Abstract
A connection arrangement (4, 4) of two components (1, 2) according to the invention has a curved surface portion having a contact point on at least one of these components. The curved surface portion can extend over the entire surface of a groove, for example. The other component has a taper. When assembling the two components before a force is applied, a line connection is created from the 2-contact point connection and when force is applied, the line connection changes through plastic deformation into a strip connection, on the basis of which the two components (1, 2) hold together.
Claims
1. Connection arrangement of an orthopedic system for connecting a plurality of components, wherein the connection arrangement comprises a first component and a second component, on each of which at least one contact surface is arranged, wherein the contact surface is curved, wherein when assembling the first and the second component before a force is introduced from a 2-contact point connection, a line connection is created and when the force is applied the line connection changes into a strip connection by plastic deformation, on the basis of which the two components hold together.
2. Connection arrangement according to claim 1, wherein the line connection and the strip connection are formed all around on the components.
3. Connection arrangement according to claim 1, wherein one of the two contact surfaces are made of metal and the other contact surface is made of ceramic.
4. Connection arrangement according to claim 1, wherein the curved contact surface of the second component is arranged on a groove formed through a bottom, a peripheral surface, and an opening.
5. Connection arrangement according to claim 1, wherein the curve shape of the contact surface is continuously formed, wherein the function thereof can be continuously differentiated twice at any point.
6. Connection arrangement according to claim 1, wherein the contact surface is arranged on a projection of the second component.
7. Orthopedic system consisting of at least two components having a connection arrangement according to claim 1.
8. Orthopedic system consisting of at least two components having two connection arrangements according to claim 1.
9. Connection arrangement of an orthopedic system for connecting a first component to a second component, on each of which a contact surface is arranged, which when connecting the two components at contact points (KP) result in an operative connection, wherein the contact surface of one component is formed as a taper, in particular according to claim 1, wherein the contact surface of the other or second component is curved at the contact points (KP), wherein when assembling the first and the second component before a force is introduced from a 2-contact point connection, a line connection is created and when the force is applied the line connection changes into a strip connection by plastic deformation, on the basis of which the two components hold together.
10. Connection arrangement according to claim 9, wherein the contact surface of the other component is convex in cross section in the region of the contact point (KP).
11. Connection arrangement according to claim 9, wherein the contact surface of the other component has a circular cross section at least in the region of the contact point (KP).
12. Connection arrangement according to claim 11, wherein the cross section extends over the entire contact surface or only a part thereof.
13. Connection arrangement according to claim 12, wherein the cross section extends over the entire contact surface and all contact points (KP) are arranged on a surface or plane which is perpendicular to the longitudinal axis or runs obliquely thereto.
14. Connection arrangement according to claim 9, wherein the peripheral surface of the other component from the bottom of the groove to an apex (K) at which the diameter or cross section (Q) of the groove is the smallest, is formed on a cylindrical shape or in the manner of a hollow cylinder and the peripheral surface forms the contact surface from the apex (K) to the opening of the other component, wherein the contact points (KP) are arranged on the contact surface.
Description
[0030] The invention will be explained with reference to the drawings, in which:
[0031] FIG. 1: is a cross section of the connection between two components, in sections, partially in section and in a schematic representation,
[0032] FIG. 2 shows the connection point enlarged according to FIG. 1, in section, and in a schematic representation,
[0033] FIG. 3 is an alternative embodiment of the connection point in section and in a schematic representation,
[0034] FIG. 4: is a cross section of an alternative form of a connection according to the invention of three components, in section and in a schematic representation,
[0035] FIG. 5 shows the connection point enlarged according to FIG. 1, in section and in a schematic representation,
[0036] FIG. 6 is an alternative embodiment of the connection point in section and in a schematic representation,
[0037] FIG. 7 is the section Z from FIG. 6 in an enlarged representation, not to scale to make it easier to see the essential,
[0038] FIG. 8 is a cross section of an alternative form of a connection according to the invention having a large taper angle and thus a flat design,
[0039] FIG. 9 shows the connection point according to FIG. 8 enlarged, in section and in a schematic representation,
[0040] FIG. 10 shows an example of a 2-point contact between a taper and a ring, and
[0041] FIG. 11 shows the taper according to FIG. 10 having the drawn contact gap to the ring.
