Expandable sleeve for preventing bone nail from loosening

Abstract

The invention discloses an expandable sleeve for preventing a bone nail from loosening, which comprises a circular tube-shaped main body, the inner diameter of the circular tube-shaped main body is matched with that of a bone nail body, the circular tube-shaped main body is used for wrapping the bone nail body, and the expandable sleeve is characterized in that the circular tube-shaped main body is made of a bioinert and non-biodegradable material; a plurality of openings are formed in the side wall of one end of the circular tube-shaped main body. The invention further discloses a corresponding bone nail. According to the expandable sleeve capable of preventing the bone nail from loosening, after the bone nail is implanted, the fixing strength of the bone nail and a prosthesis is not changed, the using function of the bone nail and the prosthesis is guaranteed, meanwhile, the tail end of the expandable sleeve expands and deforms, the contact and acting force between the expandable sleeve and an implanted bone are effectively increased, and non-bacterial loosening is avoided; the product provided by the invention can effectively improve the use effect and prolong the service life of the bone nail and the implant.

Description

Technical Field

[0001] The invention relates to a bone screw sleeve, in particular to an expandable sleeve for preventing the bone screw from loosening, and belongs to the technical field of medical devices. Background Art

[0002] Bone screws are non-active surgical metal implants for bone joining, including cortical bone screws and cancellous bone screws, which have full threads and half threads respectively. They are widely used in dental implants, orthodontics, revision surgery, joint fusion, stabilization of new fractures and bone reconstruction. Metal materials are early studied biomaterials. They have good tensile strength and toughness and are particularly suitable for repairing hard tissue defects in the body. Commonly used metal materials include stainless steel, cobalt-chromium alloy, titanium alloy and magnesium alloy. Among them, stainless steel and cobalt-chromium alloy were first used in clinical orthopedics and achieved good results. Stainless steel is inexpensive and has good mechanical properties. It is currently widely used in clinical applications, but it has the problem of poor corrosion resistance. Cobalt-chromium alloy has good wear resistance, but its biological toxicity cannot be ignored. Subsequently, inert metal titanium and titanium alloys were used in the field of orthopedics. They have no effect on the adhesion and growth of osteoblasts and have strong mechanical properties. However, the elastic modulus of titanium alloy does not match that of natural bone tissue, which is much stronger than the mechanical properties of bone. When implanted in the body, it will produce a stress shielding effect on the surrounding bone tissue, causing poor growth or even degeneration of bone tissue due to lack of stress stimulation. In addition, during the service process, the bone screws are worn with the bones, and the particles produced interact with the surrounding bone tissue cells, causing chronic inflammatory reactions and aseptic loosening, which affects the patient's prognosis. Its occurrence mechanism is complex, including wear particles, autophagy, stress shielding, etc. The most important reason is the abnormal bone metabolism induced by wear particles, which causes bone loss. Especially for patients with osteoporosis, the risk of bone screw loosening may be increased. Osteoporosis is a disease in which bone density decreases, causing bones to become brittle and fragile. In orthopedic surgery, bone screws are implanted into bones. If osteoporosis causes bones to become brittle, the bones cannot provide sufficient support for the bone screws, which will cause the bone screws to loosen. In view of the above clinical status and needs, it is urgent to develop instruments and related materials for preventing bone screw loosening, and provide means and strategies for the prevention and treatment of bone screw loosening.

[0003] Chinese invention patent CN116833425A discloses a new type of titanium alloy orthopedic implant based on additive manufacturing and its manufacturing method, which applies lattice structure to orthopedic implants to form biological combination between orthopedic implants and host bones at their meshing surfaces, and new bone tissue can grow into the surface of the porous structure to avoid implant loosening, reduce stress effects, extend the service life of the implant, and significantly promote fracture healing; Chinese invention patent CN113017809A discloses an orthopedic reduction nail locker, including a fixed plate and a sliding block with a slide groove fixed on the inner side, a threaded through hole opened on the inner side and connected to a bone screw, a column tube fixed to the upper end face of the bone screw, and a gasket, a convex nut and a concave nut are respectively threadedly connected to the outer surface. Both sides of the fixed plate are threadedly connected to the fixed block, and the lower end face is sutured with a binding. The invention facilitates the alignment of the fractured ends of the patient's bones, can fix the upper end of the bone screw, and is not easy to loosen. At the same time, it can prevent the bone screw from pulling the patient's bones and causing pain to the patient, which is beneficial to the patient's recovery. Chinese utility model patent CN213217529U discloses an anti-loosening degradable bone screw, including a rod and a top cap, which is fixed at one end of the rod, and the other end is provided with a thread and a plurality of anti-retraction grooves to prevent the bone screw from rotating in the opposite direction and becoming loose, and can introduce the bone powder squeezed out of the thread into the bone powder hole through the introduction hole. After the bone screw is absorbed, the stored bone powder can fill the bone hole, thereby improving the healing effect.

