Abstract
An orthopedic joint device having an upper part, on which upper connecting members for fastening to a patient are arranged, and a lower part, which is fastened to the upper part with articulation about a pivot axis. A flexion-moment-controlled halting device is arranged between the upper part and the lower part, which halting device blocks flexion movement and, when a predetermined flexion moment is exceeded, releases the flexion movement.
Claims
1. An orthopedic joint device, comprising: an upper part, on which are arranged upper connection members for securing the upper part to a patient; a lower part, which is fastened on the upper part in an articulated manner about a pivot axis; a retaining device arranged between the upper part and the lower part, wherein the retaining device has a flexion-moment-controlled design and arrests flexion movement of the lower part relative to the upper part and, when a predetermined flexion moment is exceeded, releases the lower part for flexion movement relative to the upper part; wherein the orthopedic joint device is designed in the form of an orthotic or prosthetic knee joint, an orthotic or prosthetic elbow joint, or an orthotic or prosthetic wrist joint.
2. The orthopedic joint device as claimed in claim 1, further comprising a damper device arranged between the upper part and the lower part and damps a flexion movement and/or extension movement of the lower part relative to the upper part.
3. The orthopedic joint device as claimed in claim 2, wherein the damper device is designed such that it can be switched between a high damping resistance and a low damping resistance.
4. The orthopedic joint device as claimed in claim 3, wherein the damper device is assigned an axial-force-dependent switching device which, when an axial force acting on the lower part drops below a certain value, enables the reduced damping resistance.
5. The orthopedic joint device as claimed in claim 3, wherein the damper device is assigned a mechanical switch or a sensor-controlled switch provided with an actuator.
6. The orthopedic joint device as claimed in claim 1, wherein the retaining device is designed in the form of a force-fitting or form-fitting retaining device.
7. The orthopedic joint device as claimed in claim 1, wherein a retaining force exerted by the retaining device is adjustable.
8. The orthopedic joint device as claimed in claim 1, wherein the upper part is mounted in a displaceable manner in relation to the lower part.
9. The orthopedic joint device as claimed in claim 8, further comprising a displacement-counteracting spring element arranged between the upper part and the lower part.
10. The orthopedic joint device as claimed in claim 1, wherein the retaining device has at least one of a magnetic coupling, a suction-cup coupling, a prestressed snap spring, and a hydraulic arresting unit with a switchable arresting valve.
11. (canceled)
12. The orthopedic joint device as claimed in claim 1, further comprising a separate hydraulic damper arranged between the upper part and the lower part.
13. The orthopedic joint device as claimed in claim 1, wherein the retaining device has, or forms, a sensorless-operation release mechanism.
14. An orthopedic joint device, comprising: an upper part having upper connection members to secure the upper part to a patient; a lower part pivotally connected to the upper part; a retaining device arranged between the upper part and the lower part, the retaining device having a flexion-moment-controlled design that stops flexion movement of the lower part relative to the upper part and, when a predetermined flexion moment is exceeded, releases the lower part for flexion movement relative to the upper part; wherein the orthopedic joint device is designed in the form of an orthotic or prosthetic knee joint, an orthotic or prosthetic elbow joint, or an orthotic or prosthetic wrist joint.
15. The orthopedic joint device as claimed in claim 14, further comprising a damper device arranged between the upper part and the lower part and damps a flexion movement and/or extension movement of the lower part relative to the upper part.
16. The orthopedic joint device as claimed in claim 15, wherein the damper device is designed such that it can be switched between a high damping resistance and a low damping resistance.
17. The orthopedic joint device as claimed in claim 16, wherein the damper device is assigned an axial-force-dependent switching device which, when an axial force acting on the lower part drops below a certain value, enables the reduced damping resistance.
18. The orthopedic joint device as claimed in claim 16, wherein the damper device is assigned a mechanical switch or a sensor-controlled switch provided with an actuator.
19. The orthopedic joint device as claimed in claim 14, wherein the retaining device is designed in the form of a force-fitting or form-fitting retaining device.
20. The orthopedic joint device as claimed in claim 14, wherein a retaining force exerted by the retaining device is adjustable.