[0042] All figures contain partial, schematic representations of the invention and are used by way of example to explain the invention. Special embodiments of the invention can deviate from these figures.
[0043] FIG. 1 shows the connection arrangement 4 of two orthopedic components, here a shaft 17 of a first component 1 with a ball head 18 of a second component 2. The region of the shaft 17 shown in FIG. 1 has a projection or attachment 5 at its first end 7. Starting from a location 19 of the shaft 17, the diameter D1 of the attachment 5 decreases continuously up to its distal end 6. In the embodiment according to FIG. 1, the attachment 5 is formed in the form of a truncated cone. The truncated cone has a peripheral or contact surface 27. The two components can be part of a hip joint prosthesis, a shoulder joint prosthesis or a finger or ankle prosthesis or other joint prostheses.
[0044] The second component 2 has a recess or groove 10. The groove 10 is delimited by a peripheral surface 16 and a base surface or a bottom 12 and opposite the bottom by an opening 14. The peripheral surface 16 can be formed entirely or partially as a contact surface 29. The contact surface 29 can be formed in a portion or a region of the peripheral surface 16. Starting from the second end 11 of the component 2, from the opening 14 of the groove 10, the peripheral surface 16 of the groove 10 is wholly or partially curved. The curvature creates a convexly curved surface 28 which is identical to the contact surface 29 and in FIG. 1 identical to the peripheral surface 16. Starting from the opening 14 of the groove 10, the amount of the diameter or the cross section Q of the groove 10 decreases to a point, the apex K. From this apex K, the amount of the cross section Q increases again until the region in which the peripheral surface 16 merges into the base surface 12 of the groove 10. Thereby, a curved surface 28 of the groove 10 is created, which comprises a surface portion 23 which is formed as an ascent, an apex K, and a surface portion 30 which is designed as a descent.
[0045] When joining the shaft 17 of the first component 1 with the ball head 18 of the second component 2, a contact between the two components is created at a contact point KP. In this embodiment of the invention, the contact point KP lies on the peripheral surface 16 or the contact surface 27 below the apex K in the direction of the second end 11 or the opening 14. The gap between the contact point KP and the base surface 12 of the groove 10 is designated in FIG. 1 by the reference sign HN. The gap AB (see FIG. 7) of the contact point KP from the apex K depends on the type of truncated cone of the first component and the curvature of the contact surface 27.
[0046] The contact between the two components is thus in this embodiment below the apex K in the direction of the orifice. The contact point KP at which the operative connection takes place is arranged at a distance from the apex K on the contact surface 27, 29 in the direction of the opening of the second component 2. Only if the truncated cone is not one according to the invention, but a cylinder, for example, does the contact point and apex coincide. In the case of a truncated cone or taper having a very large angle, the contact point is close to the orifice of the groove 10.
[0047] The contact surface 27 of the component 1 and the contact surface 29 of the component 2 are in operative connection. Through the inventive design of the curved contact surface 29 or surface 28 of the groove 10 and the contact surface 27 of the shaft 17, the contact point of the two components can be precisely determined and fixed. This is particularly the case if the contact surface 27 forms a mathematical function, such as a circle or a parabola in cross section. A circle is particularly easy to calculate the position of the contact point KP. This is of great advantage in the case of components which, owing to their application, can have only a small length in the longitudinal direction. A secure connection of the two components can be achieved despite the shallow depth T of the groove 10. Orthopedic systems having secure connections between two components can be provided in the region of shoulder joints or for small children, or in the veterinary sector.
[0048] FIG. 2 shows the connection arrangement 4 of two components in an enlarged representation. It can be seen that the contact of the first component 1 with the second component 2 concentrates on a narrow contact region. A line contact is created between the contact surface 29 and the contact surface 27, at the contact point KP.
