Orthopedic system and prosthetic foot with such a

Description

[0001] The invention relates to an orthopaedic system with a leaf spring element and a bearing component supported on a main surface of the leaf spring element, which is fixed to the leaf spring element, and to a prosthetic foot with such an orthopaedic system.

[0002] Leaf spring elements are frequently used in orthotic systems to store deformation energy and simultaneously limit forces. Modern leaf spring elements are made of fiber-reinforced composites or incorporate fiber-reinforced composite components and are part of complex systems, such as prosthetic feet. To use leaf spring elements effectively, they must be mounted in brackets so that other components can be attached to them. Brackets or other components are attached to a leaf spring element, for example, by positive locking, where the component to be mounted, such as a metal part, is screwed onto the leaf spring element. Such a solution is described in US 10,390,974 B2 and EP 3,128,958 B1.

[0003] It is known from WO 2020 / 1523 41 A1 that a leaf spring element can be connected to a support via an adhesive bond, a clamping connection, and / or a positive-locking connection. In the case of positive-locking connections using screws, holes are drilled into the leaf spring element through which corresponding bolts or screws are then inserted, thus connecting it to the other component. Holes weaken the leaf spring component and are therefore not suitable for all applications; in particular, fiber-reinforced composites are impaired in their mechanical properties by holes or disturbances in the fiber structure. Especially in areas of large deformation of the leaf spring elements, attachments cannot be mounted, or can only be mounted with great difficulty.

[0004] US 6 290 730 B1 shows a foot-ankle prosthesis with an ankle component, a keel component, and a shock absorber component positioned between them. The individual components are held together by a retaining device. The shock absorber component is made of an elastic polyurethane material.

[0005] US Patent 2006 / 069450 A1 discloses a foot prosthesis comprising a spring element and a fastening element. The fastening element is attached to the spring element by screws. An elastic element for absorbing compressive forces is arranged between the fastening element and the spring element. The elastic element is bonded to both the fastening element and the spring element.

[0006] German patent DE 10 2019 101 843 A1 relates to a prosthetic foot insert with a leaf spring and a holder. A damping element is arranged between the leaf spring and the holder, and is bonded to both the holder and the leaf spring.

[0007] DE 10 2014 006 571 B3 discloses a prosthetic foot with a structural component having proximal connecting means and a sole-side guide element. A spring-damper system is arranged between the structural component and the guide element, which is positively locked to the guide element and the structural component.

[0008] German patent DE 10 2011 014994 A1 discloses a prosthetic foot insert with a roof spring and a base spring. Upper connecting elements are arranged on the roof spring. A coupling element is arranged between the roof spring and the base spring. The base spring, the roof spring, and the coupling element can be formed in one piece.

[0009] US 5,800,569 A relates to a prosthetic foot with a footplate and an ankle plate. An ankle block is positioned between the footplate and the ankle plate, bonded to both and made, for example, of polyurethane.

[0010] The object of the present invention is therefore to provide an orthopaedic system with a leaf spring element that allows greater design freedom without limiting the durability and load-bearing capacity of the overall system.

[0011] According to the invention, this problem is solved by an orthotic system with the features of the main claim and a prosthetic foot with such an orthotic system. Advantageous embodiments and further developments of the invention are disclosed in the description, the dependent claims, and the figures.

