Interface screw

Abstract

This invention relates to an interface screw, comprising a screw head, a screw shaft, and a screw tip connected sequentially along the axial direction. The screw shaft has a first threaded section and a helical fixing structure. One end of the first threaded section extends to the screw head. The helix of the helical fixing structure extends from the other end of the first threaded section toward the screw tip along the helical extension line of the first threaded section. The helical fixing structure includes multiple fixing parts, which are spaced apart along the helix of the helical fixing structure. When implanted into a bone tunnel, the spaced-apart fixing parts of this invention can reduce rotational friction on the ligaments, thereby reducing ligament damage. After implantation into the medullary tract, the uneven compressive force exerted on the ligaments by the bonding forces between the multiple fixing parts and the bone makes it easier for the ligaments to embed into the bone within the bone tunnel, improving the ligament fixation effect.

Description

Technical Field

[0001] This invention relates to the field of orthopedic medical devices, and in particular to an interface screw. Background Technology

[0002] When the anterior and posterior cruciate ligaments of the human knee joint are damaged, the damaged ligaments need to be reconstructed and fixed. Currently, clinicians commonly use interface screws to fix the ligaments in the bone tunnel by compression.

[0003] However, in order to improve the stability of ligament fixation, traditional interface screws need to be equipped with locking threads to compress and fix the ligament. During the process of screwing into the bone tunnel, the threads of the traditional interface screw will generate a large rotational friction, which will cause varying degrees of damage to the ligament. The greater the tightening force of the interface screw, the greater the damage to the ligament. Summary of the Invention

[0004] Based on this, an interface screw is provided to solve the problem of how to ensure effective fixation of ligaments while reducing damage to ligaments.

[0005] This invention provides an interface screw for fixing a ligament to the bone marrow tract. The interface screw includes a screw head, a screw shaft, and a screw tip connected sequentially along the axial direction. The screw shaft has a first threaded section and a helical fixing structure. One end of the first threaded section extends to the screw head. The helix of the helical fixing structure extends from the other end of the first threaded section toward the screw tip along the helical extension line of the first threaded section. The helical fixing structure includes multiple fixing parts, which are spaced apart along the helix of the helical fixing structure. When the interface screw is implanted into the bone tunnel, the multiple fixing parts are used to generate bonding force with the bone tissue of the bone tunnel, thereby fixing the ligament to the bone marrow tract.

[0006] In one embodiment, the fixation part includes a hole, and when the interface screw is implanted into the bone tunnel, the bone tissue of the bone tunnel can be embedded in the hole so that the fixation part and the bone tissue of the bone tunnel can form a bonding force.

[0007] In one embodiment, the fixation portion includes protrusions that, when the interface screw is implanted into the bone tunnel, embed the protrusions into the bone to create a bonding force between the fixation portion and the bone tunnel, and at least a portion of the ligament is embedded between adjacent protrusions.

[0008] In one embodiment, the plurality of protrusions are divided by threads with the same pitch and helix angle as the first thread segment, and / or the plurality of protrusions are equally spaced, with the spacing between adjacent protrusions being 0.5cm to 1.5cm.

[0009] In one embodiment, the thread height corresponding to the protrusion is greater than or equal to the thread height of the first thread segment.

[0010] In one embodiment, the portion of the protrusion facing away from the screw is spherical, or the protrusion is a sphere.

[0011] In one embodiment, the helix of the helical fixing structure extends to the tip of the screw.

[0012] In one embodiment, the screw is provided with a second threaded section, and the helical fixing structure is located between the first threaded section and the second threaded section along the axial direction of the interface screw.

[0013] In one embodiment, the pitch of the first threaded segment is equal to the pitch of the second threaded segment, and / or the helix angle of the first threaded segment is equal to the helix angle of the second threaded segment.

[0014] In one embodiment, the screw is provided with a second threaded section, wherein the helix of the first threaded section and its helix extension are spaced apart from each other along the axial direction of the interface screw from the helix of the second threaded section.

[0015] In one embodiment, the second threaded segment extends from the screw head to the screw tip; or, one end of the second threaded segment extends to the screw head, and the other end is also provided with the spiral fixing structure along its helical extension line.

[0016] In one embodiment, the screw tip includes a tapered body and a through hole penetrating the end face of the tapered body. The interface screw has a through hole that extends from the end face of the screw head to the tapered body along the axial direction of the interface screw and communicates with the through hole. The diameter of the through hole is larger than the diameter of the through hole.

