, comprising:

a knee joint, comprising:

a proximal upper part configured to be fastened to a patient;

a distal lower part pivotally connected to the proximal upper part;

an ankle joint;

a foot part pivotally connected to the ankle joint;

a shin part positioned between the ankle joint and the knee joint;

a force transmission mechanism coupled to the foot part and operable to provide a plantar flexion of the foot part when the knee joint is flexed, the force transmission mechanism comprising a hydraulic system, the hydraulic system comprising:

a first unit comprising a first cylinder and a first piston, the first unit being arranged on the upper part or a thigh part, the first piston dividing the first cylinder into a first hydraulic chamber and a second hydraulic chamber;

a second unit comprising a second cylinder and a second piston, the second unit being arranged on the shin part or the foot part, the second piston dividing the second cylinder into a third hydraulic chamber and a fourth hydraulic chamber;

at least one hydraulic line fluidly connecting the first and second units.

16. The orthopedic device as claimed in claim 15 , wherein the force transmission mechanism further comprises a mechanical coupling mechanism that transmits at least one of tensile force and compressive force.

17. The orthopedic device as claimed in claim 16 , wherein the mechanical coupling mechanism is mounted on a first bearing point protruding dorsally or ventrally with respect to a knee axis of the knee joint and is mounted on a second bearing point ventrally or dorsally with respect to an ankle joint axis of the ankle joint, wherein the first and second bearing points lie on different sides of a connection line extending between the knee axis and the ankle joint axis.

18. The orthopedic device as claimed in claim 16 , wherein the mechanical coupling mechanism is designed as an articulated rod or tensioning member.

19. The orthopedic device as claimed in claim 17 , wherein at least the first bearing point is adjustable.