Patellar absorbable nail cable fixation device

Abstract

This application relates to an absorbable patellar nail-cable fixation device, comprising a hollow bone screw having a cap, a body, and a tip; and a cable having a front fusion section extending from the cap into the body and fixedly connected to both the cap and the body. Both the cable and the hollow bone screw are made of absorbable material. This application achieves patellar fixation and is absorbed by the body after implantation, minimizing harm to the patient.

Description

Technical Field

[0001] The present application belongs to the technical field of medical devices, and in particular relates to a patella absorbable nail cable fixation device. Background Art

[0002] Patellar fractures are common intra-articular fractures, accounting for approximately 1% of all fractures, with an incidence rate of 13.5 per 100,000 person-years. Patellar fractures disrupt the integrity of the patellofemoral joint, impairing knee function and requiring surgical treatment in most cases. The goal of surgery is to restore the flatness of the patellar surface and provide strong fixation to facilitate early functional rehabilitation of the knee. Numerous surgical procedures are available for patellar fractures, with the most common being open reduction and Kirschner wire tension band fixation, proposed by the AO in the 1950s. However, postoperative complications such as peri-incisional pain and pin withdrawal remain high. Furthermore, traditional fixation designs make percutaneous minimally invasive fixation difficult, and prolonged recovery times significantly increase perioperative risks. According to statistical studies, approximately 47% of patients experience symptoms due to internal fixation irritation, and 15% require premature fixation removal due to local complications.

[0003] The mainstream technique for patellar fracture fixation is the tension band technique. Despite decades of development and continuous refinement, clinical case reports indicate suboptimal clinical results. With the continuous advancement of biomechanical research and treatment concepts, domestic and international scholars have attempted to mitigate risks through improved surgical procedures, the invention of new instruments, and robotic navigation.

[0004] A conventional hollow nail-cable locking system for patellar fractures includes a hollow screw, a set screw, and a pull cable. One end of the set screw is threadedly connected to the hollow screw, while the other end of the set screw is fixedly connected to the pull cable. Both the hollow screw and the set screw are made of metal, while the pull cable is made of a metal steel cable or a composite material. This hollow nail-cable locking system requires removal from the body later, which can cause some damage to the patient. Furthermore, due to its material, this hollow nail-cable locking system cannot be absorbed by the body, which can cause local complications and require prior removal, compromising the treatment effect. Summary of the Invention

[0005] In view of the above analysis, embodiments of the present invention aim to provide a patella absorbable nail cable fixation device to solve one or more of the above problems existing in the prior art.

[0006] The object of the present invention is achieved like this:

[0007] A patella absorbable nail cable fixation device, comprising:

[0008] A hollow bone screw, comprising a screw cap, a screw body and a screw tip;

[0009] a cable having a front fusion section extending from the nail cap into the nail body and fixedly connected to both the nail cap and the nail body;

[0010] Wherein, the cables and hollow bone screws are both made of absorbable materials.

[0011] Furthermore, the front fusion section is fixedly connected to the nail cap and the nail body by injection molding.

[0012] Furthermore, the axial length of the nail cap is L1, the axial length of the nail body is L2, the length of the front braided segment is L3, and L3>L1;

[0013] Preferably, L3=L1+(0.8-1.0)×L2.

[0014] Furthermore, the hollow bone screw has a central channel, which passes through the nail cap, the nail body and the nail tip;

[0015] Preferably, the front fusion section is fixed in the channel wall of the central channel.

[0016] Furthermore, the front end fusion section is a hollow cylindrical structure; or, the front end fusion section includes a plurality of scattered single wires, and the plurality of scattered single wires are evenly distributed in the channel wall of the central channel.

[0017] Furthermore, the front end fusion section is a cylindrical hollow tube structure; the front end fusion section includes a front end braiding section, and the front end braiding section is a grid structure woven from multiple single wires.

[0018] Furthermore, the front end braided segment is a cylindrical hollow tube structure; the front end braided segment is a grid structure woven from multiple single wires.