[0049] The line contact is determined by the radius R of the contact surface 29 or the surface 28 of the component 2 and the angle of the contact surface 27 of the component 1. The position of the contact point KP can be determined by appropriate changes. With a constant radius R and a smaller amount of the angle , the contact point KP moves away from the opening of the second end 11 of the second component 2 to the apex K at which the diameter of the groove 10 is the smallest. The amount of H, the height at which the contact point KP is arranged away from the opening 14, increases. If, on the other hand, the angle increases with the same radius R, the distance H of the contact point KP from the opening 14 is reduced accordingly.
[0050] In the embodiment according to FIG. 2, the curved contact surface 29 or surface 28 at location M merges into the second end 11 of component 2. This second end 11 is formed as a flat side 20. An intersection point M is created between the contact surface 29 of the groove 10 and the flat side 20. The intersection point M is the point that also defines the end of the curvature of the contact surface 29 in the direction of the second end 11 of the groove 10. After joining the components 1 and 2, the intersection point M and a point A on the contact surface 27 on the shaft 17 of the first component 1 are arranged spaced apart from one another. The point A lies at the intersection point M in a horizontal extension of the flat side 20 in the direction of the shaft 17 on the first component 1. A connection arrangement 4 according to the invention has a distance between the intersection point M and the point A, which decreases in the direction of the contact point KP until the amount of the distance at the contact point KP is 0.
[0051] In the embodiment according to FIGS. 1 and 2, the peripheral surface 16 corresponds to the contact surface 29 and the surface 28.
[0052] FIG. 3 shows an alternative embodiment of a connection 4 according to the invention of two orthopedic components 1 and 2. The peripheral surface 16 of the groove 10 comprises a plurality of portions or regions. The peripheral surface 16 is formed starting from the flat side 20, of the opening 14 of the groove 10 by a flat surface portion 21. This surface portion 21 is arranged at an angle to the flat side 20. A curved portion 23 adjoins the surface portion 21. The above description of the contact surface 29 applies to the curvature of this surface portion 23. The curved portion 23 extends from an intersection point M to the apex K and is formed as an ascent. This means that the diameter of the groove 10 is reduced in the region of the surface portion 23, starting from the intersection point M to the apex K. The intersection point M is formed at the transition from the surface portion 21 to the surface portion 23. This intersection point M is arranged at a distance X from the flat side 20. After joining the two components 1 and 2, point A is arranged in a horizontal extension of the intersection point M on the contact surface 27 on the shaft 17 of component 1 and thus also at the same distance X from the flat side 20 of the second component. The two points, intersection point M and point A, are arranged spaced apart from one another. A further curved surface portion 30 can be arranged after the curved surface portion 23. The curved surface portions 23 and 30 can include values of the same or different sizes with regard to their degree of curvature and their length. The surface portion 23 is formed as an ascent; the surface portion 30 is formed as a descent. The above description for the ascent can also apply to the descent, with the difference that in the case of the descent, the diameter of the groove 10 increases from the apex K in the direction of the bottom 12. The ascent and the descent can also be shaped differently. The curved surface portions 23 and 30 and the apex K, which lies between these two surface portions 23 and 30, form the curvature, the contact surface 29. Following the curved surface portion 30, a further surface portion 22, which is the same or similar to the surface portion 21, can be arranged and formed. In the embodiment according to FIG. 3, the peripheral surface 16 of the groove 10 is formed by at least two surface portions; four (21, 23, 22, 30) surface portions are shown. The contact region 29 corresponds to the surface portions 23 and 30 between which the contact point KP is arranged. The surface portions 23, 30 each have a curvature that follows the above description. The proportion of the region of the surface portions 21, 23 and 30, 23 can, based on the peripheral surface 16, be of the same size or different sizes. A secure connection according to the invention is created when the proportion of the curved surface portions 23 and 30 is 50% of the surface 28, preferably 30%, particularly preferably 15%.
[0053] This embodiment is an example of the fact that the contact surface 29 forms only part of the peripheral surface 16. Only this region is decisive for the strength of the connection because the contact point KP is only in this region.
