Multi-curvature ankle joint prosthesis

Abstract

The utility model provides a multi-curvature ankle joint prosthesis which comprises a tibia prosthesis connected with a tibia, a talus prosthesis connected with a talus and a cushion block with one side connected with the tibia prosthesis, a joint contact surface is arranged on the other side of the cushion block, and a talus contact surface matched with the joint contact surface is arranged on one side of the talus prosthesis. The curvature of the sagittal plane Z in the talus contact face is reduced from front to back, and the instantaneous rotation center of the talus prosthesis on the joint contact face is in an arc shape. According to the multi-curvature ankle joint prosthesis, the talus contact face and the anatomical structure of the human body are high in consistency, the natural form and the motion mode of the ankle joint are accurately restored, the ankle joint prosthesis better conforms to biomechanics and kinematics in the motion process, the motion stability of the human body is improved, local friction stress of the ankle joint prosthesis is smaller, and the ankle joint prosthesis is more stable in motion. And the service life of the ankle joint prosthesis is prolonged, so that the durability of the ankle joint prosthesis is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to artificial joint technical field, concretely relates to a multi-curvature ankle joint prosthesis. BACKGROUND

[0002] Ankle joint osteoarthritis is a common disease of middle-aged and old people, and its causes can be divided into systemic and local biomechanical factors, which is manifested as ankle pain, limited ankle joint movement, and further affects walking, seriously affects the quality of life of middle-aged and old people, and brings long-term distress to patients. Ankle joint prosthesis system is used to replace the damaged joint of patients with severe ankle joint disease or injury, and can simulate the movement and function of natural ankle joint. The ankle joint prosthesis usually includes a tibial prosthesis (located at the ankle position of the lower limb) and a talus prosthesis (located at the back of the foot), the tibial prosthesis is provided with a pad block in sliding contact with the talus prosthesis, the prosthesis is usually made of metal, and the pad block is usually made of wear-resistant material. Ankle joint prosthesis can significantly improve the symptoms of ankle joint disease such as pain, stiffness and motor dysfunction, and improve the quality of life of patients.

[0003] However, the existing ankle joint prosthesis structure is relatively simple, the curvature of the joint contact surface on the pad block is single, and the consistency with the ankle joint structure in real biomechanics and kinematics is poor, so that the stress on the pad block is concentrated when the joint moves, which not only leads to poor biological movement stability, but also causes severe prosthesis wear and poor durability, and the applicability of the ankle joint prosthesis is not strong. The present application solves this technical problem. UTILITY MODEL CONTENT

[0004] In view of the deficiencies of the prior art, the utility model provides a multi-curvature ankle joint prosthesis, the contact points of the talus contact surface and the joint contact surface of the pad block are different with different angles of the talus prosthesis, the talus contact surface has high consistency with the human anatomical structure, accurately restores the natural form and movement mode of the ankle joint, and the ankle joint prosthesis is more consistent with biomechanics and kinematics during movement, thereby improving the movement stability of the human body, the amplitude of the talus contact surface and the joint contact surface is larger during sliding contact, stress concentration is avoided, the local friction force of the ankle joint prosthesis is smaller, the service life of the ankle joint prosthesis is improved, and the durability of the ankle joint prosthesis is improved.

[0005] To achieve the above-mentioned purpose, the utility model takes the technical scheme that a kind of multi-curvature ankle joint prosthesis, including the tibial prosthesis being connected with tibia, the talus prosthesis being connected with talus, still include the pad block being connected with the tibial prosthesis on one side, the other side of the pad block is provided with joint contact surface, one side of the talus prosthesis is provided with talus contact surface matched with the joint contact surface;

[0006] The curvature of the talus contact surface on the sagittal plane Z decreases from front to back, and the instantaneous rotation center of the talus prosthesis on the joint contact surface is arc-shaped.

[0007] The anterior thickness of the joint contact surface on the sagittal plane Y is less than the posterior thickness.

[0008] The medial thickness of the joint contact surface on the coronal plane X is greater than the lateral thickness.

[0009] The joint contact surface comprises an inner joint contact surface arranged on the medial side of the tibial prosthesis and an outer joint contact surface arranged on the lateral side of the tibial prosthesis, and the highest point of the inner joint contact surface is lower than the highest point of the outer joint contact surface.

[0010] The talar contact surface comprises an inner talar contact surface in contact with the inner joint contact surface and an outer talar contact surface in contact with the outer joint contact surface, and the curvature of the sagittal plane of the inner talar contact surface and the outer talar contact surface decreases from front to back.

