Ankle joint prosthesis

Abstract

The application discloses an ankle joint prosthesis, which comprises a tibia component, a pad and a talus component connected in sequence, and a plurality of bionic ligaments; the tibia component comprises a first intramedullary canal handle and a platform connected to the lower end of the first intramedullary canal handle; the pad comprises a pad body, and the upper surface of the pad body is provided with a cylindrical boss; the talus component comprises a second intramedullary canal handle and a connecting piece connected to the upper end of the second intramedullary canal handle; and the bionic ligaments are connected to the pad and the talus component respectively. The ankle joint prosthesis can completely replace the bone and cartilage of the ankle joint surface, thereby overcoming the problem that the cartilage surface cannot be repaired by an ankle arthroscopy surgery. The ankle joint prosthesis is used for replacing the original damaged ankle joint by using metal and polymer components, so that the discomfort symptom is relieved and the joint activity ability is reserved, and the ankle joint prosthesis is a full freedom ankle joint prosthesis which can completely reserve six activity modes of flexion, extension, inversion, eversion, internal rotation and external rotation.

Description

Technical Field

[0001] This invention relates to the field of artificial prostheses, and more specifically to an ankle joint prosthesis. Background Technology

[0002] The ankle joint is one of the joints that bears the greatest and most frequent weight during daily activities. A significant portion of the population suffers from ankle injuries of varying degrees. Ankle replacement surgery is a relatively new treatment method that has been gradually developed and promoted in recent years. It involves removing part of the distal tibia and proximal talus bone and replacing them with metal prosthetic components, thereby completely eliminating pain.

[0003] Because the talus articular surface is a complex curved surface, its flexion, extension, and sliding motion on the tibial articular surface are inevitably accompanied by inversion / exversion and rotation. Furthermore, due to the differences in strength between the anterior and posterior, and medial and lateral tibial muscle groups, the ankle joint itself cannot maintain a completely neutral position when the human body is bearing weight while standing, walking, and running; instead, it undergoes complex internal and external rotation and inversion / exversion movements. Therefore, the ankle joint is a complex joint with six modes of movement: flexion, extension, inversion, eversion, internal rotation, and external rotation. Generally, the ankle joint can dorsiflex about 30 degrees, plantarflex about 40 degrees, and inversion / exversion about 30 degrees, and also has a slight capacity for internal and external rotation.

[0004] While existing ankle prostheses allow for ankle joint movement, most only enable limited flexion and extension, with almost complete loss of pronation, supination, inversion, and eversion. Patients experience a distinct feeling of restriction and discomfort during standing, walking, and running compared to their natural ankle joint. Furthermore, the prosthesis bears significant stress due to its resistance to the body's natural movement habits, leading to prosthesis-bone wear, prosthesis deformation, and even fracture. Some prostheses can achieve slight inversion or eversion, but their structure is poorly adapted to this type of movement, resulting in significant joint surface wear and potentially further dislocation. Some prostheses employ a purely spherical joint design, allowing movement in all directions. However, this excessive flexibility lacks stability and support, leaving patients without directional support when supporting their weight on the ankle, thus affecting their mobility. Over time, this can cause severe stress and chronic tearing damage to the ligaments and tendons surrounding the ankle joint. Most existing ankle prostheses have a very small fixation volume within the tibia and talus, often consisting of only a few tiny nail-like structures, or even no protrusions at all, relying solely on surface friction and bone cement for fixation. Because metal, bone cement, and bone still differ in elastic modulus and other mechanical properties, the bone-metal interface experiences significant wear, leading to a higher risk of long-term failure such as prosthesis loosening and displacement. Summary of the Invention

[0005] The purpose of this invention is to provide an ankle joint prosthesis that fully preserves six modes of movement: flexion-extension, inversion-exversion, and internal-external rotation, and has full degrees of freedom.

