Bone screw and bone fixation device

Abstract

The application discloses a bone screw and a bone connecting device. The bone screw comprises a rod body, a tail part and a first external thread. The tail part is connected with the end of the rod body, and the tail part is provided with a cutting edge. The surface of the tail part is also provided with a second external thread. The second external thread comprises a first end and a second end. The first end is located on the side away from the rod body of the second end. The outer diameter of the first end is smaller than the bottom diameter of the first external thread. The outer diameter of the second end is larger than the bottom diameter of the first external thread. The second external thread gradually increases in the direction from the first end to the second end. In the application, a part of the second external thread can be pre-installed in the nail hole of the bone, and the thread tapping is cut from the inner wall of the nail hole of the bone, so that the surgeon can screw the bone screw into the nail hole of the bone.

Description

Technical Field

[0001] This application belongs to the field of medical devices, and in particular relates to a bone screw and a bone-setting device. Background Technology

[0002] When a bone fractures, different types of bone screws are typically used to connect the broken segments, depending on the location of the fracture. Specifically, a connector can be implanted into the body, and then bone screws are used to connect and fix the connector to two or more bone segments. In these techniques, considerable force is often required to screw the bone screws into the bone, making the process relatively difficult. Summary of the Invention

[0003] This application provides a bone screw and a bone-setting device to facilitate screwing the bone screw into the bone.

[0004] This application provides a bone screw, comprising:

[0005] The rod body has a first external thread on its surface; and

[0006] The tail section is connected to the end of the rod body, and the tail section is provided with a cutting edge and a second external thread on its surface;

[0007] The second external thread includes a first end and a second end. The first end is located on the side of the second end away from the rod body. The outer diameter of the first end is smaller than the root diameter of the first external thread, and the outer diameter of the second end is larger than the root diameter of the first external thread. The outer diameter of the second external thread gradually increases along the direction from the first end to the second end.

[0008] Optionally, the tail portion includes a transition section connected to the rod body, and the second end is located at the connection between the transition section and the rod body.

[0009] Optionally, the transition segment includes:

[0010] A first transition segment, one end of which is connected to the rod body, has a first outer contour angle; and

[0011] The second transition segment is connected to the other end of the first transition segment, and the second transition segment has a second outer contour angle, which is greater than the first outer contour angle.

[0012] Optionally, the second transition segment has a first end portion at one end opposite to the first transition segment, and the outer surface of the first end portion is spherical.

[0013] Optionally, in the axial section of the bone screw, the included angle between the tangents at both ends of the outer contour line of the first end has a first included angle, which is greater than or equal to the outer contour angle of the second transition segment.

[0014] Optionally, the first end is located in the first transition section or the second transition section.

[0015] Optionally, the side wall of the tail is provided with a chip removal groove, and the cutting edge is located at the end edge of the chip removal groove.

[0016] Optionally, the length of the chip removal groove is greater than the maximum depth of the chip removal groove;

[0017] Wherein, the length of the chip removal groove is the distance between the two ends of the chip removal groove along the axial direction of the rod body;

[0018] The depth of the chip removal groove is the distance between the bottom and the opening of the chip removal groove in the radial direction of the rod.

[0019] Optionally, the cutting edge is an acute angle.

[0020] Optionally, in the radial section of the tail, the inner contour line of the chip removal groove includes a first straight line segment, and the outer contour line of the tail includes a first arc line connected to the first straight line segment. The first arc line and the second straight line segment are tangent at the connection point of the first arc line and the first straight line segment. The second straight line segment and the first arc line are located on the same side of the first straight line segment, and the angle between the second straight line segment and the first straight line segment is an acute angle.

[0021] Optionally, the chip removal groove extends along the axial direction of the rod body to the rod body, and the chip removal groove includes a first portion located on the rod body and a second portion located at the tail end;

[0022] Wherein, along the direction from the tail towards the rod, the depth of the first part gradually decreases to zero; the depth of the chip removal groove is the distance between the bottom of the chip removal groove and the opening of the groove in the radial direction of the rod.

[0023] Wherein, along the direction from the tail towards the rod, the distance between the bottom of the groove in the second part and the axis of the rod remains unchanged.

[0024] Optionally, the outer diameter of the second end is equal to the outer diameter of the first external thread.

[0025] Secondly, embodiments of this application also provide a bone-setting device, comprising:

[0026] Fasteners; and

[0027] The bone screw as described in any of the preceding claims is used to screw the fixation member to the bone.

[0028] In this embodiment, by providing a cutting edge and a second external thread at the tail of the rod, the bone screw achieves a self-tapping effect during insertion into the bone, thereby reducing the force required to screw the bone screw into the bone. Furthermore, during surgery, a mounting hole for fixing the bone screw can be drilled in the bone. The inner diameter of the mounting hole is approximately the same as the root diameter of the first external thread. At this time, the first end of the second external thread can be pre-inserted into the mounting hole, while the second end is located outside the mounting hole. The portion of the second external thread whose outer diameter is equal to the inner diameter of the mounting hole abuts against the inner wall of the mounting hole, allowing the second external thread to directly tap against the inner wall of the mounting hole when the bone screw is rotated. In contrast, without the second external thread, a clamping force is required to press the end of the first external thread near the tail against the end face of the mounting hole to prevent slippage of the first external thread at the end face of the mounting hole during screw rotation. Therefore, the bone screw of this embodiment can further reduce the force required to screw the bone screw into the bone. Attached Figure Description

[0029] The technical solution and its beneficial effects will become apparent from the following detailed description of specific embodiments of this application, in conjunction with the accompanying drawings.