[0011] The other side of the talar prosthesis is provided with three talar support rods connected with the talar bone.

[0012] One side of the pad is provided with a wedge-shaped block, one side of the tibial prosthesis is provided with a wedge-shaped groove, the wedge-shaped block is embedded in the wedge-shaped groove, and the other side of the tibial prosthesis is provided with a plurality of tibial support rods connected with the tibial bone.

[0013] Compared with the prior art, the ankle joint prosthesis has the advantages that:

[0014] (1) The ankle joint prosthesis, the contact points of the talar contact surface and the joint contact surface of the pad are different with different angles of the talar prosthesis, the curvature of the sagittal plane of the talar contact surface decreases from front to back, the talar contact surface has high consistency with the human anatomical structure, the natural form and motion mode of the ankle joint are accurately restored, the ankle joint prosthesis is more consistent with biomechanics and kinematics during motion, the motion stability of the human body is improved, the sliding contact range of the talar contact surface and the joint contact surface is larger, stress concentration is avoided, the local friction force of the ankle joint prosthesis is smaller, and the service life of the ankle joint prosthesis is improved, thereby improving the durability of the ankle joint prosthesis.

[0015] (2) The joint contact surface comprises an inner joint contact surface arranged on the medial side of the tibial prosthesis and an outer joint contact surface arranged on the lateral side of the tibial prosthesis, and the highest point of the inner joint contact surface is lower than the highest point of the outer joint contact surface, the talar contact surface comprises an inner talar contact surface in contact with the inner joint contact surface and an outer talar contact surface in contact with the outer joint contact surface, and the curvature of the sagittal plane of the inner talar contact surface and the outer talar contact surface decreases from front to back, which is different from the existing talar prosthesis, the joint contact surface and the talar contact surface adopt an asymmetric structure, the structure has high consistency with the human anatomical structure, and the biomechanical and kinematic performance of the prosthesis is further improved.

[0016] (3) The talus prosthesis is provided with three talus connecting talus support rods, so that the stability of the talus prosthesis after being implanted into the talus is stronger, and the ankle joint prosthesis is more firm and reliable. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is the overall external structure schematic diagram of the utility model;

[0018] Figure 2 is the plan view of the talus prosthesis of the utility model;

[0019] Figure 3 is the three-dimensional structure schematic diagram of the talus prosthesis of the utility model;

[0020] Figure 4 is the sagittal plane structure schematic diagram of the talus prosthesis of the utility model;

[0021] Figure 5 is the three-dimensional structure schematic diagram of the cushion block of the utility model;

[0022] Figure 6 is the sagittal plane structure schematic diagram of the cushion block of the utility model;

[0023] Figure 7 is the coronal plane structure schematic diagram of the cushion block of the utility model;

[0024] Figure 8 is the schematic diagram of the combination structure of the cushion block and the talus prosthesis of the utility model.

[0025] Wherein, in the drawing: 1, tibial prosthesis;11, wedge-shaped groove;12, tibial support rod;2, talus prosthesis;21, talus contact surface;211, talus inner contact surface;212, talus outer contact surface;22, talus support rod;3, cushion block;31, joint contact surface;311, joint inner contact surface;312, joint outer contact surface;32, wedge-shaped block;4, instantaneous rotation center. DETAILED DESCRIPTION

[0026] In order to more clearly illustrate the technical features of the scheme, the following through specific implementation, the scheme is described.

[0027] Referring to Figures 1-8 A multi-curvature ankle joint prosthesis, comprising a tibial prosthesis 1 connected with a tibia, a talus prosthesis 2 connected with a talus, and a cushion block 3 connected with the tibial prosthesis 1 on one side, the other side of the cushion block 3 is provided with a joint contact surface 31, and the talus prosthesis 2 is provided with a talus contact surface 21 matched with the joint contact surface 31 on one side;

[0028] The curvature of the talus contact surface 21 on the sagittal plane Z decreases from front to back, and gradually decreases, and the instantaneous rotation center 4 of the talus prosthesis 2 on the joint contact surface 31 is arc-shaped.

[0029] The sagittal plane Y of the articular contact surface 31 is thicker on the front side than on the back side, as shown in particular in Figure 6 where a > b and the angle a between the line connecting the two edges of the articular contact surface 31 and the vertical line is less than 90 degrees.

[0030] The coronal plane X of the articular contact surface 31 is thicker on the medial side than on the lateral side, as shown in particular in Figure 7 The distance between the top surface of the articular lateral contact surface 312 and the bottom surface of the wedge 32 is c, and the distance between the top surface of the articular medial contact surface 311 and the bottom surface of the wedge 32 is d, where d is greater than c.

