Flexible device for treating fracture

Abstract

The invention relates to a device (1) for treating bone fractures, in particular for treating femoral fractures, such as femoral neck fractures, comprising a fastening part (4) which can be fastened in or on a first bone part, the fastening part (4) having at least one opening (5) through which a bone screw (6) and an adjusting screw (7) are guided, a surface with a threaded surface is arranged on the inner side of the opening (5), an adjusting screw (7) is meshed in the threaded surface, a bone screw (6) can freely slide in the opening, and the adjusting screw (7) is configured to enable the bone screw (6) to selectively slide laterally and then abut against at least one limiting portion (26) of the adjusting screw (7). According to the invention, an adapter (10) which can be fixed in the bone screw (6) and which can be laterally released is provided, said adapter (10) forming a barrier (11) for the adjustment screw (7) when the adjustment screw (7) is laterally moved.

Description

Technical Field

[0001] The present invention relates to a device for treating bone fractures, in particular a device for treating femoral fractures (e.g. femoral neck fractures), the device comprising a fixing portion that can be fixed in or on a first bone portion, wherein the fixing portion has at least one opening, through which a bone screw and an adjusting screw are guided, wherein the inner side of the opening is provided with a surface having a threaded surface, the adjusting screw is engaged in the threaded surface, the bone screw can slide freely in the opening, and the adjusting screw is configured to allow the bone screw (after lateral sliding if necessary) to abut against at least one limit portion of the adjusting screw. Background Art

[0002] Femoral fractures, especially femoral neck fractures, are a difficult type of fracture to treat. In the case of femoral neck fractures, this is especially true because they are more common in older, often elderly people, further complicating good treatment. Femoral neck fractures are often caused by a bone structure that is no longer intact, for example due to progressive osteoporosis.

[0003] One of the difficulties in treating a femoral fracture is to position the broken bone parts in relation to one another and to fix them in this position at least immediately after treatment. Adding to the difficulty is the fact that the muscles surrounding the bone are in an unfavorable position due to the fracture and the influence of these muscles in terms of tensile, compressive and possibly torsional forces must also be considered, which should be avoided.

[0004] In the treatment of femoral neck fractures, a fixation part with openings, such as a nail or a bone plate, is used, through which a bone screw can be guided, which, after being pre-drilled, passes through a first lateral bone part and is screwed into a second medial bone part separated from the first bone part due to the fracture. In order to move the bone screw after it is screwed into the second medial bone part, so that the second bone part is positioned relative to the first bone part, it is known in the prior art to use a compression screw, which engages in a thread located on one side of the bone screw and is used in conjunction with the bone screw. By screwing the compression screw in adjacent to the bone screw, the compression screw can initially be screwed in until it abuts against the fixation part. Further screwing in will then cause the compression screw to be pulled sideways, so that the bone parts are positioned relative to each other. In this case, it has been shown that there is a disadvantage that there is no limit to the degree of compression, and its magnitude depends on the judgment of the medical staff. In particular, when treating elderly patients, if the compression is too great, the bone screw is very likely to be pulled out of the bone part that has been previously damaged and is therefore no longer intact. In addition, excessive compression may also lead to an inability to heal the fracture site ideally.

[0005] A substitute device for treating fractures is known from AT 524767A4, and this substitute device belongs to the aforementioned type. In such a device, there is also a cooperation relationship between a bone screw and another screw, in this case, the other screw being an adjusting screw. The bone screw is installed in the opening of the fixing part in a laterally movable manner. Initially, the inward movement and rotation of the bone screw are restricted by the adjusting screw. However, the lateral movement of the bone screw can be achieved within a predetermined range, which is defined by the limiting part of the adjusting screw. The limiting part abuts against the bone screw obliquely at an angle of several degrees, thus contacting the bone screw in an inclined manner. This movement gap can be adjusted, for example, between 0 mm and 12 mm. During the healing process, the second inner bone part into which the bone screw is screwed can thus respond to the acting force within the set range. Different situations can be considered accordingly according to patient-specific parameters such as height, weight, bone density, and / or fracture type. According to the device of AT 524767A4, the lateral mobility of the bone screw can be set specifically on the premise that its inward movement is restricted. However, if it is desired to apply additional tensile force to the inner bone part, this device cannot achieve it. Summary of the Invention

[0006] The present invention precisely aims to solve the above problems. The object of the present invention is to improve the device of the aforementioned type so that it can also generate compressive force when necessary.

