US20040254579A1 - Bone connection device - Google Patents

Abstract

An implantable orthopedic device having a load-bearing element, such as a bone plate, with at least one opening for a fixation element and one insert which can be inserted in an inclined opening in a receptacle in the bore. This insert has an external form that is at least partially complementary to the internal form of the receptacle and a central through-bore for receiving the body of the fixation element such as a bone screw. The insert also provides a locking system for holding the insert in the receptacle, in which the insert exhibits at least one locking mechanism with which conformal locking with the load-bearing element may be achieved.

Description

BACKGROUND OF THE INVENTION
• The invention concerns an implantable orthopedic device with a load-bearing element such as a bone plate, with at least one opening for a fixation element such as a bone screw. An insert is provided that can be inserted into the opening in a receptacle in which the external shape of the insert is at least partially complementary to the internal shape of the receptacle. The insert has a central through-bore for mounting a body of the fixation element. The implantable orthopedic device has a structure for holding the insert in the receptacle.[0001]
• A series of implantable orthopedic devices with load-bearing elements, such as bone plates, with openings for the insertion of fixation elements in such load-bearers are known from the prior art. Among them are proposals for the mono-axial as well as poly-axial attachment of fixation elements, particularly screws.[0002]
• As an example for a device of this type having poly-axial attachment of screws in load-bearing elements is shown in U.S. Pat. No. 5,954,722. Other bone plates with inserts are shown in U.S. Pat. Nos. 5,976,141 and 5,607,428.[0003]
• Among the proposals in the prior art is WO 00/53110 (U.S. Patent Publication No. 2002/0045901) which publication relates to an elongated bore in a load-bearing element, which is, on one end, semicircular with rounded-off edges, and which exhibits on the opposing end what essentially is a half thread. The threaded end extends at an angle of more than 180 degrees. With this, it is possible to screw a screw into the threaded side at right angles to the load-bearing element, so that the screw is also firmly connected to the load-bearing element. On the opposite side of the bore, it is possible to screw in a screw at a desired angle perpendicular to the load-bearing element, particularly poly-axially. These screws are, however, not stably locked in the axial direction.[0004]
• The prior art exhibits the disadvantage that the screws are intended exclusively for insertion with specifically designed load-bearing elements, and thus only a specific type of insertion, such as, for example, poly-axial attachment or mono-axial attachment, is possible. Inserts for bone plates are known from U.S. Pat. No. 5,190,545.[0005]
SUMMARY OF THE INVENTION
• It is an object of the invention to improve the prior art devices in such a way that a true variety of screws or other means of attachment for various types of attachment can be inserted.[0006]
• This object is achieved by an insert which can be engaged with the load-bearing element in a manner which results in the insert being firmly fixed. With a suitable insert, an angled position and specifically any desired defined angular position can be obtained. Of particular advantage is that the secure fixing of the insert can be assured directly and automatically with the insertion of the fixation element.[0007]
• These and other objects of the invention are achieved by an implantable orthopedic device or bone stabilization device comprising an elongated bone plate having a plurality of apertures extending through the bone plate. At least one insert is provided having a body with a threaded bore and outer surface for engaging an inner surface of the aperture. At least part of the aperture is surrounded by a locking surface and the insert outer surface has a resilient extension for engaging the locking surface. Thus, the insert may be inserted into the aperture from a top surface of the plate with a resilient extension engaging the locking surface in the aperture thereby resiliently coupling the plate in the insert. The threaded bore of the insert could be angled with respect to the top surface of the plate or could be perpendicular thereto. Preferably, the axis of the aperture extending from a top plate surface to a bottom plate surface is perpendicular to the plate top and bottom surfaces. The locking surface could be a ledge or a ridge extending at least partially around the inner surface of the aperture or one could utilize the bottom plate surface as a ridge for engaging the resilient extensions of the insert. The extension on the insert may have an outwardly extending lip which engages under the ledge or plate bottom surface to prevent the insert from being removed from the aperture.[0008]
