Orthopaedic implant assembly with micro-porous fluid damping and rigid stop, prosthesis and method of manufacture

Abstract

The present application relates to a kind of orthopedic implant assemblies with micro-porous fluid damping and rigid limit, including the elastic metal bearing plate of top layer, the metal substrate of bottom layer, surrounding side wall;Three closed form a sealed chamber;In the sealed chamber, fill the porous metal framework of topological structure, and in the aperture of porous metal framework, high viscous medical fluid is filled;The elastic metal bearing plate is sealed and covered on the side wall by edge portion;The inside of at least one of metal substrate, side wall is equipped with pressure relief blind end cavity, and the pressure relief blind end cavity is equipped with elastic energy dissipation microsphere, and pressure relief blind end cavity is communicated with the high viscous medical fluid by flow limiting net plate.The present application solves the stress concentration and aseptic loosening problem under high-frequency impact of existing orthopedic implant, while solving the fatal safety hazard of existing shock-absorbing prosthesis fatigue fracture, structure collapse after rupture.

Description

Technical Field

[0001] This invention relates to an orthopedic implant component, prosthesis, and preparation method with microporous fluid damping and rigid restraint, which can be used for joint replacement (such as tibial support for total knee replacement), and belongs to the field of orthopedic implant technology in medical devices. Background Technology

[0002] Currently, most total knee arthroplasty (TKA) prostheses widely used in clinical practice are absolutely rigid structures (such as cobalt-chromium-molybdenum alloys or dense titanium alloys), directly connected to bone or bone cement. In recent years, a very small number of patents (such as publication number US8979938B2, publication date 2015-3-17) have explored placing a liquid sac or hydraulic buffer under the bearing surface of the prosthesis, attempting to buffer the impact through hydrostatic pressure.

[0003] The existing technology has the following technical problems:

[0004] 1) Defects of rigid prostheses: Traditional rigid prostheses cannot absorb the high-frequency impact loads generated by patients during daily gait, leading to severe stress concentration at the bone cement-bone interface. Long-term impact can cause interfacial micromovement, which in turn can lead to catastrophic long-term aseptic loosening, and this is currently the main reason for joint revision surgery.

[0005] 2) Fatal safety hazards of existing hydraulic cushioning prostheses: Existing liquid sacs or hydraulic cushions are designed with a "waterbed effect," making them highly susceptible to fatigue fracture or seal rupture under long-term cyclic loading on the human body. Once ruptured, the prosthesis loses its internal support, causing the structure to collapse instantly and leading to serious clinical accidents.

[0006] 3) Single energy dissipation mechanism: Existing hydraulic designs only utilize the compressibility of fluids or static pressure as a "buffer" and do not truly utilize fluid dynamics mechanisms to "dissipate" high-frequency kinetic energy. Summary of the Invention

[0007] This invention aims to solve the problems of stress concentration and aseptic loosening of existing orthopedic implants under high-frequency impact, and to overcome the fatal safety hazards of fatigue fracture and structural collapse after fracture of existing shock-absorbing prostheses. It provides a rigid box structure with "micron-level compliance" and certain safety as an orthopedic implant component or prosthesis, and provides its preparation method.

[0008] The present invention adopts the following technical solution:

[0009] An orthopedic implant assembly with microporous fluid damping and rigid restraint includes a top elastic metal support plate, a bottom metal substrate, and surrounding sidewalls; the three are sealed to form a sealed chamber; solid metal micropillars are arranged in an array extending upward from the metal substrate within the sealed chamber, and a porous metal skeleton with a topological structure is also filled within the sealed chamber, with a high-viscosity medical fluid filling the pores of the porous metal skeleton; the elastic metal support plate is sealed to the sidewalls by its edge portion; there is a restraining stroke of 10-500 μm between the inner surface of the elastic metal support plate and the top of the solid metal micropillars, and the space within this restraining stroke is completely filled by the porous metal skeleton; at least one of the metal substrate and the sidewalls has a pressure relief blind end cavity, and the pressure relief blind end cavity contains elastic energy-dissipating microspheres. The pressure relief blind end cavity is kept in communication with the high-viscosity medical fluid through a flow-limiting mesh plate, the pore size of the flow-limiting mesh plate being smaller than the diameter of the elastic energy-dissipating microspheres to prevent the microspheres from entering the sealed chamber.

[0010] Preferably, the porous metal skeleton and the metal micropillar are fused together.

[0011] Preferably, the elastic metal bearing plate adopts a gradient thickness design with a thin center and gradually thickening towards the edge, and a stress relief groove with a circular transition is processed on the inner side at the connection with the side wall to reduce the edge stress concentration coefficient.

[0012] Preferably, the metal substrate extends downwards with a central keel or short handle, and the pressure relief blind end cavity may also be disposed within the central keel or short handle.

[0013] Preferably, the elastic energy-dissipating microspheres are made of silicone.

[0014] Preferably, the porous metal skeleton of the topological structure has a three-dimensional fully connected pore structure inside, which is integrally formed by 3D printing, and the porosity is 60%-70%.

[0015] Preferably, the high-viscosity medical fluid is a cross-linked hyaluronic acid gel.