[0012] The orthotic system, comprising a leaf spring element and a bearing component supported on a main surface of the leaf spring element and fixed to the leaf spring element, provides for at least one elastomeric element to be arranged between the bearing component and the main surface of the leaf spring element. This elastomeric element is attached to the leaf spring element and the bearing component in a manner that transmits tensile and shear forces. Thus, an elastic connection exists between the bearing component and the leaf spring element, allowing relative movement between them. This enables the bearing component to be arranged and positioned securely and reliably, even in areas of high deformation of the leaf spring element, despite its secure and robust attachment to the leaf spring element.The attachment of the bearing component to the leaf spring element in such a way that tensile and shear forces applied to the leaf spring element via the bearing component can be securely and permanently transferred to the leaf spring element allows for virtually any positioning of the bearing component on the leaf spring element, regardless of the deformation of the leaf spring element during use of the orthotic system. This increases the design freedom in the construction of the orthotic system or the overall system of which the orthotic system is a part.The support component has at least one stop which, in a starting position where no forces are transmitted from the support component to the leaf spring element by the use of the orthotic system, is positioned relative to a secondary surface or a stop element of the leaf spring element. Leaf spring elements have a longitudinal extent and, in cross-section along this longitudinal extent, are essentially rectangular with two long sides and two opposing short sides. The surface corresponding to the long sides is a primary surface, and the surface corresponding to the short sides or narrow sides is a secondary surface. One or more stops may be arranged laterally next to the leaf spring element. The distance to the secondary surface allows for movement transverse to the longitudinal extent of the leaf spring element.Compensating and displacement movements are enabled and absorbed by the elastomer element. Deformations of the elastomer element are permitted until the stop makes contact with the leaf spring element. A secondary surface can also be formed within the leaf spring element in a bore or slot. Thus, a stop arranged on or in the bearing component can engage in a slot, bore, or other recess, whereby, without a load, particularly without a load in the main plane, the stop is not in direct contact with the leaf spring element.Alternatively or additionally to direct contact with the leaf spring element, a stop element can be arranged or formed on the leaf spring element. This stop element abuts against or comes into contact with a stop or recess in the bearing component when a load limit is exceeded and the relative displacement between the bearing component and the leaf spring element is too great. This displacement can be a rotation or a shift of the bearing component relative to the leaf spring element.

[0013] In one embodiment, the bearing component has at least one flat support surface over which the elastomeric element rests and connects to the leaf spring element. The flat support surface allows for a large-area distribution of forces and avoids peak loads of forces that are transmitted from the typically rigid bearing component, via the elastomeric element, into the leaf spring element.

[0014] In a further development, the bearing component is provided with several spaced-apart support surfaces, allowing the bearing component to be supported and attached to multiple, spaced-apart areas of the leaf spring element. The two support surfaces are connected by the bearing component in a bridge-like manner, enabling optimized force transmission and improved load distribution, thus allowing the mechanical properties of the leaf spring element to be optimally utilized.

[0015] In one configuration, the elastomer element is attached to the leaf spring element via a preload device. This preload device can be, for example, a clamp, a clamping system, a strap, or a screw connection. The preload applied by the device presses the three system components—the leaf spring element, the bearing component, and the elastomer element—against each other, thus preventing the components from becoming dislodged. This eliminates noise from components striking each other and, furthermore, provides the user of the orthotic system with a secure feeling due to stable force transmission.

[0016] In one embodiment, at least one elastomer element is bonded to the bearing component and / or the leaf spring element. Bonding the elastomer element to both the bearing component and the leaf spring element ensures a material-bonded connection of all three system elements in a simple, cost-effective, and durable manner. The structure of the leaf spring element is not impaired by the attachment of the bearing component. The same applies to bonding the elastomer element to the leaf spring element and coupling and fastening the elastomer element to the bearing component via another fastening device or element, such as screws. It is also possible to clamp the leaf spring element to the bearing component using clamping devices, with the elastomer element interposed.Even if a screw connection with a through hole is made through the leaf spring element, the mechanical stress of force transmission via the bearing component is reduced by the interposition of the elastomer element, resulting in an advantage in terms of design freedom and durability of the orthopaedic system.

[0017] In one embodiment, several stops or stop elements are arranged or configured opposite each other; in particular, several stops are arranged laterally next to the leaf spring element and / or the stop element, framing it or these elements from two or more sides. A stop is then preferably made on one of the secondary surfaces or on two stop elements on the leaf spring element.

[0018] Advantageously, the bearing component is elastically mounted on the leaf spring element in three rotational and three translational degrees of freedom, whereby, due to the dimensions of the elastomer element, only small rotations and / or displacements in the respective directions or about the respective axes are possible. In an advantageous embodiment, it is provided that torsion in the transverse plane is in a range between ±1° and ±5°, in particular ±2.5°. Due to the fact that there is no rigid attachment of the leaf spring element to the bearing component, compliance under torsional loads is enabled, particularly in the frontal and transverse planes, the reference plane being the plane in which the main surface of the leaf spring element lies.The connection between the bearing component and the leaf spring element is designed to allow limited relative movement between the two components. Simultaneously, significant deformation of the leaf spring element in all directions is permitted to a limited extent without direct collision between the leaf spring element and the bearing component. Nevertheless, high mechanical forces and loads are transferred from the bearing component to the leaf spring element, with the transmission of normal forces from the leaf spring to the bearing block being the primary force transmission mechanism.

