Medical internal screws, screw assemblies and acetabular prostheses

Abstract

This utility model relates to a medical internal screw, a screw assembly, and an acetabular prosthesis. The medical internal screw includes a connected head and a shank. The head mates with a mounting hole in the acetabular cup. The outer wall of the shank has external threads and a cutting groove. The cutting groove extends along the length of the shank and passes through at least a portion of the external threads. The medical internal screw of this utility model requires less effort to remove, thus shortening surgical time.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, specifically to a medical internal screw, screw assembly, and acetabular prosthesis. Background Technology

[0002] In hip replacement surgery, acetabular cups are typically fixed with acetabular screws to improve stability after implantation. In related techniques, acetabular screws employ a split structure, consisting of an internal screw and an external screw. At least a portion of the internal screw is screwed into the external screw, allowing for separate fixation of the acetabular cup and the mating bone. However, due to an inadequate design of the internal screw, it is inconvenient to remove it from the acetabular cup or bone tissue when revision surgery is required. Utility Model Content

[0003] This utility model aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, embodiments of this utility model propose a medical internal screw that is easy to remove.

[0005] An embodiment of this utility model also proposes a screw assembly.

[0006] An embodiment of this utility model also proposes an acetabular prosthesis.

[0007] The medical internal screw of this utility model includes a connected screw head and a screw shank. The screw head is used to mate with the mounting hole of the acetabular cup. The outer wall of the screw shank is provided with an external thread and a cutting groove. The cutting groove extends along the length direction of the screw shank and passes through at least a portion of the external thread.

[0008] According to an embodiment of the present invention, the medical internal screw has a cutting groove on the outer wall of the screw portion. The cutting groove extends along the length of the screw portion and passes through at least part of the external thread. Thus, a cutting edge can be formed at the junction of the cutting groove and the external thread. When the doctor performs revision surgery on the acetabular cup and removes the medical internal screw, the cutting edge formed at the junction of the cutting groove and the external thread can work together with the external thread to cut the remaining medical external screw or bone tissue. This makes the removal of the medical internal screw easier and helps to shorten the operation time.

[0009] In some embodiments, the cutting groove passes through the entire external thread along the length of the screw portion.

[0010] In some embodiments, the cutting groove is internally threaded, and the thread direction of the cutting groove is consistent with the helical direction of the external thread.

[0011] In some embodiments, the radial depth of the cutting groove is greater than or equal to the thread height of the external thread.

[0012] In some embodiments, the cross-sectional profile of the cutting groove is U-shaped in a projection plane orthogonal to the length direction of the screw portion.

[0013] In some embodiments, the external thread has a rectangular or trapezoidal tooth profile.

[0014] In some embodiments, the screw portion has a first end near the nail head and a second end away from the nail head, and the outer diameter of the external thread and the outer diameter of the screw gradually decrease in the direction from the first end to the second end.

[0015] In some embodiments, there are multiple cutting grooves, which are arranged at circumferential intervals along the screw portion.

[0016] In some embodiments, the medical internal screw further includes a neck, which is disposed between the screw head and the screw shank. The cross-sectional profile of the neck is circular, and the outer diameter of the neck is smaller than the outer diameter of the screw head but larger than the outer diameter of the external thread.

[0017] In some embodiments, the outer wall surface of the screw head is an arc-shaped surface, which protrudes outward in a direction away from the axis of the medical internal screw.

[0018] In some embodiments, the end face of the nail head facing away from the screw is provided with a plum blossom-shaped groove.

[0019] Another embodiment of the screw assembly of this utility model includes: a medical internal screw, wherein the medical internal screw is the medical internal screw described in any one of the embodiments of this utility model; and a medical external screw, wherein the medical external screw has a mating hole, and one end of the screw portion opposite to the screw head is disposed in the mating hole.

[0020] According to the screw assembly of the present invention, the outer wall of the screw portion is provided with a cutting groove, which extends along the length of the screw portion and passes through at least part of the external thread. Thus, a cutting edge can be formed at the junction of the cutting groove and the external thread. When the doctor performs revision surgery on the acetabular cup and removes the medical internal screw, the cutting edge formed at the junction of the cutting groove and the external thread can work together with the external thread to cut the remaining medical external screw or bone tissue. This makes the removal of the medical internal screw easier and helps to shorten the operation time.

