Air cushion type knee joint prosthesis

Abstract

The utility model discloses an air cushion type knee joint prosthesis which comprises a tibia prosthesis platform, a femur prosthesis platform and a liner prosthesis arranged between the tibia prosthesis platform and the femur prosthesis platform. The lower articular surface of the pad prosthesis is fixed with the tibia prosthesis platform, and the upper articular surface of the pad prosthesis is in pressure contact with the thighbone prosthesis platform; the liner prosthesis is of a capsule structure and comprises an elastic capsule wall and a plurality of damping supporting arms, the damping supporting arms are fixed to an inner cavity of the capsule wall, the damping supporting arms are arranged in parallel at intervals, each damping supporting arm is arranged in the left-right direction, and the upper end of each damping supporting arm inclines forwards. According to the air cushion type knee joint prosthesis, the lower articular surface of the pad prosthesis is fixed with the tibia prosthesis platform, so that the stability of the pad prosthesis is ensured, and dislocation of the pad prosthesis is avoided; the liner prosthesis has elastic deformation, and when the knee joint is bent, the liner prosthesis can change the shape to adapt to the curvature change of the femoral condyle and has compliance, so that the wear resistance borne by the liner prosthesis is small, and the service life of the liner prosthesis is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of artificial knee joints of medical devices, in particular to an air cushion type knee joint prosthesis. Background Art

[0002] The knee joint is the largest joint in the human body, with complex anatomy and high requirements for movement function. Knee osteoarthritis and rheumatoid arthritis are the most common arthritis of the knee joint. In the late stage of arthritis, severe joint deformity and movement disorders occur, and total knee resurfacing surgery is required. Artificial total knee replacement can relieve joint pain, correct joint deformity, and restore joint mobility. It has become the preferred method for treating knee joint diseases. After surgery, it can effectively relieve knee pain and meet the patient's requirements for pain relief.

[0003] Unicompartmental knee prosthesis is a surgical implant used to replace the knee joint and is used in unicompartmental knee replacement surgery. Compared with total knee replacement surgery, unicompartmental knee replacement surgery can significantly reduce the patient's intraoperative bleeding and postoperative recovery time. Because it retains the anterior and posterior cruciate ligaments of the human body, it maintains the normal dynamics of the knee joint, thereby enabling patients to obtain a higher level of postoperative knee joint mobility.

[0004] For unicompartmental knee replacement surgery, whether the unicompartmental knee prosthesis can be stably and firmly matched in the patient's body is crucial to the success of the operation. It can also reduce the patient's postoperative pain and reduce the possibility of postoperative revision. The unicompartmental artificial knee system includes a femoral condyle prosthesis, a liner and a tibial plateau prosthesis. The femoral condyle prosthesis is connected and fixed to the human femoral condyle to replace the damaged condyle surface; the tibial plateau prosthesis is connected and fixed to the human tibia to replace the damaged tibial surface; the tibial liner is located between the femoral condyle prosthesis and the tibial plateau prosthesis, bearing the pressure load of the human body and meeting the requirements of sports friction function.

[0005] Unicompartmental knee prostheses mainly have two typical forms: fixed platform and mobile platform. Mobile platform type unicompartmental knee prostheses are widely used in clinical practice. The femoral condyle and tibial pad are highly matched, and the tibial pad and tibial plateau can move freely, which greatly facilitates the doctor's installation during surgery. However, in the mobile platform type unicompartmental knee prosthesis, the surface where the femoral condyle prosthesis matches the pad is usually a curved surface, which causes the femoral condyle prosthesis to not always maintain close contact with various parts of the pad during movement relative to the pad, which can cause the pad to easily fall out. At present, there is a 4.6% probability of revision after patients undergo unicompartmental knee replacement surgery. Among them, the probability of revision due to pad dislocation during revision surgery is 33%, that is, the pad in the unicompartmental knee prosthesis in the prior art is prone to dislocation, which affects the stability of the unicompartmental knee prosthesis and reduces the reliability of the use of the unicompartmental knee prosthesis. Summary of the Invention

[0006] The technical problem to be solved by the utility model is to provide an air-cushioned knee joint prosthesis that can prevent the liner from dislocating.