• Through the provision of a kit with various inserts with inclined axes, and inner bores on which the screws can be mounted, the surgeon can be provided with a bone plate able to orient bone screws at a number of defined angles in a simple manner. For this reason, the insert is provided with an oval configuration.[0009]
BRIEF DESCRIPTION OF THE DRAWINGS
• The present invention will be better understood on reading the following detailed description of non-limiting embodiments thereof, and on examining the accompanying drawings, in which:[0010]
• FIG. 1 is a top view of a load-bearing element in the form of a bone plate with a row of attachment bores according to a first embodiment of the invention;[0011]
• FIG. 2 is a sectional side view of the load-bearing element according to FIG. 1 along lines[0012]2-2;
• FIG. 3 is a top view of the load-bearing element according to FIG. 1 with the insert of the present invention inserted therein;[0013]
• FIG. 4 is a sectional side view of the load-bearing element with insert inserted according to FIG. 3;[0014]
• FIG. 5 is a perspective view of a first insert to be used with a load-bearing element according to FIG. 1;[0015]
• FIG. 6 is a side view of the long side of the insert according to FIG. 5;[0016]
• FIG. 7 is a side view of the narrow side of the insert according to FIG. 5;[0017]
• FIG. 8 is a sectional side view of a load-bearing element according to a second embodiment of the invention;[0018]
• FIG. 9 is a sectional side view of a load-bearing element according to FIG. 8 with an insert inserted according to the second embodiment;[0019]
• FIG. 10 is a sectional side view of the long side of another insert for use with a load-bearing element according to FIG. 1 or FIG. 8;[0020]
• FIG. 11 is a sectional side view of the narrow side of yet another insert for use with a load-bearing element according to FIG. 1 or FIG. 8; and[0021]
• FIG. 12 is a perspective view of an insert modified from that in FIG. 5 for use with a load-bearing element according to FIG. 1 or FIG. 8[0022]
DETAILED DESCRIPTION
• FIG. 1 shows a top view of a load-bearing element in the form of a[0023]plate1 with a row ofattachment bores2 arranged along the longitudinal direction ofplate1 according to a first embodiment of the invention.Bores2 are through-bores that exhibit an ovalcentral opening3. At opening3 there are twoside walls5 on opposite sides of axis4 which extend parallel to the direction of longitudinal axis4 ofplate1 and extend at right angles to the surfaces of the plate. Theseparallel side walls5 are connected on both ends bysemicircular walls6, each forming a semi-cylindrical boundary so that together the aforementionedoval opening3 results.
• In other forms of the invention,[0024]oval bores2 can also be provided.Bores2 can also be elliptical or of a common elongated form. What is essential is the multiplicity of functions for the selection of attachment elements or fasteners made possible byinsert10 shown in FIG. 5. Through the mostly elongated form ofplate1,elongated bores2 are preferred over circular bores in order to maintain flexibility with the insertion of screws with larger diameters. In one embodiment not shown in the drawings, the bore may be essentially cylindrical with the disadvantage that the insert has less material for providing inclined holes in the insert. The elongated form that is asymmetrical with respect to axis13 (FIG. 4) but rather is symmetrical only with respect to one of the long axes4 and the flatsurfaces enclosing axis13 actually provides the opportunity, through suitable inserts (see FIGS. 10 and 11), of firmly fixing defined angles ininclined axes43 and53.
• Arranged around the not necessarily circular or[0025]cylindrical walls5,6 formingopening3 is chamfered surface area7, extending and tapering inwardly from theupper surface8 ofplate1 that faces away from the bone during implantation. The form of this area7 can be more easily seen in the cross-section of FIG. 2 and is preferably part-spherical.