[0021] Another embodiment of the acetabular prosthesis of the present invention includes: a screw assembly, wherein the screw assembly is the screw assembly described in any one of the embodiments of the present invention; and an acetabular cup having a mounting hole thereon, wherein the screw head engages with the mounting hole.

[0022] According to an embodiment of the present invention, the acetabular prosthesis has a cutting groove on the outer wall of the screw portion. The cutting groove extends along the length of the screw portion and passes through at least part of the external thread. Thus, a cutting edge can be formed at the junction of the cutting groove and the external thread. When the doctor performs revision surgery on the acetabular cup and removes the medical internal screw, the cutting edge formed at the junction of the cutting groove and the external thread can cut the remaining medical external screw or bone tissue together with the external thread. This makes it easier to remove the medical internal screw and helps to shorten the operation time. Attached Figure Description

[0023] Figure 1 This is a perspective view of a medical internal screw according to an embodiment of the present invention.

[0024] Figure 2 This is a front view of the medical internal screw according to an embodiment of the present invention.

[0025] Figure 3 yes Figure 2 A cross-sectional view of AA.

[0026] Figure 4 This is a top view of a medical internal screw according to an embodiment of the present invention.

[0027] Figure 5 This is an exploded view of the screw assembly according to an embodiment of the present invention.

[0028] Figure 6 This is a schematic diagram of the installation of the medical internal screw and acetabular cup according to an embodiment of the present invention.

[0029] Figure label:

[0030] 1. Medical internal screw; 11. Screw head; 111. Torx-shaped countersunk groove; 12. Screw section; 13. External thread; 14. Cutting groove; 15. Neck;

[0031] 2. Medical external screw; 21. Mating hole;

[0032] 3. Achilles cup. Detailed Implementation

[0033] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0034] The following is a reference appendix. Figures 1 to 6 This invention describes a medical internal screw 1, a screw assembly, and an acetabular prosthesis according to embodiments of the present invention.

[0035] like Figures 1 to 4As shown, the medical internal screw 1 of this utility model embodiment includes a connected screw head 11 and screw shank 12. The screw head 11 is used to mate with the mounting hole of the acetabular cup 3. The outer wall of the screw shank 12 is provided with an external thread 13 and a cutting groove 14. The cutting groove 14 extends along the length direction of the screw shank 12 and passes through at least part of the external thread 13.

[0036] According to an embodiment of the present invention, the medical internal screw 1 has a cutting groove 14 on the outer wall of the screw portion 12. The cutting groove 14 extends along the length of the screw portion 12 and passes through at least part of the external thread 13. Thus, a cutting edge can be formed at the junction of the cutting groove 14 and the external thread 13. When the doctor performs revision surgery on the acetabular cup 3 and removes the medical internal screw 1, the cutting edge formed at the junction of the cutting groove 14 and the external thread 13 can cut the remaining medical external screw 2 or bone tissue together with the external thread 13. This makes it easier to remove the medical internal screw 1 and helps to shorten the operation time.

[0037] Understandably, the medical internal screw 1 and the medical external screw 2 are manufactured separately and then assembled together. The medical external screw 2 is made of absorbable material. Thus, the medical external screw 2 can stabilize the acetabular cup 3 in the early stages, and after the acetabular cup 3 achieves self-stabilization through bone ingrowth, the medical external screw 2 can be absorbed.

[0038] When a patient undergoes revision surgery due to factors such as prosthesis loosening or infection, the external medical screw 2 can be partially absorbed (i.e., there is a residue of the external medical screw 2) or completely absorbed. In this case, when the doctor unscrews the external medical screw 2, the cutting edge formed at the junction of the cutting groove 14 and the external thread 13 can work together with the external thread 13 to cut the remaining external medical screw 2 or bone tissue, so that it is easier to unscrew the internal medical screw 1 when unscrewing the acetabular cup 3.