[0016] Preferably, the overall thickness of the prosthesis is 2.0 mm to 30.0 mm; more preferably, when applied to a micro-interface buffer, the overall thickness is 2.0 mm to 4.0 mm; when applied to bone tumor defect reconstruction, the overall thickness is 4.0 mm to 30.0 mm.

[0017] Preferably, it also includes an ultra-high molecular weight polyethylene gasket and a locking structure disposed above the elastic metal support plate for fixing the ultra-high molecular weight polyethylene gasket.

[0018] Furthermore, the locking structure is a slot or a microporous coating.

[0019] Furthermore, the three-dimensional connected porous metal skeleton is a three-period minimal surface (TPMS) topology.

[0020] Furthermore, the three-period minimal surface (TPMS) topology is a Gyroid spiral surface or a Diamond surface lattice; the surface of the three-dimensional interconnected porous metal skeleton has a continuous and smooth curved transition to avoid stress concentration at the nodes of the lattice structure.

[0021] Preferably, the total cross-sectional area of ​​the metal micropillars accounts for 5%-15% of the total bottom area of ​​the sealed chamber.

[0022] Preferably, the number of metal micropillars is set to be between 10 and 50, and the diameter of a single metal micropillar is 1.0mm-2.0mm; so that the overall yield bearing capacity of the metal micropillars can reach more than 100kN.

[0023] Preferably, the elastic energy-dissipating microspheres are highly elastic compressible media with a diameter of 200 μm to 2.0 mm.

[0024] Furthermore, the elastic energy-dissipating microspheres are hollow or closed-cell foamed polymeric silicone microspheres, which have extremely high volume compressibility.

[0025] An orthopedic implant assembly with microporous fluid damping and rigid restraint includes a top elastic metal support plate, a bottom metal substrate, and surrounding sidewalls; the three are sealed to form a sealed chamber; the sealed chamber contains solid metal micropillars arranged in an array extending upward from the metal substrate; the sealed chamber is also filled with a porous metal skeleton with a topological structure, and the pores of the porous metal skeleton are filled with a highly viscous medical fluid; the metal substrate extends downward with a central keel or short handle; the elastic metal support plate is sealed and capped by its edges. On the sidewall, there is a 10-500μm limiting stroke between the inner surface of the elastic metal support plate and the top of the solid metal micropillar, and the space of the limiting stroke is completely filled by the porous metal skeleton; at least one of the central keel or short handle and the sidewall is provided with a pressure relief blind end cavity, and the pressure relief blind end cavity is provided with an elastic energy-dissipating microsphere. The pressure relief blind end cavity is kept in communication with the high viscosity medical fluid through a flow-limiting mesh plate. The pore size of the flow-limiting mesh plate is smaller than the diameter of the elastic energy-dissipating microsphere to prevent the microsphere from entering the sealed chamber.

[0026] A prosthesis comprising the aforementioned orthopedic implant components.

[0027] A method for preparing the above-mentioned orthopedic implant component with microporous fluid damping and rigid restraint includes the following steps:

[0028] S1. Integrated 3D printing: The metal substrate, sidewalls, porous metal skeleton and solid metal micropillar array are printed in one piece to ensure seamless metallurgical fusion between the root of the metal micropillar and the metal substrate, and between the side of the metal micropillar and the porous metal skeleton. At the same time, the pressure relief blind end cavity and the flow limiting mesh are integrally formed in the sidewall or central keel.

[0029] S2. Post-processing: The semi-finished product after 3D printing is subjected to ultrasonic cleaning and heat treatment to remove residual metal powder from the porous metal skeleton and the pressure relief blind end cavity.

[0030] S3. Injection and placement of the medium: Under vacuum degassing or micro-negative pressure, inject a high-viscosity medical fluid into the pores of the porous metal skeleton to completely wet it; at the same time, fill the reserved blind end cavity with elastic energy-dissipating microspheres; the blind end cavity and the sealed chamber are connected by a flow-limiting mesh plate, and the pore size of the flow-limiting mesh plate is designed to be strictly smaller than the diameter of the selected elastic energy-dissipating microspheres to ensure that the elastic energy-dissipating microspheres cannot escape or leak;

[0031] S4. Covering and Welding Seal: Cover the sealed chamber with an elastic metal support plate; in an inert gas (such as argon) protective environment or a slightly negative pressure environment, use laser beam welding (LBW) technology to weld the edge of the elastic metal support plate to the side wall to achieve a deep weld, thereby sealing the chamber.

[0032] Preferably, in step S3, if the pressure relief blind end is located inside the central keel or short handle, then silicone microspheres with a diameter of 1.0-2.0 mm are filled in; if the blind end is located inside the side wall, then silicone microspheres with a diameter of 200-500 μm are filled in.

[0033] The beneficial effects of this invention are as follows:

[0034] 1) Significant stress reduction and energy dissipation, extending prosthesis life: Utilizing the "squeezing oil film damping effect" and porous media flow mechanism from fluid mechanics. For example, under high-frequency impact during normal gait (peak value approximately 2000 N, lasting 10-20 ms), the fluid travels at high speed through a porous metal skeleton with a pore size of 200-300 μm, generating enormous viscous resistance; theoretically, this mechanism can extend the duration of sharp shock waves to more than 30 ms and reduce the peak load by 30%-40% (down to around 1200 N), thereby eliminating the high-frequency dynamic load that leads to fatigue fracture at the bone cement interface.

