CN213030815U - Bone screw for setting bone - Google Patents

Abstract

The utility model provides a bone nail, it adopts the absorbable material preparation, and include: a nail body and a screw cap. The nail body is cylindricly and includes screw thread portion and connecting portion, screw thread portion and connecting portion integrated into one piece, and the periphery of screw thread portion is provided with the screw thread, and the length of connecting portion is more than or equal to the length of screw thread portion. The screw cap is cylindricly, and the bottom surface of screw cap is disposed the fillet, and the screw cap sets up the one end at connecting portion, and the screw cap is provided with along the counter bore of direction of height indent, and the counter bore is the cross, and the center of counter bore is coaxial with the axle center of the nail body, and the external diameter of screw cap is greater than the external diameter of connecting portion, and wherein, connecting portion are connected via the curved surface with the screw cap. Under the condition, the bone screw has higher fixing strength and can be better fixed in the bone, and the screw cap of the bone screw is provided with the concave cross-shaped counter bore, so that the problem that the bone screw is easy to slip when being implanted or screwed out is solved.

Description

Bone screw for setting bone

Technical Field

The embodiment relates to the field of medical instruments, in particular to a bone screw.

Background

With the increase of population and aging, patients with bone defects caused by diseases, accidents and the like are increasing, and the clinical requirements of bone repair treatment are increasing year by year. In the orthopedic repair treatment operation, the damaged bone needs to be fixed by using bone screws, bone fracture plates and other implantation instruments. Accordingly, the demand for bone fixation implant devices has also increased.

The existing bone screw is usually made of metal materials, cannot be absorbed by a human body, and may cause the human body to generate certain rejection in the later period; in addition, the existing bone screws are generally difficult to implant and difficult to fix after being implanted into bones, and the bone screws are easy to withdraw from the bones.

SUMMERY OF THE UTILITY MODEL

The present invention has been accomplished in view of the above-mentioned prior art, and an object of the present invention is to provide a bone screw which is made of an absorbable material, is easy to operate, and is advantageous for bone tissue growth and can be better fixed inside a bone.

Therefore, the utility model provides a bone screw, a serial communication port, bone screw adopts the absorbable material preparation, bone screw includes: the nail body is cylindrical and comprises a threaded part and a connecting part, the threaded part and the connecting part are integrally formed, threads are arranged on the periphery of the threaded part, and the length of the connecting part is greater than or equal to that of the threaded part; the screw cap, it is cylindricly, the bottom surface of screw cap is configured with the fillet, the screw cap sets up the one end of connecting portion, the screw cap is provided with the counter bore along the direction of height indent, the counter bore is the cross, the center of counter bore with the axle center of the nail body is coaxial, the external diameter of screw cap is greater than the external diameter of connecting portion, wherein, connecting portion with the screw cap is connected via the curved surface.

The utility model discloses in, the preparation of absorbable material is adopted to the bone screw that connects together, the bone screw that connects together includes the nail body and screw cap, the nail body includes integrated into one piece's screw thread portion and connecting portion, the periphery of screw thread portion is provided with the screw thread, the length of connecting portion is more than or equal to the length of screw thread portion, the screw cap is connected via the curved surface with connecting portion, the screw cap is provided with the criss-cross counter bore of indent, the center of counter bore is coaxial with the axle center of the nail body, the bottom surface of screw cap is configured with the fillet, the external diameter of screw. Under the condition, the bone screw has higher fixing strength and can be better fixed in the bone, and the screw cap of the bone screw is provided with the concave cross-shaped counter bore, so that the problem that the bone screw is easy to slip when being implanted or screwed out is solved.

In addition, in the bone screw according to the present invention, optionally, the material of the screw body is selected from one of polylactic acid material, polycaprolactone, polydioxanone and polyglycolic acid, or one of more than two-component random copolymer or block copolymer selected from lactide, caprolactone, polydioxanone and glycolide. In this case, by manufacturing the bone screw using an absorbable material, not only the occurrence of a secondary operation can be effectively prevented, but also various inconveniences such as the inability to perform nuclear magnetic resonance examination or the occurrence of inflammation such as synovitis, which may be caused by the bone screw remaining in the body, can be effectively suppressed.

In addition, in the bone screw of the present invention, optionally, a nail head integrally formed with the screw body and in a gradually shrinking shape is further included. Thereby being convenient for the bone screw to be implanted into the bone.

