Bone plate

Abstract

A bone plate has an underside on the side of the bone, an upper side and a plurality of holes in the plate connecting the underside with the upper side, with a central hole axis. At least one of these holes in the plate has an internal jacket surface that tapers towards the underside, while the internal jacket surface has N≥3 recesses which extend radially away from the axis of the hole.

Claims

1. A bone plate system, comprising: a bone plate defining a lower surface configured to face bone, an upper surface opposite the lower surface, and a hole that extends along a central hole axis from the upper surface to the lower surface, wherein the hole includes an internal surface having a three-dimensional structure, the bone plate further defining a plurality of recesses that extend away from the central hole axis past the internal surface so as to divide the internal surface into a plurality of sections of the internal surface, each of the sections having respective portions of the three-dimensional structure; and a bone screw that is elongate along a central screw axis, the bone screw including a threaded head and a threaded shaft that extends from the threaded head along a central screw axis, wherein the threaded head is configured to engage the three-dimensional structure when the central screw axis defines a select angle with respect to the central hole axis among a plurality of different angles defined by the central screw axis and the central hole axis, wherein the plurality of different angles are angles at which the threaded head is configured to mate with the three-dimensional structure.

2. The bone plate system of claim 1, wherein the recesses are equidistantly spaced about the central hole axis.

3. The bone plate system of claim 2, wherein the three-dimensional structure and the threaded head engage each other between adjacent ones of the recesses.

4. The bone plate system of claim 1, wherein the hole defines an upper opening at the upper surface, the hole defines a lower opening at the lower surface, the upper opening defines a first cross-sectional dimension measured in a first plane that is perpendicular to the central hole axis, the lower opening defines a second cross-sectional dimension measured in a second plane that is perpendicular to the central hole axis, and the first cross-sectional dimension is greater than the second cross-sectional dimension.

5. The bone plate system of claim 1, wherein the three-dimensional structure comprises a thread.

6. The bone plate of claim 5, wherein the thread is a helical thread.

7. The bone plate of claim 1, wherein the three-dimensional structure is without pitch.

8. The bone plate system of claim 1, wherein the recesses extend from the upper surface to the lower surface.

9. The bone plate of claim 1, wherein each of the recesses defines a shape that is a portion of a cylinder with a respective center.

10. The bone plate of claim 9, wherein the centers are equidistantly spaced about the central axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention and developments of the invention are explained in detail based on the partly schematic illustrations of several embodiments in the figures, wherein:

(2) FIG. 1 shows a longitudinal section through a bone plate with tapered holes in the plate;

(3) FIG. 2 shows a longitudinal section through a bone plate with spherical holes in the plate;

(4) FIG. 3 shows a top view of a bone plate with three recesses in the internal jacket surface of the holes in the plate;

(5) FIG. 4 shows a variation of the bone plate according to FIG. 3 with larger recesses in the internal jacket surface of the holes in the plate;

(6) FIG. 5 shows a top view of a bone plate with thread inserts with four recesses in the internal jacket surface of the elliptic holes in the plate;

(7) FIG. 6 shows a perspective view of a bone plate according to FIG. 1 from above with the bone screws inserted;

(8) FIG. 7 shows a perspective view of a bone plate according to FIG. 1 from below with the bone screws inserted;

(9) FIG. 8 shows a longitudinal section through a bone plate with a bone screw inserted without angular misalignment; and

(10) FIG. 9 shows a longitudinal section through a bone plate with a bone screw inserted with angular misalignment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(11) The bone plate 1 illustrated in FIGS. 1 and 3 has an underside 2 on the side of the bone, an upper side 8 and a plurality of holes 3 in the plate connecting the underside 2 with the upper side 8, the holes having a central hole axis 5. The holes 3 in the plate have an internal jacket surface 4 that tapers towards the underside 2. Furthermore, the internal jacket surface 4 has three recesses 6 which extend radially away from the hole axis 5 of the hole at a uniform distance of 120° from one another. Their peripheral expansion is approximately 40° and they extend exclusively within the internal jacket surface 4. The recesses 6 extend tapered over the entire height of the bone plate 1 from the upper side 8 to the underside 2. In addition, the internal jacket surface 4 is provided with a three-dimensional structure 7 in the form of a thread.

(12) FIG. 4 illustrates a variation of the execution according to FIG. 3, wherein the recesses extend radially away from the axis of the hole past the internal jacket surface.

(13) FIGS. 2 and 5 illustrate a further alternative embodiment, wherein the holes 3 in the plate are constructed as oblong holes. The bone plate is made basically from a plastic material (PEEK) with embedded metallic thread inserts 9 from titanium, forming the holes 3 in the plate. In the case of this embodiment the holes 3 in the plate have four recesses 6, which extend radially away from the axis 5 of the hole past the internal jacket surface 4. The internal jacket surface 4 is divided into four sections of the jacket surface. The recesses extend tapered over the entire height of the bone plate 1 from the upper side 8 to the underside 2. In addition, the internal jacket surface 4 is provided with a three-dimensional structure 7 in the form of a multi-start thread. As far as material is concerned, this embodiment may also be inverted, whereby the bone plate is basically made from metal (titanium) and the embedded therein thread inserts 9 are made from plastic material (PEEK), forming the holes 3 in the plate.

(14) FIG. 6 illustrates the bone plate according to FIG. 1, with bone screws 10 inserted from above, the head portions 11 of which are spherical. FIG. 7 shows the same bone plate 1 from below.

(15) In FIG. 8, a bone plate 1 is illustrated with bone screws 10 inserted therein without angular misalignment. The internal jacket surface 4 of the hole of the bone plate 1 and the head portion 11 of the bone screw 10 have matching threads 13.

(16) FIG. 9 illustrates the same variation as FIG. 8, while the bone screw 10 is angularly misaligned.

(17) While the present invention has been described with reference to the preferred embodiments, those skilled in the art will recognize that numerous variations and modifications may be made without departing from the scope of the present invention. Accordingly, it should be clearly understood that the embodiments of the invention described above are not intended as limitations on the scope of the invention, which is defined only by the following claims.