Expansion type subtalar joint brake

Abstract

The utility model discloses an expansion type subtalar joint brake which is characterized by comprising an outer nail body and an inner nail body which are matched with each other, the inner nail body is of a circular truncated cone structure, the outer nail body comprises a columnar nail head and a plurality of expansion pieces fixedly connected with the nail head, the expansion pieces are distributed along the circumference to form a cavity, and the cavity is used for containing the inner nail body. And the outer nail body is made of a polymer based on lactic acid. According to the expansion type subtalar joint brake, the inner nail body and the outer nail body are matched, the nail head of the outer nail body is implanted into a tarsal bone tube, fixation can be firmer, and tissue cannot be cut by the outer nail body.

Description

Technical Field

[0001] The utility model belongs to the field of medical equipment, and in particular relates to an expansion-type subtalar joint brake. Background Art

[0002] Flat feet are a common foot condition affecting both children and adults. The primary pathological characteristic of flat feet is excessive pronation of the talus, leading to a collapsed arch and increased contact area between the sole of the foot and the ground. This can cause foot pain and fatigue with walking. Flat feet can be congenital or acquired.

[0003] Subtalar arthroereisis is a common minimally invasive procedure for treating flatfoot. It involves implanting a subtalar arthroereisis device within the tarsal sinus, formed by the talus and calcaneus, to limit excessive motion of the subtalar joint and correct the flatfoot deformity. Clinical feedback suggests that subtalar arthroereisis has demonstrated significant early clinical efficacy in treating flexible flatfoot in adolescents. Its minimal trauma, rapid recovery, and ease of operation have earned it a degree of recognition among clinicians, resulting in favorable treatment outcomes.

[0004] Existing subtalar joint brakes come in two configurations: Type I and Type II. Type I subtalar joint brakes are implanted in the sinus tarsi, posing a risk of dislodgement. While the front end of the Type II subtalar joint brake can be implanted within the tarsal canal, the threaded structure on the front end can cut into surrounding tissue, causing secondary damage. Furthermore, due to structural differences in the human body, there are also issues with the size mismatch between the subtalar joint brake and the sinus tarsi, leading to insecure fixation.

[0005] Therefore, providing a subtalar joint brake that is firmly fixed, not easy to fall out, does not cause tissue cutting, and is conducive to postoperative recovery is a technical problem that needs to be solved urgently by those skilled in the art. Utility Model Content

[0006] The utility model provides an expandable subtalar joint brake, which adopts an inner nail body and an outer nail body. The nail head of the outer nail body is implanted in the tarsal canal, which can not only fix more firmly, but also does not cut the tissue and can promote postoperative recovery by releasing lactic acid.

[0007] In order to solve the above technical problems, the technical solutions provided by the present invention are as follows:

[0008] An expandable subtalar joint brake comprises an outer nail body and an inner nail body that cooperate with each other. The inner nail body is a truncated cone-shaped structure. The outer nail body comprises a columnar nail head and a plurality of expansion pieces fixedly connected to the nail head. The expansion pieces are distributed along the circumference to form a cavity for accommodating the inner nail body. The outer nail body is made of a lactic acid-based polymer.

[0009] Furthermore, a through hole is provided on the expansion piece, and a protrusion is provided on the outer wall of the inner nail body, and the protrusion matches the through hole.

[0010] Furthermore, the nail head is coaxially provided with a first through hole along the axial direction, and the inner nail body is coaxially provided with a second through hole along the axial direction.

[0011] Furthermore, the inner nail body has a first end and a second end along the axial direction, the diameter of the inner nail body gradually increases from the first end to the second end, the outer wall of the first end is a smooth surface, and the protrusion is arranged on the outer wall of the second end.

[0012] Furthermore, an external thread is provided on the outer wall of the inner nail body, and an internal thread is provided on the inner wall of the outer nail body, and the external thread matches the internal thread.

[0013] Furthermore, a plurality of protrusions are provided on the outer wall of the inner nail body, the protrusions are linearly arranged into a plurality of groups, and the plurality of groups of protrusions are evenly distributed along the circumference of the inner nail body.

[0014] Furthermore, the number of the groups of protrusions is the same as the number of the expansion sheets.

[0015] Furthermore, a plurality of grooves are provided on the side wall of the expansion piece, and the grooves match the protrusions.

[0016] Furthermore, the end of the nail head is an arc surface.

[0017] Furthermore, the monomers used to prepare the lactic acid-based polymer include lactide and any one or more of glycolide, caprolactone, p-dioxanone, and trimethylene carbonate.