[0006] To achieve the above objectives, the present invention provides an ankle joint prosthesis comprising a tibial component, a padding component, and a talus component connected in sequence, as well as several bionic ligaments;

[0007] The tibial component includes a first medullary canal stem and a platform connected to the lower end of the first medullary canal stem; the lower surface of the platform includes a cylindrical groove;

[0008] The pad includes a pad body, the upper surface of which is provided with a cylindrical boss. The cylindrical groove and the cylindrical boss are adapted to each other. The cylindrical boss is inserted into the cylindrical groove so that the pad is connected to the tibia component and the tibia component can rotate relative to the pad.

[0009] The cylindrical groove is provided with a protrusion, the cylindrical boss includes a notch, the protrusion is placed in the notch, and the size of the protrusion is smaller than the notch;

[0010] The lower surface of the pad body includes an arc groove; the talus component includes a second medullary canal stem and a connector connected to the upper end of the second medullary canal stem; the upper surface of the connector includes an arc surface, the arc groove is adapted to the shape of the upper surface, the upper surface is placed in the arc groove, so that the talus component is connected to the pad, and the talus component can rotate relative to the pad.

[0011] The biomimetic ligaments connect the padding and the talus component, respectively.

[0012] Optionally, the upper surface of the connector includes an arc surface and a first side surface and a second side surface located on both sides of the arc surface, the arc surface being smoothly connected to the first side surface and the second side surface, respectively.

[0013] Optionally, the arc surface forms a first intersection with the first side surface, and the arc surface forms a second intersection with the second side surface; the arc groove bends outward at the lower ends of the first side surface and the second side surface respectively, forming a first protrusion and a second protrusion;

[0014] The talus component is capable of rotating in the direction of the first protrusion until the first intersection point abuts against the first protrusion; the talus component is capable of rotating in the direction of the second protrusion until the second intersection point abuts against the second protrusion.

[0015] Optionally, the talus component can rotate relative to the pad along the length of the arc surface, and the upper surface of the connector of the talus component does not detach from the arc groove of the pad by the traction of the bionic ligament.

[0016] Optionally, the central angle of the arc surface is 100°-130°, the radius is 20mm-25mm, and the width of the arc surface is 5mm-10mm.

[0017] Optionally, the cross-section of the protrusion is a first sector, and the cross-section of the notch is a second sector, wherein the central angle of the first sector is smaller than that of the second sector.

[0018] Optionally, the central angle of the first sector differs from the central angle of the second sector by 20°-40°.

[0019] Optionally, the first medullary canal stem and the second medullary canal stem are respectively provided with a penetrating hole for filling bone cement; the two sides of the first medullary canal stem and the second medullary canal stem are recessed to form a medullary canal stem groove.

[0020] Optionally, the bionic ligament has two ends, one end of which is connected to the pad and the other end of which is connected to the talus component, and is symmetrically distributed on both sides of the pad and the talus component.

[0021] Optionally, the tibial component and the talus component are made of titanium alloy, the pad is made of high molecular weight polyethylene, and the biomimetic ligament is made of flexible material.

[0022] The beneficial effects of this invention are as follows:

[0023] (1) The ankle joint prosthesis provided by this invention can completely replace the bone and cartilage of the ankle joint surface, thereby overcoming the problem that arthroscopic ankle surgery cannot repair the cartilage surface. By using metal and polymer components to replace the original damaged ankle joint, discomfort symptoms are relieved while joint mobility is preserved.

[0024] (2) The ankle joint prosthesis provided by this invention not only maintains sufficient flexion and extension functions, but also fully realizes the inversion, eversion, and rotation functions of the ankle joint, allowing for limited movement. The tibial component rotates relative to the pad to achieve inversion and eversion of the ankle joint, while the talus component rotates relative to the pad to achieve flexion, extension, and inversion / eversion of the ankle joint. The contact surfaces between the various structures can move smoothly and alternately, allowing for full movement while preventing scratches and collisions between the structures.