[0030] Figure 1 This is a schematic diagram of the structure of the bone screw provided in the embodiment of this application.

[0031] Figure 2 for Figure 1 A magnified view of the bone screw at point X.

[0032] Figure 3 for Figure 1 The diagram shows the state of a bone screw inserted into the screw hole in the bone.

[0033] Figure 4 for Figure 1 The diagram shows the state of the bone screw being screwed into the screw hole in the bone.

[0034] Figure 5 for Figure 1 A schematic diagram of the second structure of the tail portion shown at point X of the bone screw.

[0035] Figure 6 for Figure 5 The diagram shows the state of the bone screw being screwed into the screw hole in the bone.

[0036] Figure 7 for Figure 1 A schematic diagram of the third structure at the tail of the bone screw shown at point X.

[0037] Figure 8 for Figure 7 The diagram shows the state of the bone screw being screwed into the screw hole in the bone.

[0038] Figure 9 for Figure 1 A schematic diagram of the fourth structure at the tail of the bone screw shown at point X.

[0039] Figure 10 for Figure 9 The diagram shows the state of the bone screw being screwed into the screw hole in the bone.

[0040] Figure 11 for Figure 1 The bone screw is shown in the M-direction view.

[0041] Figure 12 for Figure 1 A partial sectional view of the bone screw shown. Detailed Implementation

[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0043] This application provides a bone screw and a bone-setting device to facilitate screwing the bone screw into the bone.

[0044] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a bone screw provided in an embodiment of this application. The bone screw 100 can be used to fix independently in a patient's body. The bone screw 100 can also be used in a bone-setting device to connect and fix the fixation member of the bone-setting device to the patient's bone 400, thereby connecting or supporting and fixing the patient's fractured or otherwise injured bone 400. This embodiment of the application does not limit this.

[0045] For example, the bone-setting device can be an intramedullary nail assembly, the fixation element is an intramedullary nail, and the bone screw 100 is a locking screw in the intramedullary nail assembly, so that the bone-setting device is suitable for cases such as femoral or tibial fractures. Alternatively, the bone-setting device can be a pedicle screw assembly, and the bone screw 100 is a pedicle screw, so that the bone-setting device is suitable for spinal defects such as damage to the posterior vertebral ligament complex, interspinous ligament, and spinous process fractures. Or, the bone-setting device can be a bone plate assembly, the fixation frame is a bone plate, and the bone screw 100 is a locking screw in the bone plate assembly, so that the bone-setting device is suitable for the fixation and treatment of fractures of various bones 400 such as the jawbone and phalanges.

[0046] Please continue to refer to the reference. Figure 2 and Figure 3 , Figure 2 for Figure 1 A magnified view of the bone screw at point X. Figure 3 for Figure 1 The diagram shows the state of a bone screw inserted into the screw hole in the bone.

[0047] like Figure 1 As shown, the bone screw 100 may include a shaft 10 and a tail 20. The surface of the shaft 10 is provided with a first external thread 11 for screwing and fixing to the bone 400. The tail 20 is connected to the end of the shaft 10. Figure 3 As shown, the tail portion 20 is provided with a cutting edge 21. The surface of the tail portion 20 is also provided with a second external thread 22. Furthermore, through the cutting edge 21 and the second external thread 22 of the tail portion 20, the bone screw 100 can achieve a self-tapping function in the corresponding hole of the bone 400. Therefore, the surgeon does not need to pre-tap the corresponding hole in the bone before screwing in the bone screw 100. Thus, the bone screw 100 of this embodiment simplifies the surgical procedure and reduces the duration and difficulty of the surgery.

[0048] like Figure 3 As shown, in order to make it easy for the bone screw 100 to be screwed into the bone 400, the outer diameter of the end of the second external thread 22 away from the rod 10 is smaller than the bottom diameter of the first external thread 11; along the direction of the tail 20 toward the rod 10, the outer diameter of the second external thread 22 gradually increases to be larger than the bottom diameter of the first external thread 11.

[0049] Of course, it can also be understood that the second external thread 22 includes a first end 221 and a second end 222. The first end 221 is located on the side of the second end 222 away from the rod body 10, that is... Figure 3 The second end 222 shown is located above the first end 221. The outer diameter of the first end 221 is smaller than the root diameter of the first external thread 11, and the outer diameter of the second end 222 is larger than the root diameter of the first external thread 11. Along the direction from the first end 221 to the second end 222 ( Figure 3 As shown in the direction from bottom to top, the outer diameter of the second external thread 22 gradually increases.

[0050] Please refer to the following. Figure 3 The technical solution of the embodiments of this application will be further explained and described in conjunction with the process of screwing in the bone screw 100 during surgery.

[0051] First, a mounting hole 41 for fixing the bone screw 100 is drilled in the bone 400. The inner diameter of the mounting hole 41 is approximately the same as the bottom diameter of the first external thread 11. Then, when the tail 20 of the bone screw 100 is inserted into the mounting hole 41, the portion of the second external thread 22 with an outer diameter smaller than the bottom diameter of the first external thread 11 can be pre-positioned in the mounting hole 41, while the portion with an outer diameter larger than the bottom diameter of the first external thread 11 is located outside the mounting hole 41. The portion with an outer diameter equal to the bottom diameter of the first external thread 11 abuts against the initial contact position of the inner wall of the mounting hole 41. At this time, when the bone screw 100 begins to rotate, the portion of the second external thread 22 with an outer diameter larger than the bottom diameter of the first external thread 11 will cut the inner wall of the mounting hole 41 from this initial contact position, thereby achieving a self-tapping operation during the process of the bone screw 100 being screwed into the mounting hole 41.