[0035] 2) Extremely high fatigue limit and punching shear resistance: For example, under a physiological peak load of 2000N, acting on an elastic metal bearing plate (assuming an area of ​​approximately 1200mm²) 2The pressure is approximately 1.6 MPa. Calculations show that the maximum Von Mises stress of a 0.5 mm thick low-modulus titanium alloy elastic metal support plate is only 80-100 MPa, far below the fatigue limit of titanium alloy (400-500 MPa). Under the micro-span support of the porous metal skeleton, the elastic metal support plate will never experience localized punching fracture and theoretically possesses an unlimited cycle life.

[0036] 3) Ultra-high redundancy ultimate compressive strength: In extreme cases, such as complete fluid leakage, this invention relies on "solid metal micropillars" to trigger hard restraint, transforming it into rigid load-bearing capacity. Based on the Gibson-Ashby model and classical materials mechanics calculations, the overall compressive failure load of this structure can reach 120,000 N (approximately 12 tons). This ultimate destructive force far exceeds the pulverization limit of the human tibial plateau (4,000-8,000 N). This means that under any catastrophic external force, the patient's bone will pulverize before the prosthesis, and the prosthesis itself has absolute structural redundancy, completely eliminating the clinical risk of rupture and collapse of traditional shock-absorbing prostheses.

[0037] 4) Internal Wear Control and Extremely High Biocompatibility: The top of the metal micropillar is designed with a gentle contact surface. When the elastic metal bearing plate sinks under extremely high impact, elastically compresses the top porous metal skeleton layer, and approaches the metal micropillar, the drastic reduction in the limiting stroke space generates a strong "squeezing oil film effect," forming a high-pressure liquid cushion. This, combined with the micron-level elastic buffer of the top porous metal skeleton layer, avoids rigid and violent collisions and localized plastic deformation between metals. The deformation of the porous metal skeleton layer above the metal micropillar remains within its elastic limit, fundamentally eliminating fatigue fracture of the microstructure and the generation of metal debris. Furthermore, because the entire damping chamber is absolutely sealed using laser welding (LBW) under inert gas protection, even if trace amounts of titanium alloy debris are generated during tens of millions of cycles, they will be permanently sealed in the highly viscous fluid inside the chamber and will never enter the joint cavity, essentially eliminating the clinical risks of macrophage phagocytosis, osteolysis, and aseptic loosening.

[0038] 5) Minimal Thermal Effect and Excellent Biothermodynamic Safety: Although the core mechanism of this invention is to convert high-frequency impact kinetic energy into fluid shear heat energy, this process will never cause the clinically concerning thermal necrosis of bone tissue. According to the thermodynamic work principle (W=F·S), under a peak load of 2000N and a limit displacement of 50μm, the maximum heat energy generated in a single gait cycle is only about 0.1 Joules. At a normal walking frequency (about 1Hz), its equivalent heating power is extremely low (≤0.1W). At the same time, the titanium alloy matrix has excellent thermal conductivity. Combined with the rich microcirculation of body fluids and blood perfusion around the human joint, it is equivalent to a highly efficient constant-temperature water cooling system. This extremely small amount of heat will be dissipated instantly, and the surface temperature of the prosthesis will always remain consistent with the core body temperature (37°C), completely eliminating the risk of bone necrosis caused by local heat accumulation.

[0039] 6) Perfect hydraulic volume compensation and anti-clogging design: Traditional sealed hydraulic prostheses are prone to seal failure under pressure due to the "water hammer effect." This invention cleverly introduces elastic energy-dissipating microspheres (polymer silicone microspheres) as "micro accumulators," utilizing their high elastic deformation to absorb the volume displacement of incompressible fluids and resolve transient high pressure. Simultaneously, the innovative flow-limiting mesh design achieves "liquid flows, spheres do not," ensuring smooth pressure transmission while maintaining unobstructed pores in the core porous energy-dissipating framework, greatly improving the system stability of the prosthesis under long-term high-frequency operation.

[0040] 7) Scientific Equal Strength Tear-Resistant Design (Theoretical Basis): In this invention, the stress model of the tibial support elastic metal bearing plate can be approximately simplified as "an elastic thin plate fixed on all four sides". According to classical materials mechanics (such as Roark's thin plate bending theory), when the fixed thin plate (elastic metal bearing plate) is subjected to a uniformly distributed load q transmitted by the polyethylene gasket above, its internal stress distribution is extremely uneven.

[0041] a) Disadvantages of stress concentration in plates of uniform thickness: If a traditional uniform thickness design (let the thickness be t) is adopted, the radial stress at the center of the plate is 3qr. 2 / 8t 2 The maximum bending stress at the edge weld is 3qr. 2 / 4t 2 (Where, r is the equivalent radius of the thin plate (elastic metal bearing plate), i.e., the distance from the center to the edge of the elastic metal bearing plate). Clearly, the edge stress is nearly twice that of the center stress. Under tens of millions of gait cycles, a plate of uniform thickness will inevitably experience fatigue fracture from the edge.