[0018] The beneficial effects of the present invention are as follows: The present invention provides an expandable subtalar joint brake, which utilizes an inner nail body and an expandable outer nail body. The cylindrical nail head at the front end of the outer nail body is implanted into the tarsal canal, allowing for deeper implantation without cutting surrounding tissue. The expansion structure at the rear end can be squeezed and fixed with the surrounding tissue as needed, making the overall fixation more secure and less likely to come out. The outer nail body is made of an absorbable and elastic lactic acid-based polymer, which not only prevents the harder inner nail body from excessively squeezing surrounding tissue and causing pain, but also releases lactic acid during the degradation process in the later stages of implantation, promoting the growth of the intercalary talar ligament and facilitating postoperative recovery. The outer and inner nail bodies have multiple fixing methods to meet different needs and provide stable fixation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an overall structural diagram of the expandable subtalar joint brake according to the first embodiment of the present utility model;

[0020] Figure 2 This is a cross-sectional view of the outer nail body of the first embodiment of the present utility model;

[0021] Figure 3 This is a cross-sectional view of the inner nail body of the first embodiment of the present utility model;

[0022] Figure 4 This is an overall structural diagram of an expandable subtalar joint brake according to a second embodiment of the present utility model;

[0023] Figure 5 This is a cross-sectional view of the outer nail body of the second embodiment of the present utility model;

[0024] Figure 6 This is a cross-sectional view of an inner nail body according to a second embodiment of the present invention;

[0025] Figure 7 This is an overall structural diagram of an expandable subtalar joint brake according to a third embodiment of the present utility model;

[0026] Figure 8 is a cross-sectional view of an outer nail body according to a third embodiment of the present invention;

[0027] Figure 9 This is a cross-sectional view of the inner nail body of the third embodiment of the present utility model.

[0028] Reference numerals include:

[0029] 100 - outer nail body 110 - nail head 120 - expansion piece

[0030] 111 - first through hole 121 - ridge 122 - internal thread

[0031] 123 - through hole 200 - inner nail body 210 - first end

[0032] 220 - second end 230 - second through hole 240 - external thread

[0033] 221—protrusion 124—groove 222—guide edge DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0035] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0036] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0038] like Figure 1 As shown in FIG, the first embodiment of the expandable subtalar joint brake provided by the present invention mainly comprises an outer nail body 100 and an inner nail body 200 that cooperate with each other. Figure 3 As shown, the inner nail body 200 is a truncated cone structure, including a first end 210 and a second end 220 along the axial direction, and the diameter of the inner nail body 200 gradually increases from the first end 210 to the second end 220. The outer wall of the first end 210 of the inner nail body 100 is a smooth surface, and the outer wall of the second end 220 is provided with a plurality of protrusions 221, and the cross section of the protrusions 221 can be trapezoidal or triangular. Figure 1 and Figure 2As shown, the outer nail body 100 includes a cylindrical nail head 110 and a plurality of expansion pieces 120 fixedly connected to the nail head 110. The plurality of expansion pieces 120 are distributed along the circumference to form a cavity for accommodating the inner nail body 100. The outer wall of the expansion piece 120 is provided with a plurality of ridges 121, which are used to squeeze and fix with the surrounding tissue during implantation, increase the frictional resistance between the outer nail body and the surrounding tissue, and prevent the nail body from moving backward. A through hole 123 is provided on the outer wall of the expansion piece 120 at the end away from the nail head 110. The through hole 123 matches the protrusion 221 to fix the inner nail body 200 and the outer nail body 100 together and prevent them from falling out. A plurality of guide ribs 222 are provided on the outer wall of the inner nail body 200. The number of the guide ribs 222 is the same as the number of the expansion sheets 120 and is evenly distributed on the outside of the inner nail body 200. The guide ribs 222 are matched with the gaps between adjacent expansion sheets 120 when implanted, playing a guiding role while preventing the inner nail body 200 from rotating relative to the outer nail body 100.

[0039] In this embodiment, the end of the nail head 110 is an arc surface, which is easy to implant and will not damage the surrounding tissue. The nail head 110 is coaxially arranged with a first through hole 111 along the central axis direction, and the inner nail body 200 is provided with a second through hole 230 along the central axis direction. The first through hole 111, the cavity and the second through hole 230 are coaxially arranged and connected for cooperation with the implantation tool.

[0040] In this embodiment, the inner nail body 200 is made of an absorbable polymer material, preferably polylactic acid or a polylactic acid-inorganic material blend, which is not only degradable and absorbable, but also provides overall mechanical support for the implant. The outer nail body 100 is made of a lactic acid-based polymer, which gives it a certain elasticity and prevents the hard inner nail body 200 from excessively squeezing the surrounding tissue and causing pain. The nail head 110 of the outer nail body 100 is implanted in the tarsal canal and releases lactic acid during the degradation process. Lactic acid can stimulate and promote the growth of the intercalary ligament between the calcaneus and talus, thereby facilitating postoperative recovery.

[0041] The monomers used to prepare the lactic acid-based polymer include lactide and any one or more of glycolide, caprolactone, p-dioxanone, and trimethylene carbonate. Preferably, a polylactic acid-trimethylene carbonate polymer made from lactide and trimethylene carbonate is used to prepare the outer nail body 100. Trimethylene carbonate degradation products do not contain acidic compounds. Therefore, upon hydrolysis, polylactic acid-trimethylene carbonate polymer (PLA-TMC) releases fewer acidic compounds than other lactic acid copolymers and is less likely to induce an inflammatory response.

