A hip screw
By designing a porous structure and internal nail locking part for the iliac nail, the problem of unstable fixation of the sacroiliac joint was solved, achieving a stable connection between the bone and the iliac nail, thus improving surgical outcomes and the patient's quality of life.
Patent Information
- Application Number
- CN202520939613.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-14
- Publication Date
- 2026-08-25
- Estimated Expiration
- 2035-05-14
AI Technical Summary
In existing technologies, the sacroiliac joint is not fixed stably, and screws may loosen or break, leading to hardware failure and persistent pain, making it difficult to achieve long-term effective fixation of the sacroiliac joint.
An iliac nail is designed with threads and a porous structure on the outer peripheral wall of the outer nail, and the inner nail is inserted into the receiving hole. The front end of the inner nail has a locking part and a protrusion. When the outer nail is screwed into the cancellous bone, bone fragments fill the gap. The porous structure promotes the ingrowth of bone cells, and the inner nail and the outer nail form a stable connection.
By allowing bone cells to grow into the porous structure, a stable connection between the iliac nail and the bone is achieved, improving surgical outcomes and patient prognosis.
Smart Images
Figure CN224671584U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of surgical instrument technology, and in particular to an iliac bone nail. Background Technology
[0002] Internal fixation techniques involving the sacrum and pelvis have been widely used to treat complex spinal and pelvic diseases, including lumbosacral degenerative diseases, complex spinal deformities, severe spondylolisthesis, spinal-pelvic reconstruction after tumor resection, severe lumbosacral infections, high-energy sacral-pelvic trauma, and pathological fractures. Despite significant advancements in sacral-pelvic internal fixation techniques over the past few decades, lumbosacral junction fixation and reconstruction remains a challenge in pediatric and adult spinal-pelvic surgery. Current problems mainly include: insufficient screw strength (screw loosening and breakage observed during postoperative follow-up); and failure of sacroiliac joint fusion, resulting in micro-movement, hardware failure, and intractable sacroiliac joint pain. Utility Model Content
[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes an iliac nail that can effectively fix the sacroiliac joint for a long period, improving surgical outcomes and patient prognosis.
[0004] An iliac nail according to a first aspect of the present invention includes: an outer nail and an inner nail. The outer nail has threads on its outer peripheral wall and a receiving hole inside. The outer nail has multiple slots on its outer peripheral wall that communicate with the receiving hole. The outer peripheral wall of the outer nail is formed with a porous structure. The inner nail passes through the receiving hole, and the diameter of the inner nail is smaller than the diameter of the receiving hole.
[0005] An iliac nail according to an embodiment of the present invention has at least the following beneficial effects: Bone fragments are generated during the insertion of the external nail into the cancellous bone. These autologous bone fragments fill the gap between the external and internal nails through slots. The porous structure itself facilitates osteocyte ingrowth, and combined with the embedded cancellous bone, the autologous bone fragments exhibit good osteoinductive properties. Later, bone tissue will ingrow into the porous structure and the slots of the external nail, ultimately achieving a more stable connection.
[0006] According to some embodiments of the present invention, the front end of the inner nail is provided with a locking part, which abuts against the front end of the outer nail to prevent the inner nail from dislodging from the receiving hole.
[0007] According to some embodiments of this utility model, the outer peripheral wall of the inner nail is symmetrically provided with a plurality of protrusions, and the protrusions abut against the inner wall of the receiving hole.
[0008] According to some embodiments of this utility model, the outer peripheral wall of the inner nail is provided with multiple debris grooves.
[0009] According to some embodiments of this utility model, the plurality of slots are symmetrically arranged in multiple sets along the length direction of the outer nail.
[0010] According to some embodiments of this utility model, each group of slots is spirally distributed around the outer nail.
[0011] According to some embodiments of the present invention, the slot extends along the length direction of the outer nail.
[0012] According to some embodiments of the present invention, the porosity of the porous structure is 60% to 85%.
[0013] According to some embodiments of the present invention, the pore size of the porous structure is 300 to 500 micrometers.
[0014] According to some embodiments of this utility model, the rear end of the inner nail is provided with a connector, which is used to connect a fixing rod.
[0015] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the installation structure according to one embodiment of the present utility model; Figure 2 This is a schematic diagram of the outer nail according to one embodiment of the present invention; Figure 3 This is a schematic diagram of the inner nail in one embodiment of the present invention.
[0017] Icon labels: External nail 100, receiving hole 110; Grooving 200; Porous structure 300; Inner nail 400, snap-fit part 410, protrusion 420, debris groove 430; Connector 500. Detailed Implementation
[0018] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.
[0019] In the description of this utility model, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0020] In the description of this utility model, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features or their sequential relationship.
[0021] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.