[0042] b) The equal strength gradient design of the present invention: To achieve fatigue-resistant "equal strength design", that is, to make the edge stress equal to the center stress, according to the above formula, the edge thickness (t_edge) and the center thickness (t_center) must satisfy a square proportional relationship, that is, t_edge2 ≈2×t_center 2 The theoretically optimal thickness ratio is derived as t_edge≈1.414×t_center.

[0043] c) Parameter settings based on clinical practice: Considering the eccentric load (point load effect) on the knee joint when going up and down stairs, the edges bear greater shear forces. Therefore, in the embodiments of this invention, the center thickness is set to 0.5mm (to maximize center deflection and increase the hydraulic volume change rate), and the edge thickness is increased to approximately three times, set to 1.5mm. This parameter not only perfectly covers the theoretical safety factor of 1.414 times, but also achieves the best balance between "highly flexible shock absorption" and "resistance to edge tearing" within the limited prosthesis space. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the orthopedic implant component with microporous fluid damping and rigid restraint (taking the tibial support as an example) of the present invention.

[0045] Figure 2 This is a sectional view of the longitudinal section of an orthopedic implant component.

[0046] Figure 3 yes Figure 2 A magnified view on the right shows edge tear prevention and two pressure relief blind-end solutions.

[0047] Figure 4 This is a cross-sectional diagram of the dual-state working principle of the TPMS shock-absorbing prosthesis. Detailed Implementation

[0048] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the orthopedic implant of the present invention (taking the tibia support as an example).

[0049] Figure 2 This is a longitudinal cross-sectional view of the implant of the present invention, clearly showing the relative positional relationship of the elastic metal support plate, the base plate, the porous metal skeleton, the solid metal micropillars and the fluid chamber.

[0050] Figure 3 It is a partially enlarged sectional view showing the elastic metal bearing plate with gradually thickened edges, the tear-resistant stress relief groove, and two pressure relief blind end layout schemes for the side walls and the central keel.

[0051] Figure 4 This is a cross-sectional view comparing the dual-state working principle of the shock-absorbing prosthesis in a static state and a compressed state. Figure 4 By comparing the left half (static, unloaded state) and the right half (high-frequency impact and compression state), the four core working mechanisms of this invention are visually demonstrated:

[0052] 1) Elastic metal bearing plate: thin in the center and thick at the edges. When under pressure, the center will be concave at the micrometer level, and the stress relief grooves at the edges will effectively prevent tearing.

[0053] 2) Energy consumption of porous fluid in TPMS: When the right side is pressurized, a transient high pressure is generated in the center of the chamber, which drives the high viscosity fluid to shuttle radially at high speed in the three-period minimal surface (TPMS) skeleton, and converts kinetic energy into heat energy through fluid shear friction;

[0054] 3) Solid metal micropillar hard restraint (Fail-Safe): When the left side is stationary, the solid metal micropillar maintains a restraint stroke of 50μm with the inner surface of the elastic metal support plate (this stroke is filled with a porous metal skeleton); when the right side is subjected to extreme impact, the elastic metal support plate sinks and contacts the micropillar, and the prosthesis instantly transforms into a rigid support to prevent the structure from collapsing.

[0055] 4) Pressure relief blind end and volume compensation: When the right side is under pressure, the displaced fluid passes through the flow-limiting mesh plate and enters the blind end of the side wall, squeezing the polymer silicone microspheres to cause elastic deformation (volume reduction), thereby absorbing fluid displacement and relieving transient high pressure in the cavity, preventing the prosthesis from bursting.

[0056] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0057] See Figure 1 and Figure 2 This embodiment provides a "sandwich" type composite structure implant, the main structure and working mechanism of which are as follows:

[0058] Overall structure: As an independent shock-absorbing component or complete prosthesis, the present invention includes an elastic metal load-bearing plate at the top, a metal substrate at the bottom, and a sealed chamber formed by the side walls.

[0059] The overall thickness is controlled within the standard prosthesis size range, such as 2.0mm to 30.0mm. Specifically, the elastic metal support plate is equipped with a locking structure (such as a slot or microporous coating) above it for securing a standard ultra-high molecular weight polyethylene (UHMWPE) gasket. Figure 1 As shown. The shock absorption mechanism of this invention is independent of the joint friction surface, fully retaining and being compatible with the wear-resistant sliding function of existing polyethylene gaskets.

[0060] See Figure 2 Porous fluid shear dissipation mechanism (TPMS topology): The sealed cavity is filled with a three-dimensional interconnected porous metal framework integrally formed by 3D printing, preferably with a porosity of 60%-70%, and the pores are filled with a highly viscous medical fluid, such as cross-linked hyaluronic acid gel. It should be noted that... Figure 2 The three-dimensional interconnected porous metal skeleton is not shown in the figure. It is filled in the sealed cavity and conforms to the shape of the sealed cavity.

[0061] Structural features of the porous metal framework: The porous metal framework is preferably a three-period minimal surface (TPMS) topology (such as a Gyroid spiral surface or a Diamond surface lattice). This structure is characterized by: extremely high specific surface area, and 100% interconnectedness of all pores in three-dimensional space (no dead-angle closed pores); its framework surface exhibits a continuous and smooth curved transition, completely eliminating nodal stress concentrations in traditional lattice structures (such as BCC / FCC rod lattices), and possessing extremely high fatigue fracture resistance.

