A modeling method and system for dynamic stress stimulation regulation of bone healing

Abstract

The application discloses a modeling method and system for dynamic stress stimulation regulation of bone healing, which is applied to the technical field of bone healing and comprises the following steps: establishing a geometric model of a fracture site; performing mesh division on the geometric model to generate a finite element model of bone and callus; assigning material properties at an initial time in the callus; applying a dynamic load constraint to the top end of cortical bone based on the finite element model to establish a bone healing model; calculating new material properties in tissue cells, judging whether the new material properties reach a preset healing standard through the bone healing model; if the preset healing standard is reached, the simulation is completed, otherwise, iterative simulation is performed through dynamic adjustment of mechanical parameters until the preset healing standard is reached, and finally, bone healing data is output. Through the bone healing model, loading parameters are adjusted in real time according to simulation data, and the accuracy and reliability of bone healing simulation are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of bone healing, and in particular to a modeling method and system for regulating bone healing through dynamic stress stimulation. Background Art

[0002] Bone healing is a complex biological process generally divided into three phases: inflammation, proliferation, and remodeling. This process involves the interplay of multiple biomechanical and biochemical factors, such as cell proliferation, collagen deposition, and ultimately bone remodeling. Dynamic mechanical stimulation has a significant impact on bone healing. Appropriate mechanical loading can promote blood circulation, stimulate cell proliferation and differentiation, and accelerate the bone healing process.

[0003] In clinical practice and research, accurately simulating and predicting the bone healing process is crucial for optimizing treatment plans and patient recovery. Common bone healing simulation methods used in existing technologies cannot accurately simulate the biomechanical and biochemical changes during bone healing, especially when considering the effects of dynamic loading and mechanical stimulation. Dynamic stimulation is crucial for the repair and regeneration of bone tissue. Most existing models use simple static loading or linear dynamic load simulations, but ignore the complexity of dynamic loading in actual treatment, such as different loading cycles and load amplitudes. Furthermore, existing simulation models often do not fully integrate methods for optimizing these stimulation parameters, limiting the effectiveness and practicality of the models in clinical applications.

[0004] In order to overcome these defects, the present application proposes a modeling method and system for regulating bone healing through dynamic stress stimulation. Summary of the Invention

[0005] The purpose of this application is to provide a modeling method and system for dynamic stress stimulation to regulate bone healing, aiming to solve the problem that existing simulation models are not fully integrated for optimizing stimulation parameters.

[0006] To achieve the above objectives, this application provides the following technical solutions:

[0007] In a first aspect, the present application provides a modeling method for regulating bone healing through dynamic stress stimulation, comprising:

[0008] Establish a geometric model of the fracture site;

[0009] Meshing the geometric model to generate a finite element model of the bone and callus;

[0010] Assign values ​​to the material properties within the callus at the initial moment;

[0011] Applying dynamic load constraints to the top of the cortical bone based on the finite element model to establish a bone healing model;

[0012] The properties of the new material in the tissue cells are calculated, and the bone healing model is used to determine whether the properties of the new material meet the preset healing standards. If the preset healing standards are met, the simulation is completed; otherwise, the mechanical parameters are dynamically adjusted to perform iterative simulation until the preset healing standards are met, and the final bone healing data is output.

[0013] In a second aspect, the present application proposes a modeling system for regulating bone healing through dynamic stress stimulation, comprising:

[0014] Model building module: establishes a geometric model of the fracture site; meshes the geometric model to generate a finite element model of the bone and callus; assigns material properties at the initial moment in the callus; applies a dynamic load constraint to the top of the cortical bone based on the finite element model to establish a bone healing model;

[0015] Judgment and simulation module: Calculate the properties of the new material in the tissue cells, and judge whether the properties of the new material meet the preset healing standards through the bone healing model; if the preset healing standards are met, the simulation is completed; otherwise, iterative simulation is performed by dynamically adjusting the mechanical parameters until the preset healing standards are met, and the final bone healing data is output.

[0016] In a third aspect, the present application provides a device comprising a processor and a memory coupled to the processor, wherein the memory stores program instructions for implementing a modeling method for dynamically stress stimulating the regulation of bone healing; and the processor is used to execute the program instructions stored in the memory to implement a modeling method for dynamically stress stimulating the regulation of bone healing.

[0017] In a fourth aspect, the present application provides a storage medium storing program instructions executable by a processor, wherein the program instructions are used to execute a modeling method for regulating bone healing through dynamic stress stimulation.

