Articular gasket prosthesis and articular prosthesis with articular gasket prosthesis

The disclosure provides an articular gasket prosthesis and an articular prosthesis with the articular gasket prosthesis. The articular gasket prosthesis includes an elastic gasket disposed between a first skeleton and second skeleton forming a joint, the elastic gasket including: an elastic matrix, having a first contact surface facing the first skeleton and a second contact surface facing the second skeleton; and multiple synovial fluid passages, distributed in the elastic matrix and communicating the first contact surface and the second contact surface, the multiple synovial fluid passages being disposed according to a predetermined manner to gradually increase hardness of the elastic matrix from a center to an edge and gradually decrease elasticity of the elastic matrix from the center to the edge.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority to Chinese Patent Application No. 201910105642.0, filed on Feb. 1, 2019 and entitled “Articular Gasket Prosthesis and Articular Prosthesis with Articular Gasket Prosthesis”, the contents of which are hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The disclosure relates to a field of artificial prosthesis replacement, and particularly to an articular gasket prosthesis and an articular prosthesis with the articular gasket prosthesis.

BACKGROUND

In a present knee joint prosthesis for an artificial knee joint replacement operation, a femoral condyle prosthesis is usually made from a medical metal, for example, stainless steel or a cobalt alloy, on a tibia side, and a gasket is made from ultra-high molecular weight polyethylene on a tibia side. For a kinematic requirement of a knee joint, a metal articular surface of the femoral condyle prosthesis is usually designed into a complex continuous spatial curved surface, but the ultra-high molecular weight polyethylene articular surface gasket on the tibia side may only be designed into a curved surface with a relatively high matching degree with the articular surface on the femur side according to a specific position (for example, an upright position), to ensure stability in an upright state. However, along with motions of the knee joint, a contact area between the femoral condyle prosthesis and the articular surface gasket may be far smaller than an ideal value, which causes excessively high pressure between the femoral condyle prosthesis and the articular surface gasket and accelerates wear to the articular surface gasket. In addition, since no close connections may be established between ligaments and tissues around the operated joint and the implanted artificial articular prosthesis like those between original articular biological tissues, stability of a mechanical system, of which balance heavily depends on soft tissues, of the knee joint is greatly reduced.

SUMMARY

The disclosure is intended to provide an articular gasket prosthesis and an articular prosthesis with the articular gasket prosthesis, to solve the problem of short service life of an articular prosthesis of a patient caused by excessively high local pressure and serious wear of an articular gasket prosthesis due to the fact that a contact area between a femoral condyle prosthesis and the articular gasket prosthesis may not be ensured in a conventional art.

To this end, according to one aspect of the disclosure, an articular gasket prosthesis is provided, which includes an elastic gasket disposed between a first skeleton and a second skeleton, wherein the first skeleton and the second skeleton form a joint, the first skeleton referring to a skeleton forming a significant sliding friction relationship with the articular gasket prosthesis of the disclosure and the second skeleton referring to a skeleton on which the articular gasket prosthesis of the disclosure is fixed, wherein the elastic gasket includes: an elastic matrix, having a first contact surface facing the first skeleton and a second contact surface facing the second skeleton; and a plurality of synovial fluid passages, distributed in the elastic matrix and communicating the first contact surface and the second contact surface, the plurality of synovial fluid passages being disposed according to a predetermined manner, so as to gradually increase a hardness of the elastic matrix from a center to an edge and gradually decrease an elasticity of the elastic matrix from the center to the edge.

In some embodiments, the plurality of synovial fluid passages include a plurality of accommodation cavity layers and a plurality of flow passages, the plurality of accommodation cavity layers are disposed in a direction from the first contact surface to the second contact surface, each of the plurality of accommodation cavity layers includes a plurality of accommodation cavities, and each of the plurality of flow passages is connected between two adjacent accommodation cavity layers of the plurality of accommodation cavity layers.

In some embodiments, volumes of the plurality of accommodation cavity layers are gradually decreased in the direction from the first contact surface to the second contact surface.

In some embodiments, the plurality of accommodation cavities are gradually reduced in the direction from the first contact surface to the second contact surface.

In some embodiments, volumes of the plurality of accommodation cavities in a same accommodation cavity layer are gradually decreased from a center to an edge of the same accommodation cavity layer.

In some embodiments, the synovial fluid passages further include an inflow passage, and a check valve is disposed in the inflow passage, the inflow passage is communicated with at least one accommodation cavity of the plurality of accommodation cavities, or the inflow passage is communicated with at least one flow passage of the plurality of flow passages, or the inflow passage is communicated with at least one accommodation cavity of the plurality of accommodation cavities and at least one flow passage of the plurality of flow passages.