[0062] Fluid Flow Direction and Energy Dissipation Principle: When the elastic metal bearing plate undergoes micron-level concave deformation under a vertical impact load, a transient high pressure is formed in the central region of the sealed chamber. Because the fluid is incompressible, the high-viscosity fluid in the central region is forced to flow radially at high speed towards the surrounding low-pressure areas (edge ​​pressure relief blind ends), combined with... Figure 2-4 As shown.

[0063] High tortuosity and energy dissipation: During fluid transport, the unique "high tortuosity" of the TPMS structure forces the fluid to constantly change its flow direction, generating intense fluid shear friction and boundary layer resistance. This "squeeze-maze shuttle" mechanism efficiently converts destructive high-frequency mechanical kinetic energy into trace amounts of heat energy, thus achieving significant "stress reduction." Simultaneously, based on the Gibson-Ashby porous material model, the apparent elastic modulus of this TPMS porous metal skeleton, at a high porosity of 60%-70%, is significantly reduced to levels approaching those of human cancellous bone (approximately 2-5 GPa). At the microscopic level, its thin-walled curved surface provides uniform "distributed elastic micro-support" for the 0.5 mm thick elastic metal support plate through "bending-dominated" elastic deformation. Together with the solid metal micropillars below, this constitutes a "two-stage load-bearing mechanism": under normal gait (deformation < 50 μm, strain within the elastic recovery range of low-modulus titanium alloy), the porous metal skeleton provides elastic support to prevent local indentation of the elastic metal load-bearing plate; under extreme impact (deformation = 50 μm), the solid metal micropillars provide rigid restraint for the load.

[0064] Rigid limit mechanism (hard limit): such as Figure 2 As shown, multiple through-hole solid metal micropillars are uniformly distributed inside the porous metal skeleton. These solid metal micropillars are integrally formed with the base plate and the porous metal skeleton using 3D printing. The micropillars extend upwards from the base plate and are completely fused with the surrounding porous metal skeleton. The height of the solid metal micropillars is slightly lower than the overall height of the porous metal skeleton, and a micrometer-level limiting stroke (height difference, e.g., 50 μm) is formed between their tops and the inner surface of the elastic metal support plate.

[0065] It is particularly important to emphasize that this limiting stroke is not a suspended physical gap, but is completely filled by the aforementioned TPMS porous metal skeleton. When the elastic metal support plate is subjected to extreme overload and sinks to this threshold, the top porous metal skeleton layer undergoes purely elastic compression (bending-dominated high elasticity based on the TPMS structure). The elastic metal support plate then forms a rigid support contact with the solid metal micropillars (through an extremely thin fluid oil film and the elastically compressed porous metal skeleton layer). This process strictly controls the deformation of the porous metal skeleton layer within the elastic recovery range of the titanium alloy, avoiding local plastic crushing. The prosthesis instantly transforms into a rigid load-bearing structure, preventing the porous metal skeleton from being completely crushed and the elastic metal support plate from excessive bending. Array arrangement and parameter design of the solid metal micropillars: The solid metal micropillars are uniformly distributed in an array inside the porous metal skeleton. To achieve a balance between "ensuring fluid flow" and "providing sufficient ultimate compressive strength," the total cross-sectional area of ​​the solid metal micropillars accounts for 5%-15% of the total bottom area of ​​the sealed chamber. In a specific embodiment, taking a conventional total knee tibial support as an example, the number of metal micropillars is set to between 10 and 50, with a diameter of 1.0mm-2.0mm for each micropillar. These micropillars act like "load-bearing columns" in a building, instantly taking over the entire load when the prosthesis encounters extreme overload (such as a patient jumping or falling) causing the elastic metal support plate to sink by 50μm. Their overall yield bearing capacity can reach over 100kN, completely eliminating the risk of prosthesis collapse.

[0066] Edge tear-resistant design: See Figure 2 The elastic metal support plate adopts a gradient thickness design (thin at the center and gradually thickening towards the edge), and stress relief grooves (Undercut) are machined on the inner side of the connection between the elastic metal support plate and the side wall to reduce the edge stress concentration factor.

[0067] Fluid pressure relief blind end (volume-compensated safety valve): At least one pressure relief blind end cavity is provided in the non-load-bearing area of ​​the sealed chamber. See also Figure 3 This invention provides two preferred cavity layout schemes: Scheme 1, located inside the thickened sidewall of the prosthesis, with a pre-filled micron-sized highly elastic compressible medium (such as medical silicone microspheres with a diameter of 200-500 μm); Scheme 2, located inside the central axis of the central keel or short stalk below the prosthesis base plate, with a pre-filled millimeter-sized highly elastic compressible medium (such as medical silicone microspheres with a diameter of 1.0-2.0 mm). Specifically, at the connection between the pressure relief blind end and the sealed chamber, an integrally printed metal flow-limiting mesh plate (or narrowed channel) with a pore size strictly smaller than the diameter of the silicone microspheres is provided.