21. The orthopedic joint device as claimed in claim 14, wherein the upper part is displaceably mounted relative to the lower part.
Description
[0020] Exemplary embodiments of the invention will be explained hereinbelow with reference to the accompanying figures, in which:
[0021] FIG. 1 shows a schematic illustration of an orthopedic joint device having a magnetic retaining device;
[0022] FIG. 2 shows a variant of FIG. 1 having a negative-pressure-based retaining device;
[0023] FIG. 3 shows a variant of the invention having a spring-loaded retaining device;
[0024] FIG. 4 shows a variant of the invention having a hydraulic retaining device;
[0025] FIG. 5 shows a further variant of FIG. 1; and
[0026] FIGS. 6-8 show variants of FIGS. 1 to 3 having an additional hydraulic damper.
[0027] FIG. 1 shows a schematic sectional illustration of an orthopedic joint device in the form of an artificial knee joint having an upper part 10, on which are arranged upper connection means 11 in the form of an upper-leg socket for securing to a patient. As an alternative to an embodiment in the form of a prosthetic knee joint, the artificial knee joint may also be designed in the form of an orthotic knee joint in which the upper part 10 is designed in the form of an upper-leg splint and the upper connection means are designed in the form of a cuff, tab, strap or the like, in order for the orthosis to be fitted to the patient's upper leg by way of the upper-leg splint. As an alternative to an embodiment in the form of an artificial knee joint, other uses are provided with the orthopedic joint device and are covered by the invention, for example for prostheses and/or orthoses for upper and lower extremities such as ankle orthoses, elbow orthoses, wrist orthoses and prostheses for ankles, knees, elbows or hands.
[0028] A pivot pin 20 is formed on the upper part 10, and a lower part 30, which is secured on the upper part 10, is mounted such that it can be pivoted about said pivot pin 20. The lower part 30 may be designed in the form of a lower-leg splint with fastening means for securing the lower-leg splint to the lower leg, in the case of an embodiment in the form of an orthosis. The fastening means may be designed in the form of straps, cuffs or the like and wrap around the lower leg; if appropriate, a foot part may be arranged on the lower-leg splint, to form a KAFO (Knee Ankle Foot Orthosis). In the case of the artificial knee joint being embodied in the form of a prosthetic knee joint, the lower part 30 is designed in the form of a lower-leg tube, on which a prosthetic foot (not illustrated) is secured. Upper-extremity prostheses or ortheses are constructed in a corresponding manner.
[0029] The pivot pin 20 is designed in the form of a continuous pivot pin; it is also possible, in principle for a multi-link joint to form a non stationary joint pin.
[0030] The upper part 10 projects distally beyond the pivot pin 20 and has a magnet 41 fastened on it, the magnet butting against a yoke 42, which is fastened on the lower part 30. The magnet 41 and the yoke 42 together form the retaining device 40, via which the knee joint is locked in the extended position illustrated. In such a locked position, it is not possible for the lower part 30 to pivot relative to the upper part 10 about the pivot pin 20; the user or patient can trust in the extended knee joint being secured when he is standing, walking or sitting.
[0031] The right-hand illustration of FIG. 1 shows to the knee joint in a flexed, bent position. Application of a flexion moment about the pivot pin 20, for example when a hip moment is applied or a heel is placed down with sufficient loading of a ground-reaction force vector running behind the pivot pin 10, causes the retaining force of the retaining device 40 to be exceeded, and therefore the magnet 41 disengages from the yoke 42 and the upper part 10 can be pivoted freely relative to the lower part 30 about the pivot pin 20.
[0032] The exemplary embodiment illustrated in FIG. 1 shows no further damping component or damping device; it is also possible, in principle, for the upper part 10 and the lower part 30 to have provided, and arranged, between them a damper device which damps a flexion movement and/or extension movement of the upper part 10 relative to the lower part 30. Such a damper device is advantageously designed in the form of a hydraulic damper or pneumatic damper; it is also possible, in principle, for a solid damper to be arranged between the upper part 10 and the lower part 30.
