Intelligent artificial joint system based on self-adaptive mechanism and application

Abstract

The invention provides an intelligent artificial joint system based on a self-adaptive mechanism and application. The intelligent artificial joint system comprises an artificial joint, a sensor arranged in the artificial joint and an in-vitro control module, the in-vitro control module comprises a near-infrared light source array, a control unit and a wireless communication unit; the artificial joint is obtained by performing 4D printing on a shape memory composite material containing photothermal conversion materials, the artificial joint comprises a joint connection area, a bone interface area and a supporting area, and the contents of the photothermal conversion materials in different areas are different; at least one sensor is arranged in each area of the artificial joint; the near-infrared light source array is used for emitting near-infrared light to heat the artificial joint; and the control unit is used for receiving the illumination parameters of the near-infrared light source array and the data output by the sensor, and issuing an instruction for adjusting the illumination parameters based on the illumination parameters. According to the scheme, in-vitro monitoring and self-adaptive adjustment of the artificial joint are achieved, it is ensured that the artificial joint is optimally matched with the bone, and the problem that a traditional static artificial joint cannot adapt to mechanical requirement changes in the bone healing process is solved.

Description

Technical Field

[0001] This invention relates to the field of biomedical technology, particularly to the field of smart materials technology, and especially to a smart artificial joint system and its application based on an adaptive mechanism. Background Technology

[0002] Artificial joint replacement surgery is an effective treatment for severe joint diseases, but its long-term success rate is limited by complications such as prosthesis loosening, wear and tear, infection, and poor osseointegration. Bone growth occurs in three stages. The first stage involves blood clots forming between the bone wound and the artificial joint, and the removal of necrotic tissue to form granulation tissue; this process usually takes place within 14 days. In the second stage, osteogenic precursor cells differentiate into osteoblasts and attach to the surface of the joint, forming new bone-like tissue that gradually expands and eventually calcifies into bone tissue; this process usually takes place 2 to 3 months post-surgery. The third stage is the bone remodeling period, during which bone density gradually increases; this process stabilizes around 6 months post-surgery.

[0003] Current technologies primarily optimize prostheses by focusing on materials (such as highly cross-linked polyethylene and porous tantalum) and fixation methods (bone cement and bio-based). However, once implanted, the prosthesis's mechanical state and biological environment become uncontrollable factors. Although smart prostheses that have emerged in recent years integrate sensors to wirelessly monitor bone ingrowth, these smart prostheses still have significant limitations: 1) Functional passivity: Existing monitoring systems can only sense the state and cannot make changes. When stress shielding, abnormal loading, or delayed bone integration is detected, in-situ intervention is not possible. 2) Structural staticity: Traditional prostheses are rigid static structures whose mechanical properties cannot be adjusted after implantation. They cannot adapt to the dynamic mechanical changes in bone during healing, nor can they actively correct minor alignment deviations caused by surgery or bone remodeling. 3) System complexity: "Fully integrated" smart prostheses with integrated batteries, wired sensors, or complex circuits present challenges in terms of reliability, safety, and lifespan. 4) Delayed intervention: Any therapeutic intervention (such as medication or revision surgery) requires additional implantation procedures, making early, minimally invasive, and immediate adjustments impossible.

[0004] Therefore, there is an urgent need to develop an intelligent artificial joint system and application based on an adaptive mechanism. Summary of the Invention

[0005] This invention provides an intelligent artificial joint system and application based on an adaptive mechanism, which realizes the monitoring and adaptive adjustment of the artificial joint outside the body, ensuring the best fit between the artificial joint and the bone, and avoiding the problem that traditional static artificial joints cannot adapt to changes in mechanical requirements during bone healing.

[0006] In a first aspect, the present invention provides an intelligent artificial joint system, comprising: an artificial joint, a sensor embedded in the artificial joint, and an external control module; the external control module includes a near-infrared light source array, a control unit, and a wireless communication unit. The control unit is connected to the near-infrared light source array; the control unit is connected to the sensor via the wireless communication unit; The artificial joint is 4D printed from a shape memory composite material containing photothermal conversion material; the artificial joint includes a joint connection region, a bone interface region, and a support region, and the content of photothermal conversion material varies in different regions; each region of the artificial joint contains at least one sensor, which includes at least one of a temperature sensor, a position sensor, or a stress sensor; The near-infrared light source array is used to emit near-infrared light to heat the artificial joint; The control unit is used to receive the illumination parameters of the near-infrared light source array and the data output by the sensor, and to issue instructions based on the illumination parameters and the data output by the sensor; wherein, the instructions are used to adjust the illumination parameters.

[0007] Preferably, the shape memory composite material includes shape memory materials, photothermal conversion materials, and bioactive materials; The content of the photothermal conversion material in the support region is 0 wt%, the content of the photothermal conversion material in the bone interface region is 5 wt% to 10 wt%, and the content of the photothermal conversion material in the joint connection region is 15 wt% to 20 wt%.

[0008] Preferably, the shape memory composite material includes shape memory materials, photothermal conversion materials, and bioactive materials; The shape memory material is a copolymer of polylactic acid and polycaprolactone in a mass ratio of 1:1. The photothermal conversion material is polydopamine-coated hydroxyapatite nanorods; The bioactive material includes at least one of magnesium powder, calcium carbonate, or growth factors.

[0009] Preferably, the mass fraction of the photothermal conversion material in the shape memory composite material is 0wt%~20wt%; the mass fraction of the bioactive material in the shape memory composite material is 1.5wt%~3wt%.

[0010] Preferably, the artificial joint is prepared by the following method: (1) Add the photothermal conversion material and the bioactive material to the solvent and mix well, then add the shape memory material and mix well to obtain a mixed solution; (2) The mixed solution is dried and then extruded by screw extrusion to obtain printing wire; (3) 4D printing is performed using the printing filament to obtain the artificial joint; wherein the content of the photothermal conversion material in the printing filament used in different regions of the artificial joint is different, and the printing parameters are different.

