Subtalar joint brake and use method thereof

Abstract

The present invention provides a subtalar joint brake, which belongs to the field of orthopedic implants and is installed on the user's subtalar joint through surgery. The brake is characterized in that it comprises: a front resistance section, a middle resistance section and an inner resistance section arranged in sequence, wherein the cross sections of the front resistance section, the middle resistance section and the inner resistance section are all circular, the diameter of the cross section of the front resistance section increases first and then decreases along the axial direction, the range of the change difference of the diameter of the cross section of the middle resistance section along the axial direction is 0 to 3 / 500 of the overall length of the subtalar joint brake, and the diameter of the cross section of the inner resistance section gradually decreases in the direction away from the middle resistance section. The length of the front resistance section is 1 / 2 of the overall length of the subtalar joint brake, the length of the middle resistance section is 1 / 4 of the overall length of the subtalar joint brake, and the length of the inner resistance section is 1 / 4 of the overall length of the subtalar joint brake.

Description

Technical Field

[0001] The invention belongs to the field of orthopedic implants, and in particular relates to a subtalar joint brake for correcting flexible flatfoot deformity and a use method thereof. Background Art

[0002] The incidence of flexible flatfoot in children and adults is 5%. Its main pathological feature is excessive eversion of the subtalar joint leading to arch collapse, causing foot pain and fatigue after walking. Subtalar braking refers to the placement of a subtalar joint brake in the tarsal sinus to limit excessive eversion of the subtalar joint. It is a minimally invasive surgery that is currently widely used.

[0003] Currently, the widely used subtalar brakes are mainly divided into two categories: wedge-shaped self-locking type and calcaneal blocking type. Among them, the wedge-shaped self-locking type is the most widely used. According to the design shape, they are mainly divided into cylindrical (MBA prosthesis), conical (Talar-Fit prosthesis) and outer conical and inner cylindrical (HyproCure prosthesis).

[0004] Since the tarsal sinus has an irregular shape, none of the prostheses currently available on the market can match it, leading to postoperative dislocation, pain caused by uneven stress distribution, and even talar neck fracture or screw breakage. Summary of the invention

[0005] In order to solve the above problems, a subtalar joint brake is provided, and the present invention adopts the following technical solutions:

[0006] The present invention provides a subtalar joint brake, which is installed on the subtalar joint of the user through surgery, and is characterized in that it comprises: a front resistance section, a middle resistance section and an inner resistance section arranged in sequence, wherein the cross sections of the front resistance section, the middle resistance section and the inner resistance section are all circular, the diameter of the cross section of the front resistance section first increases and then decreases along the axial direction, the range of the change difference of the diameter of the cross section of the middle resistance section along the axial direction is 0 to 3 / 500 of the overall length of the subtalar joint brake, and the diameter of the cross section of the inner resistance section gradually decreases in the direction away from the middle resistance section.

[0007] The subtalar joint brake provided by the present invention may also have the following feature: the length of the front resistance section is 1 / 2 of the overall length of the subtalar joint brake.

[0008] The subtalar joint brake provided by the present invention may also have the following feature: the length of the middle resistance section is 1 / 4 of the overall length of the subtalar joint brake.

[0009] The subtalar joint brake provided by the present invention may also have the following feature: the length of the internal resistance section is 1 / 4 of the overall length of the subtalar joint brake.

[0010] The subtalar joint brake provided by the present invention may also have the following characteristics: the material of the subtalar joint brake is titanium alloy.

[0011] The subtalar joint brake provided by the present invention may also have the following characteristics: after the subtalar joint brake is installed, the front resistance section is located in the tarsal cavity and contacts the bone, the middle resistance section is located between the tarsal cavity and the tarsal canal, and the inner resistance section is located in the tarsal canal.

[0012] The present invention provides a method for using the above-mentioned subtalar joint brake, characterized in that it comprises the following steps: step S1, making a 1-2 cm incision in the tarsal sinus and separating subcutaneous tissue to the tarsal sinus; step S2, inserting a guide needle of the subtalar joint brake from the anterolateral to the posterior medial side of the foot and passing it out from above the medial talar process; step S3, implanting a trial mold of the subtalar joint brake when the subtalar joint is in varus position and determining a suitable size according to a judgment standard; step S4, installing the subtalar joint brake in the tarsal canal along the guide needle so that the end of the inner resistance section of the subtalar joint brake away from the middle resistance section is located at 40% of the talar axis.