[0039] In other words, when unscrewing, the cutting edge of the cutting groove 14 and the threaded sidewall can form a "barbed cut surface" to cut the remaining second nail body or bone tissue, thereby providing axial loosening torque for unscrewing the medical internal screw 1, making it easier to unscrew the medical internal screw 1 from the acetabular cup 3.

[0040] Optionally, such as Figure 1 As shown, the cutting groove 14 passes through the entire external thread 13 along the length of the screw portion 12. It can be understood that the length of the cutting groove 14 on the screw portion 12 is not less than the length of the external thread 13 on the screw portion 12, thereby making the cutting edge formed at the junction of the cutting groove 14 and the external thread 13 longer (more), which further improves the convenience of removing the medical internal screw 1 and shortens the operation time.

[0041] Optionally, such as Figure 1 and Figure 2As shown, the cutting groove 14 is internally threaded, and the thread direction of the cutting groove 14 is consistent with the helical direction of the external thread 13. Because the thread direction of the cutting groove 14 is consistent with the helical direction of the external thread 13, when the medical internal screw 1 is screwed into the medical external screw 2, the cutting groove 14 and the external thread 13 can together form a "guide surface" to reduce the pushing torque of the medical internal screw 1. Furthermore, when the medical internal screw 1 is removed, the consistent thread direction of the cutting groove 14 with the helical direction of the external thread 13 makes it easier to unscrew the medical internal screw 1, thereby further improving the convenience of assembling and disassembling the medical internal screw 1.

[0042] For example, the cutting groove 14 and the external thread 13 can both be right-handed.

[0043] Optionally, the radial depth of the cutting groove 14 is greater than or equal to the thread height of the external thread 13. It can be understood that the thread height = (thread outer diameter - thread inner diameter) / 2. Since the radial depth of the cutting groove 14 is greater than or equal to the thread height of the external thread 13, the cross-section formed by the cutting groove 14 and the sidewall of the external thread 13 can be increased, making it easier to install and remove the medical internal screw 1.

[0044] For example, the radial depth of the cutting groove 14 is greater than the thread height of the external thread 13, that is, part of the cutting groove 14 is formed on the outer wall surface of the screw portion 12.

[0045] Optionally, such as Figure 3 As shown, in the projection plane orthogonal to the length direction of the screw portion 12, the cross-sectional profile of the cutting groove 14 is U-shaped. This facilitates the machining and manufacturing of the cutting groove 14, reduces machining difficulty, and improves the cutting effect when the medical internal screw 1 is unscrewed due to the U-shaped cross-sectional profile of the groove.

[0046] like Figures 1 to 3 As shown, the tooth profile of the external thread 13 is rectangular or trapezoidal. Compared with the option of a triangular tooth profile for the external thread 13, the rectangular or trapezoidal tooth profile of the external thread 13 has a better self-locking effect, which helps to reduce the probability of the medical internal screw 1 loosening. In addition, the cutting edge formed by the rectangular or trapezoidal tooth profile and the cutting groove 14 is larger, making it easier to disassemble and assemble the medical internal screw 1.

[0047] Optionally, such as Figure 1 and Figure 2 As shown, the screw portion 12 has a first end close to the nail head 11 and a second end away from the nail head 11. In the direction from the first end to the second end, the outer diameter of the external thread 13 and the outer diameter of the screw gradually decrease, which can help the medical external screw 2 absorb and eliminate stress, and facilitate the disassembly and removal of the medical internal screw 1 during repair.

[0048] Optionally, such as Figure 3 and Figure 4 As shown, there are multiple cutting grooves 14, which are arranged at intervals along the circumference of the screw portion 12. This allows for more cutting edges formed by the cutting grooves 14 and the external thread 13, i.e., a larger sectional area formed by the cutting grooves 14 and the thread sidewall, thereby further improving the convenience of removing the medical internal screw 1 and shortening the operation time.

[0049] For example, there are four cutting grooves 14, which are arranged at equal intervals along the circumference of the screw portion 12.

