Positioning aid in rotational osteotomy and mounting set for positioning Kirschner wires

Abstract

Positioning aid (6, 6') for freehand rotational osteotomy, wherein the positioning aid (6, 6') has two channels (13, 14, 13', 14') for receiving Kirschner wires (20, 21) which are arranged at a fixed angle (α, α') to each other, characterized in that the positioning aid (6, 6') has one or more implant plate connection means (9) for releasably fixing the positioning aid (6, 6') to an implant plate (1).

Description

[0001] The invention relates to a positioning aid in rotational osteotomy for positioning two Kirschner wires at a predetermined angle to each other and a mounting set for positioning Kirschner wires.

[0002] Previously, the only way to correctly set such a rotation angle was through the so-called "PSI rotational osteotomy," which uses patient-specific instruments (PSI). However, this procedure is very complex in terms of the preparatory steps.

[0003] Furthermore, instruments are known for the aforementioned purpose with which the rotation angle can be variably adjusted. Such devices have mechanical joints, e.g., hinges, which rotate with the Kirschner wires when they are rotated against each other. These devices are also mechanically complex. Moreover, the movement of the wires during rotation can be obstructed by the instrument.

[0004] Furthermore, the sterilization of medical devices is of central importance. The use of mechanical joints should be largely avoided in this process.

[0005] Based on the aforementioned prior art, the object of the present invention is now to ensure that the rotation angle is correctly set even in the case of "free hand rotational osteotomy", i.e. without the use of patient-specific devices.

[0006] Furthermore, the solution should be mechanically simple and easy to handle.

[0007] The problem according to the invention is solved by a positioning aid having the features of claim 1.

[0008] The positioning aid according to the invention is suitable for freehand rotational osteotomy.

[0009] The positioning aid has at least two channels for receiving Kirschner wires. The channels are arranged at a fixed angle to each other.

[0010] The positioning aid is removable from the implant plate after the angular position has been set, allowing the Kirschner wires to be rotated relative to each other until they are parallel. This rotation without additional aids is known to specialists as a freehand osteotomy.

[0011] To ensure support of the positioning aid during the positioning of the Kirschner wires and subsequent removal after the Kirschner wires have been placed in the predefined angular position, the positioning aid has several implant plate connection means for the detachable fixing of the positioning aid to an implant plate.

[0012] Accordingly, the implant plate can serve both as an anchor for the positioning aid and as a stop during the parallel alignment of the Kirschner wires. The positioning aid itself, however, would block the movement of the Kirschner wires. It can therefore be removed after the wires have been inserted.

[0013] The present invention of the positioning aid can be manufactured cost-effectively, unlike existing instruments, and can be sterilized just as easily for further use, e.g. in an ultrasonic bath.

[0014] Advantageous embodiments of the invention are the subject of the dependent claims.

[0015] At least one implant plate connection element can advantageously be designed as a tooth-like attachment for a form-fitting engagement with a corresponding opening in an implant plate. This achieves a releasable fixation that is particularly stable against lateral forces.

[0016] One of the channels may have an opening slot, in particular an opening slot running parallel to the longitudinal extent of the channel, to facilitate the easy release of the positioning aid for the positioned Kirschner wires.

[0017] The positioning aid can advantageously have a positioning body as a molded part in which the channels run, at least partially. Furthermore, the positioning aid has a projection with the implant connection element, this projection extending from the edge of the positioning body. Advantageously, the projection can be designed to overlap the implant plate, such that the overlap forms a second positive-locking connection with the implant plate. This double positive-locking connection provides additional security for the positioning aid.

[0018] The positioning aid can also have a pipe extension that protrudes from the positioning body and through which one of the aforementioned channels leads out of the positioning body. This pipe extension allows the positioning body to be smaller, and consequently, the wound opening required to accommodate the positioning aid can also be smaller.

[0019] The opening slot can advantageously be positioned partially within the pipe joint. Due to its location within the pipe joint, the opening slot can be more easily and elastically widened under the influence of deformation forces, allowing the Kirschner wire to be pulled out of the channel with less force.

[0020] Advantageously, the channels are arranged with a fixed angular offset relative to each other. This means that – unlike in the prior art – mechanical joints can be advantageously omitted.