[0011] Preferably, the artificial joint is prepared by the following method: The 4D printing parameters include: printing speed of 20~50mm / s, printing temperature of 190~200℃, heated bed temperature of 50~70℃, and printing path density of 15%~50%; preferably, the printing path density is different in different areas.

[0012] More preferably, the printing speed of the joint connection area is 20~25mm / s, the printing temperature is 200℃, the heated bed temperature is 65℃, and the printing path density is 50%.

[0013] More preferably, the printing speed of the bone interface region is 30~40mm / s, the printing temperature is 200℃, the heated bed temperature is 65℃, and the printing path density is 25%.

[0014] More preferably, the printing speed of the support area is 30~40mm / s, the printing temperature is 190℃, the heated bed temperature is 55℃, and the printing path density is 15%.

[0015] Preferably, the external control module further includes an infrared thermal imaging unit, and the control unit is connected to the infrared thermal imaging unit; The infrared thermal imaging unit is used to acquire thermal radiation emitted from the surface of the artificial joint and obtain temperature data. The control unit is also used to receive the temperature data and the data output by the sensor, and to issue the command based on the illumination parameters, the temperature data and the data output by the sensor.

[0016] Preferably, the near-infrared light source array includes a plurality of near-infrared LED light sources arranged in an array; preferably, the near-infrared LED light sources are near-infrared LED light sources with wavelengths between 800 and 1000 nm; wherein, the illumination parameters include current, voltage, and irradiation time.

[0017] Preferably, the control unit is further configured to receive medical images of the artificial joint inside the patient's body transmitted from the outside, to determine the alignment of the artificial joint with the bone based on the medical images, and when there is a gap in the alignment, to issue a second command to activate the near-infrared light source array so as to deform the artificial joint.

[0018] Preferably, when the sensor is a temperature sensor, the control unit is further configured to determine whether the temperature data output by the temperature sensor exceeds a preset temperature threshold, and when the determination result is yes, issue a first instruction to reduce the illumination parameter.

[0019] Preferably, when the sensor is a stress sensor, the control unit is further configured to determine whether the stress data output by the stress sensor exceeds a preset stress threshold, and when the determination result is yes, issue a second command to turn on the near-infrared light source array so as to cause the artificial joint to deform.

[0020] Secondly, an application of an intelligent artificial joint system based on the first aspect above in the field of joint injury rehabilitation includes: using the intelligent artificial joint system to achieve adaptive matching of the growth rate of the artificial joint and the injured joint.

[0021] Preferably, after implanting an artificial joint with built-in sensors and a temporary shape into the patient, the application method includes: The control unit activates a near-infrared light source array aligned with the artificial joint to restore the artificial joint to a first shape; wherein the volume of the first shape is larger than the volume of the temporary shape. The control unit acquires data from the sensor in real time and adjusts the illumination parameters of the near-infrared light source array based on the data to adaptively match the growth rate of the artificial joint with that of the damaged joint.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects: (1) This invention provides an intelligent artificial joint system and application based on an adaptive mechanism. By combining 4D printing technology with gradient biomimetic design, and using shape memory composite materials as the key material, the artificial joint can actively deform according to instructions from an external control unit, adapting to the constantly changing mechanical needs of the bone during the healing process. This significantly improves the mechanical adaptability of the artificial joint, thereby reducing the occurrence of postoperative complications such as bone resorption and loosening. Simultaneously, driven by an external near-infrared light source array and combined with the photothermal conversion material of the artificial joint inside the body, the shape and mechanical properties of the artificial joint are changed in real time, ensuring that the mechanical matching and bio-adaptation of the artificial joint dynamically change with bone healing. The 4D printing technology precisely encodes the deformation program, enabling the artificial joint to actively recover to a predetermined shape under specific external stimuli, adapting to changes in bone structure during the patient's postoperative recovery process.

[0023] (2) In this invention, near-infrared light signals are emitted by an external near-infrared light source array, and the light energy is converted into heat energy by the photothermal conversion material inside the artificial joint, driving the shape memory composite material to undergo a preset deformation. This light-driven system can precisely adjust the shape of the artificial joint, avoiding the static problems of traditional artificial joints. At the same time, by integrating an infrared thermal imaging unit and sensors, the state of the artificial joint can be monitored in real time through a remote control unit, ensuring that the output of the light source meets the actual needs and avoiding local overheating or insufficient illumination problems. Through non-contact light driving, the external control unit can realize remote adjustment of the artificial joint without the need for secondary surgery, reducing the risk to the patient; by monitoring the temperature change of the artificial joint in real time through the infrared thermal imaging unit, it is ensured that the temperature of the artificial joint under external stimulation is kept within a safe range, thereby avoiding damage to the performance of the artificial joint or discomfort to surrounding tissues due to overheating.

[0024] (3) The artificial joint of the present invention adopts a gradient biomimetic design based on 4D-printed shape memory composite material, which can adaptively deform according to the remote stimulation and physiological feedback of the external near-infrared LED light source. Since the joint connection area of ​​the artificial joint contains a high concentration of photothermal conversion material, when a change in mechanical load is sensed, it can adjust its deformation through the light-driven system to avoid stress concentration, local overload, or bone resorption. At the same time, the artificial joint can automatically change its shape according to the adjustment command of the external near-infrared light source, so that the artificial joint can always maintain the best fit with the patient's bones. Furthermore, through the adjustment of the external near-infrared light source, the artificial joint can automatically adjust its stiffness and shape according to the dynamic changes of the bone during the bone healing process, optimize the mechanical state, and ensure the long-term stability of the artificial joint.

