DE20110946U1 - Bone plate - Google Patents

Description

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A 56 107 U Aesculap AG & Co. KG

&zgr; - 279 Am Aesculap-Platz

28 June 2001 78532 Tuttlingen

BONE PLATE

The invention relates to a bone plate for connecting bone parts that are separated from one another, with at least one fastening element receptacle for receiving a fastening element for fixing the bone plate to the bone parts and with a contact surface that can be placed at least partially on the bone parts, wherein one end of the bone plate forms an insertion end and a connecting line from the insertion end to the other end of the bone plate essentially defines a longitudinal direction.

Bone plates of the type described above are used to splint pertrochanteric femur fractures or condylar femur and tibia fractures. To insert them, a surgeon opens the human body through a small incision and pushes the bone plate under the skin and through the muscle. During the insertion process, it can also be connected to a holding instrument, which in this case also serves as a targeting device to fix it to the bone parts with fastening elements, such as bone screws or nails.

The shape of the bone plate itself has proven to be disadvantageous in such bone plates, because the

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Known, for example, from EP 0 617 927 Bl, it has an inserter whose shape can injure body tissue that is to be penetrated.

It is therefore an object of the present invention to improve a bone plate of the type described at the outset in such a way that it can be particularly easily inserted into the human body and brought close to the bone parts to be connected without damaging the body tissue to be penetrated.

This object is achieved according to the invention in that the introducer carries a spreading body and that the spreading body has a cross-section that increases in the direction towards the other end of the bone plate.

This special design of the insertion end makes it possible to insert the bone plate into the body through a particularly small incision. In addition, inserting the bone plate is made easier for a surgeon because the increasing cross-section virtually eliminates the risk of injury to the body tissue being penetrated. The spreader divides the body tissue simply by inserting the bone plate, without the need for additional instruments.

Preferably, the bone plate and the expansion body are formed in one piece. Such a bone plate is particularly easy to manufacture. In addition, there is a space between the expansion body and

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the bone plate has no transition, which could injure body tissue to be penetrated.

In principle, the expansion body can be shaped as desired at one end. However, it is advantageous if it has a substantially wedge-shaped expansion body end. This design makes it much easier to insert the bone plate into the body, because the wedge-shaped expansion body end can easily and safely split the muscle tissue that needs to be penetrated before it is placed on the femur bone, without damaging it.

It is particularly advantageous if the end of the expansion body has a wedge angle of between 8° and 15° between the contact surface forming the rear side of the bone plate and the front surface forming the front side of the bone plate. A wedge angle in the specified angle range ensures that the muscle tissue to be penetrated by the bone plate can be easily pushed aside without being injured.

According to a preferred embodiment of the form of the invention, the end of the expansion body can have two side surfaces connecting the front and the back, the surface normals of which form a surface angle of between 30° and 50°. Compared to parallel oriented side surfaces, those inclined relative to each other have the advantage that they additionally support the splitting of the muscle tissue by the wedge-shaped end of the bone plate, and thus facilitate the insertion of the bone

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In particular, these can advantageously run towards each other in the direction of the spreader body end and form a cutting line which, with the longitudinal direction, forms a
towards the other end of the bone plate
It is also advantageous to
if the side surfaces extend over more than half
the extension of the bone plate in the longitudinal direction.

With another advantageously designed bone plate
It can be provided that the end of the expansion body has an acute angle between 40° and 60°, which is formed by an intersection angle of the side surfaces in the direction defined by the
contact surface or the front surface defined level in the
The area of the insertion end is defined. A spreading body with such an acute angle in addition to the wedge shape ends in a single point and
Unlike a purely wedge-shaped spreader end, it has no front edge. This makes it even easier to divide the muscle tissue when inserting the bone plate.

In principle, it is advantageous if the spreading
has a rounded tip or edge. This can further reduce the risk of injury, because with a sharp tip or edge there is a greater risk of
penetrating body tissue is significantly increased.

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Advantageously, it can be provided that a cross-sectional area oriented transversely to the longitudinal direction increases in several stages or continuously starting from the insertion end up to a maximum value of the cross-sectional area and decreases from this in several stages or continuously towards the other end of the bone plate. This increases both the stability of the bone plate as a whole and a contact area between a surface of the femur bone and the contact surface, which in turn contributes to an improved connection between the bone plate and the femur bone. This can be achieved, for example, by several side surfaces that are inclined relative to one another.

It is particularly advantageous if the at least one fastening element receptacle is arranged in the region of the increasing cross-section. This allows the increase in the cross-sectional area to be extended over as large an area as possible.