[0013] Function and Effect of the Invention

[0014] The subtalar joint brake according to the present invention is surgically installed on the patient's subtalar joint for correcting flexible flatfoot deformity, and is characterized in that it includes an anterior resistance section, a middle resistance section and an inner resistance section arranged in sequence, and the cross sections of the anterior resistance section, the middle resistance section and the inner resistance section are all circular, and the cross section diameters of each section have characteristics, specifically, the cross section diameter of the anterior resistance section first increases and then decreases along the axial direction, the cross section diameter of the middle resistance section is relatively fixed along the axial direction, and the cross section diameter of the inner resistance section gradually decreases in the direction away from the middle resistance section. The subtalar joint brake of the present invention uses a spherical fitting method to fit the foot CT of children with flatfoot, which can fit the irregular subtalar joint surface to the greatest extent, disperse the contact stress between the talus and calcaneus and the brake, avoid postoperative pain, and make the brake conform to the anatomical morphology of the Chinese foot. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic structural diagram of a subtalar joint brake according to an embodiment of the present invention;

[0016] Figure 2 is a design fitting curve diagram of the subtalar joint brake according to an embodiment of the present invention;

[0017] Figure 3 It is a schematic diagram showing that the subtalar joint brake according to an embodiment of the present invention is installed. DETAILED DESCRIPTION

[0018] The specific implementation of the present invention is described below with reference to the accompanying drawings and embodiments.

[0019] <Example>

[0020] The present embodiment provides a subtalar joint brake and a method for using the same. The subtalar joint brake is surgically installed at the user's subtalar joint to correct flexible flatfoot deformity. After installation, the contact area with the joint surface is increased to reduce the user's pain.

[0021] Figure 1 It is a schematic structural diagram of a subtalar joint brake according to an embodiment of the present invention.

[0022] The subtalar joint brake 100 is columnar, such as Figure 1 As shown, it includes a front resistance section 1, a middle resistance section 2 and an inner resistance section 3 which are arranged in sequence along the axis.

[0023] The cross sections of the front resistance section 1, the middle resistance section 2 and the inner resistance section 3 are all circular.

[0024] The subtalar joint brake provided in this embodiment is obtained by calculating and fitting the foot CT scans of 20 children with flat feet, taking full account of the irregular geometric surfaces of the tarsal canal and tarsal cavity, and adopting spherical fitting.

[0025] In this embodiment, the material of the subtalar joint brake 100 is titanium alloy.

[0026] The specific fitting method is as follows:

[0027] First, a base line is set along the tarsal canal, and the tarsal canal is filled using a spherical fitting method. The least square method is used to fit the center of the sphere to obtain a guide line for surgery. Based on the guide line, a standardized brake that can fit the tarsal canal to the greatest extent is generated, wherein the innermost installation position of the subtalar joint brake 100 is 40% of the talar axis.

[0028] Figure 2 It is a design fitting curve diagram of the subtalar joint brake according to an embodiment of the present invention.

[0029] In this embodiment, the spherical fitting method uses 21 spheres to sequentially generate and fit the structure of the subtalar joint brake 100 from the outside to the inside according to the internal structure of the human body when it is in a neutral position, that is, in a non-weight-bearing state.

[0030] In this embodiment, from outside to inside refers to the direction in which the guide needle passing through the tarsal canal enters from the front and outside of the foot to exits from above the medial talar process when the subtalar joint brake 100 is installed.

[0031] like Figure 2 As shown, the curve graph generated by fitting is a diameter change diagram of the cross section of the subtalar joint brake 100 from outside to inside along the axis, sphere No. 1 is the outermost sphere, sphere No. 21 is the innermost sphere, and the specific diameters of the 21 spheres are shown in Table 1.

[0032] Table 1 Sphere fitting results

[0033] Sphere number Diameter(mm) 1 3.79853762 2 4.090653426 3 4.32846453 4 4.593975292 5 4.511380223 6 4.198162496 7 3.906113336 8 3.686496074 9 3.531261336 10 3.41562255 11 3.386827788 12 3.346816882 13 3.332755221 14 3.324430556 15 3.287343485 16 3.205195183 17 3.099468622 18 2.972747424 19 2.686074031 20 2.422054205 21 2.14898951

[0034] like Figure 1 , Figure 2 As shown in Table 1, the front resistance section 1, the middle resistance section 2 and the inner resistance section 3 of the subtalar joint brake 100 of this embodiment are integrally formed as a whole. The front resistance section 1, the middle resistance section 2 and the inner resistance section 3 are divided according to the change rate of the diameters of adjacent spheres. The specific structure is as follows:

[0035] In this embodiment, the total length of the subtalar joint brake 100 is 20 mm.