[0025] (3) Two biomimetic ligaments made of flexible material are added between the talus component and the pad of the ankle joint prosthesis. These ligaments can not only limit the angles of ankle flexion, extension and inversion, but also effectively prevent joint dislocation during ankle flexion, extension and inversion movements.

[0026] (4) The tibial and talar components each contain a medullary stem, which innovatively adopts a prism-like structure instead of the commonly used cylindrical or conical structure, enhancing its resistance to rotational loosening. Several bone cement penetration holes are added to the center of the medullary stem to provide interlocking fixation of bone cement and enhance pull-out resistance. There are also a pair of recessed grooves on each side of the medullary stem, which further resists the vertical loosening and displacement of the prosthesis along the long axis of the tibia. Attached Figure Description

[0027] Figure 1 This is a rear view of the ankle joint prosthesis of the present invention.

[0028] Figure 2 This is a three-dimensional view of the ankle joint prosthesis of the present invention.

[0029] Figure 3 This is a perspective view of the tibia component of the present invention.

[0030] Figure 4 This is a perspective view of the pad of the present invention.

[0031] Figure 5 This is a top view of the ankle joint prosthesis of the present invention, wherein, Figure 5 'a' is a top view of the ankle joint prosthesis in an upright position. Figure 5 b is a top view of the ankle joint prosthesis in the internal rotation state.

[0032] Figure 6 This is a perspective view of the talus component of the present invention.

[0033] Figure 7 These are three views of the talus component of the present invention, wherein, Figure 7 'a' is a top view of the talus component. Figure 7 b is the left view of the talus component. Figure 7 c is the front view of the talus component.

[0034] Figure 8 This is a three-dimensional view of the biomimetic ligament of the present invention.

[0035] Figure 9 This is a three-dimensional view of the biomimetic ligament connection talus component of the present invention.

[0036] Figure 10 This is a perspective view of the biomimetic ligament connection pad of the present invention.

[0037] Figure 11 This is another perspective view of the gasket of the present invention.

[0038] Figure 12 This is a cross-sectional view of the gasket of the present invention.

[0039] Figure 13 This is a rear view of the ankle joint prosthesis of the present invention in an inverted position.

[0040] Figure 14 This is a right view of the ankle joint prosthesis of the present invention, wherein, Figure 14 'a' is a right view of the ankle joint prosthesis in an upright position. Figure 14 b is a right view of the ankle joint prosthesis in dorsiflexion.

[0041] In the figure, 1-tibial component, 11-first medullary canal stem, 12-platform, 121-cylindrical groove, 1210-protrusion, 1211-protrusion side, 2-pad, 21-pad body, 211-arc groove, 2111-first protrusion, 2112-second protrusion, 22-cylindrical boss, 220-notch, 3-talus component, 31-connector, 310-upper surface, 3100-arc surface, 3101-first side, 3102-second side, 3103-first intersection, 3104-second intersection, 311-bottom surface, 32-second medullary canal stem, 4-bionic ligament, 5-penetrating hole, 6-medullary canal stem groove. Detailed Implementation

[0042] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Figure 1 This is a rear view of the ankle joint prosthesis of the present invention. In the description of the present invention, unless otherwise specified, the terms "upper," "lower," "left," "right," "front," and "rear" are all used to refer to... Figure 1 Based on this, when describing inward and outward directions, the left foot is used as the example, i.e., using... Figure 1 The right side of the mid-ankle prosthesis is the medial side. (Definition) Figure 1 The horizontal direction is the x-axis, the vertical direction is the y-axis, and the direction perpendicular to the paper is the z-axis; the ankle joint prosthesis rotates around the x-axis as flexion and extension, moves around the y-axis as internal and external rotation, and moves around the z-axis as inversion and eversion. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0044] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] The ankle joint plays a crucial role in standing, walking, and running. The ankle joint has six range of motion: flexion, extension, inversion, eversion, internal rotation, and external rotation. Generally, the ankle joint can dorsiflex about 30 degrees, plantar flexion about 40 degrees, and inversion / eversion about 30 degrees, with a slight ability to internally and externally rotate. The range of motion of the ankle joint must be limited to enhance stability; otherwise, it can easily lead to injuries such as sprains and fractures. At the same time, the various structures within the ankle joint should have a high degree of adaptability to reduce joint surface wear and prevent structural dislocation.