[0052] Of course, it can also be understood as:

[0053] First, a mounting hole 41 for fixing the bone screw 100 is drilled in the bone 400. The inner diameter of the mounting hole 41 is approximately the same as the bottom diameter of the first external thread 11. Then, when the tail 20 of the bone screw 100 is inserted into the mounting hole 41, the first end 221 can be pre-placed into the mounting hole 41, while the second end 222 is located outside the mounting hole 41. The portion of the second external thread 22 whose outer diameter is equal to the bottom diameter of the first external thread 11 will abut against the inner wall of the mounting hole 41 at the initial contact position. At this time, when the bone screw 100 begins to rotate, the portion of the second external thread 22 whose outer diameter is greater than the bottom diameter of the first external thread 11 will cut the inner wall of the mounting hole 41 from this initial contact position, thereby achieving a self-tapping operation during the process of the bone screw 100 being screwed into the mounting hole 41.

[0054] In contrast, if the tail 20 does not have a second external thread 22, the end of the first external thread 11 near the tail 20 will abut against the end face of the pin hole 41. In this case, in order to screw the bone screw 100 into the bone 400, in addition to rotating the bone screw 100, a larger clamping force needs to be applied to press the first external thread 11 against the end face of the pin hole 41. Otherwise, the first external thread 11 may slip on the end face of the pin hole 41 during the rotation of the bone screw 100.

[0055] Therefore, it can be seen that the bone screw 100 provided in this application embodiment can reduce the amount of force required to screw the bone screw 100 into the bone 400.

[0056] For example, such as Figure 3As shown, the tail portion 20 may include a transition section 23 connected to the rod body 10. At least a portion of the second external thread 22 extends away from the rod body 10 from the connection point of the transition section 23 and the rod body 10. The outer diameter of the transition section 23 gradually decreases along the direction from the rod body 10 toward the tail portion 20. The outer diameter of the portion of the second external thread 22 provided in the transition section 23 is the outer diameter of that portion of the transition section 23. Therefore, the transition section 23 can be completely screwed into the rivet hole 41 through the self-tapping effect of the second external thread 22 and the cutting edge 21.

[0057] Of course, at least part of the second external thread 22 extends away from the connection between the transition section 23 and the rod 10, which can also be understood as the second end 222 being located at the connection between the transition section 23 and the rod 10. At this time, the first end 221 can be located on the transition section 23 of the tail 20, or it can be located outside the transition section 23 of the tail 20. This application embodiment does not limit this.

[0058] In this embodiment, the transition section 23 may be directly connected to the rod body 10, and the first external thread 11 may be connected to the second external thread 22. For example, along the direction from the tail 20 toward the rod body 10, the outer diameter of the second external thread 22 gradually increases to be the same as the outer diameter of the first external thread 11, and the inner diameter of the second external thread 22 gradually increases to be the same as the inner diameter of the first external thread 11. Furthermore, the outer diameter of the second end 222 of the second external thread 22 is equal to the outer diameter of the first external thread 11. At this time, after the second external thread 22 taps to form an internal thread on the inner wall of the nail hole 41, the first external thread 11 can smoothly follow the second external thread 22 into the internal thread, making the entire process of screwing the bone screw 100 into the nail hole 41 smoother and more convenient. Of course, in some other embodiments, the first external thread 11 may not be connected to the second external thread 22, and this embodiment does not limit this.

[0059] Please refer to Figure 7 and Figure 8 , Figure 7 for Figure 1 A schematic diagram of the third structure at the tail of the bone screw shown at point X. Figure 8 for Figure 7 The diagram shows the state of the bone screw being screwed into the screw hole in the bone.

[0060] In the first embodiment of the transition segment 23, the transition segment 23 can be frustum-shaped. Therefore, in the axial section of the bone screw 100, both outer contour lines of the transition segment 23 are straight lines. Of course, the transition segment 23 can also be frustum-shaped. Therefore, in the axial section of the bone screw 100, the two outer contour lines of the transition segment 23 are arc lines. This application embodiment does not limit this.

[0061] like Figure 7 As shown, when the transition section 23 is frustum-shaped, the end of the transition section 23 facing away from the rod 10 can also be provided with a first end portion 24 to form the free end portion 20. The outer surface of the first end portion 24 is spherical. It can be understood that, taking the bone screw 100 as a locking screw in the bone plate assembly or an interlocking screw in the intramedullary nail assembly as an example, after the bone screw 100 is installed, it will penetrate the corresponding bone 400 of the patient. At this time, since the free end portion 20 is spherical, when the bone screw 100 pierces from one side of the bone 400 to the other side of the bone 400, the free end portion 20 can avoid the sharp corner irritating or even piercing the soft tissue on the surface of the bone 400.

[0062] Of course, depending on the application scenario of the bone screw 100, when the transition section 23 is frustum-shaped, the tail 20 may only have the aforementioned frustum-shaped transition section 23 so that the end face of the tail 20 is flat; or, the free end of the tail 20 may also be conical, which is not limited in this embodiment.

[0063] When the outer surface of the first end portion 24 is spherical, the first end portion 24 can be entirely hemispherical, meaning that in the axial section of the bone screw 100, the outer contour line of the first end portion 24 is a semi-circular arc. Alternatively, when the outer wall surface of the first end portion 24 is spherical, the first end portion 24 can also be non-hemispherical, meaning that in the axial section of the bone screw 100, the outer contour line of the first end portion 24 is a major or minor arc. Below, the technical solution of the embodiment of this application will be further explained and described using the example of the outer contour line of the first end portion 24 being a minor arc in the axial section of the bone screw 100.