[0054] FIG. 4 shows an orthopedic system consisting of a first component 1, a second component 2, and a third component 8, a connecting part, an adapter 8. The same reference numerals have the same meaning as described above. This orthopedic system has two connection arrangements 4 and 4 according to the invention. A first connection arrangement 4 is arranged between the second component 2 and the adapter 8, and a second connection arrangement 4 is arranged between the adapter 8 and the first component 1. The above description applies to the connection arrangement 4 between the second component 2 and the adapter 8.
[0055] The adapter 8 has a groove 9 in the shape of a through opening. The contact surface 29 on the peripheral surface 16, the surface 28 of the groove 9, is curved in accordance with the above description. The shaft 17 of the first component 1 is formed in accordance with the above description. An arrangement according to FIG. 4 can provide an orthopedic system made up of a plurality of components 1, 2, 8 having a plurality of connection arrangements 4, 4 according to the invention.
[0056] As an alternative to the arrangement of the curved contact surface 29 shown in FIG. 4, this can also be arranged on other surfaces, for example on the outer peripheral surface 26 of the adapter 8 or on the attachment 5 of the first component 1. Regardless of the arrangement of the curved contact surface 29, a connection arrangement 4, 4 according to the invention has a curved surface 16, 28, 29 arranged on one component and a contact surface 27 in operative connection thereto arranged on a second or third component. Both the curved surface 29 and the contact surface 27 can be partial regions of individual surfaces.
[0057] FIG. 5 shows an example of a component 2 of a ball head having a diameter D2 and the positioning of the contact point KP on the peripheral surface 16. The contact point KP is arranged at a distance H from the flat side 20. T is the depth of the groove 10 and extends from the bottom 12 of the groove 10 to the opening 14 to the flat side 20 of the component 2. The peripheral surface 16 of the groove 10 is curved as above. Starting from the intersection point M, which is arranged on the flat side 20 according to FIG. 5, the curvature extends in the direction of the central axis Y. As a result, the contact point KP is arranged offset in the direction of the central axis Y to the intersection point M. A distance B is formed between the contact point KP and the intersection point M. In the embodiment according to FIG. 5, the value corresponds to H=T/3. Depending on the applications, the contact point KP can be arranged om another location, but it is always arranged below the apex K.
[0058] A connection arrangement according to the invention of two components has on at least one of these components a curved surface portion having an apex K and a contact point KP. The curved surface portion can extend over the entire surface of a groove, for example. Then a closed azimuth is created from the apexes, a circumferential line which is formed from a plurality of contact points KP lined up in a row. After joining the two components, a linear operative connection is created at this apex or at this azimuth.
[0059] FIG. 6 shows an alternative connection arrangement 4 of two orthopedic components, here a shaft 17 of a first component 1, having a ball head 18 of a second component 2. The shaft 17 has a projection or an attachment 5 at its first end 7. Starting from a location 19 of the shaft 17, the diameter D1 of the attachment 5 continuously decreases to its distal end 6 and forms a truncated cone. The truncated cone has a peripheral or contact surface 27. Like all other design variants, the two components can be part of a hip joint prosthesis, a shoulder joint prosthesis, or a finger or ankle prosthesis or other joint prostheses.
[0060] The second component 2 has a recess or groove 10. The groove 10 is delimited by a peripheral surface 16 and a base surface or a bottom 12 and opposite the bottom by an opening 14. In this embodiment, the peripheral surface 16 is made in two parts, i.e. it consists of two different geometric shapes. Starting from the second end 11 of component 2, from the opening 14 of the groove 10, the peripheral surface 16 of the groove 10 is curved and forms the contact surface 29 on which the contact point KP is located. The curvature of the contact surface 29 creates a convexly curved surface. Starting from the opening 14 of the groove 10, the amount of the diameter D1 of the groove 10 decreases to a point, the apex K. From this apex K, the amount of the diameter D1 to the bottom 12 remains constant, i.e. from this apex K the peripheral surface 16 forms a hollow cylinder 32. The cavity in the hollow cylinder 32 serves to receive the remaining part of the shaft 17, the part of the attachment 5 which is arranged between the contact point KP, and the distal end 6 of the shaft 17. Synovial fluid will be present in this region when implanted.