[0007] The present invention achieves the above object in the following way: In a device of the aforementioned type, an adapter that can be fixed in the bone screw is provided. The adapter is configured to be laterally releasable and constitutes a blocking part for the adjusting screw when the adjusting screw moves laterally.

[0008] Through the present invention, the particularly achievable advantage is that the desired compression amount can now be actively and as needed set. This effect can be achieved through a relatively simple structural design because only an adapter needs to be provided. When the adjusting screw moves laterally (usually when it is unscrewed), the adapter constitutes a blocking part, causing the adjusting screw to finally abut against the adapter. If the adjusting screw is then continued to be moved laterally (usually by unscrewing the adjusting screw in the opening thread), the adjusting screw will drive the adapter to move laterally together, and then drive the bone screw connected to the adapter to move laterally together, thereby realizing the lateral movement of the bone screw and accordingly completing the positioning or compression of the two bone parts. Through the adjusting screw (which is itself set to enable the bone screw to abut against it when necessary after the lateral slip of the bone screw), the fractured bone parts can be more closely positioned through its cooperation with the adapter, and compression can be achieved when necessary, thus significantly enhancing the functionality of the device.

[0009] Within the scope of the present invention, the fixing part is preferably configured as a longitudinally extending structure. The fixing part can be a bone plate or a nail, especially an intramedullary nail.

[0010] The fixing part has at least one opening for a bone screw. The opening can be designed such that both the bone screw and the adjustment screw can be guided through the opening and thus be positioned as a whole in the opening. However, separate openings can also be provided for the bone screw and the adjustment screw respectively. If a common opening is provided for the bone screw and the adjustment screw, the opening is generally designed to be threadless in the contact area of the bone screw, so that the bone screw can slide in the opening. In contrast, threads are provided in the area where the adjustment screw is located, so that the adjustment screw can be screwed into the opening. If a common opening is provided for the bone screw and the adjustment screw, the cross-section of the opening can be configured to be approximately pear-shaped. This cross-sectional shape is formed by the transition of two arcuate opening elements to each other, thus forming an opening for both the bone screw and the adjustment screw. One or both of these two arcuate elements can cover an angle greater than 180°, preferably greater than 270°. These two opening elements transition to each other to form a single opening. The larger arcuate opening element is used to carry the bone screw with a larger load, while the adjustment screw, in addition to being used for the compression mechanism, is mainly used to limit the medial movement of the bone screw and to set its lateral movement purposefully. Therefore, its diameter is smaller and it is suitable for the smaller second arcuate opening element.

[0011] In particular, when the fixing part is configured as a longitudinally extending structure (such as a bone nail or a bone plate), additional openings can be provided for accommodating other screws, whereby the fixing part can be fixed to the first bone part without penetrating or contacting the second bone part.

[0012] Preferably, the fitting area of the first fitting end of the adapter includes an external thread, and the bone screw includes an internal thread that mates with the external thread at its lateral end. In this case, the adapter can be simply and releasably mounted on or inside the bone screw. The adapter is preferably designed to have an enlarged structure relative to the bone screw at a position away from the fixing area, thus forming a blocking part for the adjustment screw. For example, the adapter can have a cross-sectional dimension that is approximately 2% to 15% larger than that of the bone screw, preferably 3% to 10%.

[0013] In principle, as long as it can be ensured that the adapter can form a blocking part for the adjustment screw when the adjustment screw undergoes lateral movement, the adapter can adopt any desired structural form. However, in view of the fact that the adapter needs to be installed first and then disassembled during use, for ease of operation, the adapter is preferably configured as a longitudinally extending pin-shaped structure. In this case, the adapter can be provided with a tip in the area of the first fitting end, and the tip is located in front of the external thread when viewed in the side view direction. With the help of this tip, the adapter can be more easily inserted into the bone screw, especially when the adapter is in a pin-shaped structure. For this purpose, the bone screw should be provided with a fitting opening. Specifically, the bone screw can be provided with an opening extending along the center, which is usually necessary structurally.

[0014] At the lateral end of the adjusting screw, the adjusting screw may be provided with a socket for a wrench or a similar tool. Thus, the adjusting screw can be conveniently operated, and can be used to set the lateral clearance of the bone screw, and can also be used to position or press two fractured bone parts.

[0015] Preferably, the adjusting screw is provided with an enlarged flange portion at the lateral adjusting screw end. This flange portion has multiple functions. On the one hand, this flange portion can serve as a limiting surface for the bone screw to limit its lateral movement during the healing process. On the other hand, during the process of positioning or pressing two bone parts, this flange portion can serve as a limiting structure and abut against the protrusion of the adapter, thereby activating the above-mentioned mechanism for the active and directional lateral movement of the bone screw.