[0021] For easier operation and selection, the positioning aid can have a label to indicate the size of the angular offset of the channels relative to each other and / or the direction of rotation.

[0022] Advantageously, the positioning body with the channels can be designed as a single, preferably monolithic, block. This block can be manufactured at comparatively low production costs and, due to its easy sterilization, can be reused repeatedly.

[0023] The positioning body can preferably be made of a plastic material, a ceramic material or a metallic material.

[0024] Also according to the invention is a mounting set comprising an implant plate and a positioning aid according to the invention, wherein the implant plate and the positioning aid have corresponding connecting means.

[0025] The corresponding connecting means are advantageously designed to form a positive fit when connecting the implant plate and the positioning aid, thereby enabling secure positioning of the Kirschner wires.

[0026] The implant plate may have openings for fixing the implant plate to a bone by means of mechanical connecting elements, preferably screws.

[0027] The implant plate may also have additional openings as the aforementioned corresponding connecting means, which preferably transition into the openings for fixing the implant plate.

[0028] The mounting arrangement may also include Kirschner wires for positioning in the channels of the positioning aid.

[0029] The assembly set according to the invention can in particular comprise several of the positioning aids according to the invention, wherein these positioning aids differ from each other in that each positioning aid has a different angular offset between the channels than the other positioning aids.

[0030] The invention is explained in more detail with reference to the following figures, using an exemplary embodiment. The individual details of the exemplary embodiment are in no way to be considered limiting to the subject matter of the present invention. Rather, the exemplary embodiment reveals to those skilled in the art numerous further variations, which are also part of the present invention. The figures show: Fig. 1 Perspective front view of an implant plate for fixing to a bone; Fig. 2. Perspective rear view of the implant plate Fig. 3 Perspective view of a first positioning aid according to the invention; Fig. 4 Perspective view of a second positioning aid according to the invention; Fig. 5 First side view of the second positioning aid; Fig. 6 Second side view of the second positioning aid; Fig. 7 First perspective view of a Kirschner wire; Fig. 8 Second perspective view of the Kirschner wire; Fig. 9 First side view of a bone with a mounting set according to the invention; Fig. 10 rotated side view of the Fig. 9; Fig. 11 Enlargement of the Fig. 9; and Fig. 12 further enlarged side views with parallel Kirschner wires; Fig. 13 enlarged view of the Fig. 12; and Fig. 14 rotated views of the Fig. 13.

[0031] The positioning aid according to the invention is used in rotational osteotomy. In this procedure, a bone is sawn through, then the two bone halves are rotated relative to each other, and finally fixed. An implant plate 1, as described in [reference missing], is used to fix the bone halves. Fig. 1 is shown.

[0032] The implant plate 1 has a longitudinal axis A and multiple openings 2 for fixing the implant plate 1 to both bone halves. The openings 2 have steps 3 for countersinking a screw head into the plate surface. The openings 2 are designed as two overlapping openings 2a and 2b to accommodate a positioning aid 6, in addition to the screw head. The overlapping opening also allows for some play before the final fixation of the implant plate 1.

[0033] Fig. Figure 2 shows the back of the implant plate, which has an uneven surface structure 4 with a plurality of depressions 5 for improved fixation of the implant plate 1 on the bone surface.

[0034] Fig. Figure 3 shows a positioning aid 6, with the implant plate connection element 9 designed as plug teeth 7 and 8. The implant connection element 9, together with the corresponding connection element 10 of the implant plate 1, here in the form of openings 2b, forms a positive fit, in particular by insertion.

[0035] The prongs 7 and 8 are conically shaped to facilitate their insertion into the openings 2b. The implant connection element 9 is arranged on a projection 11 with a covering area 18, which covers the implant plate 1 in a direction Z, preferably perpendicular to the longitudinal axis A of the implant plate 1, preferably completely covering it. The prongs 7 and 8 protrude from the covering area 18.

[0036] A positioning body 12 is arranged to the side of the cover area 18, which is preferably integrally, and particularly preferably seamlessly, connected to the projection 11.

[0037] This positioning body 12 has two channels 13 and 14 oriented at an angle to each other for the passage of two Kirschner wires 20 and 21. The channels 13 and 14 are formed at a fixed, unchangeable angle α to each other. The first of the channels 13 is closed. The second of the channels 14 has an opening slot 15 extending through the length of the channel 14, which allows the Kirschner wire 21 to pass through laterally.