In some embodiments, the articular gasket prosthesis further includes a gasket matrix, the gasket matrix is disposed between the first skeleton and the second skeleton, the gasket matrix is provided with an accommodation groove, the elastic gasket is disposed in the accommodation groove, and a hardness of the gasket matrix is higher than a hardness of the elastic gasket.

In some embodiments, a positioning protruding portion is disposed on a circumferential sidewall of the elastic matrix, and a positioning groove is formed at the position, corresponding to the positioning protruding portion, of the accommodation groove.

In some embodiments, a flow groove is formed in a bottom surface of the gasket matrix, and a communicating hole is formed in a bottom of the accommodation groove and communicated with the flow groove such that a synovial fluid is able to enter the accommodation groove through the flow groove and the communicating hole.

In some embodiments, the gasket matrix further includes a communicating passage, an inlet of the communicating passage extends onto a top surface of the gasket matrix, and an outlet of the communicating passage is communicated with the inflow passage.

In some embodiments, the articular gasket prosthesis further includes a reinforcing ring, and the reinforcing ring is disposed on a circumferential outer side of the gasket matrix.

In some embodiments, both of a penetration layer and integration layer of the reinforcing ring are of a porous structure, the penetration layer is able to form contact fusion with the gasket matrix, soft tissues around the joint are able to grow into the integration layer, and an isolation layer is disposed between the penetration layer and the integration layer.

In some embodiments, both of the penetration layer and integration layer of the reinforcing ring are of a porous structure, a pore diameter of the porous structure of the penetration layer is 500 μm to 3,000 μm, and a pore diameter of the porous structure of the integration layer is 400 μm to 2,000 μm.

In some embodiments, the elastic gasket is made from an elastic transparent polymer material or composite material.

According to the other aspect of the disclosure, an articular prosthesis is provided, which includes the articular gasket prosthesis being the abovementioned articular gasket prosthesis.

In some embodiments, the articular prosthesis is a knee joint prosthesis, and the knee joint prosthesis further includes a tibial plateau prosthesis and a femoral condyle prosthesis.

With application of the technical solutions of the disclosure, the synovial fluid passages are disposed in the elastic gasket according to the predetermined manner, and parameters such as sectional shapes, pore diameters, lengths, volumes, positions, arrangement direction and density of the synovial fluid passages are regulated to gradually increase the hardness of the elastic matrix from the center to the edge and also gradually decrease the elasticity from the center to the edge, so that different elasticity and hardness indexes may be achieved at different predetermined parts of the elastic gasket to make the elastic gasket close to mechanical characteristics of a human joint as much as possible, the elastic gasket may fully contact with an articular skeleton during joint motions, pressure between contact surfaces is further kept within an ideal range, and a using effect and service life of the articular gasket prosthesis are ensured. In addition, such a porous structure design that the pore aperture of the integration layer of the reinforcing ring is 400 μm to 2,000 μm enables soft tissues such as an articular capsule and primary ligament residues wrapping the articular gasket prosthesis after an operation to grow in pores of the porous structure of the integration layer to form biological tissue integration and enables the soft tissues such as ligaments to grow in the pores of the porous structure in a postoperative healing process, so that a postoperative knee joint system is more stable.

Herein, the drawings include the following drawing reference signs:

DETAILED DESCRIPTION OF THE EMBODIMENTS

An articular gasket prosthesis of the application is applied to artificial joint replacement operations and configured to absorb impacts generated by joint motions and reduce frictional damage between articular skeletons. For example, in a human knee joint, a femur swings and rotates relative to a tibia to implement leg bending and turning, and cartilages on a distal femur (femoral condyle) and a proximal tibia (tibial plateau) and meniscus structure act as a gasket between the femur and the tibia. Bending trends of upper and lower surfaces of the meniscus structure are approximate to those of a curved surface of the distal femur and a curved surface of the proximal tibia, a contact area of the joint is enlarged, stability of the joint is improved, and pressure is reduced. Meanwhile, the meniscus structure also has high elasticity and may be properly deformed to absorb impacts and shocks and adapted to an anatomic form of the distal femur when the knee joint moves to ensure coordination of a geometric form of the knee joint, thereby maintaining motion coordination of the knee joint.