[0016] The bone screw may be provided with a groove, and the adjusting screw cooperates with this groove to limit or particularly prevent the rotation of the bone screw. In addition, the adjusting screw can also be set at a certain angle relative to the bone screw to cooperate with the groove of the lateral narrowing structure in the bone screw, thereby preventing the medial movement of the bone screw.

[0017] In addition, the bone screw, the adjusting screw and their openings can in particular be constructed as described in AT 524767A4, the entire content of which is hereby incorporated by reference into this text. Description of the Drawings

[0018] Other features, advantages and functions of the present invention will be further clarified by the embodiments described below. The accompanying drawings referred to include:

[0019] Figure 1 Showing an intramedullary nail;

[0020] Figure 2 Showing Figure 1 Another view of the intramedullary nail shown;

[0021] Figure 3 Showing a schematic diagram of the interaction of the intramedullary nail, the adjusting screw and the bone screw, and the interaction of the adjusting screw and the bone screw in the first position;

[0022] Figure 3 Showing a further schematic diagram of the interaction of the adjusting screw and the bone screw in the second position;

[0023] Figure 5 Showing a further schematic diagram of the interaction of the adjusting screw and the bone screw in the third position;

[0024] Figures 6a to 6c Showing a bone screw with a groove and the interaction with bone screws of different lengths;

[0025] Figures 7a to 7c Showing a schematic diagram of a unit composed of an intramedullary nail, a bone screw and an adjusting screw, where the adjusting screw sets different clearances;

[0026] Figure 8 Shows a cross-sectional view of a unit composed of a bone screw, an adjustment screw, and an adapter;

[0027] Figure 9 Shows Figure 8 The state of the unit shown after the adjustment screw moves;

[0028] Figure 10 Shows the adapter. Detailed implementation

[0029] In Figure 1 And Figure 2 It shows the fixing part 4. The fixing part 4 is configured as a bone nail, especially an intramedullary nail. However, the fixing part 4 can also be configured as a bone plate, although within the scope of the present invention, it is more preferable that the fixing part 4 is configured as a bone nail.

[0030] As Figure 1 And Figure 2 Shown, the fixing part 4 or the intramedullary nail extends longitudinally and has a longitudinal axis X. The intramedullary nail is provided with an opening 5, and the opening 5 has a first transverse axis Y1. The first transverse axis Y1 can form an angle of 30° to 40° with the longitudinal axis X, for example. If the fixing part 4 is a bone plate, a similar opening 5 can be provided. As Figure 1 Shown, the opening 5 is composed of two arc segments 51 and 52. The upper first arc segment 51 is for the bone screw 6, and the arc segment 52 below the opening 5 is for the adjustment screw 7. The two arc segments 51 and 52 of the opening 5 are connected to each other in a transitional manner, thereby forming an opening 5 that can be shared by the two screws. The angle coverage of each arc segment exceeds 270°. The segment of the opening 5 for the bone screw 6 is larger in cross-section than the segment of the opening 5 for the adjustment screw 7. This is because the bone screw 6 is used for bearing force and thus needs to be configured to be stronger; while the adjustment screw 7 is used for precisely controlling the mobility of the bone screw 6 and can thus be configured to be relatively less strong.

[0031] The opening 5 can also be configured such that the larger opening segment for the bone screw 6 is located below, and the smaller opening segment for the adjustment screw 7 is located above.

[0032] In the inner region of the opening 5, a smooth surface 8 is provided at the position where the bone screw 6 is or was located. Thereby, the bone screw 6 can slide in the opening 5, and its movement inside or outside is not blocked. In the region of the smaller opening segment for the adjustment screw 7, a threaded surface 9 is provided for cooperating with the adjustment screw 7 in the manner described below. Therefore, in addition to the fixing part 4 (in Figure 1 And Figure 2In addition to the intramedullary nail, it further includes a bone screw 6 and an adjustment screw 7. The second horizontal axis Y2 coincides with the longitudinal axis of the adjustment screw 7, or extends parallel to it in an offset manner, and forms a non-zero angle with the first horizontal axis Y1.