[0025] (4) The artificial joint of the present invention incorporates bioactive materials that can neutralize the acidic products generated during the degradation process, alleviate local inflammatory reactions, promote osteogenesis, and improve bone healing. Furthermore, the combination of shape memory polymer materials and 4D printing technology allows for safe degradation in a biological environment without causing immune rejection or allergic reactions, ensuring the biosafety of the artificial joint during long-term use. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of an intelligent artificial joint system based on an adaptive mechanism provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of another intelligent artificial joint system based on an adaptive mechanism provided in an embodiment of the present invention; Reference numerals: 10-artificial joint; 20-external control module; 101-sensor; 201-near-infrared light source array; 202-control unit; 203-wireless communication unit; 204-infrared thermal imaging unit. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] Currently, for any problems that arise with implanted prostheses (such as loosening or infection), the majority of solutions involve removal and reimplantation. This solution is a highly invasive, costly, and risky secondary procedure. Clearly, there is a clinical need for a technique that can intervene and adjust the course of the disease non-implantably in its early or potential stages.

[0030] In summary, in order to overcome the limitations of "static implantation" of artificial joints, this invention aims to create an intelligent extracorporeal joint that can respond to the dynamic needs of the human body, can be remotely and wirelessly controlled via external commands, and can achieve adaptive deformation, biomechanical optimization, and synergistic treatment. Its goal is to improve the success rate of treatment, reduce surgical risks, and improve the convenience of postoperative mobility for patients through in-situ adjustment.

[0031] The following describes the specific implementation of the concept in this application.

[0032] Please refer to Figure 1 This invention provides an intelligent artificial joint system based on an adaptive mechanism, comprising: an artificial joint 10, a sensor 101 embedded in the artificial joint, and an external control module 20; the external control module 20 includes a near-infrared light source array 201, a control unit 202, and a wireless communication unit 203; The control unit 202 is connected to the near-infrared light source array 201; the control unit 202 is connected to the sensor 101 via the wireless communication unit 203. The artificial joint 10 is obtained by 4D printing of a shape memory composite material containing photothermal conversion material; the artificial joint 10 includes a joint connection region, a bone interface region and a support region, and the content of photothermal conversion material is different in different regions; each region of the artificial joint 10 has at least one sensor 101, and the sensor 101 includes at least one of a temperature sensor, a position sensor or a stress sensor. The near-infrared light source array 201 is used to emit near-infrared light to heat the artificial joint; The control unit 202 is used to receive the illumination parameters of the near-infrared light source array 201 and the data output by the sensor 101, and to issue instructions based on the illumination parameters and the data output by the sensor; wherein, the instructions are used to adjust the illumination parameters.

[0033] In this embodiment of the invention, an artificial joint fabricated using shape memory composite material as the key material, combined with 4D printing technology and gradient biomimetic design, can actively deform according to instructions from an external control unit, adapting to the constantly changing mechanical needs of the bone during the healing process. This significantly improves the mechanical adaptability of the artificial joint, thereby reducing the occurrence of postoperative complications such as bone resorption and loosening. Simultaneously, driven by an external near-infrared light source array and combined with the photothermal conversion material of the artificial joint inside the body, light energy can be converted into heat energy. By heating to the glass transition temperature, the shape and mechanical properties of the artificial joint can be changed in real time, ensuring that the mechanical matching and biofit of the artificial joint dynamically change with bone healing. The precise encoding of the deformation program using 4D printing technology allows the artificial joint to actively recover to a predetermined shape under specific external stimuli, adapting to changes in bone structure during the patient's postoperative recovery process.

[0034] It should be noted that sensors include, but are not limited to, temperature sensors, position sensors, stress sensors, piezoresistive sensors, etc., and sensors can be any one type or any combination of several.

[0035] In a preferred embodiment, the shape memory composite material includes shape memory materials, photothermal conversion materials, and bioactive materials; The shape memory material is a copolymer made of polylactic acid and polycaprolactone in a mass ratio of 1:1; The photothermal conversion material is polydopamine-coated hydroxyapatite nanorods (HA@PDA); Bioactive materials include at least one of magnesium powder, calcium carbonate, or growth factors.

[0036] It should be noted that at least one can be any one or any combination of several in any proportion.

[0037] In this invention, the shape memory material is a copolymer of polylactic acid (PLA) and polycaprolactone (PCL). PLA has good biocompatibility, can bind well to bone tissue and gradually degrade, making it suitable for use in artificial joints. PCL has good flexibility, which can effectively improve the mechanical properties of PLA, and its slow degradation rate adapts to the bone healing cycle. Therefore, in order to improve the toughness of the shape memory material and reduce the risk of brittle fracture of pure PLA, PLA is copolymerized with flexible and biodegradable PCL to obtain the shape memory material. The glass transition temperature of this shape memory material is 45~60℃, which prevents it from deforming too quickly due to temperature changes in the in vivo environment, while avoiding excessively rapid degradation that could affect the service life of the artificial joint.

[0038] In this invention, the photothermal conversion material is prepared from the biomimetic polymer polydopamine (PDA) and the natural mineral hydroxyapatite nanorods (HA). PDA possesses high photothermal conversion efficiency and high biocompatibility, and not only significantly enhances interfacial bonding but also promotes the initial adhesion and proliferation of osteoblasts, accelerating bone matrix mineralization. Hydroxyapatite is the main inorganic component of bone, exhibits no immune rejection, and can induce bone growth. Therefore, this photothermal conversion material combines photothermal conversion functionality with long-term safety.

[0039] Specifically, the preparation method of the photothermal conversion material includes, but is not limited to: dispersing hydroxyapatite nanorods in Tris-HCl buffer (pH around 8.5), then adding dopamine hydrochloride and mixing, stirring at room temperature (e.g., 25°C) for 6-24 hours, and generating polydopamine when the system turns brown, then filtering and washing to obtain the photothermal conversion material; wherein, the mass ratio of hydroxyapatite nanorods to dopamine hydrochloride is 1:(1-4) (e.g., 1:1, 1:2, 1:3 or 1:4).