In addition, in the bone screw according to the present invention, optionally, the screw head is formed in a circular truncated cone shape and connected to the screw portion of the screw body. Thereby reducing the damage of the bone nail to the bone tissue.

Additionally, in the bone screw of the present invention, optionally, the thread is a thread of a dental type. In this case, the friction between the bone screw and the implanted bone can be increased, whereby a better fixation of the bone screw inside the bone can be facilitated.

Additionally, in the bone screw according to the present invention, optionally, the crest of the thread has a chamfer. Therefore, the possibility of secondary damage of the bone tunnel caused by the bone screw can be reduced.

Additionally, in the bone screw of the present invention, optionally, the screw thread is a zigzag screw thread, a cross section of the screw thread is a non-isosceles trapezoid, and corners of two sides of the screw thread are rounded transitions. Thereby, the bone screw can be better fixed inside the bone.

In addition, in the bone screw according to the present invention, optionally, a pitch between the adjacent two of the threads is equal. In this case, the friction force of the bone screw with the bone tissue can be increased, and the fixation of the bone screw inside the bone can be facilitated.

In addition, in the bone screw according to the present invention, optionally, the thread of the screw thread is located farther from a side angle of one side of the screw cap than a side angle of one side of the screw cap. In this case, a better implantation of the bone screw inside the bone is enabled and a better fixation of the bone screw inside the bone is facilitated.

Additionally, in the bone screw of the present invention, optionally, the ratio of the length of the screw portion to the length of the screw body is 0.2 to 0.5. Therefore, the bone screw can better fit different damaged bones.

According to the utility model discloses, an adopt absorbable material preparation, convenient operation, and be favorable to bone tissue to grow and can be better fix the bone screw of setting inside the bone is provided.

Drawings

Fig. 1 is a perspective view showing one angle of a bone screw according to an embodiment of the present invention.

Fig. 2 is a perspective view showing another angle of the bone screw according to the embodiment of the present invention.

Fig. 3 is a sectional view showing a bone screw according to an embodiment of the present invention.

Fig. 4 is a partial sectional view showing a part of fig. 3 according to an embodiment of the present invention.

Fig. 5 is a partial sectional view showing another part of fig. 3 according to the embodiment of the present invention.

Fig. 6 is a front view of a screw cap showing a bone screw according to an embodiment of the present invention.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same components are denoted by the same reference numerals, and redundant description thereof is omitted. The drawings are schematic and the ratio of the dimensions of the components and the shapes of the components may be different from the actual ones.

It is noted that the terms "comprises," "comprising," and "having," and any variations thereof, in the present disclosure, such that a process, method, system, article, or apparatus that comprises or has a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include or have other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

In bone surgery, it is often necessary to fix a fracture site (also referred to as "damaged bone") with bone screws. The utility model provides a bone screw (also called as a bone screw 10). The utility model discloses in, the bone nail that coaptates adopts the preparation of absorbable material to can implant inside the bone and can be better fixed comparatively easily, can be absorbed the emergence that restraines the secondary operation by the human body after implanting.

Fig. 1 is a perspective view showing one angle of a bone screw 10 according to the present embodiment.

The utility model provides a bone screw 10 which is made of absorbable material and comprises a screw body 110 and a screw cap 120. The nail body 110 may have a cylindrical shape and include a screw part 111 and a coupling part 112, the screw part 111 and the coupling part 112 being integrally formed, an outer circumference of the screw part 111 may be provided with a screw, and a length of the coupling part 112 is greater than or equal to a length of the screw part 111. The screw cap 120 may be cylindrical, the bottom surface of the screw cap 120 is configured with a rounded corner, the screw cap 120 may be disposed at one end of the connection portion, the screw cap 120 may be provided with a counterbore 121 (see fig. 2) recessed along the height direction, the counterbore 121 may be cross-shaped, the center of the counterbore 121 may be coaxial with the axis of the nail body 110, the outer diameter of the screw cap 120 is greater than the outer diameter of the connection portion 112, wherein the connection portion 112 and the screw cap 120 are connected via a curved surface.