[0019] Furthermore, the length of the nail body is 12-80 mm, the length of the nail cap is 3-8 mm, the diameter of the central channel is 1.2-1.5 mm; the thickness of the side wall of the nail body is 1.3-1.5 mm;

[0020] Preferably, the diameter of the single wire of the front braided segment is 0.1-0.5 mm, the diameter of the front braided segment is 2-3 mm, and the area of a single mesh on the front braided segment is 1-2 mm. 2 .

[0021] Furthermore, the mesh density on the front braided segment gradually increases from the nail tip toward the nail cap.

[0022] Furthermore, the cable also has a rear end braided segment, which is formed by spirally winding multiple single wires, and the rear end braided segment is braided to transition with the front end braided segment.

[0023] Furthermore, it includes an operating hook configured to pass the cable through human tissue along the outer contour of the skeleton;

[0024] Preferably, the operating hook is made of absorbable material, and the operating hook is fixedly connected to the rear end braided segment by injection molding.

[0025] Furthermore, the operating hook is curved, and the arc bending angle of the operating hook fits the outer surface of the bone.

[0026] Furthermore, both the nail cap and the nail body are provided with external threads.

[0027] Furthermore, a first axial groove is provided on the external thread of the nail cap, and the first axial groove axially spans 1-2 threads close to the end of the nail body; a second axial groove is provided on the external thread on the nail body, and the second axial groove axially spans 3-5 threads close to the end of the nail cap; and the first axial groove and the second axial groove are both V-shaped axial grooves as a whole.

[0028] Furthermore, the straight line where the V-shaped tip of the first axial groove and the axis of the hollow bone screw are located are located in a first plane, the straight line where the V-shaped tip of the second axial groove and the axis of the hollow bone screw are located in a second plane, and the angle between the first plane and the second plane is 45°-90°.

[0029] Furthermore, the first axial groove and the second axial groove are both inclined V-shaped axial grooves as a whole, and the notches of the two axial grooves face the screw-up direction of the external threads on the nail cap and the nail body.

[0030] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0031] a) The patellar absorbable nail-cable fixation device provided by the present invention comprises hollow bone nails and cables made of absorbable materials. They are absorbed by the human body after implantation, eliminating the need for surgical removal and reducing harm to the patient.

[0032] b) In the absorbable patellar nail-cable fixation device provided by the present invention, the cable and the hollow bone screw are fixedly connected by injection molding. The front fusion section of the cable has a certain length and is integrated into the side wall of the hollow bone screw, forming an integrated structure with the side wall of the hollow bone screw. This not only ensures that the hollow bone screw has sufficient hardness, but also improves the stability of the connection between the cable and the hollow bone screw.

[0033] c) The absorbable patellar nail-cable fixation device provided by the present invention has a hollow bone screw with an external thread on its cap. Compared with traditional hollow bone screws with external threads only on the nail body, it can be implanted into the patella more smoothly and has better stability after implantation.

[0034] d) In the absorbable patellar nail-cable fixation device provided by the present invention, the external threads of the hollow bone screw cap and the external threads of the screw body are both provided with axial grooves, and the axial grooves in the two parts are staggered. This structural arrangement can increase the self-tapping force when screwing into the bone, reduce resistance, and more conveniently screw into the bone, preventing bone splitting during the screwing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this specification. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0036] Figure 1 A schematic structural diagram of the absorbable patellar nail and cable fixation device provided by the present invention;

[0037] Figure 2 This is a schematic diagram of the disassembled parts of the absorbable patellar nail and cable fixation device provided by the present invention;

[0038] Figure 3 A schematic structural diagram of the front end braided section of the cable provided by the present invention;

[0039] Figure 4 A partial cross-sectional schematic diagram of the patella absorbable nail-cable fixation device provided by the present invention;

[0040] Figure 5 This is a schematic diagram of the partial structure of the hollow bone screw provided by the present invention.