[0019] Advantageously, the leaf spring element is made of a fiber-reinforced composite material, while the bearing component is made of a metal or metal alloy, particularly a light metal alloy. This ensures that the respective mechanical loads are optimally absorbed and transmitted by the respective material.

[0020] The support component is designed, in particular, as a bearing block with a bearing receptacle, allowing for the articulated connection of other components of a complete orthotic system, especially another prosthetic component. Instead of an articulated connection of other components to the support component, one or more components can be rigidly or resiliently attached to the support component. A pyramid adapter can be directly attached to or formed on the support component or coupled to the rest of the support component via an elastic component. The connection of other components to the support component, especially a lateral and / or proximal connection, can also be designed to be rotationally fixed or torsionally rigid, which includes both a one-piece and a multi-part design.

[0021] In one embodiment, the bearing component is arranged in the middle third between the ends of the leaf spring element. This allows force to be applied to those areas of the leaf spring element that are particularly flexible, as the rest of the leaf spring element's support is located at its ends. Applying the force in areas of high deformation ensures that the spring properties of the leaf spring element are fully utilized and that a sensitive response is achieved when forces are applied from the bearing component, via the elastomer element, into the leaf spring element.

[0022] The elastomeric element(s) preferably consist of a permanently elastic material, in particular a polyurethane elastomer, which advantageously has a Shore A hardness between A40 and A80, preferably between A50 and A70, and most preferably between A55 and A65. The use of other elastomers that are permanently elastic and durable over their service life is also possible.

[0023] The invention relates in particular to a prosthetic foot insert with an orthotic system as described above. With this design, it is possible to reduce the load on the leaf spring element by distributing the load over a large area across the entire width of the main surface. Load peaks caused by a direct coupling of the bearing component to the leaf spring element are avoided. Furthermore, the prosthetic foot offers increased flexibility for the user, as rotational compliance in the frontal plane is achieved through the connection of the bearing component via at least one elastomer element. The use of the prosthetic foot during rotations is also facilitated by rotational compliance in the transverse plane.

[0024] Exemplary embodiments of the invention are explained in more detail below with reference to the figures. The same reference numerals denote identical components. The figures show: Figure 1 - an exploded view of an orthotic system; Figure 2 - schematic sectional views of a prosthetic foot; Figure 3 - a schematic overall view of a prosthetic foot; Figure 4 - a bottom view of an orthotic system; Figure 5 - a front view of an orthotic system; Figure 6 - a bottom view of a support component; Figure 7 - an enlarged sectional view through a variant; Figure 8 - a cross-sectional view through the variant according to Figure 7 ; as well as Figure 9 - three views of a clamped variant.

[0025] In the Figure 1An exploded view shows an orthopedic system with a bearing component 600 in the form of a bearing block, which has a bearing receptacle 640 with associated bearing shells 641. An axis is inserted in the bearing receptacle 640 around which the bearing component 600 can be pivoted. The bearing component 600 can, for example, be pivotably attached to a support, which in turn has a proximal fastening device for fixing it to another prosthetic component, for example, as part of a prosthetic foot that is attached to an ankle joint, a lower leg tube, or a lower leg socket. The bearing component 600 has a bridge-like structure and has two flat support surfaces on its underside, which will be explained in more detail later.

[0026] Below the bearing component 600, a leaf spring element 40 made of a fiber-reinforced composite material is shown. The leaf spring element 40 has a substantially rectangular cross-section, with a top and a bottom as the main surface 41 and two short side edges as secondary surfaces 43. The leaf spring element 40 is essentially straight, but can also have a slight curvature or a wave-like shape. A heel element 45 can be attached to the bottom of the leaf spring element 40. Alternatively, cushioning elements or coupling devices for connecting further components of a complete system can be attached to the bottom and / or top of the leaf spring element 40.