[0046] like Figure 1 As shown, this invention provides an ankle joint prosthesis, comprising a tibial component 1, a pad 2, and a talus component 3 connected in sequence, and also including several bionic ligaments 4. One end of each bionic ligament 4 is connected to the pad 2, and the other end is connected to the talus component 3. In this embodiment, two bionic ligaments 4 are provided, respectively connecting the left and right sides of the pad 2 and the talus component 3. The tibial component 1 and the talus component 3 are made of titanium alloy, the pad 2 is made of high molecular weight polyethylene, and the bionic ligaments 4 are made of flexible material.

[0047] Tibial component 1 rotates relative to pad 2 to achieve internal and external rotation of the ankle joint prosthesis.

[0048] like Figures 1-5 As shown, the tibial component 1 includes a first medullary canal stem 11 and a platform 12 connected to the lower end of the first medullary canal stem 11. The lower surface of the platform 12 includes a cylindrical groove 121. The pad 2 includes a pad body 21, the upper surface of which is provided with a cylindrical boss 22. The cylindrical groove 121 and the cylindrical boss 22 are adapted in shape. The cylindrical boss 22 is inserted into the cylindrical groove 121, realizing the connection between the pad 2 and the tibial component 1, so that the tibial component 1 can rotate relative to the pad 2, that is, the tibial component 1 rotates relative to the pad 2 about the y-axis. The tibial component 1 rotates to the left relative to the pad 2, corresponding to the external rotation of the ankle joint prosthesis; the tibial component 1 rotates to the right relative to the pad 2, corresponding to the internal rotation of the ankle joint prosthesis (e.g., ...). Figure 5(As shown in b). To limit the rotation angle of inward and outward rotation, a protrusion 1210 is provided in the cylindrical groove 121, and the cylindrical boss 22 includes a notch 220. When the cylindrical boss 22 is inserted into the cylindrical groove 121, the protrusion 1210 is placed in the notch 220. The size of the protrusion 1210 is smaller than that of the notch 220. In this example, the cross-section of the protrusion 1210 is a first sector, and the cross-section of the notch 220 is a second sector. The central angle of the first sector is smaller than that of the second sector. The difference between the central angle of the first sector and the central angle of the second sector is 20°-40°. Preferably, the central angle of the first sector is 60°, the central angle of the second sector is 90°, and the difference between the central angles of the first sector and the second sector is 30°. The center of the protrusion 1210 inserted into the notch 220 corresponds to the upright state of the ankle joint prosthesis (e.g., Figure 5 As shown in a), at this time, the ankle joint prosthesis has a maximum internal and external rotation range of 15° and 15° respectively.

[0049] In some embodiments, to achieve a tighter locking of the tibia component 1 and the pad 2 during maximum internal and external rotation, an acute angle is formed between the protrusion side 1211 and the bottom surface of the platform 12. The two protrusion side 1211s of the protrusion 1210 are inclined surfaces, each sloping towards the center of the protrusion 1210. That is, the top edge of the protrusion side 1211 is closer to the center of the protrusion 1210 than the bottom edge. The shape of the notch 220 also matches the shape of the protrusion 1210. Therefore, when the protrusion side 1211 of the protrusion 1210 contacts the cylindrical boss 22, the interface between the protrusion 1210 and the cylindrical boss 22 is inclined. Compared with a straight surface, the inwardly inclined surface is more effective in locking the tibia component 1 and the pad 2 together, increasing the difficulty for the protrusion 1210 to slip out of the notch 220 and reducing the possibility of dislocation between the tibia component 1 and the pad 2 due to excessive internal and external rotation angle.