[0038] An end face 16, at which one or both channels 13 and 14 open, has a label 17 indicating the angle of the two channels to each other.

[0039] The angle denotes an offset of one channel 14 relative to the other channel 13 compared to a parallel alignment of both channels 13 and 14. In the variant of Fig. 3. This angle α is 10°. The positioning aid 6 has the first label 17 to indicate the size of the angle α. In addition, the positioning aid 6 can have a second label 16 indicating the intended direction of rotation.

[0040] One of the channels 13 extends beyond the cuboidal base contour of the positioning body 12 in a pipe connection 19. This ensures good positioning and guidance of the Kirschner wire 21.

[0041] Fig. 4-6 shows a further positioning aid 6' in modification of the Fig. 3. Analogous components are designated with analogous reference symbols.

[0042] The difference of the positioning aid 6' of the Fig. 4-6 for positioning aid 6 of the Fig. 3 consists of the size of the angle α' between channels 13 and 14, which in Fig. 4-6 20°. Accordingly, the pipe connection 19' protrudes more from the position body 12'. Furthermore, one or more of the markings 15' and 16' have different specifications.

[0043] Fig. 7 and Fig. Figure 8 shows the design of a Kirschner wire 20, 21, known per se, and its end section. The Kirschner wire 20, 21 can be made of solid material or have a sleeve shape. The end section 22 can have a drill attachment for creating a channel in a bone 30.

[0044] Based on the Fig. 9-14 explains in more detail the function of the positioning aid according to the invention in practical use.

[0045] First, the implant plate 1 is placed on a predefined bone 30. Then, the implant plate 1 is fixed unilaterally at one or more preferably adjacent and particularly preferably external openings 2. This can be done, for example, by screwing it in.

[0046] The positioning aid 6 is then positioned on the implant plate 1, which is attached on one side. In the exemplary embodiment of the Fig. For this purpose, the positioning aid 6 is detachably attached to the implant plate 1 by inserting the plug teeth 7 and 8 into the openings 2b.

[0047] The Kirschner wires 20, 21 can already be pre-positioned in the positioning aid 6 at the corresponding angle α before the positioning aid 6 is attached to the implant plate 1.

[0048] The required rotation angle, and therefore the required positioning aid 6, can be defined or determined in advance based on the anatomy, e.g., by a CT scan. Correctly setting this rotation angle is a challenge, and the positioning aid provides support in this process.

[0049] After positioning the positioning aid and fixing the Kirschner wires 20, 21 on or in the bone 30, the bone 30 is divided into at least two bone sections 31 and 32. This can be done, for example, by sawing or other methods of spatial division.

[0050] The positioning aid 6 is then removed. First, the Kirschner wire 21 is removed from the channel 14 via the opening slot 15. This can be done, for example, by a combination of linear movement and rotation.

[0051] Typically, a Kirschner wire also exhibits a certain degree of flexibility, which further facilitates its removal. The positioning aid can then be guided away from the bone, for example, in a coaxial direction to the longitudinal axis of the second Kirschner wire 20.

[0052] Finally, Kirschner wire 21 is rotated relative to Kirschner wire 20 while bone segment 31 is rotated relative to bone segment 32 until both wires are aligned parallel to each other at the edge of implant plate 1. The non-rotated bone segment 32 is the bone segment to which the implant plate is fixed. The rotated bone segment initially has no fixation to the implant plate until the rotation is complete.

[0053] The parallel alignment and contact of both Kirschner wires 20, 21 with the implant plate 1 indicates that bone section 31 has assumed its desired final position relative to bone section 32. It was rotated at an angle of 20° – that is, the angle between the two channels in the positioning aid 6.

[0054] Ideally, the center of rotation lies in the middle of the theoretical bone axis.

[0055] The positioning aid 6 ensures that the wires 20, 21 have a predetermined angle to each other, which corresponds to the intended rotation angle.

[0056] After rotation, all bone sections 31, 32 are completely fixed together and with the implant plate 1.