[0033] FIG. 2 illustrates a variant of FIG. 1, the component bearing the same reference signs corresponding to one another. In contrast to FIG. 1, the retaining device 40 is of vacuum-based construction in FIG. 2, the retaining force being realized via a vacuum effect. The upper part 10 has fastened on it a suction cup 43, which butts against a smooth surface 44, which is formed or arranged on the lower part 30, and provides for fixed abutment via a negative pressure in the enclosed volume. It is only when a predeterminable flexion moment is exceeded that the suction cup 43 is disengaged from the smooth surface 44, and ambient air enters into the volume between the suction cup 43 and the smooth surface 44 and results in pressure equalization, the ambient air therefore no longer keeping the suction cup 43 pressed against the smooth surface 44. The retaining force provided by the suction cup 43 is overcome and the knee joint is released for the flexing movement.
[0034] FIG. 3 shows a variant of the invention in which the retaining device 40 is of resilient design and comprises a roller 45 or a bolt, which is fastened on the lower part 30, and a leaf spring 46, which is arranged on the upper part 10. At a front end, the leaf spring 46 has a convexity or shaping which is designed to correspond to the contour of the roller 45, and therefore, in the locked state according to the left-hand illustration of FIG. 3, the knee joint is locked in a quasi form-fitting manner. On account of prestressing, the spring 46 pushes against the roller 45, and therefore the joint, e.g. a knee joint, elbow joint, ankle joint or wrist joint in the form of an orthosis or prosthesis, is retained in the extended position since the convexity or curvature of the spring 46 accommodates the roller 45. When a sufficiently high flexion moment is applied about the pivot pin 20, the curvature or convexity at the end of the leaf spring 46 moves out of the roller 45, the roller 45 rolls on the spring 46 and the joint can flex essentially freely.
[0035] The embodiments illustrated according to FIGS. 1 to 3 may also have the components of the retaining device 40 arranged the other way round. In this case, the magnet 41 is arranged on the lower part 30 and the yoke 42 is arranged on the upper part 10, the smooth surface 44 is located on the upper part 10 and the suction cup 43 is located on the lower part 30, just as the spring 46 is located on the lower part 30 and the roller 45 is located on the upper part 10. Provision is likewise made for the retaining force of the retaining device 40 to be designed to be adjustable in each case; in the case of a magnetic retaining device, this can be achieved by the distance between the yoke 42 and magnet 41 being increased, by material being introduced, or else by the contact surface area between the magnet 41 and the yoke 42 being reduced in size. A similar variation can be achieved for the vacuum-assisted concept according to FIG. 2, in which the surface area or the enclosed volume can be reduced or increased in size. The resilient locking can be varied in terms of retaining force by virtue of the prestressing of the spring 46 being adjusted.
[0036] FIG. 4 illustrates a further variant of the invention. The retaining device 40 is of hydraulic design and therefore forms, at the same time, a damper device 50. The retaining device 40 with the damper device 50 has a piston rod 51, which is mounted in a pivotable manner on the upper part 10. A piston 53 is arranged at the end of the piston rod 51 and is guided in a hydraulic cylinder 52, which for its part is secured in an articulated manner on the lower part 30. The piston 53 subdivides the cylinder 52 into an extension chamber and a flexion chamber. In the case of flexion, the hydraulic fluid is directed, through a bypass 54, from the flexion chamber into the extension chamber. The bypass 54 contains a nonreturn valve 55, which is prestressed via a spring. The spring prestressing can be adjusted via an adjustment device 56, for example a screw. If the flexion moment applied is one which exceeds the spring prestressing of the nonreturn valve 50, the nonreturn valve 55 opens and the hydraulic fluid can flow from the flexion chamber, through the bypass 54, into the extension chamber and, possibly, an equalizing tank. The joint, e.g. knee, elbow or ankle, bends counter to the resulting flow resistance and allows flexion. Flexion is therefore released, the flexion movement being damped. In the case of extension, the hydraulic fluid flows out of the extension chamber through a return-flow channel (not illustrated), which is likewise provided with a nonreturn valve, albeit one acting in the opposite direction, and back into the flexion chamber. The flexed position of the joint is shown in the right-hand illustration.