[0050] The talus component 3 rotates relative to the pad 2 to achieve flexion, extension, inversion, and eversion of the ankle joint prosthesis.

[0051] like Figures 6-14 As shown, the talus component 3 includes a second medullary canal stem 32 and a connector 31 connected to the upper end of the second medullary canal stem 32. The lower surface of the pad body 21 includes an arc groove 211. The shape of the upper surface 310 of the connector 31 is adapted to the shape of the arc groove 211. The upper surface 310 of the connector 31 is placed in the arc groove 211 of the pad 2 to realize the connection between the talus component 3 and the pad 2. The talus component 3 can rotate relative to the pad 2.

[0052] The talus component 3 is roughly mushroom-shaped, with the connector 31 forming the mushroom head and the second medullary canal stem 32 forming the mushroom stem. The upper surface 310 of the connector 31 includes an arc surface 3100 and a first side surface 3101 and a second side surface 3102 located on both sides of the arc surface 3100. The arc surface 3100 smoothly connects to the first side surface 3101 and the second side surface 3102, respectively. The arc surface 3100 and the first side surface 3101 form a first intersection 3103, and the arc surface 3100 and the second side surface 3102 form a second intersection 3104. The top view of the connector 31 is a rectangle with rounded corners, and the left / right views are arc-shaped. The arc groove 211 bends outwards at the lower ends of the first side surface and the second side surface, respectively, forming a smooth first protrusion 2111 and a second protrusion 2112.

[0053] Two bionic ligaments 4 are included, each a flat band with rounded ends, 24 mm long, 20 mm wide, and 2 mm thick. They are made of flexible medical-grade silicone (MED-4735 silicone rubber), possessing a certain degree of elasticity and providing strong tensile force when tensioned. One end of the bionic ligament 4 is connected to the talus component 3 via the bottom surface 311 of the connector 31, and the other end is connected to the pad 2 via the side surface of the pad body 21. Each end of the bionic ligament 4 has a pair of screws, and the bottom surface 311 of the connector 31 and the side surface of the pad body 21 each have holes for the screws to pass through. Preferably, the screws used to connect to the pad 2 have a diameter of 2 mm, and the screws used to connect to the talus component 3 have a diameter of 3 mm.

[0054] The connector 31, placed within the arc groove 211, can move relative to the pad 2 within the arc groove 211, that is, the connector 31 rotates around the z-axis. Specifically, the connector 31 of the talus component 3 rotates toward the first protrusion 2111 until the first intersection 3103 abuts against the first protrusion 2111. Restricted by the first protrusion 2111, the connector 31 cannot continue to rotate to the left, corresponding to eversion of the ankle joint prosthesis; the connector 31 of the talus component 3 rotates toward the second protrusion 2112 until the second intersection 3104 abuts against the second protrusion 2112. Restricted by the second protrusion 2112, the connector 31 cannot continue to rotate to the right, corresponding to inversion of the ankle joint prosthesis (e.g., Figure 13(As shown). When the first intersection 3103 abuts against the first protrusion 2111 or the second intersection 3104 abuts against the second protrusion 2112, the talus component 3 has a strong tendency to return to its neutral position and flip back to the neutral position. Therefore, it can effectively provide resistance and prevent excessive inversion and valgus dislocation. Preferably, when the first intersection 3103 abuts against the first protrusion 2111 or has a tendency to further outvert beyond the first protrusion 2111, the second intersection 3104 abuts against the apex of the inner wall of the arc groove 211; when the second intersection 3104 abuts against the second protrusion 2112 or has a tendency to further invert beyond the second protrusion 2112, the first intersection 3103 abuts against the apex of the inner wall of the arc groove 211, thereby again restricting the inversion and valgus of the talus component 3. The misaligned movement of the articular surface (upper surface 310) of the talus component 3 and the articular surface of the liner (surface of the arc groove 211) provides resistance to the inversion and eversion movements. However, the contact surfaces or points are relatively smooth, which is relatively consistent with the real state of the human ankle joint inversion and eversion movements, which is between unresisted and resistant. In addition, the bionic ligament 4 can also limit the inversion and eversion of the ankle joint prosthesis. When the connector 31 moves around the z-axis, the connector 31 will pull the bionic ligament 4 to stretch or compress. When the inversion and eversion angle is too large, the bionic ligament 4 on one side of the connector 31 will embed into the arc groove 211, thereby hindering larger angles of inversion and eversion movements, and further preventing excessive inversion and eversion and joint dislocation.