[0050] Optionally, such as Figure 1 and Figure 2 As shown, the medical internal screw 1 also includes a neck 15, which is located between the screw head 11 and the threaded portion 12. The cross-sectional profile of the neck 15 is circular, and its outer diameter is smaller than that of the screw head 11 but larger than that of the external thread 13. On one hand, the neck 15 can improve the connection strength between the screw head 11 and the threaded portion 12, reducing the risk of breakage at the junction of the screw head 11 and the threaded portion 12 when the medical internal screw 1 is tightened. On the other hand, the neck 15 can cooperate with the medical external screw 2, helping to integrate the medical external screw 2 and the medical internal screw 1 into a single unit, resulting in better implantation outcomes.

[0051] Optionally, such as Figure 2 As shown, the outer wall surface of the screw head 11 is an arc-shaped surface, which protrudes outward in a direction away from the axis of the medical internal screw 1. The outer wall surface of the screw head 11 can match the wall surface of the mounting hole of the acetabular cup 3, allowing the medical internal screw 1 to move in a small range of motion, thereby adapting to the micro-movement of the acetabular cup 3, eliminating stress concentration, and promoting osseointegration, further enhancing the fixation effect of the acetabular cup 3.

[0052] like Figure 1 As shown, the end face of the nail head 11 facing away from the screw part 12 is provided with a plum blossom-shaped countersink 111. The plum blossom-shaped countersink 111 can provide better anti-slip performance, improve the safety of surgical operation, and the plum blossom-shaped countersink 111 can provide greater torque during rotation, thereby increasing fixation stability.

[0053] For example, the medical internal screw 1 can be made of metal materials such as titanium alloy or cobalt-chromium alloy, or the medical internal screw 1 can be made of other materials with lower elastic modulus as needed.

[0054] like Figure 5 As shown, another embodiment of the screw assembly of the present invention includes a medical internal screw 1 and a medical external screw 2. The medical internal screw 1 is the medical internal screw 1 of the present invention. The medical external screw 2 is provided with a mating hole 21. One end of the screw shank 12 away from the screw head 11 is provided in the mating hole 21.

[0055] According to the screw assembly of the present invention, since the outer wall of the screw portion 12 is provided with a cutting groove 14, the cutting groove 14 extends along the length direction of the screw portion 12 and passes through at least part of the external thread 13, a cutting edge can be formed at the junction of the cutting groove 14 and the external thread 13. When the doctor performs revision surgery on the acetabular cup 3 and removes the medical internal screw 1, the cutting edge formed at the junction of the cutting groove 14 and the external thread 13 can cut the remaining medical external screw 2 or bone tissue together with the external thread 13. This makes it easier to remove the medical internal screw 1 and helps to shorten the operation time.

[0056] like Figure 5 As shown, the medical internal screw 1 and the medical external screw 2 are separate structural components that can be connected together. For example, the stability of the connection between the medical internal screw 1 and the medical external screw 2 can be further improved by adding injection molding or adhesive bonding. In addition, since the medical internal screw 1 and the medical external screw 2 are separate structural components, they can be processed independently, saving manufacturing time.

[0057] like Figure 5 and Figure 6 As shown, another embodiment of the acetabular prosthesis of the present invention includes a screw assembly and an acetabular cup 3. The screw assembly is the screw assembly of the present invention. The acetabular cup 3 is provided with a mounting hole (not shown), and the screw head 11 mates with the mounting hole.

[0058] According to the embodiment of the present invention, the acetabular prosthesis has a cutting groove 14 on the outer wall of the screw portion 12. The cutting groove 14 extends along the length of the screw portion 12 and passes through at least part of the external thread 13. Thus, a cutting edge can be formed at the junction of the cutting groove 14 and the external thread 13. When the doctor performs revision surgery on the acetabular cup 3 and removes the medical internal screw 1, the cutting edge formed at the junction of the cutting groove 14 and the external thread 13 can cut the remaining medical external screw 2 or bone tissue together with the external thread 13. This makes it easier to remove the medical internal screw 1 and helps to shorten the operation time.