[0040] In this invention, bioactive materials (such as magnesium powder, calcium carbonate, and other alkaline bioactive minerals) are incorporated into the artificial joint. These bioactive materials neutralize the acidic products generated during degradation, alleviating the local acidic environment and reducing local inflammatory responses. Simultaneously, the release of magnesium and calcium particles promotes osteogenic processes, aiding in the biointegration between the bone and the artificial joint, and improving the speed and effectiveness of bone healing. Furthermore, the combination of shape memory polymer materials and 4D printing technology ensures safe degradation in a biological environment without causing immune rejection or allergic reactions, guaranteeing the biosafety of the artificial joint during long-term use.

[0041] In a preferred embodiment, the mass fraction of photothermal conversion material in the shape memory composite material is 0 wt% to 20 wt% (e.g., 0 wt%, 1 wt%, 2 wt%, 5 wt%, 10 wt%, 12 wt%, 15 wt%, 16 wt%, 18 wt% or 20 wt%); and the mass fraction of bioactive material in the shape memory composite material is 1.5 wt% to 3 wt% (e.g., 1.5 wt%, 2 wt%, 2.5 wt% or 3 wt%).

[0042] In this invention, by limiting the amount of each component in the shape memory composite material, the prepared shape memory composite material possesses both excellent deformability and bone healing properties. In a preferred embodiment, the content of photothermal conversion material in the support region is 0 wt%, the content of photothermal conversion material in the bone interface region is 5 wt% to 10 wt% (e.g., 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, or 10 wt%), and the content of photothermal conversion material in the joint connection region is 15 wt% to 20 wt% (e.g., 15 wt%, 15.5 wt%, 16 wt%, 16.5 wt%, 17 wt%, 17.5 wt%, 18 wt%, 18.5 wt%, 19 wt%, 19.5 wt%, or 20 wt%).

[0043] In this invention, photothermal conversion materials can convert light energy into heat energy, thereby enabling shape memory composite materials to reach their glass transition temperature and deform. By using shape memory composite materials with varying contents of photothermal conversion materials in different regions, not only is a gradient biomimetic design of the artificial joint achieved, but different regions also have different photothermal response rates, allowing each region to achieve independent deformation control and improving the responsiveness and flexibility of the artificial joint. Specifically, the support region needs to provide support for the artificial joint and bear greater forces, so more shape memory material is used, thus eliminating the need for photothermal conversion materials to ensure sufficient stiffness. At the joint connection, shape memory composite materials with a high content of photothermal conversion materials can be used to improve the photothermal conversion capacity and osteogenic activity of this area, ensuring stronger deformation response and osseointegration support, thereby achieving deformation and mechanical optimization. For the bone interface region, the content of photothermal conversion materials is 5wt%~10wt%, which enables this region to have a certain load-bearing and deformation capacity while controlling material costs and avoiding excessive photothermal response, achieving zoned response.

[0044] In a preferred embodiment, the artificial joint is prepared by the following method: (1) Add the photothermal conversion material and the bioactive material to the solvent and mix well, then add the shape memory material and mix well to obtain a mixed solution; (2) After drying the mixed solution, it is extruded by screw extrusion to obtain the printing wire; (3) 4D printing is performed using printing filaments to obtain artificial joints; wherein the content of photothermal conversion material in the printing filaments used in different areas of the artificial joints is different, and the printing parameters are different.

[0045] In this invention, 4D printing technology is used for integrated molding, employing different shape memory composite materials in different areas. The artificial joint is completed through multi-material printing path planning and collaborative printing. It should be noted that before printing, a suitable 3D model needs to be designed based on the patient's joint shape and needs to ensure that each artificial joint matches the patient's bone structure. After printing, necessary post-processing is performed on the artificial joint, such as curing, cleaning, and finishing, to ensure that the surface of the artificial joint is smooth and free of defects from the printing process.

[0046] It should be noted that the location of the sensor needs to be reserved in advance during the 4D printing process.

[0047] In a preferred embodiment, the artificial joint is prepared by the following method: the 4D printing parameters include: a printing speed of 20~50 mm / s (e.g., 20 mm / s, 25 mm / s, 30 mm / s, 35 mm / s, 40 mm / s, 45 mm / s or 50 mm / s), a printing temperature of 190~200℃ (e.g., 190℃, 195℃ or 200℃), a heated bed temperature of 50~70℃ (e.g., 50℃, 55℃, 60℃, 65℃ or 70℃), and a printing path density of 15%~50% (e.g., 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50%); preferably, the printing path density is different in different regions.

[0048] It should be noted that, in order to ensure the accuracy of the gradient biomimetic design, the printing layer thickness is selected to be 0.1~0.15mm. A layer thickness of 0.1mm is selected in the joint connection area, and the printing layer thickness can be slightly increased in other areas to improve printing speed and reduce printing time.

[0049] In this embodiment of the invention, for high-precision printing, especially in areas with high photothermal conversion material content, the printing speed is selected at 20-30 mm / s to ensure that the artificial joint can respond correctly under external stimulation. For printing areas with coarser precision, such as the support area, the speed can be appropriately increased to 30-50 mm / s to further control the material's hierarchical structure and response characteristics through printing speed, ensuring the effectiveness of the gradient biomimetic design. Regarding the heated bed temperature, it is set at 50-60°C in the support area to effectively avoid material warping in the initial stage of printing, while avoiding excessive thermal stress on the material; in areas containing photothermal conversion material, it is set at 60-70°C, which helps to improve adhesion and material stability, ensuring that material does not fall off or poorly adhere during printing in fine areas.

[0050] In a more preferred embodiment, the printing speed of the joint connection area is 20~25 mm / s (e.g., 20 mm / s, 21 mm / s, 22 mm / s, 23 mm / s, 24 mm / s or 25 mm / s), the printing temperature is 200°C, the heated bed temperature is 65°C, and the printing path density is 50%.

[0051] In a more preferred embodiment, the printing speed of the bone interface region is 30-40 mm / s (e.g., 30 mm / s, 32 mm / s, 35 mm / s, 36 mm / s, 38 mm / s or 40 mm / s), the printing temperature is 200°C, the heated bed temperature is 65°C, and the printing path density is 25%.