[0036] The diameter of the cross section of the front resistance section 1 increases first and then decreases along the axial direction, that is, it has a maximum value in the middle part excluding the two ends.

[0037] In this embodiment, as shown in Table 1, among the spheres obtained by fitting the spheres numbered 1-10, the diameters of spheres No. 1-4 gradually increase, and the diameters of spheres No. 4-10 gradually decrease, that is, the diameter of sphere No. 4 has a maximum value of 4.59 mm.

[0038] The length L1 of the front resistance section 1 is 1 / 2 of the overall length of the subtalar joint brake 100, i.e., 10 mm. In this embodiment, the length of the subtalar joint brake 100 from the end of the front resistance section 1 close to the middle resistance section 2 has a maximum diameter of 4.59 mm at 4 mm.

[0039] The diameter of the middle resistance section 2 along the axial direction varies from 0 to 3 / 500 of the overall length of the lower joint brake 100 , that is, in this embodiment, the variation is 0 mm to 0.12 mm, that is, the diameter of the middle resistance section 2 varies very slightly.

[0040] In this embodiment, as shown in Table 1, the diameters of the spheres numbered 11-15 gradually decrease in a small range, and the variation difference ranges from 0 mm to 0.12 mm.

[0041] The length L2 of the middle resistance section 2 is 1 / 4 of the entire length of the lower joint brake 100, that is, 5 mm.

[0042] The diameter of the cross section of the inner resistance section 3 gradually decreases along the axis and in a direction away from the middle resistance section 2 .

[0043] In this embodiment, as shown in Table 1, the diameters of the spheres numbered 16-21 gradually decrease.

[0044] The length L3 of the internal resistance section 3 is 1 / 4 of the overall length of the lower joint brake, ie, 5 mm.

[0045] Figure 3 It is a schematic diagram showing that the subtalar joint brake according to an embodiment of the present invention is installed.

[0046] The specific use process of the subtalar joint brake 100 of this embodiment is as follows:

[0047] Step S1, make a 1-2 cm incision in the tarsal sinus and separate the subcutaneous tissue to the tarsal sinus.

[0048] Step S2, inserting the guide pin of the subtalar joint brake 100 from the anterolateral side to the posterior medial side of the foot and passing it out from above the medial talar process.

[0049] Step S3, implanting the trial mold of the subtalar joint brake 100 in the valgus position of the subtalar joint and determining the appropriate size according to the judgment standard. The judgment standard is that the trial mold of the subtalar joint brake 100 retains 2°-4° of valgus of the subtalar joint after implantation.

[0050] Step S4, installing the subtalar joint brake 100 in the tarsal canal along the guide needle passing through the tarsal canal, so that the end of the inner resistance section 3 of the subtalar joint brake 100 away from the middle resistance section is located at 40% of the talar axis.

[0051] The subtalar joint brake 100 of this embodiment is installed in the tarsal canal along the guide line penetrating the tarsal canal during surgical installation. Figure 3 As shown, the innermost end of the inner resistance section 3, ie, the end thereof away from the middle resistance section 2, is located at 40% of the talar axis 200.

[0052] The talar axis 200 is specifically: the central axis of the tarsal canal is used as a vertical plane, and the section of the axis included in the plane tangent to the two ends of the talus 21 is the talar axis 200. The direction of the talar axis is set with the human body sagittal axis as a reference, and 40% of the talar axis is the brake installation position.

[0053] After installation, the front resistance section 1 of the subtalar joint brake 100 is in direct contact with the bone in the tarsal cavity, thereby achieving a braking effect; the diameter of each cross section of the middle resistance section 2 remains unchanged, and it is a transition section from the tarsal cavity to the tarsal canal, that is, it is located between the tarsal cavity and the tarsal canal; the inner resistance section 3 is located in the tarsal canal, and the innermost end is located at 40% of the talar axis 200, which is used to prevent the subtalar joint brake 100 from slipping out of the tarsal canal after surgery.