[0022] Reference Figures 1 to 3As shown, an iliac bone screw according to one embodiment of this utility model includes an outer screw 100 and an inner screw 400. Both the outer screw 100 and the inner screw 400 are made of titanium alloy. Titanium alloy has good biocompatibility and will not cause an immune response. This characteristic of titanium alloy ensures that the outer screw 100 and the inner screw 400 can integrate well with human tissue, thereby improving the patient's treatment effect and quality of life. The outer screw 100 has threads on its outer peripheral wall. It is foreseeable that the first 1 / 3 of the outer screw 100 uses a large-pitch deep thread. The thread pitch of the first 1 / 3 of the outer screw 100 is 4.5mm, and the thread depth is 1.2mm. The design of the first section of the outer screw 100 is sharper, facilitating cutting into the bone and ensuring efficient bone fragment collection. The threads of the last 2 / 3 of the outer screw 100 are small-pitch shallow threads. The thread pitch of the last 2 / 3 of the outer screw 100 is 3.2mm, and the thread depth is 0.8mm. The additional threads in the rear section increase the load-bearing area, improve pull-out resistance, and optimize stress distribution. The outer nail 100 has a receiving hole 110 inside, and multiple slots 200 on its outer peripheral wall, communicating with the receiving hole 110. During insertion, bone fragments are generated and enter the receiving hole 110 through the slots 200. The outer peripheral wall of the outer nail 100 is formed with a porous structure 300; the outer side wall of the outer nail 100 is composed of the porous structure 300. The porous structure 300 is embedded in the spiral grooves of the outer side wall of the outer nail 100. Bone cells more easily grow into the porous structure 300, ultimately forming a structure stably connected to the outer nail 100, significantly improving long-term fixation. The inner nail 400 passes through the receiving hole 110, and the diameter of the inner nail 400 is smaller than the diameter of the receiving hole 110. The purpose of the inner screw 400 is to increase structural stability. The inner screw 400 supports the outer screw 100, preventing deformation during use. The outer screw 100 generates bone fragments during insertion into the cancellous bone. These autologous bone fragments fill the gap between the outer screw 100 and the inner screw 400 through the slot 200. The porous structure 300 itself facilitates osteoblast ingrowth, and combined with the embedded cancellous bone, the autologous bone fragments exhibit good osteoinductive properties. Later, bone tissue will grow into the porous structure 300 and the slot 200 of the outer screw 100, ultimately achieving a more stable connection.
[0023] Reference Figures 1 to 3 As shown, it can be understood that the inner nail 400 has a locking portion 410 at its front end, which abuts against the front end of the outer nail 100 to prevent the inner nail 400 from disengaging from the receiving hole 110. The locking portion 410 includes three symmetrically arranged claws. The receiving hole 110 extends to the front end of the outer nail 100. During insertion into the receiving hole 110, the claws deform and contract inward to pass through the receiving hole 110. After extending out of the front end of the receiving hole 110, the claws reset and open outward to abut against the front end of the outer nail 100, thus fixing the outer nail 100 and the inner nail 400 axially and preventing the inner nail 400 from disengaging from the receiving hole 110.
[0024] Reference Figures 1 to 3 As shown, it can be understood that multiple protrusions 420 are symmetrically arranged on the outer peripheral wall of the inner nail 400, and the protrusions 420 abut against the inner wall of the receiving hole 110. Since the outer diameter of the inner nail 400 is smaller than that of the receiving hole 110, the protrusions 420 abut against the inner wall of the receiving hole 110, which can prevent the inner nail 400 from shaking. This achieves a more stable connection between the outer nail 100 and the inner nail 400. The protrusions 420 on the surface of the inner nail 400 can be integrally machined with the inner nail 400, or they can be manufactured separately and then fixed by welding.
[0025] Reference Figures 1 to 3 As shown, it can be understood that the outer peripheral wall of the inner nail 400 has multiple debris grooves 430. The debris grooves 430 serve to accommodate bone fragments. Since the outer nail 100 produces too much bone fragments during insertion into the cancellous bone, the debris grooves 430 provide more space to accommodate the bone fragments, preventing them from compressing the surrounding normal bone tissue and thus improving the prognosis.
[0026] Reference Figures 1 to 3 As shown, it can be understood that three sets of grooves 200 are symmetrically arranged along the length of the external nail 100. The more grooves 200 there are, the more space can be provided to accommodate bone fragments from the autologous bone, making it easier for bone cells to grow into them and resulting in a more stable connection with the bone. However, the more grooves 200 there are, the lower the structural strength of the external nail 100, and the greater the risk of breakage during use. Conversely, the fewer grooves 200 there are, the higher the structural strength of the external nail 100, and the lower the risk of breakage during use. However, the space for bone cell growth is smaller, and the connection between the external nail 100 and the bone is less stable. Therefore, three sets of grooves 200 are selected to achieve a stable connection between the external nail 100 and the bone while meeting the structural strength requirements.
