Method for producing ceramic coating on surface of endoprosthesis

Abstract

FIELD: medicine.SUBSTANCE: method for producing a ceramic coating for an endoprosthesis is disclosed, including preparing the initial components, preparing a ceramic mass, molding the blank, drying and thermal stabilization, characterized in that the porous coating is applied to the entire surface of the endoprosthesis by layer-by-layer application of an aqueous suspension consisting of the following components in a ratio, %: TZ-3Y-SBE ceramics – 14–16; carboxymethyl cellulose (CMC) – 1–3; deionized water – the rest.EFFECT: increased biocompatibility.1 cl, 4 dwg

Description

[0001] The invention relates to the field of medicine, in particular traumatology and orthopedics, and can be used in the manufacture of endoprostheses for restoring joint function.

[0002] The fixation strength of a porous-coated endoprosthesis stem in the bone increases threefold compared to a smooth-surfaced endoprosthesis. To achieve this, the prostheses are coated with various materials: polymers, metal alloys, and ceramics based on tricalcium phosphate and hydroxyapatite.

[0003] Cementless fixation using porous coatings has the following advantages: the technique is simplified and the duration of the operation is reduced, there is no negative impact of the monomer on the tissue, and its implementation is significantly easier during revision operations.

[0004] A method for manufacturing a ceramic endoprosthesis is known, which includes preparing a slip from a ceramic material, pouring the slip into a mold and firing the endoprosthesis, characterized in that an aqueous slip is prepared from a ceramic material containing Al2O3 and MgO, with the following content of components, wt. %:

[0005] Al2O398.4 - 99.4

[0006] MgO 0.6 - 1.6

[0007] and pour it into a plaster mold, and after firing the endoprosthesis, a fluoropolymer coating is applied to the contact surfaces of the hinge joint of the endoprosthesis, heated to 330 - 350°C, and kept at this temperature for 3-5 minutes. (Patent No. 2007971, Russian Federation).

[0008] However, this method has very low biocompatibility.

[0009] A known method of electroplasma spraying of biocompatible coatings based on magnesium-containing tricalcium phosphate, consisting in preliminary preparation of the implant surface by air-abrasive treatment and ultrasonic degreasing and subsequent electroplasma spraying of a titanium sublayer and a biocompatible layer, characterized in that ultrasonic degreasing is carried out in an aqueous solution of surfactants at a temperature of up to 40 ° C for 5-7 minutes, electroplasma spraying of the titanium sublayer is carried out from a spraying distance of 120-150 mm for 12-15 s, with a plasma-forming gas flow rate of 20 l / min, a dispersion of no more than 150 μm and an arc current of 350 A, electroplasma spraying of magnesium-containing tricalcium phosphate powder is carried out from a spraying distance of 50-60 mm for 10-12 s, with a plasma gas flow rate of 20 l / min, dispersion of no more than 90 µm and an arc current of 350 A (Patent No. 2641597, Russian Federation).

[0010] However, this invention has low biocompatibility.

[0011] Also known is a method for manufacturing a ceramic knee joint endoprosthesis, for example from aluminum oxide, including the preparation of the initial components, the preparation of a ceramic mass, the molding of a blank, drying, pre-firing mechanical treatment, firing, post-firing mechanical treatment and thermal stabilization, wherein after the stage of post-firing mechanical treatment, a porous coating of the required thickness is applied to the surface of the endoprosthesis in contact with the tissues by layer-by-layer application of an aqueous suspension, for example, aluminum oxide, with a density of 2.4 - 2.6 g / cm, pH 3.5 - 4.0, grain size of 1-10 μm and powder from the fired material of the ceramic endoprosthesis with a grain size of 0.1 - 0.2 mm, and the firing of the coating is carried out simultaneously with thermal stabilization (patent No. 2141292, Russian Federation) - prototype.

[0012] However, this invention also has insufficient biocompatibility.

[0013] The objective of the proposed invention is to eliminate the shortcomings of the prototype, namely, to increase biocompatibility.

[0014] The stated problem is solved by the proposed method for producing a ceramic coating for an endoprosthesis, which includes the preparation of the initial components, the preparation of the ceramic mass, the molding of the blank, drying and thermal stabilization, wherein the porous coating is applied to the entire surface of the endoprosthesis by layer-by-layer application of an aqueous suspension consisting of the following components in the ratio, %:

[0015] Ceramics TZ-3Y-SBE 14-16 Carboxymethylcellulose (CMC) 1-3 Deionized water rest

[0016] The novelty of the proposed invention lies in the fact that the porous coating is applied to the entire surface of the endoprosthesis by layer-by-layer application of an aqueous suspension consisting of the following components in the ratio, %:

[0017] Ceramics TZ-3Y-SBE 14-16 Carboxymethylcellulose (CMC) 1-3 Deionized water rest

[0018] The ceramic content of TZ-3Y-SBE is below 14%, CMC is below 1%, which leads to a decrease in the biocompatibility of the resulting coating.