[0055] The connector 31, placed within the arc groove 211, can rotate within the arc groove 211 along the length of the arc surface 3100, that is, the connector 31 rotates around the x-axis. The connector 31 of the talus component 3 rotates forward along the length of the arc surface 3100, corresponding to plantar flexion of the ankle joint prosthesis; the connector 31 of the talus component 3 rotates backward along the length of the arc surface 3100, corresponding to dorsiflexion of the ankle joint prosthesis (e.g., ...). Figure 14 (As shown in b). The range of motion of plantar flexion and dorsiflexion is limited by the bionic ligament 4. By pulling on the bionic ligament 4, the angles of plantar flexion and dorsiflexion are controlled, so that the upper surface 310 of the connector 31 of the talus component 3 does not detach from the arc groove 211 of the pad 2.

[0056] The upper surface 310 of the connector 31 has a central angle of 100°-130°, a radius of 20mm-25mm, and a width of 5mm-10mm for its arc surface 3100. Preferably, the central angle of the arc surface 3100 is 121.68°, the radius is 22.73mm, and the width is 7mm. Under this design, when the articular surface (upper surface 310) of the talus component 3 and the articular surface of the liner (surface of the arc groove 211) remain in contact, the maximum angle of inversion / valgus is 26.31°. If the two articular surfaces are slightly separated, the maximum angle of inversion / valgus can reach 30° due to the limitations of the bionic ligament 4. Theoretically, the limit angle of plantar flexion and dorsiflexion of the hip joint prosthesis is 60.84° (half of 121.68°), but due to the length of the bionic ligament 4 and the surrounding bones and soft tissues of the ankle joint prosthesis, the maximum dorsiflexion of the ankle joint prosthesis is about 30°, and the maximum plantar flexion is about 40°. The flexion, extension, and inversion / extension angles all meet the needs of normal human ankle joint movement.

[0057] The first medullary canal stem 11 and the second medullary canal stem 32 are generally quadrangular prisms, with trapezoidal shapes in their left / right views. To enhance the connection between the hip joint prosthesis and the medullary canal, penetrating holes 5 for filling bone cement are provided through the first medullary canal stem 11 and the second medullary canal stem 32; the sides of the first medullary canal stem and the second medullary canal stem are recessed to form medullary canal stem grooves 6. After the first medullary canal stem 11 and the second medullary canal stem 32 can be inserted into the tibial medullary canal, they are firmly fixed to the bone using bone cement. The bone cement passes through the penetrating holes 5, forming an interlocking structure, effectively preventing prosthesis loosening, and the medullary canal stem grooves 6 can further enhance the bonding effect of the bone cement. Optionally, the first medullary canal stem 11 has a length (along the y-axis) of 30 mm and a thickness (along the x-axis) of 12 mm. Its anterior surface forms an angle of 6.69° with the y-axis, and its posterior surface forms an angle of 16.33° with the y-axis. The anterior surface is closer to a vertical shape than the posterior surface, conforming to the structural regularity of the medullary canal surface of the distal tibia. The second medullary canal stem 32 has a length (along the y-axis) of 10 mm, a thickness (along the x-axis) of 10 mm, and a width (along the z-axis) of 18 mm. The diameter of the penetrating hole 5 is 8 mm.