[0052] In a more preferred embodiment, the printing speed of the support area is 30-40 mm / s (e.g., 30 mm / s, 32 mm / s, 35 mm / s, 36 mm / s, 38 mm / s or 40 mm / s), the printing temperature is 190°C, the heated bed temperature is 55°C, and the printing path density is 15%.

[0053] In this invention, a high path density is employed in the joint connection region to further enhance structural compactness, reduce porosity, and improve mechanical strength and pre-strain accumulation capacity. Simultaneously, a relatively low path density is used in the bone interface region, resulting in a porosity higher than the joint connection region but lower than the support region. A low path density is used in the support region to increase porosity, providing space for osteoblast migration, vascular invasion, and extracellular matrix deposition, significantly improving the bone-implant interface integration rate and long-term stability. Thus, this artificial joint, employing gradient porosity and gradient photothermal conversion materials, combined with different printing speeds, successfully simulates the cortical-cancellous transition structure of natural bone, maximizing the bioactive surface area while ensuring mechanical strength.

[0054] In a preferred embodiment, such as Figure 2 As shown, the external control module 20 also includes an infrared thermal imaging unit 204, and the control unit 202 is connected to the infrared thermal imaging unit 204. Infrared thermal imaging unit 204 is used to acquire thermal radiation emitted from the surface of the artificial joint and obtain temperature data; The control unit 202 is also used to receive temperature data and sensor output data, and issue commands based on the illumination parameters, temperature data and sensor output data.

[0055] Specifically, the control unit is also used to determine whether there is a temperature value in the temperature data that exceeds a preset safety threshold, and if the determination result is yes, it issues a first instruction to reduce the illumination parameters based on the data output by the sensor. For example, when the sensor is a temperature sensor, if the determination result is yes, then the current illumination parameters need to be appropriately reduced based on the current temperature data output by the temperature sensor, such as reducing the light source intensity or illumination time in the corresponding area. It should be noted that... Figure 1 and Figure 2 Only one sensor is shown, but this does not mean that the intelligent artificial joint system has only one sensor.

[0056] In this embodiment of the invention, after the infrared light source array is activated, the infrared thermal imaging unit also starts and detects the thermal radiation emitted by the surface of the artificial joint in real time, acquiring stable data. This temperature data is then transmitted to the control unit. The control unit generates a thermal image based on this temperature data to indicate the temperature distribution in different areas of the artificial joint surface. It analyzes the temperature data to determine if any local areas exceed the safe temperature range (e.g., exceeding 60°C). If the determination is yes, overheating is confirmed, and the control unit issues a command to adjust the illumination parameters of the infrared light source array accordingly. Thus, during the long-term use of the artificial joint, the illumination parameters of the near-infrared light source array can be adjusted in real time based on the monitored temperature data, achieving intelligent monitoring and regulation.

[0057] In a preferred embodiment, the near-infrared light source array includes a plurality of near-infrared LED light sources arranged in an array.

[0058] In a more preferred embodiment, the near-infrared LED light source is a near-infrared LED light source with a wavelength between 800 and 1000 nm; wherein, the illumination parameters include current, voltage and illumination time.

[0059] In this embodiment of the invention, a near-infrared LED light source with strong penetrating power and a wavelength between 800 and 1000 nm is selected. This allows the near-infrared light emitted by the light source to penetrate skin, soft tissue, and bone, reaching the photothermal conversion material within the artificial joint without causing excessive heat damage to the tissue. Simultaneously, the photothermal conversion material has strong absorption capacity in the near-infrared band (800-1000 nm), enabling efficient conversion of light energy into heat energy to drive the deformation of the artificial joint. Furthermore, the use of an array of several near-infrared LED light sources not only ensures coverage of the required irradiation area of ​​the artificial joint but also helps provide uniform illumination, thereby avoiding localized overheating or excessive irradiation. Additionally, the power of each LED light source can be adjusted according to the needs of different areas. In the joint connection area, the LED array can provide stronger illumination, while in other areas, it provides lower power illumination to ensure a uniform response of the photothermal conversion material.

[0060] In a preferred embodiment, the control unit is further configured to receive medical images of the artificial joint inside the patient's body transmitted from the outside, to determine the alignment of the artificial joint with the bone based on the medical images, and if there is a gap in the alignment, to issue a second command to activate the near-infrared light source array so as to cause the artificial joint to deform.

[0061] Specifically, by combining postoperative medical imaging (such as X-rays), the alignment of the artificial joint with the bone can be further determined. If a tiny gap is found on one side, the near-infrared light source array can be activated, the area can be selected through the control unit interface, and targeted near-infrared light irradiation can be applied. After the area reaches the glass transition temperature, it will deform further to achieve a perfect fit.

[0062] In a preferred embodiment, when the sensor is a temperature sensor, the control unit is also used to determine whether the temperature data output by the temperature sensor exceeds a preset temperature threshold, and when the determination result is yes, to issue a first instruction to reduce the illumination parameter.

[0063] Specifically, a temperature sensor is installed inside the artificial joint. During use, it is used to monitor the temperature of the corresponding area of ​​the artificial joint in real time. Based on this temperature, it determines whether the artificial joint has reached the glass transition temperature. At the same time, it can also reduce the light parameters in time after detecting that the temperature is too high.

[0064] In a preferred embodiment, when the sensor is a stress sensor, the control unit is also used to determine whether the stress data output by the stress sensor exceeds a preset stress threshold, and when the determination result is yes, to issue a second command to turn on the near-infrared light source array so as to cause the artificial joint to deform.