[0068] Working mechanism (dynamic volume compensation and return flow): See Figure 3Because viscous fluids are incompressible, when the elastic metal support plate is impacted and sinks, the fluid (volume ΔV) expelled from the sealed chamber is forced into the blind end through the flow-limiting mesh. Since the medium pre-placed in the blind end is hollow or closed-cell foamed polymer silicone microspheres, which have extremely high volume compressibility, the high pressure of the fluid forces the microspheres to shrink, thereby absorbing and compensating for this fluid displacement, maintaining the peak pressure within the cavity within a safe threshold, and preventing weld cracking. When the impact load is unloaded (the patient raises their leg), the elastic metal support plate and the porous metal skeleton elastically reset, generating negative pressure within the cavity. Simultaneously, the compressed silicone microspheres release elastic potential energy and expand back to their original shape, pushing the fluid back into the main chamber, achieving perfect system reset. Furthermore, the flow-limiting mesh physically intercepts the microspheres absolutely within the blind end (liquid flows through, but the microspheres do not), completely eliminating the risk of microsphere leakage and blockage of the porous metal skeleton.

[0069] Structural Strength and Bionic Mechanics Explanation: Regarding Scheme Two, according to the principles of materials mechanics, the stress in the central axis region of a cylinder approaches zero when subjected to bending and torque. A micro-cavity is placed at the center of the keel, resulting in minimal loss of the cross-sectional moment of inertia (theoretically calculated to be less than 2%). This cleverly utilizes the previously redundant internal space without affecting the overall bending and shear strength of the prosthesis. This design is similar to the medullary cavity structure of human long bones, conforming to the principles of orthopedic bionic mechanics.

[0070] It should be noted that in this embodiment:

[0071] 1) Replacement of elastic metal bearing plate materials: In addition to low modulus β-titanium alloys (such as Ti-Nb-Ta-Zr), nickel-titanium shape memory alloys with superelasticity (Nitinol) or medical PEEK (polyether ether ketone) polymer materials with high strength can also be used.

[0072] 2) Fluid medium alternatives: In addition to hyaluronic acid gel, other biocompatible non-Newtonian fluids with shear-thinning or shear-thickening properties (such as medical-grade hydrogels or polymer solutions) can also be used.

[0073] 3) Pressure relief medium alternatives: In addition to silicone microspheres, the compressible medium in the pressure relief blind end can also be a sealed micro titanium alloy bellows, or a small amount of medical-grade inert gas (such as nitrogen / argon).

[0074] 4) Alternative and extended solutions for rigid limit stroke (50μm):

[0075] Numerical range extension: 50μm is only a preferred embodiment; the limiting stroke range covered by this invention is from 10μm to 500μm. Its core limiting logic is: this stroke height must be less than or equal to the maximum elastic compression of the top porous metal skeleton layer under extreme impact to ensure that plastic yielding does not occur.

[0076] Multi-level limiting alternative: Solid metal micropillar arrays can contain two or more micropillars of different heights, forming a stepped multi-level buffer limiting mechanism.

[0077] Gap medium replacement: In addition to filling the porous metal skeleton within the micron-level limiting stroke between the top of the micropillar and the elastic metal support plate, the porous metal skeleton can also be left unfilled, and a pure liquid oil film gap can be formed by filling it with only high viscosity fluid.

[0078] A shock-absorbing tibial support prosthesis for total knee arthroplasty and its preparation method, comprising the following steps:

[0079] Step 1 (Structural Design): Design the tibial support prosthesis model, setting the total thickness to 4.0 mm. The thickness of the central area of ​​the elastic metal support plate is set to 0.5 mm, smoothly transitioning to 1.5 mm towards the edge. The diameter of the solid metal micropillars is set to 1.5 mm, and the limiting stroke (height difference) between the top of the micropillar and the inner surface of the elastic metal support plate is set to 50 μm. This stroke space is filled with a porous metal skeleton.

[0080] Step 2 (Integrated 3D Printing): Using selective laser melting (SLM) technology and medical-grade Ti-6Al-4V powder, the base plate, outer sidewalls, a connected porous metal skeleton with a porosity of 65%, and a solid metal micropillar array are integrated into a single 3D printing process. This ensures seamless metallurgical-grade fusion between the micropillar roots and the base plate, and between the micropillar sides and the porous metal skeleton, providing extremely high overall shear and compressive strength.

[0081] Step 3 (Post-processing): Perform ultrasonic cleaning and heat treatment on the printed semi-finished product to ensure that there is no residual metal powder inside the porous metal skeleton.

[0082] Step 4 (Injection and Insertion of Media): Under vacuum degassing or micro-negative pressure, inject medical cross-linked hyaluronic acid gel into the pores of the porous metal framework, ensuring complete saturation. Simultaneously, fill the pressure relief blind end cavity with medical-grade polymer silicone microspheres through pre-drilled microsphere filling holes, then seal the filling holes with titanium plugs or laser spot welding. If the blind end is located inside the central keel below the prosthesis, use silicone microspheres with a diameter of 1.0-2.0 mm; if the blind end is located inside the side wall, use silicone microspheres with a diameter of 200-500 μm. The connecting hole between the blind end and the main chamber is designed to be strictly smaller than the diameter of the selected microspheres (e.g., 0.5 mm or 100 μm) to ensure that the silicone microspheres cannot escape or leak under any hydraulic shock.