[0027] In the illustrated embodiment, two elastomeric elements 71, 72 are arranged between the upper surface of the main surface 41 of the leaf spring element 40 and the lower surface with the support surfaces of the bearing component 600. These elements bear against both the leaf spring element 40 and the bearing component 600. Stops 630 are located laterally next to the leaf spring element 40 and next to the elastomeric elements 71, 72. These stops are formed on the bearing component 600. The stops 630 are downward-projecting projections that ensure lateral limitation of any displacement of the bearing component 600 relative to the leaf spring element 40. The elastomeric elements 71, 72 are attached to each other on the leaf spring element 40 and the bearing component 600, in particular by bonding or welding.Alternative fastening methods, for example a positive locking fastening in addition to or as an alternative to this, are provided that they enable the transmission of shear forces and tensile forces to the respective elastomer elements 71, 72.

[0028] As an alternative to the four stops 630, only two stops 630 arranged diagonally, opposite each other, or one behind the other on one side may be arranged or configured. Another alternative is that, instead of a lateral arrangement and a possible stop of the stops 630 on the secondary surfaces 43, a stop element is arranged or configured on the surface of the leaf spring element 40, which is framed by two or more stops and initially allows and then limits relative displacement of the leaf spring element 40 relative to the bearing component 600 when a limit load is present. This limits excessive deformation of the elastomer elements 71, 72 and defines the maximum displacement from the bearing component 600 to the leaf spring element 40.Such a restriction of movement can also be achieved by forming or incorporating a slot, recess or indentation in the leaf spring element 40, into which a corresponding element, for example a pin, tab or pin, is inserted and comes into contact with the leaf spring element 40 after overcoming elastic restoring forces of the elastomer elements 71, 72.

[0029] In the Figure 2The figures show cross-sectional views through a prosthetic foot with an orthotic system described above. The bearing component 600 described above is visible, as are the two elastomer elements 71, 72 and the leaf spring element 40, on the upper side of which the bearing component 600 with the stops 630 is arranged. The respective flat support surfaces 610, 620 are formed on the underside of the bearing component 600, running essentially parallel to the main surface 41 of the leaf spring element 40. In the illustrated embodiment, the elastomer elements 71, 72 are bonded to both the leaf spring element 40 and the bearing component 600. In the heel area of ​​the prosthetic foot, padding elements 30 are arranged and attached to the upper and lower sides of the leaf spring element 40.The lower cushioning element 30 rests on a base spring 20, which is coupled or connected to the leaf spring element 40 in the forefoot area. The upper cushioning element 30 rests on a support 10, on which the bearing component 600 is pivotably mounted about the pivot axis in the bearing receptacle 640. A pyramid adapter for attaching the prosthetic foot to a proximal prosthetic component is attached to the upper side of the support 10.

[0030] In the Figure 3 Is the prosthetic foot according to Figure 2The assembly is shown in a perspective view. The support 10 is pre-tensioned relative to the base spring 20 by a clamping device and clamps the leaf spring element 40 between the two padding elements 30. The upper padding element 30 allows for slight displacement of the support 10 relative to the leaf spring element 40 in the heel area or in the rear area. The elastic mounting and the arrangement of the stops 630 relative to the secondary surfaces 43 of the leaf spring element 40 allow for controlled, slight rotation both about an axis perpendicular to the transverse plane and about an axis perpendicular to the frontal plane. In principle, rotation about an axis perpendicular to the sagittal plane is also possible, which runs essentially parallel to the axis of the bearing receptacle 640.Due to the pivotable mounting of the carrier 10 on the mounting component, a uniform load will be distributed across both the rear and front elastomeric elements 71, 72, so that while rotation by this degree of freedom is possible, it is practically irrelevant. In addition to rotation by three degrees of freedom, the mounting via the elastomeric elements 71, 72 also allows displacement in three degrees of freedom.

[0031] In the bottom view of the Figure 4 It can be seen that the secondary surfaces 43 of the spring element 40 are arranged in relation to the stops 630 of the bearing receptacle 600, thus allowing rotation and displacement of the entire spring element 40 relative to the bearing component 600 in all three rotational and three translational degrees of freedom.

[0032] In the Figure 5A frontal view of the bearing component 600 is shown, including the front, flat contact surface 610, the two lateral stops 630, and the elastomer elements 71, 72 between the leaf spring element 40 and the contact surface 610. Figure 6In a bottom view, the bearing component 600 with the two flat support surfaces 610, 620 for the two elastomer elements 71, 72, which are arranged relative to each other, can be seen. The stops 630 are positioned at a distance to the right and left, or medially and laterally, of the lateral edges of the elastomer elements 71, 72. The elastomer elements 71, 72 extend over the entire width of the leaf spring element 40, thus enabling a uniform force transmission across the entire width of the leaf spring element 40 due to their elastic properties. Because of this large-area force transmission, load peaks on the leaf spring element 40 are avoided, the mechanical stress is reduced, and damage is prevented.The bearing component 600 has a bridge-like structure, creating a space or gap between the two elastomer elements 71, 72, so that in the event of a central load via the bearing receptacle 640, the force transmission along the longitudinal extent of the leaf spring element 40 is distributed over two defective areas or surfaces.