[0064] like Figure 7 As shown, in the axial section of the bone screw 100, the included angle between the tangents at both ends of the outer contour line of the first end 24 has a second included angle α2. The outer contour angle of the frustum-shaped transition segment 23 is β1, that is, in the axial section of the bone screw 100, the included angle between the two outer contour lines of the transition segment 23 is β1. α2 equals β1. Therefore, in the axial section of the bone screw 100, both outer contour lines of the transition segment 23 are tangent to the outer contour line of the first end 24. At this time, the outer surface of the transition segment 23 and the outer surface of the first end 24 are smoothly connected, making the bone screw 100 more aesthetically pleasing overall.

[0065] The transition segment 23 and the first end 24 can be integrally formed by milling. For example, the bone screw 100 can be made of stainless steel or titanium alloy, in which case the transition segment 23 and the first end 24 are machined using a machining tool. It is understood that during the process of the machining tool moving from the transition segment 23 to the first end 24 or from the first end 24 to the transition segment 23, since the outer surfaces of the transition segment 23 and the first end 24 are smoothly connected, the machining tool does not need to adjust its angle, making the cutting tool movement smoother and reducing the machining difficulty of the bone screw 100.

[0066] The transition segment 23 and the first end 24 can also be integrally molded by injection molding or other methods. For example, the bone screw 100 can be made of a bio-absorbable material such as polylactic acid, in which case the mold can be injection molded to form the transition segment 23 and the first end 24. Understandably, because the outer surfaces of the transition segment 23 and the first end 24 are smoothly connected, the stress at the connection between the transition segment 23 and the first end 24 is more uniform, thus making it less prone to cracking at the connection between the transition segment 23 and the first end 24.

[0067] Alternatively, the transition segment 23 and the first end 24 can be detachably connected. For example, the end of the transition segment 23 facing the first end 24 may have a first threaded hole, while the side of the first end 24 facing the transition segment 23 may have a first threaded protrusion capable of being screwed into the first threaded hole; or, the end of the transition segment 23 facing the first end 24 may have a first insertion hole, while the side of the first end 24 facing the transition segment 23 may have a first insertion rod capable of being inserted into the first insertion hole. This embodiment of the present application does not limit this. It is understood that when the transition segment 23 and the first end 24 are detachably connected, the first end 24 of different shapes can be replaced according to the different actual usage requirements of the bone screw 100, so that the usage scenarios of the bone screw 100 are more flexible and varied.

[0068] like Figure 7 As shown, the starting point of the second external thread 22 at the end furthest from the rod 10 can be located in the transition section 23, or it can be understood that the first end 221 of the second external thread 22 is located in the transition section 23. It is understood that after the second external thread 22 is machined, the bone screw 100 needs to undergo shape inspection, which includes measuring the outer diameter of the starting point of the second external thread 22 at the end furthest from the rod 10 (i.e., the first end 221). In actual measurement, having the starting point of the second external thread 22 at the end furthest from the rod 10 located in the transition section 23 facilitates inspection using an optical measuring instrument.

[0069] Specifically, after the bone screw 100 is placed in the optical measuring instrument, the light source of the optical measuring instrument illuminates the bone screw 100 to form a projection. At this time, the operator needs to operate the optical measuring instrument to take points at the outer contour of the projection and fit the multiple points to form the outer contour line of the bone screw 100. Among them, the outer contour line of the part corresponding to the transition section 23 in the projection is a straight line, so only two points are needed to fit and form this straight line; while the outer contour line of the part corresponding to the first end 24 in the projection is a minor arc, so at least three points are needed to fit and form this minor arc. Therefore, the embodiment of this application makes it simpler to measure the outer diameter at the starting point of the second external thread 22 away from the rod 10. In addition, the fewer points taken, the greater the error of the minor arc formed by fitting, which will lead to a corresponding decrease in the accuracy of subsequent measurements. Therefore, the embodiment of this application also makes the measurement of the outer diameter at the starting point of the second external thread 22 away from the rod 10 more accurate.

[0070] Furthermore, during the milling process, since conical surfaces, planes, and other straight surfaces are easier to set the tool on than spherical surfaces, setting the starting point of the second external thread 22 at the end away from the rod 10 at the transition section 23 can improve the machining accuracy of the second external thread 22 and reduce the machining difficulty of the second external thread 22.

[0071] In the axial direction of the bone screw 100, a gap can be provided between the starting point of the second external thread 22 at the end away from the rod 10 and the first end 24. This can also be understood as a gap being provided between the first end 221 of the second external thread 22 and the first end 24. Therefore, even if inaccurate tool setting leads to an incorrect starting point for machining the second external thread 22, the probability of the machining tool starting machining the second external thread 22 from the first end 24 can still be reduced.

[0072] Please refer to Figure 9 and Figure 10 , Figure 9 for Figure 1 A schematic diagram of the fourth structure at the tail of the bone screw shown at point X. Figure 10 for Figure 9 The diagram shows the state of the bone screw being screwed into the screw hole in the bone.

[0073] In the first embodiment of the transition segment 23, in the axial section of the bone screw 100, the included angle between the tangents at both ends of the outer contour line of the first end 24 has a second included angle α2. The outer contour angle of the frustum-shaped transition segment 23 is β1, that is, in the axial section of the bone screw 100, the included angle between the two outer contour lines of the transition segment 23 is β1. α2 is greater than β1.