[0031] The articular contact surface 31 comprises an articular medial contact surface 311 arranged on the medial side of the tibial prosthesis 1 and an articular lateral contact surface 312 arranged on the lateral side of the tibial prosthesis 1, the highest point of the articular medial contact surface 311 being lower than the highest point of the articular lateral contact surface 312.

[0032] The talus contact surface 21 comprises a talus medial contact surface 211 in contact with the articular medial contact surface 311 and a talus lateral contact surface 212 in contact with the articular lateral contact surface 312, the curvature of the sagittal plane of the talus medial contact surface 211 and the talus lateral contact surface 212 decreasing from front to back.

[0033] The other side of the talus prosthesis 2 is provided with three talus support rods 22 connected to the talus.

[0034] One side of the pad 3 is provided with a wedge 32, one side of the tibial prosthesis 1 is provided with a wedge groove 11, the wedge 32 is embedded in the wedge groove 11, and the other side of the tibial prosthesis 1 is provided with a plurality of tibial support rods 12 connected to the tibia.

[0035] The specific working principle of the utility model is as follows:

[0036] As shown in Figure 4 Unlike the fixed curvature of the existing talus contact surface 21, in the present scheme, when the talus prosthesis 2 moves relatively on the pad 3, the contact points of the talus contact surface 21 and the articular contact surface 31 of the pad 3 are different with different angles of the talus prosthesis 2, wherein the curvature of the sagittal plane Z of the talus contact surface 21 decreases continuously from front to back, thereby making the instantaneous rotation center 4 of the talus prosthesis 2 on the articular contact surface 31 arc-shaped, the talus contact surface 21 has high consistency with the human anatomical structure, accurately restores the natural form and movement mode of the ankle joint, the ankle joint prosthesis is more consistent with biomechanics and kinematics during movement, improves the movement stability of the human body, the sliding contact range of the talus contact surface 21 and the articular contact surface 31 is larger, stress concentration is avoided, the local friction force of the ankle joint prosthesis is smaller, the service life of the ankle joint prosthesis is improved, and the durability of the ankle joint prosthesis is improved.

[0037] In addition, the ankle prosthesis of the present scheme has the following advantages:

[0038] 1. Single radius design may lead to inappropriate prosthesis size, causing complications such as pain, impact, bone loss, etc., while multi-curvature design can be customized according to individual differences of patients, more accurately matching the patient's anatomy, thereby reducing the risk of complications;

[0039] 2. Improve patient satisfaction: Multi-curvature design can provide more natural and comfortable ankle joint movement, thereby improving the quality of life and satisfaction of patients;

[0040] 3. Facilitate individualized design of ankle prosthesis: Multi-curvature design can be customized according to factors such as patient's gender, age, bone characteristics, etc., providing more accurate treatment options for patients. In summary, the multi-curvature design of ankle prosthesis is more consistent with human anatomy, which can improve the biomechanics and kinematics of ankle joint, reduce the risk of complications, improve patient satisfaction, and promote the individualized development of ankle prosthesis design.

[0041] The joint contact surface 31 includes an inner joint contact surface 311 arranged on the medial side of the tibial prosthesis 1 and an outer joint contact surface 312 arranged on the lateral side of the tibial prosthesis 1, the highest point of the inner joint contact surface 311 is lower than the highest point of the outer joint contact surface 312, the talar contact surface 21 includes a talar inner contact surface 211 in contact with the inner joint contact surface 311 and a talar outer contact surface 212 in contact with the outer joint contact surface 312, the curvature of the sagittal plane of the talar inner contact surface 211 and the talar outer contact surface 212 decreases from front to back. Unlike the existing talar prosthesis 2, the joint contact surface 31 and the talar contact surface 21 adopt an asymmetric structure, which has strong consistency with the human anatomical structure, further improving the biomechanics and kinematics of the prosthesis.

[0042] The talar prosthesis 2 is provided with three talar connecting talar support rods 22, and the stability of the talar prosthesis 2 after implantation into the talus is stronger, and the ankle prosthesis is more firm and reliable.

[0043] It should be noted that in the anatomy of the human body, the structure of the ankle joint, in recent decades, considerable attention has been paid to the sagittal geometry of the talus, previous studies have generally described the sagittal geometry of the talar dome using a single radius curve and found that the medial radius of the talar dome is significantly larger than the lateral radius. Recently, Nozaki et al. evaluated the anteroposterior radii of 50 dry talus trochlea from an Asian population using a dual-radius approach. They showed that the shape of the talus is bilaterally asymmetric, resulting in opposite axial rotations during ankle plantarflexion and dorsiflexion. While distal morphology has been well understood, studies on the corresponding tibial plateau are still lacking. The present scheme is based on the prior art and further research is carried out, the ankle joint is divided into multiple sagittal planes for research based on computer tomography (CT) data, so as to determine the curvature of the tibial prosthesis 1 sagittal plane tibial articular surface 31 and talar contact surface 21.