[0033] In the Figures 7 and 8Variants of the invention are shown, in which two elastomer elements 71, 710, 72, 720 are arranged between the support surfaces 610, 620 and the leaf spring element 40. The respective elastomer elements 71, 710, 72, 720 can be attached to the respective component, i.e., the bearing component 600 and the leaf spring element 40, in different ways. In one embodiment, the elastomer element 710, 720 arranged on the bearing component 600 at the contact surface is positively locked to the bearing component 600, while the other elastomer element 71, 72 is bonded to the surface of the leaf spring element 40. The upper elastomer element 710, 720 can have side walls or a recess into which the lower elastomer element 71, 72 is inserted.The elastomer elements 71, 710, 72, 720 can be positioned so that displacement and / or rotation relative to each other is either not possible or only possible in certain directions. Depending on the shape of the elastomer elements, rotation about an axis perpendicular to the transverse plane may be possible. Rotation and tilting of the bearing component 600 relative to the leaf spring element 40 remain possible due to the elastic properties of the elastomer elements 71, 710, 72, 720. It is also possible to use different fastening methods at different positions, such that, for example, the upper elastomer element 710 is bonded to the front area of ​​the bearing component 600, and the lower elastomer element 71 is positively engaged or secured to the leaf spring element 40 via a clamping device. In principle, both elastomer elements 71, 710 can also be bonded to their respective components.The arrangement of several elastomer elements 71, 710; 72, 720 between the bearing component 600 and the leaf spring element 40 increases the design freedom in the development of the elastic properties. With an interchangeable attachment of an elastomer element, adjustments to the individual preferences of the user can be easily made. For example, if a user desires less compliance at one or more points in the orthotic system or the prosthetic foot, this can be achieved by replacing, for example, the elastomer elements 710, 720, which are positively attached to the bearing component 600 via a screw connection.Due to the preferably metallic design of the bearing component 600, it is easily possible to screw elastomer elements 710, 720 onto the bearing component 600 without any significant structural impairment of the strength properties or mechanical properties.

[0034] To prevent separation between elastomer elements 71, 710; 72, 720 that are not fixed to one another, preload devices 60 in the form of straps are arranged on both the bearing component 600 and the leaf spring element 40 in the illustrated embodiment. The preload devices 60 can be flexible and rigid or elastic. They are guided in guides on the bearing component 600 and below the leaf spring element 40 and cause a preload of the bearing component 600 towards the leaf spring element 40. This presses the paired elastomer elements 71, 710, 72, 720 together and holds them permanently in place. The pretensioning device 60 can also be designed to be detachable, so that to replace elastomer elements 71, 710, 72, 720 the pretensioning device 60 is detached and reattached each time.The preloading device 60 can also be designed differently, for example as a screw connection.

[0035] In the Figure 8 It can be seen that the lateral stops 630 are positioned relative to both the leaf spring element 40 and the lower elastomer element 71 attached to the leaf spring element 40. The upper elastomer element 710, arranged on the bearing component 600, fills the gap or space between the inside of the stop 630 and the lower elastomer element 71, thus providing additional lateral guidance. Besides bridging this gap, the side walls of the upper elastomer element 710 can also leave a gap to the inner surfaces of the respective stop 630 or only one stop 630. Depending on the design of the elastomer elements, it is possible to influence the movement behavior of the bearing component 600 relative to the leaf spring element 40.