[0074] It is understandable that when the bone screw 100 needs to be screwed into the screw hole 41 to a specific depth, the area S of the portion of the inner wall of the screw hole 41 that is screwed into the second external thread 22 is considered. With the shape of the first end 24 and the inner diameter of the screw hole 41 remaining constant, as the angle β1 decreases, the area S of the portion of the inner wall of the screw hole 41 that is screwed into the second external thread 22 also gradually decreases (this can be compared with other screw screws). Figure 8 and Figure 10 The area S of the portion of the inner wall of the screw channel hole 41 into which the second external thread 22 is screwed changes in size. Accordingly, the force required to screw the bone screw 100 into the screw channel hole 41 is also reduced. Therefore, the bone screw 100 can be screwed into the bone 400 with less effort.

[0075] In the second embodiment of transition section 23, such as Figure 3 As shown, transition segment 23 may include a first transition segment 231 and a second transition segment 232.

[0076] Please continue to combine Figure 2 and Figure 3 One end of the first transition segment 231 is connected to the rod body 10, and the first transition segment 231 has a first outer contour angle γ1. The second transition segment 232 is connected to the other end of the first transition segment 231, and the second transition segment 232 has a second outer contour angle γ2. The second outer contour angle γ2 is greater than the first outer contour angle γ1.

[0077] Please refer to Figure 4 , Figure 4 for Figure 1 The diagram shows the state of the bone screw being screwed into the pin hole 41. Assuming the bone screw 100 needs to be screwed into the pin hole 41 to a specific depth, the area S of the portion of the inner wall of the pin hole 41 screwed into the second external thread 22 is considered. With the shape of the first end 24 fixed, the outer contour angle of the second transition section 232 unchanged, and the inner diameter of the pin hole 41 unchanged, if the length of the second transition section 232 in the axial direction of the bone screw 100 is increased until the outer diameter of the end of the second transition section 232 near the rod 10 is the same as the outer diameter of the first external thread 11, the area S of the portion of the inner wall of the pin hole 41 screwed into the second external thread 22 will be larger than in the embodiments of this application (see comparison). Figure 4 and Figure 8 The area S of the portion of the inner wall of the screw channel hole 41 into which the second external thread 22 is screwed changes. Correspondingly, the force required to screw the bone screw 100 into the screw channel hole 41 also increases. Therefore, the bone screw 100 can be screwed into the bone 400 with less effort.

[0078] In some implementations, γ2 is less than 90 degrees, and the sum of γ1 and γ2 is greater than 90 degrees.

[0079] The end of the second transition segment 232 facing away from the first transition segment 231 may be connected to a third transition segment. The third transition segment has a third outer contour angle, which is greater than the second outer contour angle γ2, so that the bone screw 100 can be screwed into the bone 400 with less effort. Of course, the end of the third transition segment facing away from the second transition segment 232 may also be provided with a fourth transition segment, the outer contour angle of the fourth transition segment being greater than the outer contour angle of the third segment. This application embodiment does not limit this.

[0080] like Figure 3 As shown, the end of the second transition segment 232 facing away from the first transition segment 231 may also be provided with a first end portion 24 to form the free end portion of the tail 20. The outer surface of the first end portion 24 may be spherical. It is understood that, taking the bone screw 100 as a locking screw in a bone plate assembly or an interlocking screw in an intramedullary nail assembly as an example, the bone screw 100 will penetrate the corresponding bone 400 of the patient after it is installed in place. At this time, since the free end portion of the tail 20 is spherical, when the bone screw 100 pierces from one side of the bone 400 to the other side of the bone 400, the free end portion of the tail 20 can avoid irritation or even puncture to the soft tissue on the surface of the bone 400 due to the sharp corner.

[0081] Of course, depending on the application scenario of the bone screw 100, the end face of the first end 24 can also be flat, or the first end 24 can also be conical. This application embodiment does not limit this.

[0082] When the outer surface of the first end portion 24 is spherical, the first end portion 24 can be entirely hemispherical, meaning that in the axial section of the bone screw 100, the outer contour line of the first end portion 24 is a semi-circular arc. Alternatively, when the outer wall surface of the first end portion 24 is spherical, the first end portion 24 can also be non-hemispherical, meaning that in the axial section of the bone screw 100, the outer contour line of the first end portion 24 is a major or minor arc. Below, the technical solution of the embodiment of this application will be further explained and described using the example of the outer contour line of the first end portion 24 being a minor arc in the axial section of the bone screw 100.

[0083] like Figure 2 As shown, in the axial section of the bone screw 100, the angle between the tangents at both ends of the outer contour line of the first end 24 is a first angle α1. The outer contour angle of the second transition segment 232 is γ2, that is, in the axial section of the bone screw 100, the angle between the two outer contour lines of the second transition segment 232 is γ2. α1 equals γ2. Therefore, in the axial section of the bone screw 100, the outer contour line of the second transition segment 232 is tangent to the outer contour line of the first end 24. At this time, the outer surface of the second transition segment 232 and the outer surface of the first end 24 are smoothly connected, making the bone screw 100 more aesthetically pleasing overall.

[0084] The second transition segment 232 and the first end 24 can be integrally formed by milling. For example, the bone screw 100 can be made of stainless steel or titanium alloy, and the second transition segment 232 and the first end 24 are machined using a machining tool. It is understood that during the process of the machining tool moving from the second transition segment 232 to the first end 24 or from the first end 24 to the second transition segment 232, since the outer surfaces of the second transition segment 232 and the first end 24 are smoothly connected, the machining tool does not need to adjust its angle, making the cutting tool movement smoother and reducing the machining difficulty of the bone screw 100.

