Bodkin broaching tip for self-drilling bone anchor

Abstract

To provide a bone anchor tip for penetrating a hard or dense bone.SOLUTION: A tip 10 for a bone anchor 12 has cutting edges 16 that converge at the end of the body to form a point 20, thereby defining a series of cutting surfaces 14. The cutting surface may be planar or curved, and may be multi-faceted. The tip may include a broach that extends parallel or at an angle to the tip. The broach may be partially or completely interrupted by one of the cutting surfaces. The tip is designed to be coupled to any of a variety of bone anchor types, including those that have mechanical retention structures, those that change shape in response to insertion into bone, or those that have threads for advancing the anchor into bone. The anchor and the body may be integrally formed together, or the anchor and the body may be formed from different materials.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to orthopedic bone anchors, and more particularly to bone anchor tips for penetrating hard or dense bone. [Background technology]

[0002] Self-drilling bone anchors are commonly used in arthroscopic repairs because they do not require a pre-drilled pilot hole for implantation. This approach allows clinicians to avoid the potential difficulty and hassle of repositioning a pre-drilled osteotomy to insert the anchor, which can be difficult if there is residual soft tissue at the implantation site. Self-drilling also eliminates implantation errors, such as not implanting the bone anchor along the same longitudinal axis as the pilot hole, which can lead to slippage and fracture of the bone anchor. Most conventional self-drilling bone anchors use a conical or cone-like tip to create the osteotomy in the bone. These conical tips are effective in soft to medium-density bone but have difficulty penetrating harder, denser bone. Summary of the Invention [Means for solving the problem]

[0003] Thus, there is a need for an improved self-drilling bone anchor tip that can penetrate harder, denser bone. The devices disclosed herein are self-drilling bone anchors and tips that provide a more efficient cutting geometry than allows for penetration into harder, denser bone. The unique cutting geometry of the bone anchor also significantly reduces the frequency of bone surface sloughing during implantation. Therefore, osteotomies created by the anchors disclosed herein are more efficient, require fewer hammer blows than osteotomies created with traditional conical or cone-like tips, and are far less likely to crack the bone during osteotomy creation. The efficiency of the cutting geometry of the anchors disclosed herein also allows for softer materials, such as polymers, biocomposites, and biological materials, to be used as the base material for the drilling tip and anchor, thereby opening up more possibilities for regenerative medicine that does not require metal components to remain in the body.

[0004] According to one design aspect, a device for insertion into bone has a body extending along a longitudinal axis and at least two cutting edges extending along the body and converging at an end of the body to form a point aligned with the longitudinal axis. The cutting edges define a cutting plane therebetween, which can be planar or curved. The cutting plane may include a first portion extending at a first angle relative to the longitudinal axis and a second portion extending from the first portion at a second angle relative to the longitudinal axis that is different from the first angle. The body may also include a broach having an outer surface extending parallel to the longitudinal axis or at an angle relative to the longitudinal axis. The broach may be at least partially interrupted by one of the at least one cutting surfaces, or may be fully interrupted by one of the at least one cutting surfaces. The body is intended to be coupled to an anchor, such as one having a mechanical retention structure, one intended to change shape in response to insertion into bone, or one having threads for advancing the anchor into bone. The anchor and body may be integrally formed together, or the anchor and body may be formed from different materials.

[0005] The present invention will be more fully understood and appreciated from a reading of the following detailed description in conjunction with the accompanying drawings, in which: [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram of a self-drilling tip for a bone anchor. [Figure 2] FIG. 2 is a side view of a self-drilling tip for a bone anchor having three cutting edges defining three cutting planes. [Figure 3] FIG. 3 is an end view of a self-drilling tip for a bone anchor having three cutting edges that define three cutting planes. [Figure 4] FIG. 4 is a side view of a self-drilling tip for a bone anchor having four cutting edges defining four cutting surfaces. [Figure 5] FIG. 5 is an end view of a self-drilling tip for a bone anchor having four cutting edges defining four cutting surfaces. [Figure 6] FIG. 6 is a side view of a self-drilling tip for a bone anchor having six cutting edges defining six cutting surfaces. [Figure 7] FIG. 7 is an end view of a self-drilling tip for a bone anchor having six cutting edges defining six cutting surfaces. [Figure 8] FIG. 8 is a perspective view of a self-drilling tip for a bone anchor having a flat cutting surface. [Figure 9] FIG. 9 is an end view of a self-drilling tip for a bone anchor having a flat cutting surface. [Figure 10] FIG. 10 is a perspective view of a self-drilling tip for a bone anchor having a curved cutting surface. [Figure 11] FIG. 11 is an end view of a self-drilling tip for a bone anchor having a curved cutting surface. [Figure 12] FIG. 12 is a side view of a self-drilling tip for a bone anchor having a single angle cutting surface. [Figure 13]FIG. 13 is a side view of a self-drilling tip for a bone anchor having a multi-angle cutting surface. [Figure 14] FIG. 14 is a side view of a self-drilling tip for a bone anchor having a double interrupted broach. [Figure 15] FIG. 15 is a side view of a self-drilling tip for a bone anchor having a dual layer broach. [Figure 16] FIG. 16 is a side view of a self-drilling tip for a bone anchor having multiple interrupted broaches. [Figure 17] FIG. 17 is a side view of a self-drilling tip for a bone anchor having a double layer broach extending parallel to the longitudinal axis of the self-drilling tip. [Figure 18] FIG. 18 is a side view of a self-drilling tip for a bone anchor having a double layer broach extending obliquely relative to the longitudinal axis of the self-drilling tip. [Figure 19] FIG. 19 is a side view of a self-drilling tip for a bone anchor having a fully interrupted broach. [Figure 20] FIG. 20 is a side view of a self-drilling tip for a bone anchor having a partially interrupted broach. [Figure 21] FIG. 21 is a side view of a self-drilling tip for a bone anchor having an uninterrupted broach. [Figure 22] FIG. 22 is a series of side views of different anchor bodies that may be equipped with self-drilling tips. [Figure 23] FIG. 23 is a side view of a pair of single-body and multi-body anchors for use with a self-trilling tip. [Figure 24] FIG. 24 is a series of side views of different anchor body assemblies for use with a self-drilling tip. DETAILED DESCRIPTION OF THE INVENTION