[0061] In this embodiment, the contact surface 29 is formed preferably circular.
[0062] When joining the shaft 17 of the first component 1 with the ball head 18 of the second component 2, the contact of the two components is created at the contact point KP. The contact point KP lies on the peripheral surface 16 or the contact surface 29 below the apex K in the direction of the second end 11 or the opening 14. The gap between the contact point KP and the apex K depends on the geometric configuration of the truncated cone of the first component 1 and the curvature of the contact surface 29 of the second component 2.
[0063] This embodiment has the decisive advantage that the precise location of the contact point KP can easily be determined by the circular design of the contact surface 29, inter alia from the taper angle of the projection 5 and the radius R. The formation of the cavity above the apex K as a hollow cylinder 32 considerably simplifies the production of component 2.
[0064] FIG. 7 shows a section Z from FIG. 6. The circular contact surface 29 can be seen, on which the contact point KP is located and which merges into the hollow cylinder 32 at the apex K. At the contact point KP, the contact surface 29 touches the contact surface 27 of the projection 5 of the shaft 17.
[0065] FIG. 8 shows again schematically a connection arrangement 4 according to the invention having a second orthopedic component 2, namely a ball head and a first orthopedic component, namely a shaft 1, the upper end of which is formed as a taper. The peripheral surface 16 or the contact surface 29 of the ball head is formed as part of a ring having the radius R. A complete ring is shown for clarity. The longitudinal axis is identified by reference numeral 33. In this embodiment, the longitudinal axis 33 also forms the axis of rotation.
[0066] FIG. 9 shows the connection point, i.e. a contact point KP enlarged according to FIG. 8, in section and in a schematic representation. At the contact point KP, here designated P1, the part of the first orthopedic component 1 designed as a taper touches the contact region 29 of the ball head formed as a ring having the radius R. The taper angle of the projection 5 is marked here with a and forms the male taper. The distance P2-P3 denotes the gap at orifice. The contact point P1 is at a height H from the gap at orifice.
[0067] FIGS. 10 and 11 show in a 3D representation the joining process of two components 1, 2, which are initially arranged at an angle that deviates from an orthogonal alignment. The attachment 5 of a first component 1 is inserted into a groove 10 of a second component 2, wherein a 2-point contact is first created between the attachment 5, the taper 35 of a first component 1, and an annular contact surface 29 of a second component 2. This 2-point contact is created when two components (1 and 2) are arranged at an angle that deviates from 90 to one another. Reference numeral 33 shows the longitudinal axis of component 1; reference numeral 37 shows the longitudinal axis of component 2. These two axes are arranged at an angle that deviates from 90 to one another. This initially results in a 2-point contact. With the reference numeral 36, the contact points of a 2-point contact are designated (see FIG. 10).
[0068] FIG. 11 shows the taper 35 according to FIG. 10 and the contact surface 29 of the component 2. Components 1 and 2 are arranged at an angle to one another, deviating from 90. Thereby, a 2-contact point connection is created between components 1 and 2. One of the two contact points is shown and provided with the reference numeral 36. The second contact point is arranged at a distance of 180 from the first contact point. There is a gap 38 between the contact points, which increases starting from a contact point 36 in the direction of the second contact point 36. The gap 38 has its greatest width in the region of half the distance between the contact points.
[0069] The joining condition according to FIGS. 10 and 11 of two components is not stable and permanent and should be avoided. The arched surface according to the invention on at least one component transfers the connection when further joining from a 2-contact point connection to a line contact. Starting from the joining state according to FIG. 10, the attachment 5 of the first component 1 is inserted further into the groove 10 of the second component 2 for example. The arched contact surface 29 according to the invention transfers the 2-contact point connection to a line contact and at the same time to an orthogonal alignment of the two components 1 and 2. This makes it possible to convert the joining state according to FIGS. 10 and 11 into a joining state according to FIG. 1. In the embodiment according to FIG. 1, the two components 1 and 2 are arranged at a 90 angle to one another. Thereby, before the force is applied, a line contact is created that extends over the entire peripheral surface.