[0085] The second transition segment 232 and the first end 24 can also be integrally molded by injection molding or other methods. For example, the bone screw 100 can be made of a bioabsorbable material such as polylactic acid, in which case the mold can be injection molded to form the second transition segment 232 and the first end 24. It is understandable that because the outer surfaces of the second transition segment 232 and the first end 24 are smoothly connected, the stress at the connection between the second transition segment 232 and the first end 24 is more uniform, thus making it less prone to cracking at the connection between the second transition segment 232 and the first end 24.

[0086] Alternatively, the second transition segment 232 and the first end 24 can also be detachably connected. For example, the end of the second transition segment 232 facing the first end 24 may have a second threaded hole, while the side of the first end 24 facing the second transition segment 232 may have a second threaded protrusion capable of being screwed into the second threaded hole; or, the end of the second transition segment 232 facing the first end 24 may have a second insertion hole, while the side of the first end 24 facing the second transition segment 232 may have a second insertion rod capable of being inserted into the second insertion hole. This embodiment of the application does not limit this. It is understood that when the second transition segment 232 and the first end 24 are detachably connected, the first end 24 of different shapes can be replaced according to the different actual usage requirements of the bone screw 100, so that the usage scenarios of the bone screw 100 are more flexible and varied.

[0087] like Figure 3 As shown, the starting point of the second external thread 22 at the end away from the rod 10 can be located at the second transition section 232 or the first transition section 231, that is, the second external thread 22 can extend from the first transition section 231 or the second transition section 232 toward the rod 10. It can also be understood that the first end 221 of the second external thread 22 is located at the first transition section 231 or the second transition section 232.

[0088] Understandably, after the second external thread 22 is machined, the bone screw 100 needs to undergo shape inspection, which includes measuring the outer diameter of the starting point (i.e., the first end 221) of the second external thread 22 away from the rod body 10. In actual measurement, an optical measuring instrument can be used for inspection.

[0089] Specifically, after the bone screw 100 is placed in the optical measuring instrument, the light source of the optical measuring instrument illuminates the bone screw 100 to form a projection. At this time, the operator needs to operate the light measurement to take points at the outer contour of the projection, and fit the multiple points to form the outer contour line of the bone screw 100. Among them, the outer contour line of the projection corresponding to the first transition segment 231 or the second transition segment 232 is a straight line, so only two points are needed to fit and form this straight line; while the outer contour line of the projection corresponding to the first end 24 is a short arc, so at least three points are needed to fit and form this short arc. Therefore, the embodiment of this application makes it simpler to measure the outer diameter of the starting point of the second external thread 22 away from the rod 10. In addition, the fewer points taken, the greater the error of the short arc formed by fitting, which will lead to a corresponding decrease in the accuracy of subsequent measurements. Therefore, the embodiment of this application also makes the measurement of the outer diameter of the starting point of the second external thread 22 away from the rod 10 more accurate.

[0090] Furthermore, during the milling process, since conical surfaces, planes, and other straight surfaces are easier to set the tool on than spherical surfaces, setting the starting point of the second external thread 22 at the end away from the rod 10 at the transition section 23 can improve the machining accuracy of the second external thread 22 and reduce the machining difficulty of the second external thread 22.

[0091] When the second external thread 22 is set in the second transition section 232, a gap can be set between the starting point of the second external thread 22 away from the rod body 10 and the first end 24 in the axial direction of the bone screw 100. Therefore, even if the starting point of the machining tool for the second external thread 22 is incorrect due to inaccurate tool setting, the probability of the machining tool starting to machine the second external thread 22 from the first end 24 can still be reduced.

[0092] Please refer to Figure 5 and Figure 6 , Figure 5 for Figure 1 A schematic diagram of the second structure of the tail portion shown at point X of the bone screw. Figure 6 for Figure 5 The diagram shows the state of the bone screw being screwed into the screw hole in the bone.

[0093] Alternatively, in the second embodiment of transition section 23, such as Figure 5 As shown, in the axial section of the bone screw 100, the included angle between the tangents at both ends of the outer contour line of the first end 24 has a first included angle α1. The second transition segment 232 has a second outer contour angle γ2. α1 is greater than γ2.

[0094] It is understandable that when the bone screw 100 needs to be screwed into the screw hole 41 to a specific depth, the area S of the portion of the inner wall of the screw hole 41 that is screwed into the second external thread 22 is considered. With the shape of the first end 24 and the inner diameter of the screw hole 41 remaining constant, as the angle γ2 decreases, the area S of the portion of the inner wall of the screw hole 41 that is screwed into the second external thread 22 also gradually decreases (this can be compared with other screw hole screws). Figure 6 and Figure 4 The area S of the portion of the inner wall of the screw channel hole 41 into which the second external thread 22 is screwed changes. Accordingly, the force required to screw the bone screw 100 into the screw channel hole 41 is also reduced. Therefore, the bone screw 100 can be screwed into the bone 400 with less effort.

[0095] The outer surface of the tail portion 20 of the bone screw 100 may be provided with a cutting plane (not shown in the figure) to form a cutting edge 21. Taking the outer surface of the tail portion 20 of the bone screw 100 as an example, which consists of multiple alternating straight and curved surfaces, the straight surface serves as the cutting plane mentioned above, and the connection between the straight and curved surfaces forms the cutting edge 21.

[0096] Please continue to refer to this. Figure 11 , Figure 11 for Figure 1 The image shows a view of the bone screw from the M direction. The tail portion 20 has a chip removal groove 25 on its side wall, and a cutting edge 21 is located at the end edge of the chip removal groove 25. It can be understood that by providing the chip removal groove 25, the tail portion 20 can store a certain amount of bone chips during the self-tapping process, and also remove bone chips, thereby improving the self-tapping effect of the bone screw 100.

