US-12622733-B2 - Olecranon bone plate

Abstract

The bone plate ( 1 ) according to the invention is particularly suitable for treating fractures or non-unions and for osteotomies of the olecranon and the proximal ulna. The bone plate ( 1 ) has the following parts: a distal longitudinal shaft portion ( 2 ) having a number of plate holes ( 11 ); a longitudinal central axis ( 3 ); and a proximal head part ( 4 ), which is widened compared to the distal shaft part and has two holes ( 5; 6 ) with the hole axes ( 7, 8 ) arranged on opposite sides of the central axis ( 3 ), wherein the head part ( 4 ) is bent down relative to the shaft part ( 2 ). The two holes ( 5, 6 ) are suitable for receiving a polyaxial locking screw at an angle of ±15° relative to the respective hole axis ( 7; 8 ) or a non-locking standard screw, with the two hole axes ( 7, 8 ) forming an angle α.

Inventors

• Patrick Burki
• Beat Kaspar MOOR
• Christian Sproß
• Martin OLACH

Assignees

• BONEBRIDGE AG

Dates

Publication Date

20260512

Application Date

20210810

Claims (19)

1. 1 . A bone plate comprising: a distal longitudinal shaft part provided with a plurality of shaft part plate holes; and a proximal head part, which is wider than the distal longitudinal shaft part and which is provided with first and second head part holes; wherein the bone plate has a central axis, wherein the first and second head part holes have hole axes arranged on opposite sides of the central axis, wherein the proximal head part is angled relative to the distal longitudinal shaft part, wherein the first and second head part holes are configured to receive (i) a polyaxial locking screw at an angle of ±15° relative to the respective hole axis, or (ii) a non-locking standard screw, and wherein the hole axes of the first and second head part holes converge distally at an angle α that is greater than 1°.
2. 2 . The bone plate according to claim 1 , wherein the proximal head part is provided with a third hole having a hole axis, which is arranged on the central axis.
3. 3 . The bone plate according to claim 1 , proximal head part angled relative to the distal longitudinal shaft part has a length L K that is at least 20% a length L S of the distal longitudinal shaft part.
4. 4 . The bone plate according to claim 1 , wherein a free proximal end of the proximal head part is angled by at least 70° relative to the distal longitudinal shaft part.
5. 5 . The bone plate according to claim 1 , wherein the angle α is greater than 4°.
6. 6 . The bone plate according to claim 1 , wherein centers of all shaft part plate holes are not more than 2 mm away from the central axis.
7. 7 . The bone plate according to claim 1 , wherein at least one of the first and second head part holes or the shaft part plate holes has an inner wall made of a material that has a hardness H P within which is mounted a hollow cylindrical or hollow cone-shaped insert, which rests at least partially on the inner wall and is configured to receive a head of a bone screw, the insert being arranged in the plate hole and secured against rotation and consisting of a material that has a hardness H E , and wherein H E <H P .
8. 8 . The bone plate according to claim 1 , wherein the distal longitudinal shaft part is provided with an elongated hole.
9. 9 . The bone plate according to claim 8 , wherein the distal longitudinal shaft part is provided with a thread hole having a diameter that is smaller than the diameter of the first and second head part holes, which is configured for fixing surrounding soft tissues to the bone plate.
10. 10 . The bone plate according to claim 9 , wherein the thread hole is arranged between the elongated hole and the next shaft part plate hole in the direction of the proximal head part.
11. 11 . The bone plate according to claim 1 , wherein the bone plate has an average thickness in a transition zone between the distal longitudinal shaft part and the proximal head part that is smaller than an average thickness of the distal longitudinal shaft part.
12. 12 . The bone plate according to claim 1 , wherein a constriction is provided at least between two shaft part plate holes such that at the constriction the distal longitudinal shaft part width is reduced by at least 20%.
13. 13 . The bone plate according to claim 12 , wherein the area moment of inertia of the plate cross section at the narrowest point of the constriction essentially corresponds to the area moment of inertia of the plate cross section in the area of the largest diameter of the adjacent plate hole.
14. 14 . The bone plate according to claim 1 , wherein the proximal head part is provided with a through hole for receiving a Kirschner wire.
15. 15 . The bone plate according to claim 1 , wherein the distal longitudinal shaft part does not have lateral wings running transversely to the central axis.
16. 16 . The bone plate according to claim 3 , wherein the length L K of the proximal head part angled relative to the distal longitudinal shaft part is in the range of 16-24 mm.
17. 17 . The bone plate according to claim 1 , wherein the bone plate has a geometrical shape adapted for fixation to a right ulna.
18. 18 . The bone plate according to claim 1 , wherein the bone plate has a geometrical shape adapted for fixation to a left ulna.
19. 19 . A combination comprising a bone plate according to claim 1 and at least one polyaxial bone screw.