[0065] Specifically, a stress sensor is installed inside the artificial joint. During use, it monitors the stress received by the corresponding area of ​​the artificial joint in real time. Based on this stress, the state of the artificial joint is determined. Once the stress data exceeds a preset stress threshold, the artificial joint is subjected to excessive load, and the near-infrared light source array needs to be activated immediately to deform the artificial joint until the current stress does not exceed the preset stress threshold. Then, the near-infrared light source array is turned off, and the artificial joint is cooled (e.g., by applying ice) to fix its current shape, achieving a match with the damaged joint. It should be noted that situations where the stress exceeds the preset stress threshold may occur when the patient has difficulty standing after a fall, when bone strength changes during the healing process, or when bone growth is too rapid and does not match the degradation rate of the artificial joint.

[0066] In a preferred embodiment, when the sensor is a position sensor, the control unit is further configured to determine whether the artificial joint has been displaced based on the position data output by the position sensor at different times, and when it is determined that displacement has occurred, issue a second command to activate the near-infrared light source array so as to cause the artificial joint to deform.

[0067] Specifically, this includes, but is not limited to, determining that displacement has occurred when the total displacement length within a specified time period exceeds a preset distance. In this embodiment of the invention, considering that rapid bone growth can cause displacement of the artificial joint, a position sensor is provided for monitoring.

[0068] In a preferred embodiment, each region of the artificial joint is equipped with a temperature sensor, a position sensor, and a stress sensor, which enables more precise response to various situations and flexible achievement of perfect cooperation between the artificial joint and the damaged joint under any circumstances.

[0069] The present invention also provides an application of the above-mentioned intelligent artificial joint system in the field of joint injury rehabilitation, including: using the intelligent artificial joint system to achieve adaptive matching of the growth rate of the artificial joint and the injured joint.

[0070] In a preferred embodiment, after implanting a sensor-embedded, temporarily shaped artificial joint into a patient, the application method includes: The near-infrared light source array aligned with the artificial joint is activated by the control unit, so that the artificial joint returns to a first shape; wherein the volume of the first shape is larger than the volume of the temporary shape; The control unit acquires data from the sensors in real time and adjusts the illumination parameters of the near-infrared light source array based on this data, so as to adaptively match the growth rate of the artificial joint with that of the damaged joint.

[0071] In this embodiment of the invention, since shape memory composite materials can recover from a small temporary shape to a larger initial shape, in order to achieve coordination between bone growth and the artificial joint, and to ensure that the artificial joint can continue to deform in the body after implantation, the volume of the first shape recovered after implantation is set to be smaller than the volume of the initial shape. Thus, if subsequent bone growth is slow while the artificial joint degrades quickly, resulting in a gap in alignment, the artificial joint can be recovered again by heating. Conversely, if bone growth is rapid while the artificial joint degrades slowly, and the stress on the artificial joint exceeds a preset stress threshold due to bone compression, the artificial joint can be further deformed under bone compression to reduce the volume of the current shape by heating. That is, bone compression is equivalent to the external force that triggers deformation. When the stress is detected to be below the preset stress threshold, illumination is stopped, and the artificial joint is cooled to maintain its current shape. In this way, the intelligent artificial joint system achieves adaptive matching between the growth rate of the artificial joint and the damaged joint.

[0072] Specifically, the wireless communication unit includes, but is not limited to, using the Bluetooth 5.0 Low Energy communication protocol to connect to the control unit, thereby reducing wiring complexity. The control unit includes, but is not limited to, a terminal.

[0073] In one specific implementation, the external control module further includes a wireless power supply unit; an energy receiving and rectification module is also provided within the artificial joint, thus powering the sensors and / or microcontroller circuits within the body through the cooperation of the wireless functional unit and the energy receiving and rectification module. The wireless power supply method can be one or more of electromagnetic induction coupling, magnetic coupling, or near-field communication (NFC). Furthermore, the sensors can be passive or semi-passive sensors, and the external control module acquires temperature, strain, or pressure signals through read / write methods, thereby reducing energy consumption at the implantation site and improving long-term reliability.

[0074] Compared to traditional artificial joints that require complex built-in electronic components such as batteries, sensors, and circuits, this invention simplifies the design and manufacturing of artificial joints through a non-invasive external adjustment system, reduces system complexity and failure rate, and improves the reliability and lifespan of artificial joints.

[0075] In this invention, the use of "and / or" between multiple technical features indicates that these technical features are connected by an "and / or" relationship, meaning that it can be any one of these technical features, or any combination of two or more of these technical features.

[0076] The present invention will be further described below by way of examples, but the scope of protection of the present invention is not limited to these embodiments.

[0077] In the following examples, the mass amounts of each component in the shape memory composite material are expressed in parts by mass.

[0078] Example 1 like Figure 2 As shown, an intelligent artificial joint system based on an adaptive mechanism includes: an artificial joint 10, a sensor 101 built into the artificial joint, and an external control module 20; the external control module 20 includes a near-infrared light source array 201, a control unit 202, a wireless communication unit 203, and an infrared thermal imaging unit 204. The control unit 202 is connected to the near-infrared light source array 201 and the infrared thermal imaging unit 204 respectively; the control unit 202 is connected to the sensor 101 through the wireless communication unit 203. The artificial joint 10 is 4D printed from a shape memory composite material containing photothermal conversion material (HA@PDA); the artificial joint 10 includes a joint connection region, a bone interface region, and a support region, and the content of photothermal conversion material varies in different regions; each region of the artificial joint 10 has at least one sensor 101, and the sensor 101 includes a temperature sensor and a stress sensor. The near-infrared light source array 201 is used to emit near-infrared light to heat the artificial joint; Infrared thermal imaging unit 204 is used to acquire thermal radiation emitted from the surface of the artificial joint and obtain temperature data; The control unit 202 is used to receive the illumination parameters, temperature data and sensor output data of the near-infrared light source array 201 and the sensor 101, and to issue instructions based on the illumination parameters, temperature data and sensor output data; wherein, the instructions are used to adjust the illumination parameters.