[0097] Of course, it is also understood that in the embodiments of this application, the outer surface of the tail portion 20 may have a cutting plane to form a cutting edge 21, or it may only have a chip removal groove 25 to form a cutting edge 21, or it may have both a cutting plane and a chip removal groove 25 to form a cutting edge 21. The embodiments of this application do not limit this. Below, taking the example of the tail portion 20 having a chip removal groove 25 on its side wall to form a cutting edge 21, the technical solution of the embodiments of this application will be further explained and described.

[0098] The chip removal groove 25 can be spirally arranged along the axial direction of the rod 10 and extend to the rod 10. Specifically, the chip removal groove 25 can extend from the first end 24 to the rod 10, or it can extend from the transition section 23 to the rod 10. It is understood that compared to a linear arrangement, the spiral arrangement allows for an increase in the overall length of the chip removal groove 25. With the increase in the overall length of the chip removal groove 25, the chip storage capacity increases, thereby improving the self-tapping performance of the bone screw 100.

[0099] Alternatively, the chip removal groove 25 may also extend along the axial direction of the rod 10 to the rod 10.

[0100] The chip removal groove 25 may include a first part located on the rod 10 and a second part located on the tail 20.

[0101] Along the direction from the tail 20 toward the rod 10, the depth of the first part gradually decreases to zero. The depth of the chip removal groove 25 is the distance between the bottom and the opening of the chip removal groove 25 in the radial direction of the rod 10.

[0102] Of course, the aforementioned gradual decrease in depth of the first part to zero along the direction from the tail 20 towards the rod 10 can also be understood as: along the direction from the tail 20 towards the rod 10, the bottom of the groove in the first part is inclined towards the outer surface of the rod 10. Therefore, during the process of screwing the bone screw 100 into the bone 400, the waste stored in the chip removal groove 25 is discharged out of the chip removal groove 25 along the inclined direction of the bottom of the groove in the first part.

[0103] Along the direction from the tail 20 toward the rod 10, the distance between the bottom of the groove in the second part and the axis of the rod 10 remains unchanged. This can also be understood as the straight-line distance, or vertical distance, between the bottom wall of the groove in the second part and the rod 10 remaining unchanged along the direction from the tail 20 toward the rod 10.

[0104] The length of the chip removal groove 25 in the axial direction of the rod 10 is greater than the maximum depth of the chip removal groove 25. It is understood that by increasing the length of the chip removal groove 25 in the axial direction of the rod 10, the chip storage capacity of the chip removal groove 25 can be increased to improve the self-tapping performance of the bone screw 100.

[0105] The length of the chip removal groove 25 in the axial direction of the rod 10 is greater than the maximum depth of the chip removal groove 25, which can also be understood as:

[0106] The length of the chip removal groove 25 is greater than its maximum depth. The length of the chip removal groove 25 is the distance between its two ends along the axial direction of the rod 10. The depth of the chip removal groove 25 is the distance between the bottom and the opening of the groove along the radial direction of the rod 10.

[0107] like Figure 11 As shown, in order to make the cutting edge 21 less effort when tapping, the cutting edge angle of the cutting edge 21 can be set to an acute angle so that the cutting edge 21 can be sharper than an obtuse angle.

[0108] For example, in the radial section of the tail portion 20, the inner contour line of the chip groove 25 may include a first straight line segment L1, and the outer contour line of the tail portion 20 includes a first arc line L2 connected to the first straight line segment L1. The first arc line L2 is tangent to a second straight line segment L3 at the point where it connects with the first straight line segment L1. Alternatively, the first arc line L2 and the second straight line segment L3 can be understood as being tangent at the point where the first arc line L2 connects with the first straight line segment L1. The second straight line segment L3 and the first arc line L2 are located on the same side of the first straight line segment L1, and the angle between the second straight line segment L3 and the first straight line segment L1 is an acute angle, so that the cutting edge angle of the cutting edge 21 forms an acute angle.

[0109] like Figure 11 As shown, in the radial section of the tail 20, the inner contour of the chip removal groove 25 can be composed of a first straight line segment L1 and a second arc L4, so that the cross section of the chip removal groove 25 in the radial section of the tail 20 is fan-shaped.

[0110] Based on the above description of the depth of the first part gradually decreasing to zero along the direction from the tail 20 towards the rod 10, it can be understood that in the first part, along the direction from the tail 20 towards the rod 10, the curved surface corresponding to the second arc L4 is inclined in a direction away from the axis of the rod 10. Therefore, during the process of the bone screw 100 being screwed into the bone 400, the waste debris stored in the chip removal groove 25 can be smoothly discharged out of the chip removal groove 25 along the curved surface corresponding to the second arc L4.

[0111] like Figure 11 As shown, the number of chip removal grooves 25 can be one, two, three, or four, and this application embodiment does not limit this. Taking three chip removal grooves 25 as an example, the three chip removal grooves 25 can be evenly arranged along the axial direction of the tail 20 of the rod body 10, so that the force at each cutting edge 21 of the tail 20 is more even and reasonable during tapping.

[0112] like Figure 11 As shown, it can also be understood that when multiple chip removal grooves 25 are provided on the tail 20, the bottoms of the multiple chip removal grooves 25 can be disconnected from each other to ensure the strength of the tail 20 and thus prevent the tail 20 from breaking during the cutting process.

[0113] like Figure 1 As shown, the outer diameter of the rod 10 is the same at all points along its axial direction. The first external thread 11 is provided on the outer surface of the rod 10; therefore, the outer diameter of the first external thread 11 is also the same at all points along its axial direction.