• FIG. 2 shows a sectional side view of the load bearing element or[0026]bone plate1 according to FIG. 1. Similar characteristics appear in all figures with the same reference numerals. From FIG. 2, one can clearly see in a preferred embodiment, tapered area7 in the longitudinal direction of axis4, forms an angle of 37.5 degrees withsurface8. This results in an angle of 142.5 degrees toside walls5,6. Naturally, other angles are also possible, particularly it would be possible to have abore2 that has no chamfered area7, which would thus exhibit a purely cylindrical or oval-cylindrical inner boundary surface. Thetop surface8 of load-bearing element1 is formed somewhat deeper in theside area18 nearbores2. The same is true forupper edge15 ofside wall5, which are shown to be lower (closer to the plate bottom surface) in a direction opposite the bore ends in longitudinal direction4.Bottom surface9, which is closest to the bone in insertion during surgery is here locally flat. Normally,plates1 can exhibitcontinuous surfaces8 andundersurfaces9 which at each point, for the function of positioning on the bone can always be considered to be flat. But here too, positioning on curved or bent surfaces can be provided.
• FIG. 3 shows a top view of the load-bearing element or[0027]plate1 according to FIG. 1 withinsert10 located inbore2. Eachinsert10 is designed to be shaped complementary to bore2 for locking therein with respect to areas7 andside walls5.Insert10 has acentral bore11 with aninternal threading12.
• FIG. 4 shows a sectional side view of the load-[0028]bearing element1 withinsert10 according to FIG. 3 therein. For this, a first embodiment forinsert10 was selected in whichmain axis13 ofcentral bore11 runs perpendicular tosurface8. In the preferred embodiment, insert10 has anarea19 that extends beyondlower surface9 that is adjacent the bone. In particular, insert10 has locking mechanisms that are better shown in FIG. 5 and are not visible in FIG. 4 because they are along its edges. In particular, the locking mechanism can be two projecting rims that engage the underside ofplate1 after the insertion ofinsert10. This will be explained in more detail in connection with FIGS.5 to11. In any event, insert10, when it is inserted intoplate1, with itsextension area19, forms a distance spacer with regard to the bone material into which a screw that has been inserted intobore11 is turned.
• FIG. 5 shows a perspective view of an[0029]insert10 to be used with a load-bearing element1 according to FIG. 1. Thereference numeral21 refers to the surface ofinsert10 having acircumference22 that meets with the edge ofarea18 ofplate1. In the preferred embodiment, aspherical surface23 extends downwardly fromsurface21 and is shaped so as to have complementary surface contact with surface7. In cutting this recess by means of spherical cutting spherical areas are formed insurface23.Semicircular extension24 extends downwardly fromsurface23 and is in conforming contact, without any significant play, witharea6 ofbore2.
• The area lying opposite the[0030]longitudinal surface5 consists of aresilient extension25 on each side, in which, in the preferred embodiment shown, eachextension25 is provided withslots26. Eachextension25 has, on its lower edge, a projectingrim27 facing outward from the point of view of the insert with an upward-facingshoulder28 with anouter edge29. Preferably, projectingrim27 is only slightly rounded in going towardshoulder28. The surface ofrim27 that is facing toward the bone is then preferably inclined.Extension25 is also to a certain extent, flexible. In insertinginsert10,extension25 then slides intobore2 and is deflected inwardly by the projectingrim27. Onceinsert10 is completely inserted,shoulder28 slides againstunderside9 ofplate1 and locks insert10 inplate1. This locking is additionally ensured by the subsequent insertion of a bone screw (not shown). Through the pressure of the screw on the internal thread ofextension25 inward deflection ofextension25 is prevented so that projectingrim27 is secured underplate1.
• It should be noted that[0031]extension25 and with it projectingrim27 need not necessarily be arranged as twoextensions25 on the opposing longer sides ofinsert10. The design can also include resilient extensions on the narrow sides of an insert, i.e. corresponding to the location of the semicircularcylindrical extensions24.Extensions25 can also be arranged in an alternating manner. There can also be only one or two more extensions.
• [0032]Extensions25 can act as spacers. This can be even further accentuated, as shown in FIG. 12.
• FIG. 6 shows a side view of[0033]insert10 according to FIG. 5.Extension section19 is provided in side areas7. The projectingrim27 is formed on an end area ofextension25.Slots26 extend to the area ofspherical surface23. Of courseslots26 can also be designed to be shorter or longer.
• FIG. 7 shows a side view of the narrow side of[0034]insert10 according to FIG. 5.
