The invention relates to an orthosis for a lower limb, having a foot part which has a sole for supporting a foot, and having at least one leg rail which extends from said foot part and which in the fitted state extends along a lower leg and which has devices for supporting and/or fastening the leg rail on the lower leg. The invention likewise relates to a method for controlling such an orthosis.
Orthoses are function-ensuring medical aids which lie against the body and which are used to assist body parts with restricted functional capability, wherein, in particular, stabilizing, mobilizing, load-relieving and corrective functions of the orthosis are of primary concern. So-called AFOs (ankle-foot orthoses) are orthoses which are used to compensate insufficient lower leg musculature following peripheral paralysis and to ensure knee stability in the case of quadricep weakness.
Insufficient lower leg musculature is nowadays treated almost exclusively by way of so-called foot lifting orthoses which have no influence on the knee joint or the calf musculature and therefore cannot prevent the occurrence of incorrect positioning as a tertiary consequence of an impairment. Quadricep weakness is treated predominantly using orthoses which also extend across the knee, so-called KAFOs (knee-ankle-foot orthoses).
DE 10 2004 030 570 A1 describes a support element for a lower leg orthosis, in the case of which a lower-leg sleeve is connected by means of the elastically deformable support element to a foot sleeve. The lower-leg sleeve and the foot sleeve can be fastened to the lower leg and to the foot respectively by way of hook and loop fasteners. An electrical circuit with an electromechanical transducer in the form of a piezo element converts mechanical energy during the deformation of the support element into an electrical signal that is stored in a memory. A resetting or damping element is provided by means of which the spring rate of the support element can be varied in a manner dependent on a signal. The stored electrical energy is converted into mechanical energy again as required, for example in order to vary the spring rate of the support spring, in particular in order to stiffen the support element.
WO 2005/025446 A2 describes an orthosis with a sole and with a lower leg part. From the heel region of the sole to a toe region of the sole, different thicknesses and stiffnesses are provided in order to provide improved support of the foot.
It is an object of the present invention to provide an orthosis and a method for controlling an orthosis, with which an adaptation to changes in the usage conditions is possible in order to increase the wearing comfort and the benefit for the patient.
According to the invention, said object is achieved by means of an orthosis having the features of the main claim and a method having the features of the coordinate claim. Advantageous embodiments and refinements of the invention are disclosed in the subclaims, in the description and in the figures.
The orthosis according to the invention for a lower limb, having a foot part which has a sole for supporting a foot, and having at least one leg rail which extends from said foot part and which in the fitted state extends along a lower leg and which has devices for supporting and/or fastening the leg rail on the lower leg, provides that the orthosis is assigned at least one sensor for detecting orthosis parameters, which at least one sensor is coupled to a control device, and that the foot part is assigned at least one device, which is coupled to the control device, and/or materials for varying the stiffness of the sole. By means of the detection of orthosis parameters by means of sensors and the conversion of the orthosis parameters in a control device into signals with which the stiffness of the sole is varied, and individual adaptation of the sole to the ambient conditions, to the patient and to their gait behavior is possible. In particular, the stiffness of the heel lever and/or the stiffness of the forefoot lever can be varied. It is thus possible to provide a dynamically adaptive foot orthosis for patients with muscle weakness, which foot orthosis can adapt to changes in the ambient conditions and to the individual circumstances of an orthosis user. The adaptation furthermore results in a knee-stabilizing action, whereby the patient can walk in an improved manner and more safely.
The leg rail may be assigned at least one device, which is coupled to the control device, for varying the stiffness of the leg rail, such that, aside from the influencing of the stiffness of the forefoot lever and/or of the heel lever, the stiffness of the leg rail can also be varied, such that the stiffness of the leg rail can be actively varied for example in a manner dependent on the angle of inclination of the sole, the forces that occur upon heel strike, or on the basis of the ascertainment of position data of a knee joint axis.
The device for varying the stiffness in the sole may for example have an actuator for displacing a sole insert, a piezo element, a magnetorheological medium, a preloaded spring element, and/or a thermal element, by means of which, individually or in a combination of one or more of the above-stated elements with one another, the desired adaptation and adaptability of the stiffness of the sole to the respective walking situation or to a patient can be implemented.
The change in the stiffness in the leg rail may be implemented for example by means of a displacement of a leg rail insert, a piezo element, a magnetorheological medium, a preloaded spring element and/or a thermal element, by means of which, individually or in a combination of one or more of the above-stated elements with one another, the desired adaptation and adaptability of the stiffness of the leg rail to the respective walking situation or to a patient can be implemented.
A joint may be arranged between the leg rail and the foot part, which joint is assigned a brake and/or a damper device which is coupled to the control device and which is activated or deactivated in a manner dependent on the detected orthosis parameters. In this way, aside from an individual adaptation of the leg rail by means of an orientation in the joint and possibly an adaptation of the stiffness of the leg rail, the resistance moment about the joint can additionally be varied.
The leg rail may be manufactured as a separate component and arranged articulatedly on the foot part, such that retroactive installation in the joint region is possible. As an alternative to this, the leg rail and the foot part may be formed as a single piece, wherein an articulated embodiment may be implemented by means of a targeted material weakening and the formation of a so-called film hinge.
In the case of an articulated arrangement on the foot part, the leg rail may be assigned a drive for setting the orientation of the leg rail relative to the foot part and/or may be assigned a fixing device for fixing the orientation relative to the foot part. In this way, it is possible for the position of the lower leg relative to the sole to be individually set and fixed or else varied, such that a physiologically correct orientation is always realized, for example when standing.
The sensors may be arranged in the forefoot region and/or in the heel region of the sole, on the leg rail, or at the transition from the leg rail to the foot part, in order to detect relevant orthosis parameters. Likewise, at least one sensor may be arranged outside the orthosis, for example in order to detect the position of the knee axis and transmit this to the control device.