[0083] Step 5 (Sealing and Welding): A flexible metal support plate made of low-modulus Ti-Nb-Ta-Zr alloy is placed over the chamber. Under an inert gas (such as argon) protective environment or a slightly negative pressure environment, laser beam welding (LBW) technology is used to weld the edges of the flexible metal support plate to the sidewalls to achieve a deep penetration weld, thus sealing the chamber.

[0084] Mechanical performance and safety theoretical calculations: Based on preliminary theoretical deductions using classical materials mechanics, porous media fluid mechanics, and the Gibson-Ashby model, and under the premise of setting a hard limit stroke of 50 μm, this invention is expected to achieve the following effects: In dynamic loading simulating normal human gait, the maximum deformation of the prosthesis's elastic metal support plate will be physically locked within 50 μm, and the expected fluid shear energy consumption will account for 30%-40% of the total dissipated energy. In the ultimate failure theoretical calculations, when the instantaneous vertical load reaches the human bone crushing limit (approximately 8000 N), the prosthesis will trigger rigid contact between the micropillars and the elastic metal support plate, and the structure will remain intact; the theoretical calculation shows that its overall yield collapse load exceeds 100 kN.

[0085] In this embodiment, the shock-absorbing tibial support prosthesis allows surgeons to operate without altering their existing TKA osteotomy and implantation procedures during clinical surgery. After the prosthesis baseplate is fixed to the tibia with bone cement, the surgeon inserts a UHMWPE (ultra-high molecular weight polyethylene) gasket into the locking groove above the elastic metal support plate of the prosthesis, following standard procedures. High-frequency impact forces are transmitted from the femoral condyle to the PE gasket, and then evenly to the elastic metal support plate, where they are ultimately dissipated and contained by the internal "fluid-porous-microcolumn" system.

[0086] The above are preferred embodiments of the present invention. Those skilled in the art can make various modifications or improvements based on these embodiments. Without departing from the overall concept of the present invention, such modifications or improvements should fall within the scope of protection claimed by the present invention.

Claims

1. An orthopedic implant component with microporous fluid damping and rigid restraint, characterized in that: It includes a top elastic metal support plate, a bottom metal substrate, and surrounding sidewalls; the three together form a sealed chamber. The sealed cavity contains solid metal micropillars arranged in an array extending upwards from the metal substrate. The sealed cavity is also filled with a porous metal skeleton with a topological structure, and the pores of the porous metal skeleton are filled with a high-viscosity medical fluid. The elastic metal support plate is sealed on the side wall by the edge portion; there is a limiting stroke of 10-500μm between the inner surface of the elastic metal support plate and the top of the solid metal micro-pillar, and the space of the limiting stroke is completely filled by the porous metal skeleton. The metal substrate and at least one of the sidewalls are provided with a pressure relief blind end cavity. The pressure relief blind end cavity is provided with an elastic energy-dissipating microsphere. The pressure relief blind end cavity is kept in communication with the high-viscosity medical fluid through a flow-limiting mesh plate. The aperture of the flow-limiting mesh plate is smaller than the diameter of the elastic energy-dissipating microsphere to prevent the microsphere from entering the sealed cavity.

2. The orthopedic implant assembly with microporous fluid damping and rigid restraint as described in claim 1, characterized in that: The porous metal skeleton is fused with the metal micropillars.

3. The orthopedic implant assembly with microporous fluid damping and rigid restraint as described in claim 1, characterized in that: The elastic metal bearing plate adopts a gradient thickness design with a thin center and gradually thickening towards the edge, and a stress relief groove with a rounded transition is processed on the inner side at the connection with the side wall to reduce the edge stress concentration factor.

4. The orthopedic implant assembly with microporous fluid damping and rigid restraint as described in claim 1, characterized in that: The metal substrate extends downwards into a central keel or short handle, and the pressure relief blind end cavity is also disposed within the central keel or short handle.

5. The orthopedic implant assembly with microporous fluid damping and rigid restraint as described in claim 1, characterized in that: The elastic energy-dissipating microspheres are made of silicone.

6. The orthopedic implant assembly with microporous fluid damping and rigid restraint as described in claim 1 or 2, characterized in that: The porous metal skeleton of the topology has a three-dimensional fully connected pore structure inside, which is integrally formed by 3D printing, and the porosity is 60%-70%.

7. The orthopedic implant assembly with microporous fluid damping and rigid restraint as described in claim 1, characterized in that: The high-viscosity medical fluid is a cross-linked hyaluronic acid gel.

8. The orthopedic implant assembly with microporous fluid damping and rigid restraint as described in claim 1, characterized in that: The overall thickness of the prosthesis is 2.0 mm to 30.0 mm; preferably, when applied to a micro-interface buffer, the overall thickness is 2.0 mm to 4.0 mm; when applied to bone tumor defect reconstruction, the overall thickness is 4.0 mm to 30.0 mm.

9. The orthopedic implant assembly with microporous fluid damping and rigid restraint as described in claim 1, characterized in that: It also includes an ultra-high molecular weight polyethylene gasket, and a locking structure disposed above the elastic metal support plate for fixing the ultra-high molecular weight polyethylene gasket.