[0044] Methods: 100 adult ankle CT images were collected, and the three-dimensional structure of the ankle joint was reconstructed. The anatomical coordinate system of the three-dimensional ankle model was established, and the standard coronal and sagittal planes were established. The measurement results of the sagittal plane curvature include: the anteroposterior diameter of the five segments (the innermost, the inner 1 / 4, the middle, the outer 1 / 4 and the outermost) of the sagittal plane, the tibial distal arch length (TAL) and the tibial distal slot depth (TMD). Group analysis was performed to compare the differences between men and women.

[0045] Results: The sagittal plane curvature analysis showed that the anterior diameter of the tibial plateau was significantly smaller than the posterior diameter, with an average difference of 3.9-6.8mm (P<0.001) in the five sagittal planes. Among the anterior diameters, the anterior medial curvature was the smallest (35.3±5.3mm), and the anterior lateral curvature was the largest (38.0±5.8mm). Among the posterior diameters, the posterior medial curvature was the smallest (39.2±6.4mm), and the posterior lateral 1 / 4 curvature was the largest (43.5±6.9mm). One-way ANOVA (ANOVA) showed that there was a significant difference in the anteroposterior diameter between the five groups (P<0.012). Subgroup analysis showed that gender partially affected the results of vector curvature measurement.

[0046] Conclusion: The anteroposterior diameter of the tibial plateau sagittal plane can accurately and quantitatively describe the curvature of the tibial plateau sagittal plane. The results of this study show that there is a significant difference between the anterior diameter and the posterior diameter of the tibial plateau sagittal plane, and gender is an important factor affecting the curvature of the tibial plateau sagittal plane.

[0047] The technical features not described in the utility model can be realized by or using the prior art, which will not be described here. Of course, the above description is not a limitation of the utility model, and the utility model is not limited to the above examples. Changes, modifications, additions or replacements made by ordinary skilled persons in the technical field within the essential scope of the utility model should also be within the protection scope of the utility model.

Claims

1. A multi-curvature ankle prosthesis comprising a tibial prosthesis (1) to be connected with a tibia, a talus prosthesis (2) to be connected with a talus, characterized in that, The tibial prosthesis (1) is connected with a pad (3) on one side, and the other side of the pad (3) is provided with a joint contact surface (31); one side of the talus prosthesis (2) is provided with a talus contact surface (21) matched with the joint contact surface (31). The curvature of the talus contact surface (21) on the sagittal plane Z decreases from front to back, and the instantaneous rotation center (4) of the talus prosthesis (2) on the joint contact surface (31) is arc-shaped.

2. The multi -curvature ankle prosthesis of claim 1, wherein, The front side thickness of the joint contact surface (31) on the sagittal plane Y is less than the back side thickness.

3. The multi -curvature ankle prosthesis of claim 2, wherein, The inside thickness of the joint contact surface (31) on the coronal plane X is greater than the outside thickness.

4. The multi-curved ankle prosthesis of claim 3, wherein, The joint contact surface (31) includes an inside joint contact surface (311) arranged on the inside of the tibial prosthesis (1) and an outside joint contact surface (312) arranged on the outside of the tibial prosthesis (1), and the highest point of the inside joint contact surface (311) is lower than that of the outside joint contact surface (312).

5. The multi-curved ankle prosthesis of claim 4, wherein, The talus contact surface (21) includes a talus inside contact surface (211) in contact with the inside joint contact surface (311) and a talus outside contact surface (212) in contact with the outside joint contact surface (312), and the curvatures of the sagittal planes of the talus inside contact surface (211) and the talus outside contact surface (212) both decrease from front to back.

6. The multi-curved ankle prosthesis of claim 1, wherein, The other side of the talus prosthesis (2) is provided with three talus support rods (22) connected with the talus.

7. The multi-curved ankle prosthesis of claim 1, wherein, One side of the pad (3) is provided with a wedge-shaped block (32), one side of the tibial prosthesis (1) is provided with a wedge-shaped groove (11), the wedge-shaped block (32) is embedded in the wedge-shaped groove (11), and the other side of the tibial prosthesis (1) is provided with a plurality of tibial support rods (12) connected with the tibia.

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