[0042] In this embodiment, when implanting the expandable subtalar joint brake, the outer nail body 100 is first implanted into the tarsal sinus using an implantation tool, and the nail head is implanted into the tarsal canal. Then, the inner nail body 200 is pressed into the cavity of the outer nail body 100 until the protrusion 221 matches the through hole 123, and the inner nail body 200 is fixed to the outer nail body 100. The expansion piece 120 is expanded and squeezed with the surrounding tissue to complete the fixed implantation.

[0043] like Figure 4-6 This is the second embodiment provided by the present invention. This embodiment is roughly the same as the first embodiment, except that an internal thread 122 is provided on the inner wall of the cavity of the outer nail body 100, and an external thread 240 is provided on the outer wall of the inner nail body 200. The external thread 240 matches the internal thread 122. During the implantation process, the inner nail body 200 is screwed into the cavity of the outer nail body 100 through thread matching to achieve implantation and fixation.

[0044] like Figure 7-9 This is the third embodiment provided by the present invention. This embodiment is substantially the same as the second embodiment, except that a plurality of protrusions 221 are provided on the outer wall of the inner nail body 200. The protrusions 221 are arranged in multiple groups along a linear axis, and the multiple groups of protrusions 221 are evenly distributed along the circumference of the inner nail body 200. The number of groups of protrusions 221 is the same as the number of expansion plates. After the inner nail body 200 is screwed into the outer nail body 100, the inner nail body 200 is rotated within a small angle range so that the protrusions 221 are located in the gap between adjacent expansion plates, thereby preventing relative rotation between the inner nail body 200 and the outer nail body 100.

[0045] Preferably, the sidewall of the expansion piece is provided with a plurality of grooves 124, which can match the protrusions 221. After the inner nail body 200 is screwed into the cavity of the outer nail body 100, the inner nail body 200 is rotated within a small angle range so that the protrusions 221 are locked in the grooves 124 of the expansion piece, which can effectively fix the inner nail body 200 and the outer nail body 100 together and prevent them from falling out or rotating relative to each other.

[0046] The above content is only a preferred embodiment of the present invention. For ordinary technicians in this field, many changes can be made in the specific implementation methods and application scope based on the concept of the present invention. As long as these changes do not deviate from the concept of the present invention, they all fall within the scope of protection of the present invention.

Claims

1. An expandable subtalar joint brake, characterized in that: The invention comprises an outer nail body (100) and an inner nail body (200) which cooperate with each other, wherein the inner nail body (200) is a truncated cone-shaped structure, the outer nail body (100) comprises a columnar nail head (110) and a plurality of expansion pieces (120) fixedly connected to the nail head (110), the expansion pieces (120) are distributed along the circumference to form a cavity, and the cavity is used to accommodate the inner nail body (200), and the outer nail body (100) is made of a polymer based on lactic acid.

2. The expandable subtalar joint brake according to claim 1, characterized in that: A through hole (123) is provided on the expansion piece (120), and a protrusion (221) is provided on the outer wall of the inner nail body (200), and the protrusion (221) matches the through hole (123).

3. The expandable subtalar joint brake according to claim 2, characterized in that: The nail head (110) is coaxially provided with a first through hole (111) along the axial direction, and the inner nail body (200) is coaxially provided with a second through hole (230) along the axial direction.

4. The expandable subtalar joint brake according to claim 3, characterized in that: The inner nail body (200) has a first end (210) and a second end (220) in the axial direction, the diameter of the inner nail body (200) gradually increases along the direction from the first end (210) to the second end (220), and the outer wall of the first end (210) is a smooth surface, and the protrusion (221) is arranged on the outer wall of the second end (220).

5. The expandable subtalar joint brake according to claim 1, characterized in that: The outer wall of the inner nail body (200) is provided with an external thread (240), and the inner wall of the outer nail body (100) is provided with an internal thread (122), and the external thread (240) matches the internal thread (122).

6. The expandable subtalar joint brake according to claim 5, characterized in that: The outer wall of the inner nail body (200) is provided with a plurality of protrusions (221), and the protrusions (221) are linearly arranged into a plurality of groups, and the plurality of groups of protrusions (221) are evenly distributed along the circumference of the inner nail body (200).

7. The expandable subtalar joint brake according to claim 6, characterized in that: The number of groups of the protrusions (221) is the same as the number of the expansion sheets (120).

8. The expandable subtalar joint brake according to claim 7, characterized in that: The side wall of the expansion piece (120) is provided with a plurality of grooves (124), and the grooves (124) match the protrusions (221).

9. The expandable subtalar joint brake according to claim 2, characterized in that: The end of the nail head (110) is an arc surface.

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