It is advantageous if the contact surface comprises a number of surface pieces that are inclined relative to one another. This enables the bone plate to be optimally fixed to the bone parts, because for different sections of the bone with different inclinations, a surface piece of the bone plate is particularly suitable for being placed on the respective bone section and fixed to it. In addition, surface pieces are particularly easy to produce.

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Preferably, the contact surface is essentially convexly curved in the longitudinal direction towards the bone parts. A contact surface formed in this way can almost completely conform to the bone parts, particularly in the transition area between the femoral shaft and the greater trochanter. This reduces tension in the bone when the bone plate is fixed with standard fastening elements and results in additional stabilization of the bone by the bone plate.

According to a preferred embodiment of the invention, it can be provided that the contact surface is essentially concavely shaped transversely to the longitudinal direction in the direction of the bone parts. This allows the bone plate to optimally conform to the bone, particularly in the area of the femoral shaft, since it is curved essentially in a manner corresponding to the convexly shaped bone.

It is advantageous if the concave contact surface has a concavity with a radius of curvature between 15 and 25 mm. With such a radius of curvature, the contact surface fits almost completely against the femur bone.

It is advantageous if the bone plate has at least one connecting element for detachably connecting the same to at least one coupling element provided on a surgical instrument for holding and inserting the bone plate. With such a connecting element

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The bone plate can be securely connected to the instrument using the connection element, which makes insertion by a surgeon much easier.

Preferably, the connecting element can be arranged in such a way that in an insertion position in which the bone plate is connected to the instrument, the instrument extends the bone plate essentially opposite to the longitudinal axis which essentially defines an insertion direction in which the bone plate is brought to the bone parts to be connected. This design makes it easier for the surgeon to insert the bone plate, because he can recognize the position and orientation of the bone plate directly from the orientation of the insertion instrument, which essentially extends the insertion instrument, which means that the insertion instrument forms an angle of a maximum of 40° with the longitudinal direction, but which is preferably smaller than 30°.

In principle, it can be provided that the at least one connecting element can be connected to the at least one coupling element in a force-locking manner. This allows forces to be transferred from the insertion instrument to the bone plate in a safe manner during the insertion of the same.

According to a further preferred embodiment of the invention, it can be provided that the at least one connecting element can be connected in a form-fitting manner to the at least one coupling element. This allows a

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A play-free connection must be established between the insertion instrument and the bone plate.

It is advantageous if at least one connecting element is provided with at least one recess into which a corresponding projection arranged on the coupling element is inserted in the insertion position. In this way, for example, locking and/or snap connections can be realized that are easy to produce.

Preferably, the at least one recess is formed by a groove and the projection by a locking edge running transversely to the insertion direction. A groove is particularly easy to manufacture and, in conjunction with a locking edge, ensures a secure connection.

In principle, the connecting element could be arranged anywhere on the bone plate. However, it is advantageous if the connecting element is formed by a projection that protrudes essentially in the longitudinal direction of the bone plate. This reduces tension within the bone plate when it is inserted using the insertion instrument, which can arise in particular through the transfer of forces from the coupling element to the connecting element.

In principle, the connecting element could be positioned anywhere on the bone plate. However, it is advantageous if it is positioned at a location

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leading end of the bone plate facing away from the plate. This allows a surgeon to hold the bone plate with an insertion instrument and insert it in its longitudinal direction using the insertion instrument.

Preferably, it can be provided that the bone plate has at least one clamping element receptacle for clamping the bone plate with the instrument for holding and inserting, which has a clamping element acting in the direction of the bone plate. The clamping element receptacle can be used in conjunction with the clamping element provided on the instrument to establish a fixed relative position
between the instrument and the bone plate
be fixed by clamping.

In a further advantageous embodiment of the
Invention, a centering member can be provided which
interacts with a centering element of the instrument for inserting and holding the bone plate to establish a defined relative coupling position between the instrument and the bone plate in the insertion position. This is particularly advantageous if
if the instrument for inserting and holding the bone plate
at the same time has a targeting device section, which requires a clear relative positioning of the bone plate to the insertion instrument in the insertion position, so that holes in the femur bone made by means of sighting holes on the targeting device section have longitudinal axes that coincide with the fastening element receptacles of the bone plate.

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In principle, the centering element can have any shape, for example it could be a projection. Preferably, the centering element comprises a blind hole. This is easy to produce and defines a relative position between the bone plate and the insertion instrument in a clear manner.