[0041] Reference numerals:

[0042] 1. Hollow bone screw; 11. Nail cap; 111. First axial groove; 12. Nail body; 121. Second axial groove; 13. Nail tip; 14. Center channel; 2. Cable; 21. Front braided section; 22. Rear braided section; 3. Operating hook. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. It should be noted that, in the absence of conflict, the embodiments in this disclosure and the features in the embodiments can be combined, separated, interchanged and / or rearranged with each other. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0044] In the accompanying drawings, the sizes and relative sizes of components may be exaggerated for clarity and / or descriptive purposes. When the exemplary embodiments can be implemented differently, the specific process sequence may be performed in a different order than described. For example, two processes described in succession may be performed substantially simultaneously or in a reverse order from the described order. In addition, the same reference numerals represent the same components.

[0045] The terms used herein are for the purpose of describing specific embodiments and are not intended to be restrictive. As used herein, unless the context clearly indicates otherwise, the singular forms "one (kind, person)" and "said (the)" are also intended to include plural forms. In addition, when the terms "comprise" and / or "include" and their variations are used in this specification, the features, integral bodies, steps, operations, parts, assemblies and / or their groups stated are explained, but the presence or addition of one or more other features, integral bodies, steps, operations, parts, assemblies and / or their groups is not excluded. It should also be noted that, as used herein, the terms "substantially", "approximately" and other similar terms are used as approximate terms and not as degree terms, so that they are used to explain the inherent deviations of the measured values, calculated values and / or the values provided that will be recognized by those of ordinary skill in the art.

[0046] Example 1

[0047] A specific embodiment of the present invention, as Figures 1 to 5 As shown, a patella absorbable nail cable fixation device is disclosed, comprising:

[0048] A hollow bone screw 1, comprising a screw cap 11, a screw body 12 and a screw tip 13;

[0049] A cable 2 having a front fusion section extending from the nail cap 11 into the nail body 12 and fixedly connected to both the nail cap 11 and the nail body 12;

[0050] Wherein, the cable 2 and the hollow bone screw 1 are both made of absorbable materials.

[0051] It should be noted that the front-end fusion section of the cable 2 can be a plurality of scattered single wires, and the plurality of scattered single wires are evenly fused into the side walls of the nail cap 11 and the nail body 12; or, it can be a hollow cylindrical structure with a mesh woven from a plurality of single wires; or, it can be a pre-injection-molded hollow cylindrical structure without a mesh; or, it can be a strip structure, or a grid structure. It is understandable that the front-end fusion section of the cable 2 of the present application can also adopt other forms, as long as at least a part of the front end of the cable 2 is fused into the nail cap and the nail body, it falls within the scope of protection of the present application. Therefore, the front-end fusion section of the cable 2 of the present application includes but is not limited to the above-mentioned structural forms, and front-end fusion sections of various shapes and structures fall within the scope of protection of the present application.

[0052] Exemplarily, the front fusion section of the cable 2 is a hollow cylindrical structure with a mesh formed by braiding multiple single wires. Next, the example of the front fusion section of the cable 2 being a hollow cylindrical structure with a mesh is described in detail. Specifically, the front fusion section of the cable 2 is a front braided section 21. In other words, the cable 2 has a front braided section 21, which is a hollow cylindrical structure. The front braided section 21 extends from the nail cap 11 into the nail body 12 and is fixedly connected to both the nail cap 11 and the nail body 12.

[0053] In this embodiment, the axial length of the nail cap 11 is L1, the axial length of the nail body 12 is L2, the length of the front braided section 21 of the cable 2 is L3, and L3>L1. Preferably, L3=L1+(0.8-1.0)×L2.

[0054] In this embodiment, the hollow bone screw 1 has a central channel 14, which passes through the nail cap 11, the nail body 12 and the nail tip 13. The front end braided segment 21 of the cable 2 is located between the inner wall and the outer wall of the central channel 14. The front end braided segment 21 of the cable 2 is fixed in the channel wall of the central channel 14, that is, the front end braided segment 21 of the cable 2 extends from the side wall of the nail cap 11 to the side wall of the nail body 12, and is fixed to the nail cap 11 and the nail body 12. The front end braided segment 21 of the cable 2 is located in the side walls of the nail cap 11 and the nail body 12, which can not only improve the hardness of the hollow bone screw 1, but also make the connection stability of the cable 2 and the hollow bone screw 1 better.