Description

BACKGROUND OF INVENTION Field of Invention The invention relates to a bone plate suitable for the treatment of fractures or non-unions and for osteotomies of the olecranon and the proximal ulna. Brief Description of Related Art Proximal ulna/olecranon fractures are relatively common injuries in adults and can result in severe dysfunction resulting from post-traumatic instability, impingement, soft tissue contractures, malunion, or nonunion. High-energy injuries can lead to associated distal injuries such as: forearm and distal radius fractures, fractures including the intraosseous membrane or disruptions of the distal radioulnar joint. Monteggia fractures are fractures of the proximal third of the ulna with associated radial head dislocation. The bone plate according to the invention is intended for use in open reduction and internal fixation (ORIF) of the olecranon and the proximal ulna. It is indicated for fractures, osteotomies and non-unions of the olecranon and proximal ulna. From U.S. Pat. No. 8,182,517 a bone plate is known for the internal fixation of a fracture of the proximal ulna, which has a narrow, proximal head part which is bent down relative to the wider, distal shaft part and one or two hole(s) arranged on the longitudinal central axis of the bone plate. However, this known bone plate has the disadvantage that the bent-down head part is short and narrow relative to the shaft part, so that not all intra-articular fractures can be treated with it. In addition, it is difficult to properly fix the fragments resulting from a fracture with just one screw (or two longitudinally arranged screws). The invention aims to provide a remedy here. The invention is based on the object of creating a bone plate for the olecranon, which allows any type of fracture to be treated. BRIEF SUMMARY OF THE INVENTION The invention solves the problem with a bone plate with (i) a distal longitudinal shaft portion having a number of plate holds, (ii) a longitudinal central axis, and (iii) a proximal head part, which is widened compared to the distal shaft part and has two holes with the hole axes arranged an opposite sides of the central axis, wherein a) the head part is bent down relative to the shaft part; b) the two holes are suitable for receiving (i) a polyaxial locking screw at an angle of ±15° relative to the respective hole axis or (ii) a non-locking standard screw; and c) the two hole axes from an angle a; a combination of a bone plate according to the invention with at least one polyaxial bone screw; and use of the bone plate according to the invention for the treatment of fractures or non-unions and for osteotomies of the olecranon and the proximal ulna. The advantages achieved by the invention can essentially be seen in the fact that, thanks to the bone plate according to the invention with a widened head part, which is equipped with three screw holes, a broken olecranon can be optimally supported. By means of the two screw holes located to the left and right of the central axis, two screws can be placed almost parallel to the shaft part, so that all intermediate fragments can be optimally gripped and optimal mechanical stability is achieved. Further advantageous embodiments of the invention can be commented on as follows: In a special embodiment of the bone plate according to the invention, the proximal head part has a third hole with a hole axis which is arranged centrally to the central axis. Thanks to the additional third hole, practically all possible fractures can be treated with the bone plate. For example, this third, most proximally located hole can also be used to treat a simple intra-articular olecranon fracture. Rarely are all three proximal holes equipped with bone screws, because if they were, the space would be too tight, but depending on the fracture, the surgeon has the choice of where he would like to place a screw in the head part. The length LK of the proximal head part bent down relative to the shaft part is at least 20%, preferably at least 25% of the length LS of the shaft part. The relatively long head part makes it possible to support the entire proximal olecranon. In a further embodiment, the free proximal end of the head part is bent down by at least 70°, preferably at least 80°, relative to the distal shaft part. In a special embodiment, the two hole axes converge distally and the angle α is greater than 1°, preferably greater than 4°. This ensures that the polyaxial screws cannot be shot into the joint when they are set in the zero degree direction to the hole axis. In a further embodiment, the centers of all plate holes in the distal shaft part are at most 2 mm away from the central axis. In a special embodiment, at least one of the holes or the plate holes has an inner wall made of a material that has a hardness HP. In addition, a hollow cylindrical or hollow cone-shaped insert is mounted in the plate hole, which rests at least partially on the inner wall and is suitable for re