10. The orthopedic implant assembly with microporous fluid damping and rigid restraint as described in claim 10, characterized in that: The locking structure is a slot or a microporous coating.

11. The orthopedic implant assembly with microporous fluid damping and rigid restraint as described in claim 7, characterized in that: The three-dimensional connected porous metal skeleton is a three-period minimal surface (TPMS) topology.

12. The orthopedic implant assembly with microporous fluid damping and rigid restraint as described in claim 12, characterized in that: The three-period minimal surface (TPMS) topology is a Gyroid spiral surface or a diamond surface lattice; the surface of the three-dimensional interconnected porous metal skeleton has a continuous and smooth curved transition to avoid stress concentration at the nodes of the lattice structure.

13. The orthopedic implant assembly with microporous fluid damping and rigid restraint as described in claim 1, characterized in that: The total cross-sectional area of ​​the metal micropillars accounts for 5%-15% of the total bottom area of ​​the sealed chamber.

14. The orthopedic implant assembly with microporous fluid damping and rigid restraint as described in claim 1, characterized in that: The number of metal micropillars is set to be between 10 and 50, and the diameter of a single metal micropillar is 1.0mm-2.0mm; so that the overall yield bearing capacity of the metal micropillars can reach more than 100kN.

15. The orthopedic implant assembly with microporous fluid damping and rigid restraint as described in claim 1, characterized in that: The elastic energy-dissipating microspheres are highly elastic compressible media with a diameter ranging from 200 μm to 2.0 mm.

16. The orthopedic implant assembly with microporous fluid damping and rigid restraint as described in claim 15, characterized in that: The elastic energy-dissipating microspheres are hollow or closed-cell foamed polymer silica microspheres.

17. An orthopedic implant assembly with microporous fluid damping and rigid restraint, characterized in that: It includes a top elastic metal support plate, a bottom metal substrate, and surrounding sidewalls; the three together form a sealed chamber. The sealed cavity contains solid metal micropillars arranged in an array extending upwards from the metal substrate. The sealed cavity is also filled with a porous metal skeleton with a topological structure, and the pores of the porous metal skeleton are filled with a high-viscosity medical fluid. The metal substrate extends downwards with a central keel or short handle. The elastic metal support plate is sealed on the side wall by the edge portion; there is a limiting stroke of 10-500μm between the inner surface of the elastic metal support plate and the top of the solid metal micro-pillar, and the space of the limiting stroke is completely filled by the porous metal skeleton. The central keel or short handle, and at least one of the side walls are provided with a pressure relief blind end cavity. The pressure relief blind end cavity is provided with an elastic energy-dissipating microsphere. The pressure relief blind end cavity is kept in communication with the high-viscosity medical fluid through a flow-limiting mesh plate. The aperture of the flow-limiting mesh plate is smaller than the diameter of the elastic energy-dissipating microsphere to prevent the microsphere from entering the sealed cavity.

18. A prosthesis, characterized in that: Includes the orthopedic implant components as described in any one of claims 1-17.

19. A method for preparing an orthopedic implant component with microporous fluid damping and rigid restraint as described in any one of claims 1-17, characterized in that, Includes the following steps: S1. Integrated 3D printing: The metal substrate, sidewalls, porous metal skeleton and solid metal micropillar array are printed in one piece to ensure seamless metallurgical fusion between the root of the metal micropillar and the metal substrate, and between the side of the metal micropillar and the porous metal skeleton. At the same time, the pressure relief blind end cavity and the flow limiting mesh are integrally formed in the sidewall or central keel, and microsphere filling holes are reserved outside the blind end cavity. S2. Post-processing: The semi-finished product after 3D printing is subjected to ultrasonic cleaning and heat treatment to remove residual metal powder from the porous metal skeleton and the cavity inside the pressure relief blind end. S3. Injection and Insertion of Medium: Under vacuum degassing or micro-negative pressure, a high-viscosity medical fluid is injected into the pores of the porous metal skeleton to completely wet it; simultaneously, elastic energy-dissipating microspheres are filled into the blind end cavity through the reserved microsphere filling holes, and then the filling holes are absolutely sealed by titanium plugs or laser spot welding; the blind end cavity and the sealed chamber are connected by a flow-limiting mesh plate, and the aperture of the flow-limiting mesh plate is designed to be strictly smaller than the diameter of the selected elastic energy-dissipating microspheres to ensure that the elastic energy-dissipating microspheres cannot escape or leak; S4. Covering and Welding Seal: Cover the sealed chamber with an elastic metal support plate; in an inert gas protective environment or a slightly negative pressure environment, use laser welding (Laser Beam Welding, LBW) to weld the edge of the elastic metal support plate to the side wall to achieve a deep weld and seal the sealed chamber.

20. The method for preparing the orthopedic implant component with microporous fluid damping and rigid restraint as described in claim 19, characterized in that, In step S3, if the pressure relief blind end is located inside the central keel or short handle, then silicone microspheres with a diameter of 1.0-2.0 mm are filled in; if the blind end is located inside the side wall, then silicone microspheres with a diameter of 200-500 μm are filled in.

Images