[0004] Chinese utility model patent CN219374882U discloses an anti-loosening bone screw, the main body of which includes a front nail blade, a middle rod body and a tail end that are integrally arranged. A back-stop slot is opened on the outer side of the middle rod body, and the bottom of the slot extends to the front nail blade. An adaptive back-stop plug-in is arranged inside the slot, and a fixing component is arranged between the main body of the bone screw. The fixing assembly includes a circular groove provided on the tail end, a threaded core hole provided at the bottom center of the circular groove, a sleeve provided on the inner side of the anti-recession plug-in and a positioning screw inserted in the sleeve. The anti-recession slot and the anti-recession plug-in can cooperate with each other to prevent the reverse rotation of the bone screw thread structure due to the patient's limb movement, thereby preventing the bone screw and the fracture positioning piece from loosening, and ensuring the stable support of the fracture positioning piece to the fracture site; Chinese utility model patent CN217014288U discloses a denture with an anti-detachment function, including an implant and a denture body, a base is detachably mounted on the body, a fastening platform is provided between the body and the implant, a denture connecting part fixedly connected to the denture body and a spiral connecting part fixedly connected to the denture connecting part are threadedly connected to the implant. By providing the fastening platform, the implant implanted on the alveolar bone can be prevented from loosening, thereby overcoming the defect that the denture fixed by a threaded connection of the implant is easily detached due to torsion, which is not conducive to use. Summary of the invention

[0005] The object of the present invention is to provide an expandable sleeve for preventing bone screws from loosening.

[0006] The technical solution adopted by the present invention is:

[0007] An expandable sleeve for preventing a bone screw from loosening comprises a circular tubular body, the inner diameter of which matches the bone screw body and is used to wrap the bone screw body. The circular tubular body is made of a bio-inert and non-biodegradable material, and one end of the circular tubular body is provided with a plurality of openings on the side wall.

[0008] Preferably, the bio-inert and non-biodegradable material is polyetheretherketone (PEEK), polyethersulfone (PES), titanium, peptide alloy, stainless steel, or a composite material or a mixed material thereof.

[0009] Preferably, the biologically inert and non-biodegradable material is polyetheretherketone, with a number average molecular weight (M n ) is 3*10 4 ~60*10 4 .

[0010] Preferably, the number average molecular weight of the polyetheretherketone is 20×10 4 .

[0011] Preferably, the length of the opening accounts for 10% to 90% of the total length of the circular tubular body.

[0012] Preferably, the length of the opening accounts for 40% of the total length of the circular tubular body.

[0013] Preferably, the number of the openings is between 1 and 10.

[0014] The processing methods of the expandable sleeve include, but are not limited to, injection molding, extrusion, solution processing, powder hot melt die casting, cutting, die casting, additive manufacturing, 3D printing, spinning, etc. Among them, mold injection molding is preferred, and melt injection molding is performed at 340-390°C, preferably 355°C, and the obtained injection molded part is the expandable sleeve.

[0015] The invention also discloses a bone screw, comprising a bone screw body and the above-mentioned expandable sleeve.

[0016] Preferably, the inner diameter of the expandable sleeve is 101% to 105% of the diameter of the bone screw body, and the outer diameter is 106% to 110% of the diameter of the bone screw body.

[0017] Preferably, the inner diameter of the expandable sleeve is 103% of the diameter of the bone screw body, and the outer diameter is 108% of the diameter of the bone screw body.