[0058] In summary, this invention provides an ankle joint prosthesis comprising a tibial component, a pad, and a talus component connected in sequence, and several biomimetic ligaments. The tibial component rotates relative to the pad to achieve internal and external rotation of the ankle joint, while the talus component rotates relative to the pad to achieve flexion, extension, and inversion / extension of the ankle joint. The biomimetic ligaments are made of flexible material, which not only restricts the angles of flexion, extension, and inversion / extension of the ankle joint, but also effectively prevents joint dislocation during these movements. The ankle joint prosthesis provided by this invention can fully preserve six modes of movement: flexion / extension, inversion / extension, and internal and external rotation.

[0059] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. An ankle joint prosthesis, characterized in that, It includes a tibial component, a pad and a talus component connected in sequence, as well as several bionic ligaments; The tibial component includes a first medullary canal stem and a platform connected to the lower end of the first medullary canal stem; the lower surface of the platform includes a cylindrical groove; The pad includes a pad body, the upper surface of which is provided with a cylindrical boss. The cylindrical groove and the cylindrical boss are adapted to each other. The cylindrical boss is inserted into the cylindrical groove so that the pad is connected to the tibia component and the tibia component can rotate relative to the pad. The cylindrical groove is provided with a protrusion, the cylindrical boss includes a notch, the protrusion is placed in the notch, and the size of the protrusion is smaller than the notch; the two sides of the protrusion are inclined surfaces, respectively inclined towards the center of the protrusion, and the shape of the notch is adapted to the shape of the protrusion; The lower surface of the pad body includes an arc groove; the talus component includes a second medullary canal stem and a connector connected to the upper end of the second medullary canal stem; the upper surface of the connector includes an arc surface and a first side surface and a second side surface located on both sides of the arc surface, the arc surface is smoothly connected to the first side surface and the second side surface respectively, the arc surface forms a first intersection with the first side surface, and the arc surface forms a second intersection with the second side surface; the arc groove bends outwards corresponding to the lower ends of the first side surface and the lower ends of the second side surface respectively, forming a first protrusion and a second protrusion; the upper surface of the connector includes an arc surface, the arc groove is adapted to the shape of the upper surface, the upper surface is placed in the arc groove, so that the talus component is connected to the pad, and the talus component can rotate relative to the pad; The talus component can rotate toward the first protrusion until the first intersection point abuts against the first protrusion; The talus component can rotate toward the second protrusion until the second intersection point abuts against the second protrusion; The biomimetic ligaments connect the padding and the talus component respectively; The talus component can rotate relative to the pad along the length of the arc surface. Through the traction of the bionic ligament, the upper surface of the connector of the talus component does not detach from the arc groove of the pad.

2. The ankle joint prosthesis as described in claim 1, characterized in that, The central angle of the arc surface is 100°-130°, the radius is 20 mm-25 mm, and the width of the arc surface is 5 mm-10 mm.

3. The ankle joint prosthesis as described in claim 1, characterized in that, The cross-section of the protrusion is a first sector, and the cross-section of the notch is a second sector, wherein the central angle of the first sector is smaller than that of the second sector.

4. The ankle joint prosthesis as described in claim 3, characterized in that, The central angle of the first sector differs from the central angle of the second sector by 20°-40°.

5. The ankle joint prosthesis as described in claim 1, characterized in that, The first medullary canal stem and the second medullary canal stem are connected, and each has a penetrating hole for filling bone cement; the two sides of the first medullary canal stem and the second medullary canal stem are recessed to form medullary canal stem grooves.

6. The ankle joint prosthesis as described in claim 1, characterized in that, The biomimetic ligament has two ends, one end of which is connected to the pad and the other end of which is connected to the talus component, and they are symmetrically distributed on both sides of the pad and the talus component.

7. The ankle joint prosthesis as described in claim 1, characterized in that, The tibial component and the talus component are made of titanium alloy, the pad is made of high molecular weight polyethylene, and the biomimetic ligament is made of flexible material.

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