In addition, it can be advantageous if the blind hole has a conical, closed end. With a corresponding tip of the centering element, the conical, closed end allows the relative position between the bone plate and the insertion instrument to be clearly specified in all three spatial directions.

In principle, it is advantageous if the at least one fastening element holder comprises a hole. The holes are particularly easy to produce and are particularly suitable for holding fastening elements such as screws, nails or staples.

It is advantageous if at least two fastening element receptacles are provided and if the longitudinal axes of at least two of the at least two fastening element receptacles are inclined relative to one another and enclose an angle of inclination. This has the advantage that fastening elements can be fixed relative to one another with an angle of inclination in the bone parts, which, due to the special design of the femur bone, enables a particularly secure attachment of the bone plate to it. In addition,

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Longer fasteners can be used that penetrate deeper into the bone, especially the femoral head, and ensure a more stable fixation of the bone plate.

It is advantageous if the angle of inclination is between 40° and 60°. This makes it possible, on the one hand, to fix fastening elements with a longitudinal axis running transversely to the longitudinal axis of the femoral neck and, on the other hand, to insert fastening elements that are as long as possible into the femoral head.

The following description of a preferred embodiment of the invention serves to explain it in more detail in conjunction with the drawing. They show:

Figure 1: A perspective view of one of

a bone plate held by a targeting device when fixed to a femur bone;

Figure 2: a side view of the bone plate from Figure 1;

Figure 3: a side view of the bone plate of Figure 2 in the direction of arrow A;

Figure 4: a longitudinal sectional view of the bone plate of Figure 2 along line 4-4; and

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Figure 5: a cross-sectional view taken along line 5-5 in Figure 2.

In Figures 1 to 5, a device designated overall by the reference numeral
10, which can be used, for example, to connect a femoral bone 16 broken between the greater trochanter 112 and the femoral shaft 108 by means of two bone screws 106 and 107 and
two fixing screws 110 and 111 respectively.

It has an expansion body connected to it in one piece, which has a wedge-shaped
tip 12. At its other end a coupling pin 14 is arranged. A rear side 18 of the
Bone plate 10 serves as a contact surface on the femur bone 16. It defines a roughly two-thirds
the length of the bone plate 10 extending longitudinal axis 54 starting from the tip 12 in the direction of the end provided with the coupling pin 14, wherein the longitudinal axis 54 essentially corresponds to an insertion direction of the bone plate into the human body in order to
to bring it to the femur bone 16. The bone plate
10 is with respect to a longitudinal axis 54
containing mirror plane is symmetrically shaped.

The back 18 is directed towards the femur bone
16 is concavely shaped. A front side 20 is
two side surfaces 22 and 23 connected to the rear side 18. Each side surface 22 or 23 comprises six flat side surface sections 26 to 31 and 32

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to 37. The wedge-shaped tip 12 is laterally delimited by the side surface sections 26 and 32, whose surface normals lie in a common plane, with the side surface sections 26 and 32 intersecting at an acute angle 38 of approximately 50°. The front side 20 and the rear side 18 intersect, as shown in Figure 4, at a wedge angle 40 of approximately 20°. Overall, the tip 12 thus has a flat pyramid shape.

A tip surface section 42 that delimits the tip 12 on the front side 20 is adjoined by a surface area 44 that is part of a cylinder surface. It extends over approximately half of the front side 20 of the bone plate 10, essentially parallel to the longitudinal axis 54. This in turn is adjoined by a pin front surface 46 that is delimited on the one hand by the side surface sections 29, 30 and 31 and on the other hand by the side surface sections 35, 36 and 37. The coupling pin 14 defined by the latter side surface sections is essentially delimited on the front side by an end surface 48. The concavely curved rear side 18 is connected to the side surfaces 22 and 23 via connecting edges 50 and 51.

The side surface sections 35 and 36 as well as the side surface sections 29 and 30 form a wedge-shaped groove 52 and 53 in the side surfaces 22 and 23, respectively.

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Transverse to the longitudinal axis, the bone plate has two holes 56 and 57 in the surface area 44, both of which are countersunk at a cone angle 58 of 120°. The hole 56 arranged adjacent to the tip surface section is laterally offset from the plane of symmetry of the bone plate 10, while the hole 57 is arranged symmetrically to the plane of symmetry. Longitudinal axes 60 and 61 of the holes 56 and 57 run perpendicular to the longitudinal axis 54.