[0017] The aforementioned interface screw employs a spiral fixation structure with multiple fixation parts arranged at intervals. This reduces rotational friction on the ligaments during implantation into the bone tunnel, thereby minimizing ligament damage. Simultaneously, the fixation parts can bond with the bone tissue of the bone tunnel. Due to the interval arrangement of the multiple fixation parts, the bonding force between the fixation parts and the bone tissue appears as multiple discontinuous bonding points along the spiral fixation structure, resulting in uneven compression force on the ligaments. This makes it easier for the ligaments to embed into the bone tissue inside the bone tunnel, improving the ligament fixation effect. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the interface screw of the present invention;

[0020] Figure 2 This is a schematic diagram of another embodiment of the interface screw of the present invention;

[0021] Figure 3 This is a schematic diagram of another embodiment of the interface screw of the present invention;

[0022] Figure 4 for Figure 3 The diagram shown illustrates the structure of the interface screw removal spiral fixing structure.

[0023] Figure 5 This is a schematic diagram of the structure of an interface screw according to another embodiment of the present invention;

[0024] Figure 6 This is a schematic diagram of the structure of an interface screw according to another embodiment of the present invention;

[0025] Figure 7 This is a schematic diagram of the structure of an interface screw according to another embodiment of the present invention;

[0026] Figure 8 This is an axial cross-sectional view of an interface screw according to one embodiment.

[0027] Reference numerals: 10, screw head; 10a, drive hole; 20, screw; 20a, hole; 21, first threaded section; 22, spiral fixing structure; 22a, protrusion; 22b, convex ball; 22c, hole; 23, second threaded section; 30, screw tip; 30a, through hole; 30b, conical body. Detailed Implementation

[0028] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0029] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," 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 or an electrical connection; 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 invention according to the specific circumstances.

[0030] It should be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0031] See Figure 1 As shown, an embodiment of the present invention provides an interface screw for fixing a ligament to the bone marrow tract. The interface screw includes a screw head 10, a screw 20, and a screw tip 30 connected sequentially along the axial direction. The screw head 10 is provided with a drive hole 10a, which can be in the shape of a straight line, a cross, a regular polygon, or a star shape, to facilitate cooperation with an operating instrument used to implant the interface screw into the bone marrow tract and provide rotational torque for the interface screw. The screw 20 is provided with a first threaded section 21 and a helical fixing structure 22. One end of the first threaded section 21 extends to the screw head 10. The helix of the helical fixing structure 22 extends from the other end of the first threaded section 21 toward the screw tip 30 along the helical extension line of the first threaded section 21. The helical fixing structure 22 includes multiple fixing parts, which are arranged at intervals along the helix of the helical fixing structure 22. When the interface screw is implanted into the bone tunnel, the multiple fixing parts are used to generate bonding force with the bone tissue of the bone tunnel, thereby fixing the ligament to the bone marrow tract. It can be understood that the overall structure of the spiral fixing structure 22 extends in a spiral manner similar to a thread. Accordingly, the spiral line of the spiral fixing structure 22 refers to the path of the multiple fixing parts of the spiral fixing structure 22 arranged in a spiral manner. To be precise, the multiple fixing parts are arranged in a spiral shape to form the spiral fixing structure 22.

[0032] Because the multiple fixation parts of the spiral fixation structure 22 are arranged at intervals, rotational friction on the ligament can be reduced when the interface screw is implanted into the bone tunnel, thereby reducing ligament damage. At the same time, the fixation parts can also form a bonding force with the bone tissue of the bone tunnel. Based on this interval arrangement of the multiple fixation parts, the bonding force between the multiple fixation parts and the bone tissue presents as multiple discontinuous bonding force points along the spiral line of the spiral fixation structure 22, resulting in uneven compression force on the ligament. In this way, the ligament is more easily embedded into the bone tissue inside the bone tunnel, improving the fixation effect on the ligament.

[0033] Continue reading Figure 1 As shown, in some embodiments, the fixing part includes protrusions 22a, in which multiple protrusions 22a extend toward the screw tip 30 along the helical extension line of the first threaded segment 21. Based on the fact that the interior of human bone is cancellous bone, while the area near the bone surface is cortical bone, cortical bone can provide greater counter-pressure. Therefore, the first threaded segment 21, located at the end of the interface screw near the screw head 10, can achieve a more stable fixing effect. Multiple spaced protrusions 22a are located at the end near the screw tip 30. When the interface screw is implanted into the bone tunnel, the multiple protrusions 22a embed into the bone, thereby achieving bonding force with the bone tissue of the bone tunnel, and at least a portion of the ligament is embedded between adjacent protrusions 22a. The ligament compressed by the protrusions 22a will stably embed into the bone tissue, while the portion of the ligament located between the protrusions 22a experiences less compressive force. Therefore, the multiple protrusions 22a generate uneven compressive force on the ligament, ultimately embedding the ligament into the bone tissue inside the bone tunnel, thereby achieving more effective bone fixation.