[0007] To solve the above technical problem, the technical solution adopted by the utility model is:

[0008] An air-cushioned knee joint prosthesis, including a tibial prosthesis platform, a femoral prosthesis platform and a liner prosthesis placed between the two, is characterized in that: the lower joint surface of the liner prosthesis is fixed to the tibial prosthesis platform, and the upper joint surface of the liner prosthesis is in pressure contact with the femoral prosthesis platform; the liner prosthesis is in the form of a capsule structure, including an elastic capsule wall and a plurality of damping arms, the damping arms are fixed in the inner cavity of the capsule wall, the plurality of damping arms are spaced and arranged in parallel, each damping arm is arranged in the left-right direction, and the inner cavity of the capsule wall is divided into a plurality of chambers from front to back, and the upper ends of the damping arms are inclined forward.

[0009] A further technical solution lies in that: the damping arms and the capsule wall are integrally formed.

[0010] A further technical solution lies in that: the upper joint surface of the liner prosthesis is a concave spherical surface matching the femoral prosthesis platform, and the lower joint surface is a plane.

[0011] A further technical solution lies in that: the height of the upper joint surface extending upward to wrap the femoral prosthesis platform at the rear edge is greater than the height of the upper joint surface extending upward to wrap the femoral prosthesis platform at the front edge.

[0012] A further technical solution lies in that: there is a tibial inlay member embedded in the tibia and fixed thereto below the tibial prosthesis platform, and the tibial inlay member has fixing screw holes for bolts to pass through, and the front end of the bolt is conical.

[0013] A further technical solution lies in that: the number of the fixing screw holes is at least two.

[0014] A further technical solution lies in that: there are femoral inlay members embedded in the femur and fixed thereto on the inner side of the femoral prosthesis platform, and the femoral inlay members have permeation holes.

[0015] A further technical solution lies in that: there are two femoral inlay members.

[0016] The beneficial effects of adopting the above technical solutions are as follows:

[0017] In this air-cushioned knee joint prosthesis, the cushion prosthesis adopts the structure of an airbag. The lower joint surface of the cushion prosthesis is fixed to the tibial prosthesis platform, ensuring the stability of the cushion prosthesis and preventing the cushion prosthesis from dislocating. The cushion prosthesis has an elastic deformation amount. When the knee joint flexes, the cushion prosthesis can change its shape to adapt to the curvature change of the femoral condyle, showing compliance. This makes the wear resistance force on the cushion prosthesis smaller and extends the service life of the cushion prosthesis.

[0018] The upper joint surface of the cushion prosthesis maintains pressure contact with the femoral prosthesis platform, ensuring that the plane of the femoral condyle prosthesis remains in close contact with all parts of the cushion during its movement relative to the cushion prosthesis, also preventing the cushion prosthesis from dislocating.

[0019] Moreover, there are multiple damping support arms arranged at intervals and in parallel inside the cushion prosthesis. Each damping support arm is arranged in the left-right direction, and the upper end of the damping support arm tilts forward. With the setting of the damping support arms, when the cushion prosthesis is subjected to the force exerted by the tibial prosthesis platform, it can only be squeezed to deform forward, and is damped by the damping support arms when moving backward, thus restricting the backward deformation of the cushion prosthesis and further ensuring the stability of the position of the cushion prosthesis. Brief Description of the Drawings

[0020] The following further elaborates on the present utility model in detail in conjunction with the drawings and specific embodiments.