In the transition region between the surface region 44 and the pin front surface 46, a screw hole is arranged, the diameter of which decreases in one step from the front side 20 to the rear side 18, so that an annular shoulder 64 is formed. A longitudinal axis 66 of the screw hole 62 is inclined relative to the longitudinal axis 61 by an angle of inclination 68, the value of which is approximately 40°.

A longitudinal axis of a further screw bore 72 runs parallel to the longitudinal axis 66 and, similar to the screw bore 62, tapers in one step towards the rear side 18 and forms an annular shoulder 74. The diameter of the screw bore 62 corresponds to approximately 2.6 times, the diameter of the screw bore 72 to approximately 1.6 times the diameter of the two bores 56 and 57, respectively. The annular shoulders 64 and 74 are each followed by an internal thread 76 and 78 in the direction of the rear side 18.

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A conical blind hole 80 is arranged in the end face 48 of the coupling pin 14, which has an opening angle 82 of approximately 60°. The axis of symmetry of the blind hole 18 is inclined relative to the longitudinal axis 54 by a blind hole angle 84 of approximately 27°. The side surface sections 27 and 23 adjacent to the side surface sections 26 and 32 are inclined relative to one another by a surface angle 86, which has a value of approximately 40°.

To fix the bone plate 10, it is first connected to an aiming device, which is provided with the reference number 88, namely to a pin receptacle 90 of the same, which has projections 92 and 93 which essentially correspond to the grooves 52 and 53 and which penetrate into them. A holding section 94 adjoining the pin receptacle 90 forms an extension of the bone plate 10 essentially opposite to the insertion direction defined by the longitudinal axis 54.

A pressure pin 96 provided with a conical tip that can be screwed to the holding section 94 dips with its tip into the blind hole 80 and centers the bone plate 10 relative to the target device 88, thereby establishing a clear relative position between the bone plate 10 and the target device 88. This is necessary so that the longitudinal axes of four alignment holes 100 to 103 provided on a target device section 98 coincide with the longitudinal axes 60, 61, 66 and 70 of the holes 56, 57 and the screw holes 62 and 72.

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when the bone plate 10 is attached to the target device 88.

Using a drilling device (not shown), drill holes can be made in the femoral bone 16 through the pilot holes 100 to 103, whereby two bone screws 106 and 107 are inserted through the holes 56 and 57 and screwed to the femoral shaft 108. In a similar manner, two fixation screws 110 and 111 are screwed through the screw holes 62 and 72 into the greater trochanter 112 of the femoral bone 16.

When inserting the bone plate 10 into a human body, a small incision of a size sufficient to be able to insert the bone plate with its largest cross-section in the area of the transition from the surface area 44 to the pin front surface 46 is sufficient. The coupling pin 14, which projects essentially in the direction of the longitudinal axis 54, enables the bone plate 10 to be extended through the holding section 94 with a maximum constant cross-section. The wedge-shaped tip 12 divides the muscle tissue surrounding the femur bone 16 without damaging it.

Due to the flat wedge shape, in which the cross-section of the bone plate 10 increases from the tip 12 in the direction of the coupling pin 14 to over half the extent of the bone plate 10 in the direction of the longitudinal axis 54 and thus beyond the bores 56 and 57 as well as the screw bore 62, the bone

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plate 10 can be introduced to the femoral bone in a particularly tissue-friendly manner, especially when it is inserted by hand.

Claims (25)