[0114] Please continue to refer to this. Figure 12 , Figure 12 for Figure 1The diagram shows a partial cross-sectional view of the bone screw. The bone screw 100 also includes a head 30 for engaging with a screw-tightening instrument. Exemplarily, the end face of the head 30 facing away from the rod 10 may have a first groove 31. The first groove 31 engages with the screw-tightening instrument. The cross-section of the first groove 31 may be non-circular. For example, the radial cross-section of the first groove 31 may be cross-shaped, hexagonal, pentagonal, or Torx-shaped, etc., and the corresponding screw-tightening instrument may be a Phillips head screwdriver, an internal hex screwdriver, an internal pentagonal screwdriver, or a Torx screwdriver, etc., which is not limited in this embodiment. The screw-tightening instrument may be a screwdriver, an electric screwdriver, etc., which is also not limited in this embodiment.

[0115] like Figure 12 As shown, the bottom wall of the first groove 31 may be provided with a threaded hole 32. Therefore, a threaded rod, which serves as a surgical instrument, can be screwed to the threaded hole 32 so that the surgeon can hold the bone screw through the threaded rod to insert the bone screw 100 into the patient's body from outside the patient's body, or to remove the bone screw 100 from the patient's body.

[0116] like Figure 12 As shown, taking the bone screw 100 as an example where it is used in conjunction with a bone plate, the bone plate serves as a fixing component of the bone-setting device. The side wall of the head 30 of the bone screw 100 may be provided with a third external thread 33. Furthermore, after the shank 10 and / or tail 20 of the bone screw 100 are screwed and fixed to the bone 400, the head 30 can be threadedly connected to the locking hole with internal threads on the bone plate through the third external thread 33.

[0117] like Figure 12 As shown, a tool retraction groove 34 is provided at the connection between the head 30 and the rod 10, so that the tool used to process the rod 10 and / or the head 30 can retract at the tool retraction groove 34.

[0118] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0119] The bone screw 100 and bone-setting device provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An orthopedic surgical system, characterized in that, include: Drilling device used to drill holes in bone to create pin channels; and A bone screw is used to fix the screw track hole. The bone screw includes a shank and a tail. The surface of the shank is provided with a first external thread, the root diameter of which is approximately the same as the inner diameter of the screw track hole. The tail is connected to the end of the shank and is provided with a cutting edge. The surface of the tail is also provided with a second external thread. The second external thread includes a first end and a second end. Along the direction from the first end to the second end, the outer diameter of the second external thread gradually increases. The first end is located on the side of the second end away from the shank. The outer diameter of the first end is smaller than the root diameter of the first external thread, and the outer diameter of the second end is larger than the root diameter of the first external thread, so that the first end is inserted into the screw track hole and the second end is located outside the screw track hole. The portion of the outer diameter of the second external thread that is equal to the inner diameter of the screw track hole abuts against the inner wall of the screw track hole, so that when the bone screw is rotated, the second external thread can begin to tap the inner wall of the screw track hole.

2. The orthopedic surgical system according to claim 1, characterized in that, The tail section includes a transition section connected to the rod body, and the second end is located at the connection between the transition section and the rod body.

3. The orthopedic surgical system according to claim 2, characterized in that, The transition section includes: A first transition segment, one end of which is connected to the rod body, has a first outer contour angle; and The second transition segment is connected to the other end of the first transition segment, and the second transition segment has a second outer contour angle, which is greater than the first outer contour angle.

4. The orthopedic surgical system according to claim 3, characterized in that, The second transition segment has a first end portion at the end furthest from the first transition segment, and the outer surface of the first end portion is spherical.

5. The orthopedic surgical system according to claim 4, characterized in that, In the axial section of the bone screw, the tangents at both ends of the outer contour line of the first end have a first included angle, which is greater than or equal to the second outer contour angle of the second transition segment.

6. The orthopedic surgical system according to any one of claims 3 to 5, characterized in that, The first end is located in either the first transition section or the second transition section.

7. The orthopedic surgical system according to any one of claims 1 to 5, characterized in that, The tail section is provided with a chip removal groove, and the cutting edge is located at the end edge of the chip removal groove.

8. The orthopedic surgical system according to claim 7, characterized in that, The length of the chip removal groove is greater than the maximum depth of the chip removal groove; Wherein, the length of the chip removal groove is the distance between the two ends of the chip removal groove along the axial direction of the rod body; The depth of the chip removal groove is the distance between the bottom and the opening of the chip removal groove in the radial direction of the rod.

9. The orthopedic surgical system according to claim 7, characterized in that, In the radial section of the tail, the inner contour of the chip removal groove includes a first straight line segment, and the outer contour of the tail includes a first arc line connected to the first straight line segment. The first arc line and the second straight line segment are tangent at the connection point of the first arc line and the first straight line segment. The second straight line segment and the first arc line are located on the same side of the first straight line segment, and the angle between the second straight line segment and the first straight line segment is an acute angle.

10. The orthopedic surgical system according to claim 7, characterized in that, The chip removal groove extends along the axial direction of the rod body to the rod body, and the chip removal groove includes a first part located on the rod body and a second part located at the tail end; Wherein, along the direction from the tail towards the rod, the depth of the first part gradually decreases to zero; the depth of the chip removal groove is the distance between the bottom of the chip removal groove and the opening of the groove in the radial direction of the rod. Wherein, along the direction from the tail towards the rod, the distance between the bottom of the groove in the second part and the axis of the rod remains unchanged.

11. The orthopedic surgical system according to any one of claims 1 to 5, characterized in that, The outer diameter of the second end is equal to the outer diameter of the first external thread.

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