In a present knee joint prosthesis for an artificial knee joint replacement operation, a femoral condyle prosthesis is usually made from a medical metal on a femur side, and a gasket is made from ultra-high molecular weight polyethylene on a tibia side. The gasket is undiversified in material and structure and, although having certain elasticity, may even recover a deformation amplitude and buffering and wear reduction effects of a primary meniscus structure and cartilage. In addition, since the gasket made from the ultra-high molecular weight polyethylene is not elastic enough, when the knee joint starts bending for motion, an effective contact area between the femoral condyle prosthesis and the gasket may be very small along with position and angle changes between the femur and the tibia, even only linear contact or point contact may be met at some positions, and local high pressure is generated at these positions to accelerate wear of an articular surface to further affect service life of the whole knee joint as well as the life of a patient after the operation. Moreover, there are no more close connections between ligaments and soft tissues around the primary joint and the implanted artificial joint prosthesis after the operation, stability of a mechanical system, of which balance heavily depends on the soft tissues, of the knee joint is greatly reduced. For the foregoing problems, the application discloses structural improvements in the gasket.

It is to be noted that the embodiments in the application and characteristics in the embodiments may be combined without conflicts. The disclosure will be described below with a knee joint as an example with reference to the drawings and in combination with the embodiments in detail.

As shown inFIG. 1,FIG. 2andFIG. 8, each of an articular gasket prosthesis of embodiment 1 and an articular gasket prosthesis of embodiment 2 includes an elastic gasket10, the elastic gasket10is disposed between a femur structure and a tibia structure, and the elastic gasket10includes an elastic matrix and multiple synovial fluid passages distributed in the elastic matrix. The elastic matrix has a first contact surface facing the femur structure and a second contact surface facing the tibia structure, and the multiple synovial fluid passages communicate the first contact surface and the second contact surface to enable a synovial fluid to pass through the elastic matrix and flow in the elastic matrix. The multiple synovial fluid passages are disposed according to a predetermined manner to gradually increase a hardness of the elastic matrix from a center to an edge and gradually decrease elasticity of the elastic matrix from the center to the edge.

As shown inFIG. 9, in an unloaded and straightened state of a knee, the articular gasket prosthesis2is disposed on a tibial plateau prosthesis3, and an upper surface of the elastic gasket10of the articular gasket prosthesis2is attached to a femoral condyle prosthesis1. As shown inFIG. 10, a weight of a human body and an impact force are applied to the elastic gasket10of the articular gasket prosthesis2, the elastic gasket10is compressed and deformed to achieve a buffer action, and in such case, a gasket matrix20and the elastic gasket10bear a mechanical load transmitted by the femoral condyle prosthesis together. As shown inFIG. 11, in a bent state of the knee joint, the elastic gasket10is locally compressed and deformed, and in such case, the elastic gasket may ensure a relatively enough contact area with the femoral condyle even under a non-uniform load and bear the mechanical load transmitted by the femoral condyle prosthesis together with the matrix20because of the characteristic that an outer side is relatively high in hardness and low in elasticity and an inner side is high in elasticity and low in hardness.

With application of the technical solution of the embodiment, the synovial fluid passages are disposed in the elastic gasket10according to the predetermined manner, and parameters such as sectional shapes, pore diameters, lengths, volumes, positions, arrangement direction and density of the synovial fluid passages are regulated to gradually increase the hardness of the elastic matrix from the center to the edge and gradually decrease the elasticity from the center to the edge, so that different elasticity and hardness indexes may be achieved at different predetermined parts of the elastic gasket10to make the elastic gasket10close to mechanical characteristics of a human knee joint as much as possible, the elastic gasket10may fully contact with the femoral condyle during knee joint motions, pressure between contact surfaces is further kept within an ideal range, and a using effect and service life of the articular gasket prosthesis are ensured.

Preferably, in the embodiment, the elastic gasket10is made from an elastic transparent polymer material or composite material. As shown inFIG. 2andFIG. 3, in the elastic gasket10of embodiment 1, the synovial fluid passages include multiple accommodation cavity layers (T1, T2, T3and T4) and multiple flow passages12, the accommodation cavity layer T1to the accommodation cavity layer T4are disposed in a direction from the first contact surface to the second contact surface, each accommodation cavity layer includes multiple accommodation cavities11, and the flow passages12are connected between the accommodation cavities of two adjacent accommodation cavity layers. For example, the flow passage12bcommunicates the accommodation cavity11aof the accommodation cavity layer T1and the accommodation cavity11bof the accommodation cavity layer T2, the flow passage12ccommunicates the accommodation cavity11band the accommodation cavity11cof the accommodation cavity layer T3, and the flow passage12dcommunicates the accommodation cavity11cand the accommodation cavity of the accommodation cavity layer T4.