[0055] In one optional embodiment, the front braided segment 21 of the cable 2 is connected to the hollow bone screw 1 by integral injection molding. Specifically, the front braided segment 21 is fixedly connected to the screw cap 11 and the screw body 12 by integral injection molding. Because the front braided segment 21 at the front of the cable 2 has a certain length, the front braided segment 21 is not connected to the hollow bone screw 1 only at the screw cap 11, but extends all the way into the screw body 12 of the hollow bone screw 1, forming an integral structure with the side wall of the hollow bone screw 1. This not only ensures that the hollow bone screw 1 has sufficient hardness, but also makes the connection between the cable 2 and the hollow bone screw 1 more stable, improves the treatment effect, and eliminates the need to remove the screw later, reducing harm to the patient.

[0056] In this embodiment, the front braided section 21 is a cylindrical hollow tube structure. The front braided section 21 of the cylindrical hollow tube structure is a grid structure formed by weaving multiple single wires, that is, the tube wall of the front braided section 21 is a grid structure. Since the hollow bone screw 1 has different sizes, the length of the nail body 12 of the hollow bone screw 1 is 12-80mm, the length of the nail cap 11 is 3-8mm, the maximum diameter of the external thread on the nail body 12 is 4-5mm, and the diameter of the central channel 14 is 1.2-1.5mm, such as 1.3mm; the side wall thickness of the nail body 12 is 1.3-1.5mm, such as 1.45mm; the parameters of the front braided section 21 are: the diameter of the single wire is 0.1-0.5mm, the diameter of the front braided section 21 of the cylindrical hollow tube structure is 2-3mm, and the area of a single mesh on the front braided section 21 is 1-2mm 2 The above parameter combination can make the hollow bone screw 1 have a sufficiently large hardness, and the connection between the cable 2 and the hollow bone screw 1 is more stable.

[0057] Due to the difference in material properties, if the hollow bone screw 1 is made directly of absorbable material as a whole, its hardness is much lower than that of metal bone screws, and the front end braided segment 21 of the cable 2 is extended from the nail cap 11 to the nail body 12 in the form of injection molding, and is fused with the nail cap 11 and the nail body 12 as a part of the layer, that is, the front end braided segment 21 serves as a part of the side wall of the hollow bone screw 1, which can increase the overall hardness of the nail body 12 to reach a hardness that meets the treatment of patellar fractures; in addition, such a structural setting can also avoid local damage to the hollow bone screw 1 made of absorbable material due to excessive tension of the cable 2, especially avoid the connection between the cable 2 and the nail cap 11 from being pulled apart, thereby ensuring the therapeutic effect of the fixation device.

[0058] In one of the optional embodiments, the mesh density on the front braided segment 21 gradually increases from the nail tip 13 to the nail cap 11, that is, the mesh density near the nail tip 13 is smaller than the mesh density near the nail cap 11, that is, the mesh size near the nail cap 11 is smaller, and the mesh size near the nail tip 13 is larger. In this way, when the cable 2 is subjected to stress, the front braided segment can exert a more balanced pulling force on the entire nail body 12, thereby preventing local stress concentration from causing damage to the connection with the nail body 12 or the nail cap 11, and improving the working stability of the absorbable nail cable fixing device.

[0059] In this embodiment, the cable 2 further includes a rear end braided segment 22 , which is formed by spirally winding a plurality of single wires. The rear end braided segment 22 is braided to transition with the front end braided segment 21 .

[0060] In this embodiment, the absorbable patellar nail and cable system fixation device further includes an operating hook 3, which is fixedly connected to the rear braided segment 22 and configured to guide the cable 2 along the outer contour of the bone through human tissue. The operating hook 3 is also made of an absorbable material and is fixedly connected to the rear braided segment 22 by injection molding. The rear braided segment 22 extends into at least a portion of the operating hook 3. In other words, a portion of the rear braided segment 22 is integrated into the operating hook 3, becoming part of the operating hook 3. This improves the stability of the connection between the rear braided segment 22 and the operating hook 3.