[0021] Figure 1 is the structural schematic diagram of the present utility model;

[0022] Figure 2 is the cross-sectional structural schematic diagram of the present utility model;

[0023] Figure 3 is the structural schematic diagram of the cushion prosthesis in the present utility model;

[0024] Figure 4 is the structural schematic diagram of two air-cushioned knee joint prostheses of the present utility model connected;

[0025] Figure 5 is the lateral view schematic diagram of replacing a total knee replacement surgery with two air-cushioned knee joint prostheses of the present utility model;

[0026] Figure 6 is the front view schematic diagram of replacing a total knee replacement surgery with two air-cushioned knee joint prostheses of the present utility model. Detailed Embodiments

[0027] Combined with the accompanying drawings in the embodiments of the present utility model, the technical solutions in the embodiments of the present utility model are clearly and completely described. Obviously, the described embodiments are part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present utility model.

[0028] Many specific details are set forth in the following description in order to provide a thorough understanding of the present utility model, but the present utility model may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present utility model. Therefore, the present utility model is not limited by the specific embodiments disclosed below.

[0029] As Figures 1 to 6 shown, an air-cushioned knee joint prosthesis includes a tibial prosthesis platform 10, a femoral prosthesis platform 20, and a cushion prosthesis 30 disposed therebetween. The lower joint surface of the cushion prosthesis 30 is fixed to the tibial prosthesis platform 10, and the fixing method can adopt the existing embedded injection molding connection process or adhesive fixation. The upper joint surface of the cushion prosthesis 30 is in pressure contact with the femoral prosthesis platform 20. The cushion prosthesis 30 has a bladder structure. The cushion prosthesis 30 includes an elastic bladder wall and a plurality of damping arms 310. The damping arms 310 are integrally formed with the bladder wall, and can be made of soft elastic polymers such as polypropylene, polyurethane or silicone that have biocompatibility and can be prepared into an inflatable structure. The damping arms 310 are fixed to the inner cavity of the bladder wall. The plurality of damping arms 310 are spaced and arranged in parallel. Each damping arm 310 is arranged in the left-right direction, dividing the inner cavity of the bladder wall into a plurality of chambers from front to back, and the upper end of the damping arm 310 is inclined forward.

[0030] In this air-cushioned knee joint prosthesis, the cushion prosthesis 30 adopts the structure of an airbag. The lower joint surface of the cushion prosthesis 30 is fixed to the tibial prosthesis platform 10, ensuring the stability of the cushion prosthesis 30 and avoiding dislocation of the cushion prosthesis 30. The cushion prosthesis 30 has an elastic deformation amount. When the knee joint flexes, the cushion prosthesis 30 can change its shape to adapt to the change of the femoral condyle curvature, having compliance, so that the wear resistance force received by the cushion prosthesis 30 is smaller, and the service life of the cushion prosthesis 30 is improved.

[0031] The upper joint surface of the cushion prosthesis 30 remains in pressure contact with the femoral prosthesis platform 20, so that the femoral condyle prosthesis plane always remains in close contact with all parts of the cushion during the movement relative to the cushion prosthesis 30, also avoiding dislocation of the cushion prosthesis 30.

[0032] Moreover, inside the cushion prosthesis 30, there are multiple spaced and parallel damping support arms 310. Each damping support arm 310 is arranged in the left-right direction, and the upper end of the damping support arm 310 is tilted forward. Through the arrangement of the damping support arms 310, when the cushion prosthesis 30 is subjected to the force applied by the tibial prosthesis platform 10, it can only squeeze the cushion prosthesis 30 to deform forward, and is damped by the damping support arms 310 backward, thereby restricting the backward deformation of the cushion prosthesis 30 and further ensuring the stability of the position of the cushion prosthesis 30.

[0033] The upper joint surface of the cushion prosthesis 30 is a concave spherical surface matching the femoral prosthesis platform 20, and the lower joint surface is a plane. Moreover, the height that the rear edge of the upper joint surface extends upward to wrap the femoral prosthesis platform 20 is greater than the height that the front edge of the upper joint surface extends upward to wrap the femoral prosthesis platform 20, so as to ensure good wrapping between the cushion prosthesis 30 and the femoral prosthesis platform 20 and prevent the cushion prosthesis 30 from dislocating.