[0018] The expandable sleeve for preventing bone screw loosening of the present invention does not change the fixing strength of the bone screw and the prosthesis after the bone screw is implanted, thereby ensuring its use function. At the same time, the end of the expandable sleeve expands and deforms, effectively increasing its contact and force with the implanted bone, thereby avoiding the occurrence of non-bacterial loosening. The product of the present invention can effectively improve the use effect and service life of the bone screw and implant. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of an expandable sleeve that prevents loosening of a bone screw. Specific implementation methods

[0020] The present invention is further described below in conjunction with embodiments, but the description of the embodiments does not impose any limitation on the protection scope of the present invention.

[0021] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention, and the terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. In addition, although demonstrations of parameters containing specific values ​​may be provided herein, it should be understood that the parameters do not need to be exactly equal to the corresponding values, but can be approximated to the corresponding values ​​within an acceptable error tolerance or design constraint. The directional terms mentioned in the embodiments, such as "up", "down", "front", "back", "left", "right", etc., are only directions with reference to the accompanying drawings. Therefore, the directional terms used are used to illustrate rather than to limit the scope of protection of the present invention.

[0022] Unless otherwise specified, the materials and instruments used in the following examples can be obtained from conventional commercial channels.

[0023] The "biological inertness" mentioned in the present invention means that under physiological conditions, the material has high biocompatibility and safety with the body, has no or only weak physical, chemical and biological effects with surrounding tissues, has no harmful reactions to the host, and maintains the material properties of stable composition and structure.

[0024] The "non-biodegradable" mentioned in the present invention means that under physiological conditions, the material does not undergo obvious dissolution, molecular chain breakage, mechanical property degradation, etc. Example 1

[0025] like Figure 1As shown, an expandable sleeve for preventing bone screws from loosening comprises a cylindrical body 1, the inner diameter of which matches the bone screw body and is used to wrap the bone screw body 3. The cylindrical body is made of a bio-inert and non-biodegradable material, and one end of the cylindrical body is provided with a plurality of openings 2 on the side wall. The bio-inert and non-biodegradable material is PEEK, with a number average molecular weight of 20×10 4 The length of the opening accounts for 40% of the total length of the circular tubular body.

[0026] The bone screw comprises a bone screw body and the above-mentioned expandable sleeve, the inner diameter of the expandable sleeve is 103% of the diameter of the bone screw body, and the outer diameter is 108% of the diameter of the bone screw body. When in use, a hole is opened on the bone body 4, the expandable sleeve is inserted, and then the bone screw body is inserted and fixed through the expandable sleeve. Under the pressure of the bone screw body, the lower opening of the expandable sleeve expands outward, thereby better fixing the bone screw on the bone body.

[0027] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. An expandable sleeve for preventing a bone screw from loosening, comprising a circular tubular body, the inner diameter of which matches the bone screw body, and is used to wrap the bone screw body, characterized in that: The circular tubular body is made of biologically inert and non-biodegradable materials, and one end of the circular tubular body is provided with a plurality of openings on the side wall.

2. The expandable sleeve according to claim 1, characterized in that: The biologically inert and non-biodegradable material is polyetheretherketone, polyethersulfone, titanium, peptide alloy, stainless steel, or a composite material or a mixed material of the above materials.

3. The expandable sleeve according to claim 2, characterized in that: The biologically inert and non-biodegradable material is polyetheretherketone with a number average molecular weight of 3*10 4 ~60*10 4 .

4. The expandable sleeve according to claim 3, characterized in that: The number average molecular weight of the polyetheretherketone is 20×10 4 .

5. The expandable casing according to claim 1, characterized in that: The length of the opening accounts for 10% to 90% of the total length of the circular tubular body.

6. The expandable casing according to claim 5, characterized in that: The length of the opening accounts for 40% of the total length of the cylindrical body.

7. The expandable sleeve according to any one of claims 1 to 6, characterized in that: The number of the openings is between 1 and 10.

8. A bone screw, comprising a bone screw body, characterized in that It also comprises the expandable sleeve as described in any one of claims 1-7.

9. The bone screw according to claim 8, characterized in that: The inner diameter of the expandable sleeve is 101% to 105% of the diameter of the bone screw body, and the outer diameter is 106% to 110% of the diameter of the bone screw body.

10. The bone screw according to claim 9, characterized in that: The inner diameter of the expandable sleeve is 103% of the diameter of the bone screw body, and the outer diameter is 108% of the diameter of the bone screw body.

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