• FIG. 8 shows a cross-sectional view of a load-[0035]bearing element31 according to a second embodiment of the invention and FIG. 9 shows a top view of the load-bearing element31 according to FIG. 8 withinsert30 inserted according to the second embodiment. The difference between the first and second embodiments is that in the second embodiment at least along the length of the longitudinal axis4 of the load-bearing element31 is thatrecess33 is provided on thebottom surface9 aroundopening2. This recess can also be provided on the narrow side, as shown in FIG. 8. In addition, insert30 is provided with a projectingrim27 that is arranged in such a way that the bottom ofinsert30 does not project beyondlower surface9. Theunderside29 ofinsert30 is thus at least flush with theaforementioned surface9 of the load-bearing element1. Otherwise, the resilient engagement ofinsert30 inrecess2 is designed in the same way as the engagement of the first embodiment. But here, if desired, theunderside29 ofinsert30 can extend beyond theaforementioned surface9 of the load-bearing element.
• FIG. 9 shows a sectional side view of load-bearing element or[0036]bone plate31 according to FIG. 8 withinsert30 according to the second sample embodiment inserted therein.
• FIG. 10 shows a sectional side view of a long side of another[0037]insert40 to be used with a load-bearing element1 according to FIG. 1 or FIG. 8.Insert40 preferably has aflush underside29, but could also be configured similarly tounderside19 and extend beyondplate surface9. The main difference betweeninsert40 and the insert shown in FIG. 5 lies in itsinternal bore11.Axis43 ofbore11 is slanted preferably at about 15 degrees in the direction of the longitudinal axis4. Preferably, in a kit provided for surgery, there would be a series of different inserts with various angles, of, for example 5, 10, 15 and 20 degrees, to name a few possible values. Asbores2 are symmetrical with respect toaxis13, and relatively symmetrical with respect to the perpendicular to the longitudinal axis4, inserts40 can be inserted turned 180 degrees. Thus, each insert with a specified angle of, for example, 15 degrees, can be inserted at a plus 15 degree or a minus 15 degree angle.
• FIG. 11 shows a sectional side view of a narrow side of yet another[0038]insert50 to be used with a load-bearing element1 according to FIG. 1 or FIG. 8. Thepreferred insert50 has anunderside19 extending beyond thebottom plate surface9 but could also be configured similarly tounderside29 and be flush with the bottom plate surface. The main difference betweenalternate insert50 and the insert shown in FIG. 5 lies in itsinternal bore11.Axis53 ofbore11 is shown to be inclined in the direction toward longitudinal axis4 for example at an incline of 5 degrees, i.e. in a plane perpendicular to the offset shown in FIG. 10. Preferably, in a set provided for surgery, there would be a series of different inserts with various angles, of, for example, 2.5, 5, 7.5 and 10 degrees, to name a few possible values. Asbores2 are symmetrical with respect toaxis13, and relatively so with respect to the longitudinal axis4, inserts50 can be inserted turned 180 degrees, so that having each insert with a specified angle, the corresponding “negative” angle is also covered. The angles provided for the embodiments ofinsert50 according to FIG. 11 are significantly smaller, since the bore width is less than the length. The angle is about half the size than in the sample embodiments ofinsert40 according to FIG. 10. This is becauseaxis53 is angled perpendicular to the elongated portion of load-bearing element1 and bore2, such that there is less room in the insert for the bore to be angled. Generally, steep angles are not necessary, as fixation elements such as screws are generally arranged in essentially the same and/or similar angles to load-bearing element1. It is also possible to provide inserts inclined in both the aforementioned directions (i.e. with inclines corresponding toaxis43 and axis53) of FIGS. 10, 11, respectively.
• FIG. 12 shows a perspective view of an insert[0039]60 which is modified frominsert10 according to FIG. 5. Insert60 may to be used with a load-bearing element1 according to FIG. 1 or FIG. 8.Reference61 refers to a groove that is set intoextension25 to increase resilience.Groove61 runs between twoslots26. As discussed above,surface23, forming a spherical base with respect toupper surface21, is built in so as to have complementary surface contact to surface7. In the embodiment according to FIG. 12,groove61 is set at the upper end area ofslit26, in order to allow the maximum spring action. This produces anarea62 from which extendsspherical area23.
• Although the described drawings already show a whole series of possible configurations of the invention, the invention is and should be limited only by the parameters of the attached claims.[0040]
• The advantage of the invention is that it offers the surgeon, with a[0041]plate1 with conventional standard bores2, the possibility of forming a plurality of angularly-stable mono-axial bore by means of an inset, and furthermore, that this is made possible intra-operatively.
• Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.[0042]