[0059] Understandably, in the initial hip replacement surgery, according to the preoperative plan, the acetabular cup 3 is implanted into the hip socket to ensure its position and stability. Subsequently, the medical internal screw 1 and the medical external screw 2 are connected and treated as a whole. The screw assembly is aligned with the mounting hole of the acetabular cup 3, and the medical external screw 2 is screwed into the bone tissue by rotating the driving tool in a clockwise direction. The head 11 of the medical internal screw 1 mates with the mounting hole of the acetabular cup 3 to complete the auxiliary fixation of the acetabular cup 3.

[0060] At this point, the screw assembly is in the following state: the head 11 of the medical internal screw 1 is inserted into the mounting hole of the acetabular cup 3, and the medical internal screw 1 is connected to the acetabular cup 3; the medical external screw 2 is fitted into the lateral bone of the acetabular cup 3. After the acetabular cup 3 achieves self-stabilization through bone ingrowth, the medical external screw 2 can be absorbed, thereby reducing the stress on the acetabular cup 3.

[0061] If revision surgery is required, a tool is used to reverse the rotation of the screw head 11. The cutting edge of the cutting groove 14 forms a "barbed cut" with the side wall of the external thread 13, thereby removing the medical internal screw 1 from the acetabular cup 3.

[0062] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0063] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0064] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0065] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0066] In this utility model, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0067] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A medical screw (1) characterized in that, The medical internal screw (1) includes a connected head (11) and a screw portion (12). The head (11) is used to mate with the mounting hole of the acetabular cup (3). The outer wall of the screw portion (12) is provided with an external thread (13) and a cutting groove (14). The cutting groove (14) extends along the length of the screw portion (12) and passes through at least part of the external thread (13).

2. Medical endoscrew (1) according to claim 1, characterized in that The cutting groove (14) passes through the entire external thread (13) along the length of the screw portion (12).

3. Medical endosseous screw (1) according to claim 1, characterized in that The cutting groove (14) is internally threaded, and the thread direction of the cutting groove (14) is consistent with the helical direction of the external thread (13).

4. Medical endoscrew (1) according to claim 1, characterized in that The radial depth of the cutting groove (14) is greater than or equal to the thread height of the external thread (13).

5. Medical endosseous screw (1) according to claim 1, characterized in that In the projection plane orthogonal to the length direction of the screw section (12), the cross-sectional profile of the cutting groove (14) is U-shaped.

6. Medical endosseous screw (1) according to claim 1, characterized in that There are multiple cutting grooves (14), and the multiple cutting grooves (14) are arranged at intervals along the circumference of the screw portion (12).

7. Medical endosseous screw (1) according to claim 1, characterized in that The screw portion (12) has a first end close to the nail head (11) and a second end away from the nail head (11). In the direction from the first end to the second end, the outer diameter of the external thread (13) and the outer diameter of the screw gradually decrease.

8. Medical endoscrew (1) according to any one of claims 1 to 7, characterized in that The tooth profile of the external thread (13) is rectangular or trapezoidal; And / or, the medical internal screw (1) further includes a neck (15), the neck (15) being disposed between the screw head (11) and the screw portion (12), the cross-sectional profile of the neck (15) being circular, and the outer diameter of the neck (15) being smaller than the outer diameter of the screw head (11) and larger than the outer diameter of the external thread (13); And / or, the outer wall surface of the screw head (11) is an arc-shaped surface, and the arc-shaped surface protrudes outward in a direction away from the axis of the medical internal screw (1); And / or, the nail head (11) is provided with a plum blossom-shaped groove (111) on the end face opposite to the screw part (12).

9. A screw assembly, characterized by include: Medical internal screw (1), wherein the medical internal screw (1) is the medical internal screw (1) according to any one of claims 1-8; A medical external screw (2) is provided with a mating hole (21), and the end of the screw part (12) away from the head (11) is located in the mating hole (21).

10. An acetabular prosthesis, characterized in that include: A screw assembly, wherein the screw assembly is the screw assembly of claim 9; An acetabular cup (3) is provided with a mounting hole, and the nail head (11) is engaged with the mounting hole.

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