[0033] Figure 3 Shown is a schematic view of the assembled unit in the first position. In the figure, in addition to the fixation part 4 (intramedullary nail) shown again, the inserted bone screw 6 can also be seen. The bone screw 6 usually has threads at its inner bone screw end 15 for fixing the bone screw 6 to the first bone part 2, such as the femoral head. The intramedullary nail is fixed in another second bone part 3 separated from the first bone part 2. Figure 3 In it, the fracture line between the two bone parts 2 and 3 is shown schematically. In the lateral direction L, the bone screw 6 is basically smooth after the inner thread, but is provided with a number of grooves 24. The grooves 24 gradually widen near the inner bone screw end 15 and gradually narrow towards the distal bone screw end 14. Thus, by setting an oblique fit between the adjustment screw 7 and the grooves 24 (as Figures 3 to 5 shown), the setting of the lateral clearance of the bone screw 6 can be achieved, thereby limiting the maximum movement range of the bone screw 6 in the lateral direction L until it abuts against the stop portion 26 of the adjustment screw 7. The adjustment screw 7 includes a lateral adjustment screw end 18 and an inner adjustment screw end 19. The farther the lateral adjustment screw end 18 moves in the lateral direction L, the greater the lateral clearance of the bone screw 6.

[0034] As mentioned above, the adjustment screw 7 can cooperate with the grooves 24. The grooves 24 of the bone screw 6 and the interaction between the two screws can be particularly referred to Figures 6a to 6c for understanding. Figure 6a Shows a bone screw 6a having two grooves 24. In Figure 6b and Figure 6c are shown the corresponding arrangements of two adjustment screws 7 with different lengths respectively. Each adjustment screw 7 can be inserted into one of the grooves 24. Due to the tapered widening and narrowing structure of the grooves 24, the bone screw 6 can be passively moved in the lateral direction L under the action of an external force until it contacts the limiting surface of the adjustment screw 7 (if necessary, it can also contact multiple limiting surfaces). However, due to the contact of the adjustment screw 7, the movement of the bone screw 6 in the inner direction M is impossible. In addition, the rotation of the bone screw 6 is at least largely inhibited, and advantageously, the rotation can be completely prevented. Therefore, the cooperative action of the bone screw 6 and the adjustment screw 7 can achieve fixed control of the inner mobility and rotation of the bone screw 6, while still retaining the possibility of movement in the lateral direction L, provided that the corresponding clearance is set using the adjustment screw 7.

[0035] To enable a good interaction between the fixing part 4, the bone screw 6 and the adjustment screw 7, the adjustment screw 7 preferably acts on the bone screw 6 at a relatively small angle α, as Figure 6b shown in the example.

[0036] For this purpose, the respective longitudinal axes of the bone screw 6 and the adjustment screw 7 are arranged to approach each other at an angle α in the inner direction M, forming an included angle α, which can be, for example, in the range of 1° to 5°. For this purpose, the opening 5 is correspondingly configured to accommodate this included angle.

[0037] Figures 7a to 7c Different configurations are shown in a highly schematic manner, in which the movement of the bone screw 6 in the lateral direction L is defined by the adjustment screw 7 and the limiting part 26. A gap G can be provided between the bone screw 6 and the adjustment screw 7, so that during the healing process, the bone screw 6 can move in the lateral direction L according to patient-specific parameters.

[0038] Normally, the gap between at least one limiting part 26 of the adjustment screw 7 and the corresponding limiting part of the bone screw 6 is about 0 mm, 5 mm or 10 mm. The corresponding gap range of 0 mm to 10 mm can fully cover the required differences between patients.