[0037] The flow resistance can be adjusted by the spring prestressing and the adjustment device 56; it is also possible to switch over between two levels of prestressing, and therefore also two release moments, or else to achieve different resistances in the unlocked position, which therefore allows access to flexion.
[0038] FIG. 5 illustrates a further variant of the invention, in which, for example by way of a magnetic locking mechanism, the upper part 10 can be displaced relative to the lower part 30 counter to a spring force. In the exemplary embodiment illustrated, the upper part 20 has an axis guided about the pivot pin 20 in a slot 13, which is formed in the lower part 30. The slot 13 contains a spring 60, which counteracts displacement along the slot 13. If an increased axial force is applied along the slot 13, the magnet 41 is displaced relative to the yoke 42 and reduces the retaining force between the magnet 41 and the yoke 42 and therefore also the moment of flexion which has to be applied in order to provide for flexion. Corresponding embodiments are also provided for the variants of FIGS. 2 and 3. In addition to reducing the necessary flexion moment, it is also possible for displacement of the upper part 10 in relation to the lower part 30 to increase the flexion moment which has to be applied.
[0039] FIG. 6 shows a variant of FIG. 1 in which, in addition to the retaining device 40 with a magnet 41 and a yoke 42, a hydraulic damper 50 is arranged between the upper part 10 and the lower part 30. The hydraulic damper 50 is constructed in a manner analogous to the hydraulically active retaining device 40 according to FIG. 4 and has a housing 52, in which a cylinder 53 is mounted in a displaceable manner. The cylinder 53 subdivides the housing 52 into two chambersan extension chamber and a flexion chamberwhich are coupled to one another in terms of flow via overflow channels and, possibly, equalizing tanks. It is possible to adjust the hydraulic resistance within the overflow channels; if appropriate, pressure can build up in a pressure tank in order to assist a reverse movement.
[0040] In the exemplary embodiment illustrated, the piston 53 is secured on the upper part 10 at an upper bearing joint 57 by way of a piston rod 51. The upper bearing point 57 is located posterior to the pivot pin 20. The cylinder 52 is arranged on the lower part 30 at a lower bearing point 58. If the joint is flexed from the extended position according to the left-hand illustration of FIG. 6, once the magnetically active retaining device 40 has been overcome and a sufficiently large moment of flexion has been applied about the pivot pin 20, the upper part 10 pivots relative to the lower part 30. On account of the movement of the upper bearing point 57 relative to the lower bearing point 58, the hydraulic piston 53 is moved in the direction of the lower bearing point 58. Hydraulic fluid flows from the lower chamber into the upper chamber, and the hydraulic resistance within the hydraulic damper 50 damps the flexing movement of the upper part 10 relative to the lower part 30. The hydraulic resistance and therefore also the damping of the flexing action can be adjusted, for example by manually adjustable or motor-adjustable valves or throttles within the overflow channels. In the case of a movement in the opposite direction, that is to say in the case of an extension movement, the upper bearing point 57 moves away from the lower bearing point 58, the piston 53 is moved in the opposite direction and an extension movement is correspondingly damped. It is possible to provide damping resistances of different magnitudes for the extension movement or flexion movement.
[0041] FIG. 7 shows the variant of FIG. 2 with the retaining device 40 embodied in the form of a suction cup 43 and of a smooth surface 44 in combination with the hydraulic damper 50, as has been described in FIG. 6. FIG. 8 shows a variant of FIG. 3 with the resilient retaining device 40 connected to a separate hydraulic damper 50 according to FIG. 6. What has been said in each case in relation to the retaining devices according to FIGS. 2 and 3 applies correspondingly in combination with what has been said in relation to the hydraulic damper according to FIG. 6.
[0042] A use example of the invention relates to orthoses with an abovedescribed orthopedic joint device, having a retaining device which, when an applied force is exceeded, eliminates, or vastly reduces, the resistance to flexion so that injury, e.g. in the event of spasm, is avoided. Use is made here of spring-loaded or damped orthopedic joint devices, so-called dynamic joints, in order to counteract contractions or to treat the same by way of stretching exercises. The retaining device here acts as a safeguard against overload.