[0027] Reference Figures 1 to 3 As shown, it can be understood that each set of slots 200 is spirally distributed around the outer screw 100. Since the outer screw 100 rotates forward to drill into the bone, the spirally distributed slots 200 can more effectively guide bone fragments into the gaps, optimize the efficiency of bone fragment collection, and allow the generated bone fragments to flow smoothly into the slots 200.
[0028] Reference Figures 1 to 3 As shown, it can be understood that the slot 200 extends along the length direction of the outer nail 100. The slot 200 is set to a long strip shape, and the length direction of the slot 200 is parallel to the length direction of the outer nail 100. The long strip shape of the slot 200 can more effectively guide bone fragments into the gap while ensuring the bending strength of the outer nail 100, optimize the efficiency of bone fragment collection, and allow the generated bone fragments to smoothly enter the slot 200.
[0029] Reference Figures 1 to 3As shown, it is understandable that the porosity of the porous structure 300 is between 60% and 85%. A porosity between 60% and 85% provides sufficient space for bone cell ingrowth while maintaining the structure's mechanical strength. Excessively high porosity may result in a significant advantage in bone tissue and blood vessel ingrowth speed, but it may also lead to lower yield strength and potential bending failure during use. Conversely, excessively low porosity results in excellent mechanical properties for the external nail 100, but reduces the efficiency of bone tissue and blood vessel ingrowth. Furthermore, a porosity of 60%–85% is a suitable range for SLM / DLP printing processes, ensuring both accuracy and structural integrity during manufacturing.
[0030] Reference Figures 1 to 3 As shown, it is understandable that the pore size of the porous structure 300 is selected from 300 to 500 micrometers. The porous structure 300 can provide suitable space to promote osteoblast growth behavior and osteoblast integration, and improve osteoblast ingrowth efficiency. Since the elastic modulus of cancellous bone is 0.5-1.5 GPa and that of cortical bone is 12-18 GPa, while the elastic modulus of the titanium alloy with a pore size of 300-500 micrometers is 2-4 GPa, it can form a gradual transition with cancellous bone and cortical bone, reducing stress shielding.
[0031] Reference Figures 1 to 3 As shown, it can be understood that the inner screw 400 has a connector 500 at its rear end. To facilitate manufacturing and reduce costs, the connector 500 is manufactured separately from the inner screw 400 and then connected by threads. The connector 500 is used to connect the fixation rod. The connector 500 and the fixation rod are components of a screw-rod system frequently used in spinal and pelvic surgery; their specific structure and installation method are existing technology and will not be detailed further.
[0032] Working principle: Bone fragments are generated during the insertion of the external nail 100 into the cancellous bone. The bone fragments from the autologous bone fill the gap between the external nail 100 and the internal nail 400 through the slot 200. The porous structure 300 itself is conducive to the ingrowth of osteocytes. Combined with the cancellous bone embedded in the slot 200, the bone fragments from the autologous bone have good osteoinductive properties. Later, bone tissue will grow into the porous structure 300 and the slot 200 of the external nail 100, ultimately achieving a more stable connection.
[0033] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.
Claims
1. An iliac nail, characterized in that, include: An outer nail (100) has threads on its outer peripheral wall, a receiving hole (110) inside the outer nail (100), and multiple slots (200) on its outer peripheral wall, which communicate with the receiving hole (110). The outer peripheral wall of the outer nail (100) is formed with a porous structure (300). An inner nail (400) is inserted into the receiving hole (110), and the diameter of the inner nail (400) is smaller than the diameter of the receiving hole (110).
2. The iliac nail according to claim 1, characterized in that: The inner nail (400) has a snap-fit portion (410) at its front end, which abuts against the front end of the outer nail (100) to prevent the inner nail (400) from dislodging from the receiving hole (110).
3. The iliac nail according to claim 1, characterized in that: The outer peripheral wall of the inner nail (400) is symmetrically provided with a plurality of protrusions (420), and the protrusions (420) abut against the inner wall of the receiving hole (110).
4. The iliac nail according to claim 1, characterized in that: The outer peripheral wall of the inner nail (400) is provided with multiple debris grooves (430).
5. The iliac nail according to claim 4, characterized in that: The plurality of slots (200) are symmetrically arranged in multiple sets along the length direction of the outer nail (100).
6. The iliac nail according to claim 5, characterized in that: Each set of slots (200) is spirally distributed around the outer nail (100).
7. The iliac nail according to claim 6, characterized in that: The slot (200) extends along the length direction of the outer nail (100).
8. The iliac nail according to claim 7, characterized in that: The porosity of the porous structure (300) is 60% to 85%.
9. The iliac nail according to claim 8, characterized in that: The porous structure (300) has a pore size of 300 to 500 micrometers.
10. The iliac nail according to claim 1, characterized in that: The inner nail (400) has a connector (500) at its rear end, which is used to connect the fixing rod.