[0034] Furthermore, more precisely, the surface of the portion of protrusion 22a facing away from the screw 20 is spherical, or protrusion 22a is a sphere. For example, in combination with Figure 2 As shown, the fixing part includes a convex ball 22b, which makes the contact surface between the spiral fixing structure 22 of the interface screw and the ligament a smooth transition without producing sharp corners, thereby reducing the chance of damaging the ligament.

[0035] In some embodiments, multiple protrusions 22a are formed by threads with the same pitch and helix angle as the first threaded segment 21. In this way, multiple protrusions 22a can extend along the helical extension line of the first threaded segment 21 to implant the interface screw into the medullary tract. At the same time, the protrusions 22a are formed by thread division, which reduces manufacturing difficulty and effectively reduces processing costs.

[0036] The multiple protrusions 22a can be equally spaced, with the distance between adjacent protrusions 22a ranging from 0.5cm to 1.5cm, such as 0.5cm, 0.7cm, 0.9cm, 1.1cm, 1.3cm, or 1.5cm. Appropriate spacing of the protrusions 22a helps ensure the fixation effect between the spiral fixation structure 22 and the bone tunnel, while also providing sufficient space to avoid ligaments, thereby reducing the chance of ligament damage.

[0037] The thread height corresponding to the protrusion 22a is greater than or equal to the thread height of the first threaded segment 21. Therefore, during the implantation of the interface screw into the medullary tract, multiple protrusions 22a can spirally enter the medullary tract first, forming corresponding internal threads on the sidewall of the medullary tract, allowing the first threaded segment 21 to smoothly screw into the medullary tract. Because the multiple protrusions 22a are spaced apart, bone fragments accumulate in the gaps between them. These bone fragments heal more easily with the bone tissue of the bone tunnel, thereby creating a bonding force between the fixation part and the bone tissue of the bone tunnel. This restricts the rotation, posterior-posterior movement, and slippage of the interface screw, improving the fixation effect on the ligament.

[0038] like Figure 1 and Figure 2 As shown, the spiral of the spiral fixation structure 22 extends to the screw tip 30, thereby squeezing the ligament as deep as possible into the bone tunnel to fix it to the bone inside the bone tunnel.

[0039] In some implementations, combined Figure 3 As shown, the fixation part includes a hole 22c. When the interface screw is implanted into the bone tunnel, the bone tissue of the bone tunnel can be embedded in the hole 22c so that the fixation part and the bone tissue of the bone tunnel can form a bonding force.

[0040] In order to improve the bonding force between the interface screw and the bone tunnel, the screw 20 may include other threaded segments in addition to the first threaded segment 21. The number of threaded segments may be two or more. The structure of the interface screw is further explained below with the example of the screw 20 having two threaded segments. Specifically, the screw 20 is provided with a second threaded segment 23.

[0041] Along the axial direction of the interface screw, the helical fixing structure 22 is located between the first threaded segment 21 and the second threaded segment 23. In this embodiment, the helical fixing structure 22 extends from the first threaded segment 21 to the second threaded segment 23. Since one end of the first threaded segment 21 extends to the screw head 10, the second threaded segment 23 is closer to the screw tip 30 than the helical fixing structure 22. Therefore, during the process of implanting the interface screw into the bone tunnel, the second threaded segment 23 screws into the bone marrow tract first, thereby guiding the helical fixing structure 22 into the bone marrow tract, making it easier for the interface screw to be implanted into the bone marrow tract.

[0042] Furthermore, the pitch of the first threaded section 21 is equal to the pitch of the second threaded section 23 to simplify the interface screw structure and facilitate machining.

[0043] In some embodiments, the thread helix angle of the first threaded segment 21 and the thread helix angle of the second threaded segment 23 are equal, so that when the interface screw is implanted into the bone marrow tract, the threads left by the second threaded segment 23 on the side wall of the bone marrow tract can easily guide the first threaded segment 21 into the bone marrow tract.

[0044] It should be noted that the second threaded segment 23 on the screw 20 may not be arranged along the helical extension line of the first threaded segment 21. For example, in some embodiments, combined with Figure 4 As shown, to facilitate the distinction between the first threaded section 21 and the second threaded section 23, Figure 4 The interface screw shown has the helical fixing structure 22 removed. In this embodiment, along the axial direction of the interface screw, the helix of the first threaded segment 21 and its helical extension are spaced apart from the helix of the second threaded segment 23, thus forming a double-threaded structure on the interface screw, thereby increasing the lead and facilitating rapid guidance of the interface screw for implantation into the bone marrow tract.