The present invention provides a bone screw 10 made of absorbable material, as described above, the bone screw 10 may include a screw body 110 and a screw cap 120, the screw body 110 may include an integrally formed screw thread portion 111 and a connecting portion 112, the outer periphery of the screw thread portion 111 may be provided with screw threads, the length of the connecting portion 112 may be greater than or equal to the length of the screw thread portion 111, the screw cap 120 and the connecting portion 110 may be connected via a curved surface, the screw cap 120 may be provided with an inwardly recessed cross-shaped counter bore 121, the center of the counter bore 121 may be coaxial with the axis of the screw body 110, the bottom surface of the screw cap 1220 may be configured with a rounded corner, and the outer diameter of the screw cap 120 may be greater than the outer diameter of. In this case, the bone screw 10 can be provided with greater fixing strength and can be better fixed inside the bone, and the screw cap 120 of the bone screw 10 is provided with the depressed cross-shaped counter bore 121, improving the problem that the bone screw 10 is easily slipped when being implanted or unscrewed.

Fig. 2 is a perspective view showing another angle of the bone screw 10 according to the present embodiment.

In the present embodiment, as shown in fig. 1 and 2, the bone screw 10 according to the present embodiment may include a shank 110 and a screw cap 120, and the screw cap 120 may be provided at one end of the shank 110.

In some examples, the shank 110 may be integrally formed with the screw cap 120. In this case, the shank 110 and the screw cap 120 are formed as one body, whereby the shank 110 and the screw cap 120 can be suppressed from being separated from each other during the operation of the bone screw 10, thereby suppressing the possibility of the bone screw 10 slipping off due to the separation and improving the reliability of the bone screw 10.

In some examples, the tack body 110 may be elongated. In some examples, the shank 110 may be cylindrical. Thus, the nail body 110 can be in different shapes according to different application scenes.

In some examples, as shown in fig. 1 and 2, the shank 110 may include a threaded portion 111 and a connecting portion 112. In some examples, threaded portion 111 may be integrally formed with connecting portion 112.

In some examples, as shown in fig. 1-3, the length of the threaded portion 111 may be less than or equal to the length of the connecting portion 112. In some examples, the ratio of the length of the threaded portion 111 to the length of the nail body 110 may be 0.2-0.5. This enables the bone screw 10 to better fit different damaged bones, for example, as may be used in cancellous bone. However, the present invention is not limited thereto, and in some examples, the length of the threaded portion 111 may be less than or equal to the length of the connecting portion 112, or may be greater than the length of the connecting portion 112. In some examples, the ratio of the length of the threaded portion 111 to the length of the nail body 110 may be 0.2-0.7. For example, the ratio of the length of the threaded portion 111 to the length of the shank 110 may be 0.2, 0.24, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.56, 0.6, 0.65, 0.7, or the like.

In some examples, the outer circumference of the threaded portion 111 may be provided with threads.

Fig. 3 is a sectional view showing a bone screw 10 according to an embodiment of the present invention. Fig. 4 is a partial sectional view showing a part (region a) of fig. 3 according to the embodiment of the present invention.

In some examples, the threads on threaded portion 111 may be a thread type of thread. In this case, the friction between the bone screw 10 and the implanted bone can be increased, whereby a better fixation of the bone screw 10 inside the bone can be facilitated.

In some examples, as shown in fig. 3 and 4, the crests of the threads on the threaded portion 111 may have chamfers. This reduces the possibility of secondary damage to the bone tunnel caused by the bone screw 10. In some examples, the chamfer of the crest of the thread provided at the outer periphery of the threaded portion 111 may be flat-top type or dome type.

In the present embodiment, as shown in fig. 3 and 4, the thread on the thread part 111 may be a zigzag type thread, and the cross section of the thread (for example, the thread 113a and the thread 113b) may have an unequal waist trapezoid shape. In some examples, the threads are rounded at both side corners (e.g., at a and b). In this case, the thread is not easily bent or broken, is not easily worn, and can be tightly pressed against the bone tunnel implanted in the bone, thereby enabling the bone screw 10 to be better fixed inside the bone. For example, as shown in fig. 4, the crest of the thread has rounded corners (e.g., at a and b).

In some examples, as shown in fig. 3 and 4, the two side corners (see c and d in fig. 4) where the root of the thread on the shank 110 connects with the thread may be connected via a curved surface.

In some examples, the flanks of the threads on threaded portion 111 may be arcuate. However, examples of the present invention are not limited thereto, and in some examples, the flanks of the threads of the thread may be beveled.