Specifically, as shown inFIG. 3, the multiple accommodation cavities11in the embodiment are gradually reduced from the accommodation cavity layer T1to the accommodation cavity layer T4, and overall volumes of each accommodation cavity layer are gradually decreased in the direction from the first contact surface to the second contact surface. The synovial fluid passages disposed in such a manner may ensure that the elasticity of the side, close to the first contact surface, of the elastic matrix relatively high and the elasticity of the side close to the second contact surface is relatively low to facilitate contact between the first contact surface and the femoral condyle.

As shown inFIG. 3toFIG. 7, in the embodiment, the synovial fluid passages further include an inflow passage13, and the inflow passage13is communicated with the accommodation cavities11such that the inflow passage13is communicated with each accommodation cavity11in each accommodation cavity layer and the flow passages12connected between each accommodation cavity layer. Furthermore, as shown inFIG. 6andFIG. 7, a check valve14is disposed in the inflow passage13. As shown inFIG. 7, when the elastic gasket10is extruded and deformed by a load, the check valve14is closed under backpressure of the synovial fluid, and in such case, the synovial fluid may only be discharged upwards to the first contact surface through the accommodation cavities11and the flow passages12, so that friction between the first contact surface and the femoral condyle is reduced. As shown inFIG. 6, when the load on the elastic gasket10disappears, the elastic matrix is restored, negative pressure is formed in the synovial fluid passages, the check valve14is opened, and the synovial fluid may enter the accommodation cavities11and the flow passages12through the inflow passage13. Therefore, the synovial fluid may be cyclically supplemented and injected to a friction surface during knee joint motions.

As shown inFIG. 1toFIG. 3, the articular gasket prosthesis of the embodiment further includes a gasket matrix20, the gasket matrix20is disposed between the femur structure and the tibia structure, the gasket matrix20is provided with an accommodation groove21, the elastic matrix10is disposed in the accommodation groove21, and a hardness of the gasket matrix20is higher than a hardness of the elastic gasket10. An optional material matching material is that the elastic gasket10is made from a polyurethane material, the gasket matrix20is made from ultra-high molecular weight polyethylene and may function approximately as a physiological meniscus at an annular edge of the accommodation groove21to enhance a support effect and wear resistance of the elastic gasket10. Structures such as the synovial fluid passages in the elastic matrix10may be engraved and ablated from the transparent polyurethane material by use of a femtosecond laser technology.

As shown inFIG. 3, in the embodiment, the gasket matrix20further includes a communicating passage28, an inlet of the communicating passage28extends onto a top surface of the gasket matrix20, and an outlet of the communicating passage28is communicated with the inflow passage13to guide the synovial fluid into the synovial fluid passages.

In order to fix the elastic gasket10, as shown inFIG. 1andFIG. 5, a positioning protruding portion15is disposed on a circumferential sidewall of the elastic matrix in the embodiment, and a positioning groove25is formed at the position, corresponding to the positioning protruding portion15, of the accommodation groove21. After the elastic gasket10is placed in the accommodation groove21, the positioning protruding portion15may extend into the positioning groove25to prevent the elastic matrix10from being separated.

As shown inFIG. 1, the gasket matrix20further includes a patellar groove29adapted to a patella and a ligament thereof.

As shown inFIG. 1andFIG. 4, the articular gasket prosthesis of the embodiment further includes a reinforcing ring30, and the reinforcing ring30is disposed in a reinforcing ring accommodation groove23on a circumferential outer side of the gasket matrix20and preferably made from a medical metallic material. The reinforcing ring30is embedded into the circumferential outer side of the gasket matrix20to improve bonding strength of the articular gasket prosthesis. Specifically, the reinforcing ring30in the embodiment includes a penetration layer33, an isolation layer32and an integration layer31, and both of the penetration layer33and the integration layer31are of a porous structure. Preferably, in the embodiment, a pore diameter of the penetration layer33of the reinforcing ring30is 500 μm to 3,000 μm, and a pore diameter of the integration layer31is 400 μm to 2,000 μm. In a molding process, the ultra-high molecular weight polyethylene material for the gasket matrix20may penetrate the porous structure of the penetration layer33and form contact fusion with the gasket matrix20to implement fixed connection between the reinforcing ring30and the gasket matrix20. The integration layer31is exposed, ligaments and soft tissues at corresponding parts of the knee joint around the articular gasket prosthesis may grow in pores of the integration layer31to form biological tissue integration after the operation, and such biological integration enables the gasket of the tibial plateau and the soft tissues around the joint to form a stable soft tissue system similar to a normal human physiological knee joint, thereby enhancing stability of the implanted knee joint prosthesis. The isolation layer32is of a physical structure, and is disposed between the penetration layer33and the integration layer31to prevent the molten polyethylene from penetrating the integration layer31on the outer side in a making process. In a postoperative healing process, the soft tissues such as the ligaments may grow in the pores of the porous structure, and thus the postoperative knee joint system may be more stable.