[0045] Furthermore, combined Figure 5 As shown, the second threaded segment 23 extends from the screw head 10 to the screw tip 30, thereby forming a double-threaded configuration with other threaded segments on the screw 20 along the entire axial direction of the interface screw, thus improving the lead. Figure 5 As shown, when multiple fixing parts of the thread fixing structure 22 are protrusions 22a on the helical extension line of the first thread segment 21, the helical lines where the multiple protrusions 22a are located are also spaced apart from the helical lines of the second thread segment 23. It can be understood that the interval between the helical lines where the multiple protrusions 22a are located and the helical lines of the second thread segment 23 is equal to the interval between the helical lines of the first thread segment 21 and the second thread segment 23.

[0046] Preferably, combined with Figure 6 As shown, the fixing part can be a convex ball 22b, so that the contact surface between the spiral fixing structure 22 of the interface screw and the ligament is smoothly transitioned and no sharp corners are generated, thereby reducing the chance of damage to the ligament.

[0047] It should be noted that among the multiple fixation parts of the spiral fixation structure 22, only some fixation parts are holes 22c, while the others are protrusions 22a. As long as the fixation part and the bone tissue of the bone tunnel bond together when the interface screw is implanted into the bone tunnel, it is sufficient.

[0048] Taking a screw 20 with a first threaded section 21 and a second threaded section 23 as an example, in an embodiment where the helix of the first threaded section 21 and the helix of the second threaded section 23 are spaced apart, the second threaded section 23 may not extend to the screw tip 30. In some embodiments, one end of the second threaded section 23 extends to the screw head 10, and the other end is also provided with a helical fixing structure 22 along its helical extension line. Specifically, in conjunction with Figure 7As shown, multiple fixing parts, namely protrusions 22a, are provided on the helical extension line of the first threaded segment 21. Multiple holes 22c and multiple convex balls 22b are sequentially provided on the helical extension line of the second threaded segment 23. This structural design not only allows the interface screw to form a double-helix structure with a large lead, facilitating quick implantation into the bone marrow tract and reducing surgical time and patient suffering; but also, the multiple holes 22c and multiple convex balls 22b on the helical extension line of the second threaded segment 23 can reduce damage to the bone or ligaments, and the multiple holes 22c and multiple convex balls 22b utilize the bonding force between themselves and the bone tissue of the bone tunnel, improving the stability of ligament fixation within the bone marrow tract.

[0049] It should be noted that the multiple holes 22c and multiple protruding balls 22b provided on the helical extension line of the second threaded section 23 can be alternately arranged, or they can be respectively provided on different sections of the screw 20. For example, as Figure 7 As shown, multiple holes 22c are spaced apart between the second threaded section 23 and the protruding ball 22b closest to the screw head 10. At this time, the multiple protruding balls 22b are spaced apart along the helical extension line of the second threaded section 23, following the hole 22c furthest from the screw head 10. Thus, because the multiple protruding balls 22b are closer to the screw tip 30, when the interface screw is implanted into the bone tunnel, the multiple protruding balls 22b cooperate with the sidewall of the bone tunnel, making it easier and more stable for the interface screw to enter the bone tunnel.

[0050] In some embodiments, the first threaded section 21 is provided only on the part of the screw 20 near the screw head 10, and the helical fixing structure 22 is provided on the other parts of the screw 20.

[0051] Combination Figure 8 As shown, for ease of understanding, the interface screw is divided along its axial direction into a thread head section A, a thread middle section B, and a thread tail section C. The screw head 10 and the first thread section 21 are both located in the thread head section A, the screw tip 30 is located in the thread tail section C, and the spiral fixing structure 22 is set in the thread middle section B and the thread tail section C.

[0052] With this structural design, the first threaded section 21 or the double-threaded structure (i.e., the axially corresponding parts of the first threaded section 21 and the second threaded section 23 of the interface screw) located at the thread head section A can more easily form a greater clamping force with the harder cortical bone of the human skeleton, making it easier for the screw head 10 to clamp the ligament. The multiple fixing parts located at the middle section B and the tail section C of the thread can, on the one hand, provide rotational guidance for the screw insertion of the interface screw, and on the other hand, when the fixing part is a protrusion 22a, the surface protrusion 22a will generate greater stress, thus making it easier to embed into the softer cancellous bone, increasing the fixation strength. The gaps between the discontinuous protrusions 22a will accumulate bone fragments, which are more likely to heal with the bone tissue of the bone tunnel. Subsequently, the fixing part and the bone tissue of the bone tunnel will form a bonding force to restrict the rotation, forward and backward movement and slippage of the interface screw, thereby improving the fixation effect on the ligament. Correspondingly, when the fixation part is hole 22c, it can also reduce the damage to the ligament during the implantation of the interface screw into the bone tunnel and promote the growth of soft tissue, so that the bone of the bone tunnel can be embedded in hole 22c to generate bonding force, thereby limiting the rotation, forward and backward movement and slippage of the interface screw and improving the fixation effect on the ligament.