In some examples, as shown in fig. 3 and 4, the root of the thread on the threaded portion 111 (except for the corners at both sides where the root and the thread are connected) may be horizontal in parallel with the axis L of the nail body. However, the present invention is not limited thereto, and in some examples, the root of the thread on the threaded portion 111 may be concave arc-shaped.

In some examples, as shown in fig. 3 and 4, the flank angle (e.g., flank angle α) of the thread on the side of the thread distal from the screw cap 120 is greater than the flank angle (e.g., flank angle β) on the side proximal to the screw cap. In this case, the thread on the threaded portion 112 may be barbed, enabling a better implantation of the bone screw 10 inside the bone and facilitating a better fixation of the bone screw 10 inside the bone.

In some examples, the profile angle (i.e., the sum of flank angle α and flank angle β) of the threads may be 20-60 °. In some examples, the flank angle (e.g., flank angle α) of the threads on the side of the threads distal from the nut 120 may be 15-35 ° in magnitude, and the flank angle (e.g., flank angle α) of the threads on the side of the threads proximal to the nut 120 may be 5-25 ° in magnitude.

However, the present invention is not limited to this, and in some examples, the thread on the thread portion 111 may be a sawtooth thread, the thread cross section of the thread may be an isosceles trapezoid, and the thread angle of the thread may be 30 to 60 °.

In other examples, the thread may also be provided as a round root constant pitch unified thread (UNR thread), a round root coarse series unified thread (UNRC), a round root fine series unified thread (UNRF), a round root ultra fine series unified thread (UNREF), or a round root special series unified thread (UNRs).

In other examples, the thread may also be a standard coarse huh series, a standard english standard BS84 english thread with 55 angles (b.s.w.) a standard fine huh series, a general purpose cylindrical thread (b.s.f.), an additional optional huh series, a general purpose cylindrical thread (whit.s), a non-standard thread of huh type (Whit), a uniform thread of constant pitch (UN), a uniform thread of coarse series (UNC), a uniform thread of fine series (UNF), a uniform thread of ultra fine series (UNEF), or a uniform thread of special Series (UNs). In this case, different threads may be selected according to different use environments, thereby enabling bone screw 10 to accommodate different application scenarios.

In some examples, the threads on threaded portion 111 may satisfy an equal pitch between two adjacent threads. In this case, the friction of the bone screw 10 with the bone tissue can be increased, and the fixation of the bone screw 10 inside the bone can be facilitated. However, the present invention is not limited to this, and the thread on the threaded portion 111 may also satisfy that the closer the pitch between two adjacent threads is to the screw cap 120, the larger the pitch is.

In some examples, the thread heights of two adjacent ones of the threads on threaded portion 111 (i.e., half of the difference between the outer diameter and the inner diameter of threaded portion 111) may be equal.

In some examples, the thread height of the threaded portion 111 may be 1/6-1/3 of the inner diameter of the threaded portion 111. For example, the thread height of the threaded portion 111 may be 1/6, 1/5, 1/4, 1/3, or the like, which is the size of the inner diameter of the threaded portion 111.

In some examples, the widths of the threads in the threads on the threaded portion 111 (e.g., the intervals a and b in fig. 3) may be equal.

In some examples, shank 110 includes a coupling portion 112, and coupling portion 112 may be integrally formed with threaded portion 111. In some examples, the connection portion 112 may be a threadless polished rod structure. In some examples, the outer diameter of the connecting portion 112 may be equal in size to the inner diameter of the threaded portion 111. This enables the connection portion 112 and the threaded portion 111 to be better matched. In other examples, the outer diameter of connecting portion 112 may be greater than the inner diameter of threaded portion 111, and the outer diameter of connecting portion 112 may be equal to or less than the outer diameter of threaded portion 111.

In some examples, as shown in fig. 1-3, the shank 110 may include two portions, one side of which is a threaded portion 111 and the other side of which is a connecting portion 112. However, the present invention is not limited thereto, and in some examples, the nail body 110 may be divided into a plurality of portions, each of which is composed of a plurality of threaded portions 111 and a plurality of connecting portions 112. Thereby enabling the bone screw 10 to be adapted to different application scenarios.