[0079] Artificial joints are prepared by the following method: (1) 20 parts of HA@PDA and 2 parts of bioactive material were added to a solvent and mixed, and then 78 parts of shape memory material were added and mixed to obtain a first mixed solution; 10 parts of HA@PDA and 2 parts of bioactive material were added to a solvent and mixed, and then 88 parts of shape memory material were added and mixed to obtain a second mixed solution; 2 parts of bioactive material and 98 parts of shape memory material were blended to obtain a third mixture; wherein, the shape memory material was a copolymer of polylactic acid and polycaprolactone in a mass ratio of 1:1; the bioactive material was magnesium powder (particle size <50μm) and calcium carbonate nanoparticles in a mass ratio of 1:1; (2) The first mixed solution and the second mixed solution are dried and then extruded using a twin-screw extruder to obtain the first printing line and the second printing line; the third mixture is extruded using a twin-screw extruder to obtain the third printing line; (3) Using the patient's preoperative CT or MRI data, a high-precision three-dimensional digital model of the affected joint bone is reconstructed, and the printing parameters and path planning of the artificial joint are designed, and the position of the sensor is reserved; then, the printing parameters are set according to the functional requirements of different areas. For the joint connection area with high deformation requirements, the first printing line is used, with a printing speed of 20mm / s, a layer thickness of 0.1mm, a printing temperature of 200℃, a heated bed temperature of 65℃, and a printing path density of 50%. For the bone interface region, which is a highly bioactive area, a second printing line was used, with the printing speed set at 30 mm / s, layer thickness at 0.1 mm, printing temperature at 200℃, heated bed temperature at 65℃, and printing path density at 25%. For the support area in the low-response zone, a third printing line was used, with the printing speed set to 40 mm / s, layer thickness to 0.1 mm, printing temperature to 190℃, heated bed temperature to 55℃, and printing path density to 15%. The printer is started and material is deposited layer by layer according to the path plan, finally forming an artificial joint with compositional, structural and functional gradients in one go. After printing, the artificial joint is placed in a 60°C oven for annealing for 2 hours to eliminate internal stress and stabilize the dimensions.

[0080] The glass transition temperature of the three types of printing filaments obtained in step (2) was determined to be between 48 and 55 °C by differential scanning calorimetry (DSC).

[0081] Example 2 An application of an intelligent artificial joint system based on an adaptive mechanism includes: S1, the artificial joint prepared in Example 1 is heated to above its glass transition temperature (e.g., 60°C), and slightly deformed into a smaller temporary shape with the assistance of external force. This shape is slightly smaller than the target bone cavity to facilitate surgical implantation. It is then cooled below body temperature to fix the temporary shape. S2, following standard artificial joint replacement surgery procedures, prepare the bone bed; implant the artificial joint, which is in a temporary shape, into the predetermined position; S3, Postoperative in vitro remote drive and adaptive adjustment: S31, In the early postoperative period (e.g., days 1-3), initial actuation is performed: the near-infrared light source array is aligned with the patient's artificial joint via the control unit. Initial treatment parameters are set via the control unit's control panel, selecting an 808 nm wavelength near-infrared LED light source with a power density of 0.8 W / cm². 2The single irradiation time is 90 seconds. After the near-infrared irradiation is started, the near-infrared light penetrates the tissue. The joint connection area of ​​the artificial joint absorbs the light energy and rapidly heats up to above 52°C. At this time, the shape memory composite material is activated and begins to recover from the temporary shape to the designed initial shape. It stops recovering when it reaches the first shape (i.e., the shape that perfectly matches the bone bed, and the volume of the first shape is smaller than the volume of the initial shape), eliminating micro-motion intervals and enabling the artificial joint and the bone cavity to achieve an initial tight fit.

[0082] S32, Real-time Monitoring and Feedback Adjustment: During irradiation, the control unit and infrared thermal imaging unit operate continuously, displaying real-time thermal images of the artificial joint and surrounding tissues on the control unit's control panel or screen. During this process, the system has a built-in preset temperature threshold of 60℃. If the thermal imaging shows a temperature approaching 58℃, the control unit will automatically reduce the power of the corresponding near-infrared LED light source in 10% increments until the temperature returns to a safe range (e.g., 50~55℃). Simultaneously, postoperative X-rays can be used to further assess the alignment of the artificial joint with the bone. If a small gap is found on one side, the area can be manually selected via the control unit to apply a targeted booster irradiation (temporarily increasing the power density to 1.0 W / cm²). 2 (lasting 30 seconds), driving the local area to further deform in order to achieve a perfect fit; S33, Long-term dynamic adaptation, promoting osseointegration stage: 2-8 weeks post-surgery, regularly (e.g., weekly) using the control unit to provide low-power, long-duration irradiation (power density 0.5 W / cm²) to the bone interface area. 2 (This process lasts for 3-5 minutes). This not only triggers minute deformations to continuously optimize stress distribution, but also utilizes the gentle thermal effect and the continuous release of HA, magnesium, and calcium ions to stimulate osteoblast activity and accelerate bone ingrowth. Alternatively, 2-8 weeks post-surgery, after the sensor transmits data in real-time, triggering the control unit to activate the near-infrared light source array, the response area is irradiated to allow the artificial joint to adaptively match the bone cavity, achieving a tight fit.

[0083] S34, Responding to Load Changes: After the patient's rehabilitation exercises, if the sensor or clinical follow-up (such as gait analysis) feedback shows that the stress in a certain area is abnormal or exceeds the preset stress threshold, the deformation of the specific area can be finely adjusted through the external control unit to dynamically optimize the mechanical load-bearing path of the artificial joint and prevent stress shielding or concentration.

[0084] In this invention, deformation at the joint connection area alters the force path. The bone interface region adjusts the contact area and stiffness distribution through deformation, achieving a more uniform stress distribution and reducing the risk of loosening, wear, or interface failure caused by localized high stress, thus achieving load transfer adaptation. The controllable deformation of the bone interface region and the main deformation of the joint connection region achieve kinematic / mechanical coupling, ensuring continuous contact and optimized load transfer even as the joint posture changes.