Claims (15)

1. An implantable orthopedic device comprising an elongated load-bearing element with at least one opening for a fixation element and with an insert that may be inserted in a receptacle in the opening wherein the insert exhibits an external form that is at least partially complementary to an internal form of the receptacle and wherein the insert exhibits a central through-bore for mounting the body of the fixation element, and in which the implantable orthopedic device exhibits a means for holding the insert in the receptacle wherein the insert exhibits at least one locking mechanism with which conformingly locks with the load-bearing element.

2. The device as set forth inclaim 1 wherein the insert or the locking mechanism has at least one extension that goes along one side of the insert.

3. The device as set forth inclaim 2 wherein the extension is configured in a flexible manner in the standard direction or inclined to the principal plane of the load-bearing element along the axis and/or that the extension includes a groove running in the principal plane of the load-bearing element.

4. The device as set forth inclaim 1 wherein the locking mechanism include at least one projection extending away from the through-bore and intended for engagement with the load-bearing element.

5. The device as set forth inclaim 1 wherein the locking mechanisms can be fixed against the load-bearing element by means of a fixation element in the opening and remain engaged with it and cannot be released until the aforementioned fixation element has been removed from the opening.

6. The device as set forth inclaim 1 wherein the insert exhibits at least one locking mechanism which can interact with a complementary area in the area of the underside of the load-bearing element.

7. The device as set forth inclaim 6 wherein the load-bearing element exhibits at least one recess on the underside of the load-bearing element, in which the locking mechanisms can be engaged, so that the insert, does not extend beyond the aforementioned underside.

8. The device as set forth inclaim 6 wherein the locking mechanism can be engaged under the underside of the load-bearing element so that the insert extends beyond the aforementioned underside and acts as a spacer.

9. The device as set forth inclaim 1 wherein the inner bore of the insert exhibits an inclined axis that deviates from the normal axis to the principal plane of the load-bearing element, in which the aforementioned inclined axis is inclined towards a narrow side of the load-bearing element and/or in the direction of the longitudinal axis of the load-bearing element.

10. The device as set forth inclaim 1 wherein the insert and opening are elongated in the longitudinal direction.

11. A bone stabilization device comprising:

an elongated bone plate having a plurality of apertures extending through the bone plate, at least one insert having a body with a threaded bore and an outer surface for engaging an inner surface of said aperture, at least part of said aperture is surrounded by a locking surface and said insert outer surface having a resilient extension for engaging said locking surface.

12. The bone stabilization device as set forth inclaim 11 wherein said aperture has a central axis extending from a top plate surface to a bottom plate surface and said bore in said insert has a central axis inclined with respect to said aperture central axis.

13. The bone stabilization device as set forth inclaim 11 wherein the aperture is in the form of an elongate slot.

14. The bone stabilization device as set forth inclaim 13 wherein said insert has an elongate outer surface for placement adjacent an elongate inner surface of said slot and said resilient extension extends between said adjacent surfaces.

15. The bone stabilization device as set forth inclaim 14 wherein said locking surface is a ledge formed around at least part of said aperture inner surface and said extension has an outwardly extending lip for engaging said ledge.

Images