1. Bone plate for connecting bone parts that are separated from one another, with at least one fastening element receptacle for receiving a fastening element for fixing the bone plate to the bone parts and with a contact surface that can be placed at least partially on the bone parts, one end of the bone plate forming an insertion end and a connecting line from the insertion end to the other end of the bone plate essentially defining a longitudinal direction, characterized in that the insertion end ( 12 ) carries a spreading body and that the spreading body has a cross-section that increases in the direction towards the other end ( 48 ) of the bone plate ( 10 ). 2. Bone plate according to claim 1, characterized in that the bone plate ( 10 ) and the expansion body are formed in one piece. 3. Bone plate according to one of claims 1 or 2, characterized in that the expansion body has a substantially wedge-shaped expansion body end ( 12 ). 4. Bone plate according to claim 3, characterized in that the expansion body end ( 12 ) has a wedge angle ( 40 ) between the contact surface ( 18 ) forming a rear side ( 18 ) of the bone plate ( 10 ) and a front surface ( 42 ) forming a front side ( 20 ) of the bone plate ( 10 ) of between 10° and 30°. 5. Bone plate according to one of claims 3 or 4, characterized in that the expansion body end ( 12 ) has two side surfaces ( 27 , 33 ) connecting the front ( 20 ) and the back ( 18 ), the surface normals of which form a surface angle between 30° and 50°. 6. Bone plate according to claim 5, characterized in that the expansion body end ( 12 ) has a tip angle ( 38 ) between 40° and 60°, which is determined by an intersection angle ( 38 ) of the side surfaces ( 26 , 32 ) in the plane defined by the contact surface ( 18 ) or the front surface ( 42 ) in the region of the insertion end ( 12 ). 7. Bone plate according to one of the preceding claims, characterized in that the expansion body end ( 12 ) comprises a rounded tip or edge. 8. Bone plate according to one of the preceding claims, characterized in that a cross-sectional area of the bone plate ( 10 ) oriented transversely to the longitudinal direction ( 54 ) increases starting from the insertion end ( 12 ) in several stages or continuously up to a maximum value of the cross-sectional area and decreases from this in several stages or continuously in the direction of the other end of the bone plate ( 10 ). 9. Bone plate according to claim 8, characterized in that the at least one fastening element receptacle is arranged in the region of the increasing cross-section. 10. Bone plate according to one of the preceding claims, characterized in that the contact surface ( 18 ) comprises a plurality of surface pieces which are inclined relative to one another. 11. Bone plate according to one of the preceding claims, characterized in that the contact surface ( 18 ) is substantially convexly curved with respect to the longitudinal direction ( 54 ) in the direction of the bone parts ( 108 , 112 ). 12. Bone plate according to one of the preceding claims, characterized in that the contact surface ( 18 ) is curved substantially concavely transversely to the longitudinal direction ( 54 ) in the direction of the bone parts ( 108 , 112 ). 13. Bone plate according to claim 12, characterized in that the concave contact surface ( 18 ) has a concavity with a radius of curvature between 15 and 25 mm. 14. Bone plate according to one of the preceding claims, characterized in that the bone plate ( 10 ) carries at least one connecting element ( 14 ) for releasably connecting the same to at least one coupling element ( 90 ) provided on a surgical instrument ( 88 ) for holding and inserting the bone plate ( 10 ). 15. Bone plate according to claim 14, characterized in that the connecting element ( 14 ) is arranged such that in an insertion position in which the bone plate ( 10 ) is connected to the instrument ( 88 ), the instrument ( 88 ) extends the bone plate ( 10 ) essentially opposite to the longitudinal direction ( 54 ) essentially defining an insertion direction in which the bone plate is brought towards the bone parts to be connected. 16. Bone plate according to one of claims 14 or 15, characterized in that the at least one connecting element ( 14 ) can be connected to the at least one coupling element ( 90 ) in a force-fitting manner. 17. Bone plate according to one of claims 14 to 16, characterized in that the at least one connecting element ( 14 ) can be positively connected to the at least one coupling element ( 90 ). 18. Bone plate according to one of claims 14 to 17, characterized in that at least one recess ( 52 , 53 ) is provided on the at least one connecting element ( 14 ), into which a corresponding projection ( 92 , 93 ) arranged on the coupling element ( 90 ) dips in the insertion position. 19. Bone plate according to claim 18, characterized in that the at least one recess is formed by a groove ( 52 , 53 ) and that the projection is formed by a locking edge ( 92 , 93 ) running transversely to the insertion direction. 20. Bone plate according to one of claims 14 to 19, characterized in that the connecting element is formed by a projection ( 14 ) projecting substantially in the longitudinal direction ( 54 ) of the bone plate ( 10 ). 21. Bone plate according to one of claims 14 to 20, characterized in that the connecting element ( 14 ) is arranged at an end of the bone plate ( 10 ) facing away from the insertion end ( 12 ). 22. Bone plate according to one of the preceding claims, characterized in that the bone plate ( 10 ) has at least one clamping element receptacle ( 80 ) for clamping the bone plate ( 10 ) with the instrument ( 88 ) for holding and inserting, which has a clamping element ( 96 ) acting in the direction of the bone plate ( 10 ). 23. Bone plate according to one of the preceding claims, characterized in that a centering member ( 80 ) is provided which cooperates with a centering element ( 96 ) of the instrument ( 88 ) for inserting and holding the bone plate ( 10 ) to establish a defined relative coupling position between the instrument ( 88 ) and the bone plate ( 10 ) in the insertion position. 24. Bone plate according to claim 23, characterized in that the centering member comprises a blind hole ( 80 ). 25. Bone plate according to claim 24, characterized in that the blind hole ( 80 ) has a conical closed end.