[0061] In one optional embodiment, the operating hook 3 is curved. For example, the arc bending angle of the operating hook 3 can be set to 30 degrees. The curved operating hook 3 fits better with the outer surface of the skeleton and can smoothly complete the threading operation.

[0062] In this embodiment, the cap 11 of the hollow bone screw 1 is provided with an external thread, and the body 12 of the hollow bone screw 1 is also provided with an external thread. This structural arrangement enables the hollow bone screw 1 to be screwed into the patella more smoothly, preventing bone splitting during the screwing process.

[0063] Furthermore, a first axial groove 111 is provided on the external thread of the nail cap 11, and the first axial groove 111 axially spans 1-2 threads near the end of the nail body 12; a second axial groove 121 is provided on the external thread of the nail body 12, and the second axial groove 121 axially spans 3-5 threads near the end of the nail cap 11; and the first axial groove 111 and the second axial groove 121 are both V-shaped axial grooves as a whole, that is, when viewed from one axial side to the other side of the hollow bone screw 1, the first axial groove 111 and the second axial groove 121 are V-shaped axial grooves. The axial groove 121 is V-shaped; the line on which the V-shaped tip of the first axial groove 111 lies and the axis of the hollow bone screw 1 lie in a first plane, while the line on which the V-shaped tip of the second axial groove 121 lies and the axis of the hollow bone screw 1 lie in a second plane, with the angle between the first and second planes being 45°-90°. Furthermore, both the first and second axial grooves 111, 121 are inclined V-shaped axial grooves as a whole, with the notches of both axial grooves facing the direction of the external threads on the nail cap 11 and nail body 12. By providing axial grooves with the aforementioned structural parameters on the nail cap 11 and nail body 12, the self-tapping force during screwing into the bone is increased, the resistance is reduced, and screwing into the bone is more convenient, preventing bone splitting during the screwing process.

[0064] In this embodiment, the absorbable material includes but is not limited to absorbable polylactic acid composite materials and absorbable polycaprolactone and other medical materials with certain hardness, plasticity and degradability, which can achieve good fixation effect after the operation while reducing adverse effects on the human body.

[0065] It should be noted that the injection molding mold used is compatible with the outer contours of the hollow bone screw 1 and the operating hook 3. The injection molding mold includes a first cavity for molding the hollow bone screw 1 and a second cavity for molding the operating hook 3. When preparing the patellar absorbable nail cable fixation device, the cable 2 is first braided. The length of the front braided segment 21 of the cable 2 and the mesh density and other parameters are determined based on the size parameters of the hollow bone screw 1. After the cable 2 is braided, the cable 2 is loaded into the injection molding mold, so that the front braided segment 21 of the cable 2 extends into the first cavity and a portion of the rear braided segment of the cable 2 extends into the second cavity. Liquid absorbable material is injected into the first and second cavities. After solidification and molding, the patellar absorbable nail cable fixation device is obtained.

[0066] When using the patella absorbable nail-cable fixation device, firstly, a Kirschner wire is driven into the bone to be fixed, and then a hollow bone screw 1 is sleeved onto the Kirschner wire and screwed into a predetermined position in the bone.

[0067] Compared with the prior art, the absorbable patellar nail and cable fixation device provided in this embodiment has the following beneficial effects:

[0068] 1. Hollow bone screws and cables are made of absorbable materials and can be absorbed by the human body after implantation. There is no need for surgery to remove them, which reduces harm to patients.

[0069] 2. The cable and the hollow bone screw are integrally formed by injection molding. The front fusion section of the cable has a certain length and is integrated into the side wall of the hollow bone screw. This not only ensures that the hollow bone screw has sufficient hardness, but also improves the connection stability between the cable and the hollow bone screw.