The sensors may be in the form of force sensors, pressure sensors, acceleration sensors, gyroscopes, position sensors and/or angle sensors.
It is possible for multiple devices and/or materials to be provided for varying the stiffness of the sole and/or of the leg rail in mutually different orientations, in order to allow both the sole and the leg rail to be configured to be settable individually and in accordance with the situation.
The sole is advantageously designed for accommodating the entire foot in order, in the case of the typical indications for a lower leg orthosis, to be able to provide complete support of the foot such that the patient can be provided with optimum treatment.
The method according to the invention for controlling an orthosis, as has been described above, provides that the stiffness of the sole and/or of the leg rail is varied in a manner dependent on sensor values that have been ascertained by means of the sensors arranged on the orthosis. In this way, an adaptation to ambient conditions is possible. A negative change in gait behavior and in the sequences and states that are correct in terms of physiology and motion can be avoided through the wearing of an optimized and adaptively adaptable orthosis.
One aspect of the method provides that a starting value for a center of gravity position of the force action points on the sole and/or an orientation of the leg rail or of the sole in space is specified and, if the starting value is overshot by a specified amount, a variation of the stiffness of the sole and/or of the leg rail is performed in a manner dependent on the position, ascertained by means of the sensors, of the force action point and/or on the orientation of the sole and/or of the leg rail in space.
In addition or alternatively to this, the orientation of the leg rail relative to the foot part may be varied in a manner dependent on the sensor values, such that an orientation of the leg rail and thus of the lower leg that stabilizes the knee and relieves the knee of load can be achieved.
In the case of a joint being arranged between the leg rail and the foot part, the rotational resistance thereof can be varied in a manner dependent on the detected orthosis parameters, whereby an adaptation to the ambient conditions or changes in physiological status can also be compensated and taken into consideration.
An exemplary embodiment of the invention will be discussed in more detail below on the basis of the figures. The same reference designations are used to denote identical components. In the figures:
In the foot part 2, the leg rail 3 and/or the devices 4 for supporting the leg rail 3 on the lower leg, there may be arranged sensors 6 which detect orthosis parameters. It is possible for only one sensor 6 overall to be provided, it is likewise possible for one sensor 6 to be arranged in each of the various components of the orthosis, and it is likewise possible for multiple sensors 6 to be provided in or on one or more components. Furthermore, a sensor 6 may be provided as a position sensor for the position of a compromise axis, which sensor is attached to a patient outside the orthosis 1. Angle sensors for the angle in the upper ankle joint, pressure sensors for measuring the pressure load in the tibia structure, pressure sensors in the sole 21, acceleration sensors for detecting gait behavior or underlying surface conditions, and piezoelectric sensors for detecting ground contact or heel pushoff, may be provided.
In
A further variation of the orthosis is possible by means of variation of the construction of the orthosis by virtue of the orientation of the leg rail 3 relative to the sole 21 being varied. By means of the angle between the leg rail 3 and the sole 21, the load on the knee joint when standing and when walking is influenced, such that it is possible to achieve a position, which preserves the knee and which is expedient with regard to gait physiology, of the leg rail 3 and thus of the lower leg relative to the sole 21 and thus relative to the foot seated thereon over a full area.
It is furthermore possible to vary the stiffness of the leg rail 3 by means of devices which correspond to the devices 8 for varying the stiffness of the sole. It is likewise possible for a brake or an adjusting device to be assigned to the leg rail 3, such that, in the joint 9, an adjustment of the angle of the leg rail 3 with respect to the sole 21 can be performed. The adjustment may be performed in a manner dependent on the orthosis parameters ascertained by means of the sensors 5, 6.
Instead of resiliently elastic damper elements, damper devices 94 may be installed in the joint 9 or assigned to said joint 9, which damper devices are coupled to a control device 7 (not illustrated). The damper device 94 can then be set with regard to its resistance to a pivoting movement. The damper device 94 may be in the form of a hydraulic system which, at the respective contact points or force transmission points between the joint outer part 93 at the joint inner part 92, has chambers or pistons via which hydraulic fluid is conducted from one chamber into the other chamber. Between these chambers, there may be arranged a valve or a settable throttle which is coupled to the control device 7 and which provides a variable resistance in a manner dependent on sensor data. By means of the control device 7, the damper device 94 can be activated or deactivated or set with regard to the desired damping. As control parameters or orthosis parameters, there may be provided, for example, load sensors, spatial position sensors or angle sensors which detect an angle between the leg rail 3 and the foot part.
In the foot part 2, a hose system is embedded in or fastened to the sole 21. The sole 21 has flexibility, which can be varied through variation of the degree of filling of the hose system. On the leg rail 3, there is arranged an actuator 10 which, by means of a piston, pumps hydraulic fluid into, or draws hydraulic fluid out of, the hydraulic line. Depending on the degree of filling of the hydraulic line, the sole 21 stiffens or becomes flexible. It can be seen in
Instead of or in addition to the actuator 10 arranged on the leg rail 3, it is possible for two actuators 10 to be arranged on the joint body 9, which actuators act as pumps. By means of pistons, which can be driven by the pivoting movement of the leg rail 3 relative to the foot part 2, the pistons can be moved, and pressure can correspondingly be built up or depleted in the line system in the sole 21 by means of either a hydraulic fluid or a pneumatic fluid. Depending on the filling pressure, the sole 21 stiffens or becomes more flexible.
A further variant of the invention is shown in
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A further variant of the invention is illustrated in
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Number | Date | Country | Kind |
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10 2018 131 852.9 | Dec 2018 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2019/084225 | 12/9/2019 | WO | 00 |