In the embodiment, the elastic gasket10may also be independently disposed between two skeletons forming the joint to realize certain buffering and wear reduction functions and also achieve an effect of enlarging contact areas with the skeletons.

For the articular gasket prosthesis of embodiment 2, an arrangement manner and an inflow manner of the synovial fluid passages are mainly changed on the basis of embodiment 1. As shown inFIG. 8toFIG. 15, in the elastic gasket10of embodiment 2, a synovial fluid accommodation groove is formed in a lower surface of the elastic matrix, and an opening of the inflow passage13is disposed at a groove bottom of the synovial fluid accommodation groove. As shown inFIG. 14, when the elastic gasket10is extruded by a load, a closed space is formed between the synovial fluid accommodation groove and the gasket matrix20, and the synovial fluid may be discharged upwards to the first contact surface through the accommodation cavities11and the flow passages12, so that friction between the first contact surface and the femoral condyle is reduced. As shown inFIG. 13, when the load on the elastic gasket10disappears, the elastic matrix is recovered, the synovial fluid accommodation groove is separated from the gasket matrix20, negative pressure is formed in the synovial fluid passages, and the synovial fluid may enter the accommodation cavities11and the flow passages12through the inflow passage13. Therefore, the synovial fluid may be cyclically supplemented and injected to the friction surface during knee joint motions.

As shown inFIG. 15, in the embodiment, flow grooves26are formed in a bottom surface of the gasket matrix20, and communicating holes27are formed in a bottom of the accommodation groove21and communicated with the flow grooves26such that the synovial fluid may enter the accommodation groove21through the flow grooves26and the communicating holes27.

Preferably, in the embodiment, the volumes of the multiple accommodation cavities11in the same accommodation cavity layer are gradually decreased from the center to the edge such as an elasticity and hardness distribution of the elastic gasket10is closer to primary cartilage tissues of a human body.

The articular gasket prostheses of embodiment 1 and embodiment 2 are applied to a bicondylar knee joint replacement operation. An articular gasket prosthesis of embodiment 3 is applied to a unicompartmental knee joint replacement operation, and an overall structure thereof is approximate to those of the articular gasket prostheses of embodiment 1 and embodiment 2 and will not be elaborated herein.

An articular gasket prosthesis of embodiment 4 is a femoral condyle substitute, and is applied to the unicompartmental knee joint replacement operation. The gasket matrix20is disposed on the femoral condyle4, and the elastic gasket10is disposed on the gasket matrix20.

The application also provides an articular prosthesis. As shown inFIG. 9toFIG. 11, the articular prosthesis of the embodiment is a knee joint prosthesis, and includes an articular gasket prosthesis2, a tibial plateau prosthesis3and a femoral condyle prosthesis1. Herein, the articular gasket prosthesis2is an articular gasket prosthesis including part or all of the abovementioned technical features. The articular prosthesis of the embodiment has the advantages of relatively low pressure between contact surfaces and long service life.

It can be understood that the technical concept of the embodiment may also be applied to other joint structures such as a shoulder joint and a hip joint.

From the above description, it can be seen that the abovementioned embodiments of the disclosure have the following technical effects.

The synovial fluid passages are disposed in the elastic gasket according to the predetermined manner, and parameters such as sectional shapes, pore diameters, lengths, volumes, positions and arrangement direction and density of the synovial fluid passages are regulated to gradually increase the hardness of the elastic matrix from the center to the edge and gradually decrease the elasticity from the center to the edge, so that different elasticity and hardness indexes may be achieved at different predetermined parts of the elastic gasket to make the elastic gasket close to mechanical characteristics of a human joint as much as possible, the elastic gasket may fully contact with an articular skeleton during joint motions, pressure between contact surfaces is further kept within an ideal range, and a using effect and service life of the articular gasket prosthesis are ensured.

The above is only the preferred embodiment of the disclosure and not intended to limit the disclosure. For those skilled in the art, the disclosure may have various modifications and variations. Any modifications, equivalent replacements, improvements and the like made within the spirit and principle of the disclosure shall fall within the scope of protection of the disclosure.