In some examples, the bone screw 10 may include a screw cap 120, and the screw cap 120 may be disposed at one end of the screw body 110.

In some examples, as shown in FIG. 1, the nut 120 may be disposed at an end of the connecting portion 112 proximate to the shank 110. In other examples, the nut 120 may be disposed at an end of the screw body 110 away from the threaded portion 111.

Fig. 5 is a partial sectional view showing another portion (region B) in fig. 3 according to the embodiment of the present invention. Fig. 6 is a front view showing a screw cap 120 of the bone screw 10 according to an embodiment of the present invention.

In some examples, the screw cap 120 and the shank 110 may be connected via a curved surface. For example, as shown in fig. 3 and 5, the screw cap 120 and the connecting portion 112 of the nail body 110 may be connected via a curved surface (see a in fig. 5 in particular).

In some examples, as shown in fig. 1 and 2, the screw cap 120 may be cylindrical. Thereby, the screw cap 120 can be better matched with the nail body 110, and the bone screw 10 can be implanted into the bone more easily.

In some examples, the outer diameter of the screw cap 120 may be greater than the outer diameter of the shank 110. In some examples, the outer diameter of the screw cap 120 may be greater than the outer diameter of the threads on the threaded portion 111. The possibility of the bone screw 10 being implanted too deeply during implantation can thereby be effectively suppressed.

In some examples, as shown in FIGS. 2 and 6, the screw cap 120 may be provided with a counterbore 121 that is recessed in the height direction. In some examples, a counterbore 121 may be disposed on a side of the screw cap 120 away from the nail body 110, and the counterbore 121 may take the form of one of a recessed quincunx, a trident, a triangle, a square, a hexagon, a cross, or the like. Implantation of the bone screw 10 into the bone can thereby be facilitated. Preferably, as shown in FIGS. 1 and 6, the nut 120 may be provided with an inwardly concave cruciform counterbore 121. In other examples, counterbore 121 may be compounded from a variety of shapes. In this case, the bone screw 10 has both good mechanical properties to make it easier to implant into bone and to improve the problem of the bone screw 10 being susceptible to thread slippage when implanted or unscrewed.

In some examples, the center of the recessed counterbore 121 provided in the screw cap 120 may be located on the axis L of the nail body 110, such as the bone screw 10 in fig. 2 and 5, and the center 121a of the recessed cross-shaped counterbore 121 provided in the screw cap 120 may be located on the axis L of the nail body 110. In this case, a higher reliability of the bone screw 10 can be achieved.

In some examples, the counterbore 121 provided on the screw cap 120 may be formed by being recessed along the axis L. In some examples, the screw cap 120 may be cross-shaped with the recessed counterbore 121. Specifically, as shown in fig. 2 and 5, counterbore 121 may include a counterbore surface 121b, a counterbore bottom surface 121c, and a counterbore wall surface 121d, counterbore surface 121b also being a screw cap bottom surface 122, counterbore bottom surface 121c being a surface concavely formed in screw cap 120, counterbore bottom surface 121c being parallel to counterbore surface 121b, and counterbore wall surface 121d being perpendicular to counterbore bottom surface 121c or counterbore surface 121 b. In some examples, the corner of the counterbore 121 of the screw cap 120 that connects to the bottom surface 122 of the screw cap may be rounded. In some examples, as shown in fig. 6, the counterbore 121 may be divided into 4 regions, for example, a region a, a region b, a region c and a region d, wherein, as shown in fig. 2 and 6, the counterbore wall surface in the region a is vertically arranged, and the regions b, c and d are also the same as the region a, and each has a counterbore wall surface vertically arranged.

In some examples, the bottom surface of the screw cap 120 is configured with rounded corners. Specifically, referring to fig. 5 at b and c, the two corners of the screw cap 120 where the bottom surface and the side surface are connected may have rounded transitions.

In some examples, the screw cap 120 may be of a threadless design, i.e., the screw cap 120 is unthreaded. In this case, the possibility of the bone screw 10 being implanted too deeply during implantation can be suppressed, whereby the implantation efficiency can be improved and the corresponding implantation hindrance can be reduced.

In some examples, as shown in fig. 1, bone screw 10 may further include a head 130 coupled to shank 110. In some examples, the head 130 may be disposed at the other end of the shank 110 away from the screw cap 120, for example, as shown in fig. 1, the head 130 may be connected with the threaded portion 111 of the shank 110. In this case, the maximum outer diameter of stud 130 may be equal to the inner diameter of threaded portion 111. Thereby enabling a better match of the head 130 and the shank 110.