[0007] Referring to the figures, wherein like numerals refer to like parts throughout, in FIG. 1 there is seen a self-drilling tip 10 for use as part of a bone anchor 12 having a geometry designed to increase the self-drilling efficiency of the anchor 12 during installation and therefore alter the manner in which the osteotomy is formed. The tip 10 can initiate and propagate the osteotomy by cutting into and then broaching the bone material during insertion, as opposed to conventional conical drilling tips that simply drill and then expand the bone material. The tip 10 is flat or curved and includes a series of cutting surfaces 14 that extend at an angle relative to the longitudinal axis XX of the tip 10 and terminate at a point 20 aligned with the longitudinal axis XX. The cutting surfaces 14 are defined by a plurality of cutting edges 16 that intersect at the point 20 of the tip 10. The angle of the cutting surfaces 14 is preferably as small as possible, while the overall length of the tip 10 should not exceed the minimum depth of a conventional pilot hole. The diameter of the tip 10 is dictated by the diameter of the anchor 12 to which the tip 10 is attached and may be any conventional diameter used for bone placement. For harder materials, or if the user requires less placement force, a more acutely angled tip 10 may be used. For softer materials, a less angled tip 10 may be sufficient. A 22-degree angle of each cutting surface relative to the longitudinal axis has been found to work well, resulting in a 44-degree included angle for the tip 10 as a whole. It should be recognized that this angle may be varied for the particular bone or surgical procedure for which the anchor 12 is intended.

[0008] During insertion, tip 10 maintains multiple contact points with the bone, including one at point 20 and one at each cutting edge 16, for the duration of insertion. The multiple contact locations significantly reduce the effective surface area compared to conventional conical tips, greatly reducing frictional drag, minimizing the surface area over which opposing forces of bone material can act on anchor 12, and improving the cutting efficiency of tip 10 by interrupting the hoop stress compression of bone seen during expansion by cutting into the bone at multiple locations. Thus, when provided on the anchor, tip 10 assists in inserting the anchor into bone. Thus, tip 10 (and the anchor) is positioned adjacent to a bone location and applying force along the anchor's longitudinal axis until tip 10 forms a hole in the bone and can fully insert the anchor into the hole.

[0009] The tip 10 can have any number of cutting surfaces 14, as seen in the various embodiments of Figures 2-7. More specifically, as seen in Figures 2 and 3, the tip 10 may have three surfaces 14 defined by three cutting edges 16. As seen in Figures 4 and 5, the tip 10 may have four surfaces 14. As seen in Figures 6 and 7, the tip 10 may have six surfaces 14. Generally, the more surfaces 14 available, the easier the tip can form pilot holes during installation in bone.

[0010] 8 and 9, the cutting surface 14 may be flat 22, i.e., the cutting surface 14 may extend along a plane that intersects the axis XX. With reference to Figures 10 and 11, the cutting surface 14 may also be curved 24 by extending in a concave or convex manner, or any combination thereof.

[0011] 12 and 13, the cutting edge 16 can have a single face 26, as seen in FIG. 12, or can have a multi-angled face 28 defined by at least a first section 28a extending at an angle relative to at least a second section 28b, as shown in FIG. 13.

[0012] 14-16, the tip 10 may include a plurality of broaches 30 positioned circumferentially around at least a portion of the tip 10. The broaches 30 assist in the removal of material during insertion, as understood in the machining art, rather than simply pressing against the bone laterally, as is the case with conventional conical design self-drilling anchors. The broaches 30 may be present at various frequencies, have various dimensions, and may be positioned relative to one another. For example, as seen in FIG. 14, the tip 10 may have two closely spaced broaches 30. As seen in FIG. 15, the tip 10 may have two spaced broaches. As seen in FIG. 16, the tip 10 may also have several closely spaced broaches 30, for a total of four shown in FIG. 16. The number and positioning of the broaches 30 can be varied for use in bones of different hardness and to accommodate different impact force requirements. The broaches 30 can provide a more precise diameter hole and allow for easier removal of the tip 10 or anchor 12 than with a conical tip anchor, because the hole does not expand after removal of the tip 10, as is the case with a conical tip anchor. As should be appreciated from the illustrated broaches 30, the hole formed by the tip 10 need not be circular, thus providing geometries not possible with a conical anchor tip.