[0053] The screw tip 30 includes a conical body 30b and a perforation 30a penetrating the end face of the conical body 30b, thereby enabling the screw tip 30 to easily enter the bone marrow tract and facilitate the implantation of the guide screw.

[0054] Continue reading Figure 8 As shown, the interface screw has a through hole 20a, which extends along the axial direction of the interface screw from the end face of the screw head 10 to the conical body 30b and connects with the perforation 30a. This allows bone debris to enter the through hole 20a through the perforation 30a when the interface screw is implanted into the bone marrow tract, reducing the amount of bone debris between the interface screw and the inner wall of the bone marrow tract and minimizing compression of the bone marrow tract during implantation. The diameter of the through hole 20a is larger than that of the perforation 30a to ensure the structural strength of the conical body of the screw tip 30.

[0055] It should be noted that the screw head 10 can be flat, round, or countersunk. In some embodiments, the through hole 20a penetrates the end face of the screw head 10, forming a drive hole 10a.

[0056] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0057] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An interference screw for securing a ligament to a medullary canal, characterized by, The interface screw includes a screw head, a screw shaft, and a screw tip connected sequentially along the axial direction. The screw shaft has a first threaded section and a helical fixing structure. One end of the first threaded section extends to the screw head, and the other end of the first threaded section is spaced apart from the screw tip along the axial direction of the interface screw. The helical line of the helical fixing structure extends from the other end of the first threaded section toward the screw tip along the helical extension line of the first threaded section. The helical fixing structure includes multiple fixing parts, which are spaced apart along the helical line of the helical fixing structure. When the interface screw is implanted into the bone tunnel, the multiple fixing parts are used to generate bonding force with the bone of the bone tunnel, so that the ligament is fixed to the medullary canal. The fixing parts include protrusions. When the interface screw is implanted into the bone tunnel, the multiple protrusions are embedded in the bone to generate bonding force between the fixing parts and the bone of the bone tunnel, and at least a portion of the ligament is embedded between adjacent protrusions. The surface of the protrusion facing away from the screw shaft is spherical, or the protrusion is a sphere.

2. The interface screw of claim 1, wherein, The fixation part includes a hole, and when the interface screw is implanted into the bone tunnel, the bone tissue of the bone tunnel can be embedded in the hole so that the fixation part and the bone tissue of the bone tunnel can form a bonding force.

3. An interface screw according to claim 1 or 2, wherein, The plurality of protrusions are formed by threads with the same pitch and helix angle as the first threaded segment.

4. The interface screw of claim 3, wherein, The protrusions are arranged at equal intervals, with the distance between adjacent protrusions being 0.5cm to 1.5cm.

5. The interface screw of claim 3, wherein, The thread height corresponding to the protrusion is greater than or equal to the thread height of the first thread segment.

6. The interface screw of claim 1, wherein, The spiral of the spiral fixing structure extends to the tip of the screw.

7. The interface screw of claim 1, wherein, The screw is provided with a second threaded section, and the helical fixing structure is located between the first threaded section and the second threaded section along the axial direction of the interface screw.

8. The interface screw according to claim 7, characterized in that, The pitch of the first thread segment is equal to the pitch of the second thread segment, and / or the helix angle of the first thread segment is equal to the helix angle of the second thread segment.

9. The interface screw of claim 1, wherein, The screw is provided with a second threaded section, and the helix of the first threaded section and its helix extension are spaced apart from each other along the axial direction of the interface screw and the helix of the second threaded section.

10. The interface screw of claim 9, wherein, The second threaded segment extends from the screw head to the screw tip; or, one end of the second threaded segment extends to the screw head, and the other end is also provided with the spiral fixing structure along its spiral extension line.

11. The interface screw of claim 1, wherein, The screw tip includes a tapered body and a through hole penetrating the end face of the tapered body. The interface screw has a through hole that extends from the end face of the screw head to the tapered body along the axial direction of the interface screw and communicates with the through hole. The diameter of the through hole is larger than the diameter of the through hole.

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