[0036] In the Figure 9Three illustrations of a further variant are shown, in which the leaf spring element 40 is embedded between two elastomer elements 71, 715. One elastomer element 71 is arranged between the bearing component 600 at the support surface and the upper surface of the leaf spring element 40. The other elastomer element 715 is arranged below the leaf spring element 40 and supports it against a preloading device 60, which in the illustrated embodiment is designed as a clamping bracket that is detachably fixed to the bearing component 600 by means of two screws. The clamping bracket extends below the leaf spring element 40 and is U-shaped. Internal threads for receiving the screws are arranged in the two upwardly projecting legs of the clamping bracket.The leaf spring element 40 is guided laterally by the two upwardly projecting legs, whereby a lateral gap can exist between the inner surfaces of the upwardly projecting legs and the leaf spring element 40 to allow rotation and displacement relative to the bearing component 600. The two screws are guided through through holes in the bearing component 600; by loosening or tightening the screws, the preload of the elastomer components 71, 715 can be individually varied. In the lower illustration of the... Figure 9A bottom view of the orthotic system as part of a prosthetic foot is shown, revealing that the respective clamping bracket extends across the entire width below the leaf spring element 40. Here, too, two preload devices 60, spaced apart from each other along the longitudinal extension of the leaf spring element 40, are arranged on the bearing component 600 and enable force to be applied to two spaced-apart areas of the leaf spring element 40. The preload is infinitely adjustable. Besides a U-shaped design of the clamping bracket, the preload device 60 can also be designed simply as a strip-shaped plate. Instead of a screw, other force transmission devices can also be part of the preload device 60 to preload and clamp the leaf spring element 40 against the bearing component 600 with at least one interposed elastomer element 71.

[0037] The leaf spring element is advantageously supported at both ends on other components or the floor, resulting in a four-point support system with bearings at both ends and force transmission at two spaced-apart force transmission points located between the bearing points at the ends. If the support component 600 is configured as a bearing block with a bearing receptacle 640 between two support surfaces 610, 620, it is advantageous to position the receptacle 640 on the leaf spring element 40 at the midpoint of the spring length or within the middle fifth of the leaf spring element 40. This ensures a uniform load distribution on the leaf spring element 40.With respect to the overall length of the prosthetic foot insert, the positioning of the bearing receptacle 640 is shifted slightly further anteriorly due to the greater overall length of the base spring 20 compared to the leaf spring element 40 and the off-center arrangement of the leaf spring element 40 above the base spring 20. In a fully assembled prosthetic foot with a cosmetic cover, the bearing receptacle 640 is located slightly behind the center relative to the overall length, but still within the middle fifth of the total length of the prosthetic foot.

Claims

1. An orthopedic system having a leaf spring element (40) and a bearing component (600) which is supported on the main surface of the leaf spring element (40) and is fixed to the leaf spring element (40), whereas at least one elastomer element (71, 72) is arranged between the bearing component (600) and the main surface (41) of the leaf spring element (40) and is fastened to the leaf spring element (40) and to the bearing component (600) in a manner transmitting tensile forces and shear forces, whereas a further component (10) is fastened to or formed on the bearing component (600) in a rotationally rigid or elastic manner, characterized in that at least one stop (630) is arranged on the bearing component (600), which stop (630) is arranged, in a starting position, spaced apart from a secondary surface (43) and / or a stop element of the leaf spring element (40).

2. The orthopedic system as claimed in claim 1, characterized in that the bearing component (600) at least one flat support surface (610; 620).

3. The orthopedic system as claimed in claim 1 or 2, characterized in that the bearing component (600) has a plurality of support surfaces (610, 620) spaced apart from one another.

4. The orthopedic system as claimed in any one of the preceding claims, characterized in that the elastomer element (71, 72) is fastened to the leaf spring element (40) and / or the bearing component (600) via a pretensioning device (60).

5. The orthopedic system as claimed in any one of the preceding claims, characterized in that the elastomer element (71, 72) is glued to the bearing component (600) and / or the leaf spring element (40).

6. The orthopedic system as claimed in claim 1, characterized in that a plurality of stops are arranged opposite one another.

7. The orthopedic system as claimed in any one of the preceding claims, characterized in that the bearing component (600) is mounted elastically on the leaf spring element (40) in three rotational and translational degrees of freedom.

8. The orthopedic system as claimed in any one of the preceding claims, characterized in that the leaf spring element (40) is produced from a fiber composite material and the bearing component (600) is produced from a metal.

9. The orthopedic system as claimed in any one of the preceding claims, characterized in that the bearing component (600) is arranged in the middle third between the ends of the leaf spring element (40).

10. A prosthetic foot insert having an orthopedic system as claimed in any one of the preceding claims.