[0039] As Figure 8 and Figure 9 shown, in the unit composed of the above-mentioned fixing part 4, bone screw 6 and adjustment screw 7, if an adapter 10 is provided in the device 1, when the adjustment screw 7 moves laterally, this adapter can form a blocking part 11, thereby endowing the unit with additional functionality. The following will be described in conjunction with Figure 8 and Figure 9 for illustration. Figure 8 and Figure 9 show a fixing part 4 configured as an intramedullary nail, in the opening 5 of which the bone screw 6 and the adjustment screw 7 are arranged in the above-mentioned manner. The adjustment screw 7 can then limit the lateral movement of the bone screw 6 and prevent its medial movement and rotation. In addition, an adapter 10 is provided, which can be releasably fixed in the bone screw 6. For this purpose, the adapter 10 is provided with an external thread 16 in the region of the first adaptation end 12, which external thread 16 mates with the internal thread of the bone screw 6, so that the adapter 10 can be introduced into the bone screw 6 provided with a central opening 21 and can be releasably fixed therein. To achieve this introduction, the adapter 10 can also have a tip 20 at the first adaptation end 12 for inserting the adapter 10 into the central opening 21 of the bone screw 6. In the direction towards the second adaptation end 13, as Figure 10As shown, the adapter 10, when viewed from the direction of the external thread 16, first has a constant cross-section and then the cross-section gradually increases. Therefore, the adapter 10 is provided with a blocking portion 11 existing as a protrusion in this region. As shown in the figure, the blocking portion 11 can extend to cover the remaining length of the adapter 10, but this is not mandatory. The blocking portion 11 is configured to interact with the adjusting screw 7 for positioning the second bone part 2 onto the first bone part 1. To achieve the above positioning, a wrench 23 is used to unscrew the adjusting screw 7 from the opening 5. To accommodate the wrench 23, the adjusting screw 7 is provided with a matching socket 22. When the adjusting screw 7 is unscrewed from the opening 5, the screw initially has a dead stroke and then hits the blocking portion 11 of the adapter 10. As previously mentioned, since the adjusting screw 7 is arranged at an angle relative to the bone screw 6, the blocking portion 11 is configured to have a sufficient protruding height so that the flange portion 25 of the adjusting screw 7, or other limiting surfaces if necessary, can abut against the blocking portion 11, as Figure 9 shown. Once the adjusting screw 7 contacts the blocking portion 11, the adjusting screw 7 will drive the adapter 10 and ultimately drive the bone screw 6 together to move in the lateral direction L, causing the bone screw 6 to slide laterally in the opening 5, thereby pushing the second bone part 2 towards the first bone part 1, as shown by the arrow in the figure. Once the desired position is reached, including pressing if necessary, the adapter 10 can be released from the bone screw 6. Subsequently, if necessary, the adjusting screw 7 can be moved again in the medial direction M or screwed back into the opening 5 to limit the lateral clearance of the bone screw 6.

[0040] Figure 10 The adapter 10 adapted according to the present invention is shown. Since the adapter 10 has an elongated structure, it is convenient to operate, especially it can easily span Figure 8 the length range of the tissue cannula 27 shown in

[0041] The device according to the present invention expands the application range of the unit composed of the fixing portion 4, the bone screw 6 and the adjusting screw 7, because while restricting the medial movement and rotational movement of the bone screw 6 and setting its lateral movement purposefully, a tensile force can also be applied to the bone screw 6.

Claims

1. A device (1) for treating fractures, in particular for treating femoral fractures such as femoral neck fractures, comprising a fixing part (4) which can be fixed in or on a first bone part (2), wherein the fixing part (4) has at least one opening (5) through which a bone screw (6) and an adjustment screw (7) are guided, wherein the inner side of the opening (5) is provided with a surface (8) having a threaded surface (9), the adjustment screw (7) engages in the threaded surface (9), the bone screw (6) can slide freely in the opening (5), and the adjustment screw (7) is configured to allow the bone screw (6) to abut against at least one stop (26) of the adjustment screw (7) after lateral sliding if necessary, characterized in that: An adapter (10) is provided that can be fixed in the bone screw (6) and can be released laterally. The adapter (10) forms a blocking portion (11) of the adjusting screw (7) when the adjusting screw (7) moves laterally.

2. The device (1) according to claim 1, characterized in that, The fixing portion (4) is configured to extend longitudinally.

3. The device (1) according to claim 1 or 2, characterized in that, The fixing portion (4) is configured as an intramedullary nail.

4. The device (1) according to any one of claims 1 to 3, characterized in that, The adapter (10) is provided with an external thread (16) in the region of the first adapter end (12). The bone screw (6) is provided with an internal thread (17) at its lateral bone screw end (14). The external thread (16) meshes with the internal thread (17).

5. The device (1) according to claim 4, characterized in that, The adapter (10) is configured with a tip (20) in the region of the first adapter end (12). The tip (20) is located in front of the external thread (16) when observed in the lateral direction (L).

6. The device (1) according to any one of claims 1 to 5, characterized in that, The bone screw (6) is configured with a centrally extending opening (21).

7. The device (1) according to any one of claims 1 to 6, characterized in that, The adjusting screw (7) is provided with a socket (22) for a wrench (23) at its lateral adjusting screw end (18).

8. The device (1) according to any one of claims 1 to 7, characterized in that, The adjusting screw (7) is provided with a widened flange portion (25) at its lateral adjusting screw end (18).

9. The device (1) according to any one of claims 1 to 8, characterized in that, The bone screw (6) is provided with a groove (24). The adjusting screw (7) engages in the groove (24) to limit or particularly prevent rotation of the bone screw (6).

10. The device (1) according to any one of claims 1 to 9, characterized in that, The adjusting screw (7) is arranged against the bone screw (6) at an inclination and engages in the groove (24) of the laterally narrowing configuration of the bone screw (6) to prevent inward movement of the bone screw (6).

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