In other examples, the cap 120 of the bone screw 10 may be disposed at an end proximate to the threaded portion 111 and the head 130 may be disposed at an end (not shown) proximate to the connecting portion 112 of the shank 110.

In some examples, the maximum outer diameter of tack head 130 may be equal to the outer diameter of connecting portion 112. Thereby enabling a better match of the head 130 and the shank 110.

In some examples, tack head 130 may be integrally formed with tack body 110. In this case, the head 130 is formed integrally with the shank 110, whereby the separation of the head 130 and the shank 110 from each other during the operation of the bone screw 10 can be effectively suppressed, thereby suppressing the possibility of the bone screw 10 slipping off due to the separation and improving the reliability of the bone screw 10. In some examples, the head 130 may be tapered, and the head 130 may be tapered in a direction away from the nut 120. Thereby, implantation of the bone screw 10 into the bone can be facilitated.

In some examples, the stud 130 may be frustoconical. Thereby reducing the damage of the bone nail 10 to the bone tissue. In some examples, the head of the head 130 distal to the nut 120 may be spherical, and the shank of the head 130 other than the head may be frustoconical or tapered. In other examples, stud 130 may be tapered.

In some examples, stud 130 may be of a threadless design, i.e., no threads on stud 130.

In some examples, the material of bone screw 10 may be selected from one of a polylactic acid-based material, polycaprolactone, polydioxanone, and polyglycolic acid. In other examples, the material of bone screw 10 may be selected from one of more than two random or block copolymers of lactide, caprolactone, p-dioxanone, and glycolide.

In the present embodiment, by using the bone screw 10 made of the above-described material, not only the secondary removal operation can be avoided, but also inconvenience caused by leaving a bone screw made of a material that is not absorbed into the human body, such as metal, in the body, such as failure of nuclear magnetic resonance examination, inflammation such as synovitis, and the like, can be avoided.

While the present invention has been described in detail in connection with the drawings and the examples, it is to be understood that the above description is not intended to limit the present invention in any way. The present invention may be modified and varied as necessary by those skilled in the art without departing from the true spirit and scope of the invention, and all such modifications and variations are intended to be included within the scope of the invention.

Claims (10)

1. A bone screw, which is characterized in that the bone screw is made of absorbable material,

the bone screw comprises:

the nail body is cylindrical and comprises a threaded part and a connecting part, the threaded part and the connecting part are integrally formed, threads are arranged on the periphery of the threaded part, and the length of the connecting part is greater than or equal to that of the threaded part;

a screw cap having a cylindrical shape, a bottom surface of the screw cap being provided with a fillet, the screw cap being disposed at one end of the connecting portion, the screw cap being provided with a counter bore recessed in a height direction, the counter bore having a cross shape, a center of the counter bore being coaxial with an axis of the nail body, an outer diameter of the screw cap being greater than an outer diameter of the connecting portion,

wherein the connecting part is connected with the screw cap through a curved surface.

2. The bone screw according to claim 1,

the absorbable material is selected from one of polylactic acid materials, polycaprolactone, polydioxanone and polyglycolic acid, or one of more than two-component random copolymers or block copolymers selected from lactide, caprolactone, polydioxanone and glycolide.

3. The bone screw according to claim 1,

also comprises a nail head which is integrally formed with the nail body and is gradually contracted.

4. The bone screw according to claim 3,

the nail head is in a round table shape and is connected with the thread part of the nail body.

5. The bone screw according to claim 1,

the threads are thread-type threads.

6. The bone screw according to claim 1,

the crests of the threads have chamfers.

7. The bone screw according to claim 1,

the thread adopts sawtooth type thread, the thread cross-section of thread is not isosceles trapezoid, the both sides corner of thread is the fillet transition.

8. The bone screw according to claim 1,

the thread pitches between two adjacent threads are equal.

9. The bone screw according to claim 1,

the flank angle of the thread on the side of the thread far away from the screw cap is larger than the flank angle on the side of the thread close to the screw cap.

10. The bone screw according to claim 1,

the ratio of the length of the threaded part to the length of the nail body is 0.2-0.5.

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