[0054] Example Function and Effect

[0055] The subtalar joint brake provided in this embodiment is used to correct flexible flatfoot deformity, and is installed in the patient's subtalar joint through surgery. It is characterized by including anterior resistance section, middle resistance section and inner resistance section arranged in sequence, and the cross sections of the anterior resistance section, middle resistance section and inner resistance section are all circular, and the diameter of the cross section of each part has characteristics, specifically, the diameter of the cross section of the anterior resistance section first increases and then decreases along the axial direction, the diameter of the cross section of the middle resistance section is relatively fixed along the axial direction, and the diameter of the cross section of the inner resistance section gradually decreases in the direction away from the middle resistance section. The subtalar joint brake of this embodiment uses a spherical fitting method to fit the foot CT of children with flatfoot, which can fit the irregular subtalar joint surface to the greatest extent, disperse the contact stress between the talus and calcaneus and the brake, avoid postoperative pain, and make the brake conform to the anatomical morphology of Chinese feet.

[0056] Furthermore, the front resistance section, middle resistance section and inner resistance section of the subtalar joint brake provided in this embodiment respectively occupy a certain proportion of the overall length of the subtalar joint brake, so that the front resistance section can be in direct contact with the bone in the tarsal cavity, thereby achieving a braking effect; the middle resistance section is between the tarsal cavity and the tarsal canal; and the inner resistance section is located in the tarsal canal to prevent the subtalar joint brake from slipping out of the tarsal canal after surgery.

[0057] Furthermore, the material of the subtalar joint brake provided in this embodiment is titanium alloy. Titanium alloy has a low density, high strength and corrosion resistance. After the subtalar joint brake is installed, it can have little impact on human activities.

[0058] Furthermore, in the method for using the subtalar joint brake provided in this embodiment, when the subtalar joint brake is installed, its installation position is 40% of the talar axis. When the patient's foot performs inversion, eversion, dorsiflexion, and plantar flexion, the spatial position change amplitude here is the smallest. Using this as the installation position of the subtalar joint brake can prevent the brake from slipping out of the tarsal canal after surgery, causing the braking effect to deteriorate.

[0059] The above embodiments are only used to illustrate specific implementation modes of the present invention, and the present invention is not limited to the description scope of the above embodiments.

Claims

1. A subtalar joint brake, surgically installed on a user's subtalar joint, characterized in that: include: The front resistance section, middle resistance section and inner resistance section are arranged in sequence. The cross sections of the front resistance section, the middle resistance section and the inner resistance section are all circular. The diameter of the cross section of the front resistance section increases first and then decreases along the axial direction. The range of the variation difference of the diameter of the cross section of the middle resistance section along the axial direction is 0 to 3 / 500 of the overall length of the subtalar joint brake. The diameter of the cross section of the inner resistance section gradually decreases in a direction away from the middle resistance section.

2. The subtalar joint brake according to claim 1, characterized in that: in, The length of the front resistance section is 1 / 2 of the overall length of the subtalar joint brake.

3. The subtalar joint brake according to claim 1, characterized in that: in, The length of the middle resistance section is 1 / 4 of the overall length of the subtalar joint brake.

4. The subtalar joint brake according to claim 1, characterized in that: in, The length of the internal resistance section is 1 / 4 of the overall length of the subtalar joint brake.

5. The subtalar joint brake according to claim 1, characterized in that: in, The material of the subtalar joint brake is titanium alloy.

6. The subtalar joint brake according to claim 1, characterized in that: in, After the subtalar joint brake is installed, the front block section is located in the tarsal cavity and contacts the bone. The middle resistance section is located between the tarsal cavity and the tarsal canal. The internal resistance section is located in the tarsal canal.

7. A method for using the subtalar joint brake according to claims 1 to 6, characterized in that: The steps include: Step S1, make a 1-2 cm incision in the tarsal sinus and separate the subcutaneous tissue to the tarsal sinus; Step S2, inserting the guide needle of the subtalar joint brake from the anterolateral side to the posterior medial side of the foot and passing it out from above the medial talar process; Step S3, implanting the trial mold of the subtalar joint brake when the subtalar joint is in varus position and determining the appropriate size according to the judgment criteria; Step S4, installing the subtalar joint brake in the tarsal canal along the guide needle, so that the end of the inner resistance section of the subtalar joint brake away from the middle resistance section is located at 40% of the talar axis.

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