[0070] 3. The nail cap of the hollow bone screw is provided with an external thread. Compared with the traditional hollow bone screw which only has an external thread on the nail body, it can be implanted into the patella more smoothly and has better stability after implantation into the patella.

[0071] 4. Axial grooves are provided on the external threads of the hollow bone screw cap and the external threads on the screw body, and the axial grooves at the two locations are staggered. This structural setting can increase the self-tapping force when screwing into the bone, reduce the resistance, make it easier to screw into the bone, and prevent bone splitting during the screwing process.

[0072] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of this application. It should be understood that the above description is only the specific implementation methods of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application.

Claims

1. A patellar absorbable nail cable fixation device, characterized in that: It comprises an integrally formed hollow bone screw (1) and a cable (2); the cable (2) and the hollow bone screw (1) are both made of an absorbable polylactic acid composite material or an absorbable polycaprolactone material; The hollow bone screw (1) comprises a screw cap (11), a screw body (12), a screw tip (13) and a central channel (14); the cable (2) comprises a front fusion section, the front fusion section extending from the screw cap (11) into the screw body (12) and fixedly connected to the screw cap (11) and the screw body (12); the front fusion section is integrated with the side wall of the hollow bone screw (1); Wherein, the front fusion section is integrated into the channel wall fixed to the central channel (14); The front fusion section is a cylindrical hollow tube structure; the front fusion section includes a front braided section (21), and the cable (2) further has a rear braided section (22), the front braided section (21) is a grid-like structure woven from a plurality of single wires; the mesh density on the front braided section (21) gradually increases from the nail tip (13) to the nail cap (11); the rear braided section (22) is formed by spirally winding a plurality of single wires, and the rear braided section (22) and the front braided section (21) are braided in transition; The length of the nail body (12) is 12-80 mm, and the thickness of the side wall is 1.3-1.5 mm; the length of the nail cap (11) is 3-8 mm; the diameter of the central channel (14) is 1.2-1.5 mm; the diameter of the single wire of the front braided section (21) is 0.1-0.5 mm, the diameter of the front braided section (21) is 2-3 mm, and the area of a single mesh on the front braided section (21) is 1-2 mm. 2 .

2. The absorbable patellar nail cable fixation device according to claim 1, characterized in that: The front fusion section is fixedly connected to the nail cap (11) and the nail body (12) by injection molding.

3. The absorbable patellar nail cable fixation device according to claim 1, characterized in that: The axial length of the nail cap (11) is L1, the axial length of the nail body (12) is L2, the length of the front fusion section is L3, and L3>L1.

4. The absorbable patellar nail cable fixation device according to claim 3, characterized in that: L3=L1+(0.8~1.0)×L2.

5. The absorbable patellar nail cable fixation device according to claim 4, characterized in that: The central channel (14) passes through the nail cap (11), the nail body (12) and the nail tip (13).

6. The absorbable patellar nail cable fixation device according to claim 1, characterized in that: It also includes an operating hook (3) configured to pass the cable (2) through human tissue along the outer contour of the skeleton.

7. The absorbable patellar nail cable fixation device according to claim 6, characterized in that: The operating hook (3) is made of absorbable material, and the operating hook (3) is fixedly connected to the rear end braided section (22) by injection molding.

8. The absorbable patellar cable fixation device according to claim 7, characterized in that: The operating hook (3) is curved, and the arc bending angle of the operating hook (3) fits the outer surface of the bone.

9. The absorbable patellar cable fixation device according to claim 1, characterized in that: The nail cap (11) and the nail body (12) are both provided with external threads; The external thread of the nail cap is provided with a first axial groove, and the external thread of the nail body is provided with a second axial groove, and the first axial groove and the second axial groove are both inclined V-shaped axial grooves as a whole, and the notches of the two axial grooves face the screw-up direction of the external threads of the nail cap and the nail body; The straight line where the V-shaped tip of the first axial groove and the axis of the hollow bone screw are located are located in a first plane, and the straight line where the V-shaped tip of the second axial groove and the axis of the hollow bone screw are located in a second plane. The angle between the first plane and the second plane is 45°-90°.

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