[0085] It is understood that the structures illustrated in the embodiments of the present invention do not constitute a specific limitation on an intelligent artificial joint system based on an adaptive mechanism. In other embodiments of the present invention, an intelligent artificial joint system based on an adaptive mechanism may include more or fewer components than illustrated, or combine some components, or split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0086] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. The parts of the present invention not described in detail are techniques known to those skilled in the art.

Claims

1. An intelligent artificial joint system based on an adaptive mechanism, characterized in that, include: Artificial joint, sensors built into the artificial joint, and external control module; The external control module includes a near-infrared light source array, a control unit, and a wireless communication unit; The control unit is connected to the near-infrared light source array; the control unit is connected to the sensor via the wireless communication unit; The artificial joint is 4D printed from a shape memory composite material containing photothermal conversion material; the artificial joint includes a joint connection region, a bone interface region, and a support region, and the content of photothermal conversion material varies in different regions; each region of the artificial joint contains at least one sensor, which includes at least one of a temperature sensor, a position sensor, or a stress sensor; The near-infrared light source array is used to emit near-infrared light to heat the artificial joint; The control unit is used to receive the illumination parameters of the near-infrared light source array and the data output by the sensor, and to issue instructions based on the illumination parameters and the data output by the sensor; wherein, the instructions are used to adjust the illumination parameters.

2. The intelligent artificial joint system according to claim 1, characterized in that, The shape memory composite material includes shape memory materials, photothermal conversion materials, and bioactive materials; The content of the photothermal conversion material in the support region is 0 wt%, the content of the photothermal conversion material in the bone interface region is 5 wt% to 10 wt%, and the content of the photothermal conversion material in the joint connection region is 15 wt% to 20 wt%.

3. The intelligent artificial joint system according to claim 1, characterized in that, The shape memory composite material includes shape memory materials, photothermal conversion materials, and bioactive materials; The shape memory material is a copolymer of polylactic acid and polycaprolactone in a mass ratio of 1:

1. The photothermal conversion material is polydopamine-coated hydroxyapatite nanorods; The bioactive material includes at least one of magnesium powder, calcium carbonate, or growth factors. Preferably, the mass fraction of the photothermal conversion material in the shape memory composite material is 0wt%~20wt%; the mass fraction of the bioactive material in the shape memory composite material is 1.5wt%~3wt%.

4. The intelligent artificial joint system according to claim 2 or 3, characterized in that, The artificial joint is prepared by the following method: (1) Add the photothermal conversion material and the bioactive material to the solvent and mix well, then add the shape memory material and mix well to obtain a mixed solution; (2) The mixed solution is dried and then extruded by screw extrusion to obtain printing wire; (3) 4D printing is performed using the printing filament to obtain the artificial joint; wherein the content of the photothermal conversion material in the printing filament used in different regions of the artificial joint is different, and the printing parameters are different.

5. The intelligent artificial joint system according to claim 4, characterized in that, The artificial joint is prepared by the following method: The 4D printing parameters include: printing speed of 20~50mm / s, printing temperature of 190~200℃, heated bed temperature of 50~70℃, and printing path density of 15%~50%; preferably, the printing path density is different in different regions. Preferably, the printing speed of the joint connection area is 20~25mm / s, the printing temperature is 200℃, the heated bed temperature is 65℃, and the printing path density is 50%. Preferably, the printing speed of the bone interface region is 30~40mm / s, the printing temperature is 200℃, the heated bed temperature is 65℃, and the printing path density is 25%. Preferably, the printing speed of the support area is 30~40mm / s, the printing temperature is 190℃, the heated bed temperature is 55℃, and the printing path density is 15%.

6. The intelligent artificial joint system according to claim 1, characterized in that, The external control module also includes an infrared thermal imaging unit, and the control unit is connected to the infrared thermal imaging unit. The infrared thermal imaging unit is used to acquire thermal radiation emitted from the surface of the artificial joint and obtain temperature data. The control unit is also used to receive the temperature data and the data output by the sensor, and to issue the command based on the illumination parameters, the temperature data and the data output by the sensor.

7. The intelligent artificial joint system according to claim 1, characterized in that, The near-infrared light source array includes a plurality of near-infrared LED light sources arranged in an array; preferably, the near-infrared LED light sources are near-infrared LED light sources with wavelengths between 800 and 1000 nm; wherein, the illumination parameters include current, voltage and illumination time.

8. The intelligent artificial joint system according to claim 1, characterized in that, The control unit is also used to receive medical images of the artificial joint inside the patient's body sent from the outside, to determine the alignment of the artificial joint with the bone based on the medical images, and when there is a gap in the alignment, to issue a second command to turn on the near-infrared light source array so as to deform the artificial joint.

9. The intelligent artificial joint system according to any one of claims 1 to 8, characterized in that, When the sensor is a temperature sensor, the control unit is further configured to determine whether the temperature data output by the temperature sensor exceeds a preset temperature threshold, and if the determination result is yes, issue a first instruction to reduce the illumination parameter; and / or, When the sensor is a stress sensor, the control unit is also used to determine whether the stress data output by the stress sensor exceeds a preset stress threshold, and when the determination result is yes, to issue a second command to turn on the near-infrared light source array so as to cause the artificial joint to deform.

10. An application of the intelligent artificial joint system according to any one of claims 1 to 9 in the field of joint injury rehabilitation, characterized in that, include: The intelligent artificial joint system described above achieves adaptive matching of the growth rate of the artificial joint and the damaged joint; Preferably, after implanting an artificial joint with built-in sensors and a temporary shape into the patient, the application method includes: The control unit activates a near-infrared light source array aligned with the artificial joint to restore the artificial joint to a first shape; wherein the volume of the first shape is larger than the volume of the temporary shape. The control unit acquires data from the sensor in real time and adjusts the illumination parameters of the near-infrared light source array based on the data to adaptively match the growth rate of the artificial joint with that of the damaged joint.

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