[0019] The content of TZ-3Y-SBE ceramics is higher than 16%, CMC is higher than 3%, which leads to an increase in the viscosity of the suspension and the impossibility of its application to endoprostheses.

[0020] Thus, the optimal ratios of the components of the proposed aqueous suspension for the method of manufacturing a ceramic coating on the surface of endoprostheses have been selected.

[0021] The new features are significant because they lead to a technical result expressed in increased biocompatibility.

[0022] The essence of the proposed invention is considered using an example of its implementation.

[0023] After the operations of preparing the initial components, preparing the ceramic mass, molding the blank, drying, before firing mechanical processing, firing, and after firing mechanical processing, a porous coating is applied to the endoprosthesis made of ceramics by layer-by-layer application of an aqueous suspension consisting of TZ-3Y-SBE ceramics in an amount of 15%, CMC in an amount of 2%, and deionized water in an amount of 83%.

[0024] A porous coating is applied to the entire surface of the endoprostheses. For improved adhesion, the endoprostheses' surface is sandblasted with a specially prepared powder at a pressure of 2 bar. The powder is made from ceramic waste obtained during mechanical processing and then sifted over a crucible, creating a loose structure. The crucible with the powder is sintered in a muffle furnace at a temperature of 1450°C. After sintering, the resulting powder body is crushed and sieved to a particle size of 40-100 µm. This particle size is used for sandblasting endoprostheses that have undergone primary sintering. The treated endoprostheses are blasted with compressed air to clean the surface and transferred for coating. The coating is applied to the endoprostheses using an air spray.

[0025] The suspension is prepared as follows: first, weigh the required amount of ceramics in suspension. Weigh the resulting mixture and measure out the required amount of carboxymethyl cellulose (CMC). Add the CMC to the ceramics and mix. Separately measure out the required amount of deionized water and add it to the ceramics and CMC. Mix vigorously using a U3 bath. For better mixing, heat the suspension to 70°C (158°F), which will make the suspension less viscous. After mixing, bring the suspension to 70°C (158°F) and apply a vacuum to remove any bubbles. The suspension is ready.

[0026] The percentage of suspension with the best adhesion is shown below:

[0027] Ceramics TZ-3Y-SBE 15 KMC 2 Deionized water 83

[0028] To improve the coating quality and application process, a spraying method was used. After all preparation steps, the suspension is poured into an airbrush and sprayed in thin layers onto the surface for better coverage and increased coating thickness. The coating is applied layer by layer at room temperature, 15 cm from the endoprosthesis, under a pressure of 4 bar. The coating is applied layer by layer, with a 3-minute rest period between each layer. A minimum of 3 and a maximum of 6 layers is recommended. After all layers are applied, the endoprosthesis is dried in a drying oven at 70°C for 1 hour. The endoprostheses are then heat-stabilized for 18 hours, with gradual heating to 1500°C and a 2-hour hold. They are then gradually cooled to 800°C at a rate of 30°C per hour, and then cooled naturally.

[0029] As a result of spraying, a coating was obtained that completely repeats the geometry of the endoprosthesis, and is very uniform, with high adhesion.

[0030] Fig. 1 shows pictures from a microscope, Fig. 2 - from an optical profilometer.

[0031] The data in Fig. 1 and Fig. 2 demonstrate that the resulting coating has a droplet structure formed by ceramic granules approximately 20 μm in size. The proposed method can be used to create coatings for endoprostheses and implants made of various types of ceramics. The resulting TZ-3Y-SBE ceramic layer has high adhesion, completely covering the endoprosthesis or implant. Figures 3 and 4 show electron microscope images demonstrating the quality of the coating's adhesion to aluminum-reinforced zirconium (ATZ) material.

Claims

A method for producing a ceramic coating for an endoprosthesis, including the preparation of the initial components, the preparation of a ceramic mass, the molding of a blank, drying and thermal stabilization, characterized in that the porous coating is applied to the entire surface of the endoprosthesis by layer-by-layer application of an aqueous suspension consisting of the following components in a ratio of %: Ceramics TZ-3Y-SBE 14-16 Carboxymethylcellulose (CMC) 1-3 Deionized water rest

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