[0057] The positioning aid 6 according to the invention is not patient-specific; rather, the surgeon is provided with a limited number of positioning aids, each with fixed angles between the wires. The angles can advantageously be selected in 5-degree increments. Reference sign 1 implant plate 2 openings 2a Opening 2b Opening 3 levels 4 Surface structure 5 In-depth study 6 6' Positioning aid 7 tooth 8 tooth 9 Implant connection devices (canine) 10 Corresponding connection means (opening of the implant plate) 11 lead 12 12' Position body 13 13' Channel 14 14' Channel 15 15' Opening slot 16 16' Label (direction of rotation) 17 17' Label (angle offset) 18 Coverage area 19 Pipe connection 20 Kirschner wire 21 Kirschner wire 22 Final section 30 bones 31 Bone section 32 Bone section A Longitudinal axis (implant plate) Z insertion direction α α' Angle / Angle Offset

Claims

[1] Positioning aid (6, 6') for freehand rotational osteotomy, wherein the positioning aid (6, 6') has two channels (13, 14, 13', 14') for receiving Kirschner wires (20, 21) which are arranged at a fixed angle (α, α') to each other, characterized by , that the positioning aid (6, 6') of one or more implant plate connection means (9) for releasably fixing the positioning aid (6, 6') to an implant plate (1). [2] Positioning aid according to claim 1, characterized by , that at least one implant plate connection means (9) is designed as a plug tooth (7, 8) for form-fitting engagement in a corresponding opening (2b) of an implant plate (1). [3] Positioning aid according to claim 1 or 2, characterized by, that one of the channels (14, 14') has an opening slot (15, 15'), in particular an opening slot (15, 15') extending parallel to the longitudinal extent of the channel (14, 14'). [4] Positioning aid according to any of the preceding claims, characterized by , that the positioning aid (6, 6') has a positioning body (12, 12') in which at least in some areas the channels (13, 14, 13', 14') run and has a projection (11) with the implant connection means (9) which protrudes from the edge of the positioning body (12, 12'). [5] Positioning aid according to any of the preceding claims, characterized by , that the positioning aid (6, 6') has a pipe extension (19, 19') which protrudes from the positioning body (12, 12') and in which a channel (14, 14') is led out of the positioning body (12, 12'). [6] Positioning aid according to any of the preceding claims, characterized by, that the opening slot (15, 15') is arranged in the pipe extension (19, 19') in certain areas. [7] Positioning aid according to any of the preceding claims, characterized by , that the channels (13, 14, 13', 14') are arranged in a way that is unchangeable with respect to their angular offset (α, α'). [8] Positioning aid according to any of the preceding claims, characterized by , that the positioning aid (6, 6') has a label (16, 17, 16', 17') to indicate the size of the angular offset (α, α') of the channels (13, 14, 13', 14') relative to each other and / or the direction of rotation. [9] Positioning aid according to any of the preceding claims, characterized by , that the position body (12, 12') comprising the channels (13, 13', 14, 14') is formed as a single, preferably monolithic, block. [10] Positioning aid according to any of the preceding claims, characterized by, that the position body (12, 12') is made of a plastic material, a ceramic material or a metallic material. [11] Mounting set comprising an implant plate (1) and a positioning aid (6, 6') according to any of the preceding claims, characterized by , that the implant plate (1) and the positioning aid (6, 6') have corresponding connecting means (9, 10). [12] Mounting kit according to claim 11, characterized by , that the corresponding connecting means (9, 10) are designed to form a positive fit when connecting the implant plate (1) and the positioning aid (6, 6'). [13] Mounting kit according to claim 11 or 12, characterized by that the implant plate (1) has openings (2a) for fixing the implant plate (1) to a bone (30) by means of mechanical connecting means, preferably screws. [14] Mounting kit according to claim 13, characterized by, that the implant plate (1) has additional openings (2b) as corresponding connecting means (10) which preferably transition into the openings (2a) for fixing the implant plate (1). [15] Assembly kit according to one of the preceding claims, characterized by , that the assembly arrangement includes Kirschner wires (20, 21) for positioning in the channels (13, 14, 13', 14') of the positioning aid (6, 6'). [16] Assembly set according to one of the preceding claims, characterized by , that the assembly set comprises several positioning aids (6, 6') according to one of the preceding claims, wherein the positioning aids (6, 6') have a different angular offset (α, α') between the channels (13, 14, 13', 14').

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