[0013] Referring to Figure 17, the broach 30 can extend parallel 32 to the longitudinal axis XX of the tip 10, as seen in Figure 17, or can extend at an angle 34 that is oblique to the longitudinal axis, as seen in Figure 18. The broach 30 can also be interrupted 36, as seen in Figure 19, partially interrupted 38, as seen in Figure 20, non-interrupted 40, as seen in Figure 21, or any combination thereof. The interruptions in the broach 30 can help stabilize the tip 10 against undesired rotation during installation.

[0014] The tip 10 may be used in combination with different types of bone anchors 12, including conventional anchors 12 with built-in mechanical retention features 50, variable mechanical retention features 52 achieved by shape or structural changes, and screw-type anchors 12 that can be screwed into bone 54, as seen in FIG. 22. The tip 10 may also be incorporated into an anchor 12 having a single body 56, as seen in FIG. 23, or as a separate component of an anchor 12 formed as a multi-body anchor 58. The tip 10 may also be used in any joint space or surgical location where self-drilling anchors can be utilized or are currently utilized.

[0015] The tip 10 can be used with traditional biocompatible materials currently used to create osteotomies, such as biocompatible metals like stainless steel, titanium, and titanium alloys. The increased cutting efficiency of the tip 10 allows for the use of other softer biocompatible materials, such as PEEK, biocomposites, and Bioglass. The tip 10 may also be used in anchors 12 having a single body 60 comprising the same material as the tip 10, anchors 12 having a single body 62 made of multiple materials, anchors 12 having multiple bodies made of the same material 64, and anchors 12 having multiple bodies made of multiple materials 66, as seen in FIG. 24 .

Claims

1. 1. A device for insertion into a bone, comprising: a body extending along a longitudinal axis; at least two cutting edges extending along the body and defining at least one cutting plane therebetween, the at least two cutting edges converging at an end of the body to form a point aligned with the longitudinal axis; An apparatus comprising:

2. The apparatus of claim 1 , wherein the at least one cutting surface is planar.

3. The device of claim 1 , wherein the at least one cutting surface is curved.

4. 2. The device of claim 1, wherein the at least one cutting surface includes a first portion extending at a first angle relative to the longitudinal axis and a second portion extending from the first portion at a second angle relative to the longitudinal axis that is different from the first angle.

5. The device of claim 1 , wherein the body comprises at least one broach.

6. The apparatus of claim 5 , wherein the at least one broach has an outer surface extending parallel to the longitudinal axis.

7. The apparatus of claim 6 , wherein the at least one broach has an outer surface that extends at an angle relative to the longitudinal axis.

8. The apparatus of claim 6 , wherein the at least one broach is at least partially interrupted by one of the at least one cutting surfaces.

9. The apparatus of claim 6 , wherein the at least one broach is completely interrupted by one of the at least one cutting surfaces.

10. 1. An anchor for insertion into a bone, comprising: The main body and a tip coupled to the body and extending along a longitudinal axis; at least two cutting edges extending along the tip and defining at least one cutting plane therebetween, the at least two cutting edges converging at an end of the tip to form a point aligned with the longitudinal axis; An anchor.

11. The anchor of claim 10 , wherein the tip includes at least one broach.

12. The anchor of claim 11 , wherein the body includes at least one mechanical feature for engaging a bone into which the anchor is inserted.

13. The anchor of claim 12 , wherein the mechanical mechanism comprises a structure that changes shape in response to insertion of the anchor into bone.

14. The anchor of claim 11 , wherein the tip and the body are integrally formed.

15. The tip is formed from a first material and the body is formed from a material different from the first material. The anchor of claim 11 formed from a second material.

16. 1. A method for inserting an anchor into a bone, the method comprising: providing an anchor having a body, a tip coupled to the body and extending along a longitudinal axis, and at least two cutting edges extending along the tip and defining at least one cutting plane therebetween, the at least two cutting edges converging at an end of the tip to form a point aligned with the longitudinal axis; positioning the anchor adjacent to a bone location; applying a force along the longitudinal axis of the anchor until the tip forms a hole in the bone; A method comprising:

17. The method of claim 16 , wherein the tip comprises at least one broach.

18. 18. The method of claim 17, wherein the at least one broach assists in removing a portion of the bone to form the hole.

19. 20. The method of claim 18, wherein the body of the anchor includes a mechanism for mechanically engaging the bone adjacent the hole.

20. 20. The method of claim 19, wherein the tip is formed from a first material and the body is formed from a second material different from the first material.

Images