[0034] Below the tibial prosthesis platform 10, there is a tibial inlay member 110 embedded in the tibia and fixed thereto. The tibial inlay member 110 has fixing screw holes through which bolts can pass. Preferably, the front end of the bolt is tapered, which is convenient for the bolt to be driven into the fixing screw hole, and the number of the fixing screw holes is at least two to ensure that the tibial prosthesis platform 10 will not rotate and shift along the fixing screw holes. By setting the fixing screw holes, point-to-point fixation of the bolt and the tibial inlay member 110 can be achieved first when installing the tibial inlay member 110. Bone ingrowth holes can also be provided on the tibial inlay member 110, and then self-bone tissue fixation can be achieved during the subsequent bone ingrowth process, thereby achieving a more stable fixation effect of the tibial prosthesis platform 10. Compared with the existing knee joint prosthesis, in which a slot-shaped hole is provided on the tibial inlay member 110, the present application avoids the problem that the opening area of such a slot-shaped hole is relatively large, resulting in an unsatisfactory fixation effect after bone ingrowth by setting the fixing screw holes and the bone ingrowth holes.

[0035] Inside the medial side of the femoral prosthesis platform 20, there is a femoral inlay member 210 embedded in the femur and fixed thereto. In the present utility model, the femoral inlay member 210 has penetration holes, making the growth combination of the prosthesis and the bone more firm. Similarly, there are two femoral inlay members 210 to improve the fixation stability of the femoral prosthesis platform 20 and the patient's femur.

[0036] The above are only the preferred embodiments of the present utility model. Any minor simple modifications, deformations, and equivalent replacements made by anyone based on the content of the present utility model fall within the protection scope of the present utility model.

Claims

1. An air cushion knee joint prosthesis, comprising a tibial prosthesis platform (10), a femoral prosthesis platform (20) and a cushion prosthesis (30) disposed therebetween, characterized in that: The lower joint surface of the cushion prosthesis (30) is fixed to the tibial prosthesis platform (10), and the upper joint surface of the cushion prosthesis (30) is in pressure contact with the femoral prosthesis platform (20); the cushion prosthesis (30) is a capsule structure, including an elastic capsule wall and a plurality of damping arms (310), the damping arms (310) are fixed to the inner cavity of the capsule wall, and the plurality of damping arms (310) are arranged in parallel and at intervals, each damping arm (310) is arranged in the left-right direction, and the inner cavity of the capsule wall is divided into a plurality of chambers from front to back, and the upper end of the damping arm (310) is inclined forward.

2. The air cushion knee joint prosthesis according to claim 1, characterized in that: The damping support arm (310) is integrally formed with the capsule wall.

3. The air cushion knee joint prosthesis according to claim 1, characterized in that: The upper joint surface of the cushion prosthesis (30) is a concave spherical surface matching the femoral prosthesis platform (20), and the lower joint surface is a plane.

4. The air cushion knee joint prosthesis according to claim 3, characterized in that: The height to which the rear edge of the upper joint surface extends upwards to wrap around the femoral prosthesis platform (20) is greater than the height to which the front edge of the upper joint surface extends upwards to wrap around the femoral prosthesis platform (20).

5. The air cushion knee joint prosthesis according to claim 1, characterized in that: A tibial embedded component (110) is provided below the tibial prosthesis platform (10) and is embedded in the tibia and fixed thereto. The tibial embedded component (110) has a fixing screw hole (111) for a bolt to pass through.

6. The air cushion knee joint prosthesis according to claim 5, characterized in that: The number of the fixing screw holes is at least two.

7. The air cushion knee joint prosthesis according to claim 1, characterized in that: The inner side of the femoral prosthesis platform (20) is provided with a femoral embedded component (210) embedded in the femur and fixed thereto, and the femoral embedded component (210) is provided with a penetration hole.

8. The air cushion knee joint prosthesis according to claim 7, characterized in that: The femoral embedded components (210) are two in number.

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