[0018] This application provides a modeling method and system for dynamic stress stimulation to regulate bone healing, which has the following beneficial effects:

[0019] (1) This application proposes a staged dynamic load loading mode and reasonably sets various load waveforms; this loading mode is more consistent with actual biomechanical conditions and can simulate the effects of daily activities such as walking and standing on fracture healing, solving the problem of oversimplified dynamic load condition setting in the prior art. This enables the simulation to more accurately reflect the effects of dynamic loads on the fracture healing process, especially the changes in different treatment stages, which is more consistent with clinical practice;

[0020] (2) By dynamically adjusting the mechanical parameters, parameters such as loading frequency, amplitude, and duration can be automatically adjusted, and these parameters can be optimized based on simulation feedback to promote the best bone healing effect; at the same time, the predictive accuracy and clinical relevance of the bone healing model are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a flow chart of a modeling method for regulating bone healing through dynamic stress stimulation according to Example 1 of the present application;

[0022] Figure 2 This is the finite element model of the mechanical and cell diffusion environment of Example 1 of the present application;

[0023] Figure 3 This is a schematic diagram of dynamic load loading in Example 1 of the present application;

[0024] Figure 4 This is a schematic diagram of a sinusoidal wave dynamic force loading cycle according to Example 1 of the present application;

[0025] Figure 5 This is a schematic diagram of the change of bone tissue concentration over time in Example 1 of the present application;

[0026] Figure 6 This is a schematic diagram of the change of cartilage tissue concentration over time in Example 1 of the present application;

[0027] Figure 7 This is a schematic diagram of the change of fibrous tissue concentration over time in Example 1 of the present application;

[0028] Figure 8 This is a schematic structural diagram of a modeling system for regulating bone healing through dynamic stress stimulation according to Example 2 of the present application;

[0029] Figure 9 This is a schematic diagram of the device structure of Example 3 of the present application;

[0030] Figure 10 This is a schematic diagram of the storage medium structure of Example 4 of the present application. DETAILED DESCRIPTION

[0031] It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0032] The following is an analysis of the solutions in the prior art in combination with relevant technologies.

[0033] Bailon-Plaza et al. [1] proposed a bioregulatory model that considers biochemical stimulation as a controlling factor in fracture healing and studied tissue regeneration during the healing process by simulating the migration of mesenchymal stem cells. Geris [2] later expanded the model to include the effects of mechanical stimulation on cartilage and bone formation. The results showed that mechanical stimulation is crucial in the early stages of healing. Carlier [3] further developed the PDE model and elaborated on its application in simulating angiogenesis and describing revascularization, a process that is crucial in the later stages of fracture healing. However, none of these models explicitly explored the effects of dynamic loading on cell and growth factor transport.

[0034] Augat et al. [4] studied the changes in tissue differentiation and angiogenesis during fracture healing and explored the effects of different interosseous mobility on fracture healing. Their study confirmed that axial micromotion at the fracture site can promote the formation of callus tissue, thereby accelerating fracture healing. Subsequently, they further verified this conclusion through a Mianyang tibia experiment, confirming that the stability of the fracture end plays an important role in fracture healing.

[0035] Miramini[5] explored the role of fracture stability in the healing process by studying the effects of different interosseous mobility on the mechanical microenvironment of mesenchymal stem cells in the fracture callus. He analyzed the differentiation of cells in the callus by using different plate fixation methods and load sizes. The results showed that a relatively flexible plate fixation structure facilitated the formation and healing of cartilage callus.

[0036] [1]Bailon-Plaza A, van der Meulen M CA Mathematical Framework toStudy the Effects of Growth Factor Influences on Fracture Healing[J].J TheorBiol,

[0037] [2] Geris L, Sloten JV, Van Oosterwyck H. Connecting Biology and Mechanics in Fracture Healing: An Integrated Mathematical Modeling Framework for the Study of Nonunions[J]. Biomech Model Mechanobiol, 2010, 9(6):713

[0038] [3]Geris L,Gerisch A,Sloten JV,et al.Angiogenesis in Bone FractureHealing:A Bioregulatory Model[J].Journal of Theoretical Biology,2008,251(1):137-158.

[0039] [4]Augat P,Merk J,Wolf S,et al.Mechanical Stimulation by ExternalApplication of Cyclic Tensile Strains Does Not Effectively Enhance BoneHealing[J].Journal of Orthopedic Trauma,2001,15(1):54-60.

[0040] [5]Miramini S, Zhang L, Richardson M, et al. The Relationship between Interfragmentary Movement and Cell Differentiation in Early Fracture Healingunder Locking Plate Fixation[J]. Australas Phys Eng Sci Med, 2016, 39(1):123-133.

[0041] Among existing methods, most existing models use simple static loading or linear dynamic load simulation, but ignore the complexity of dynamic loading in actual treatment, such as different loading cycles, different load amplitudes, etc. At the same time, there is still a lack of an effective method to optimize the dynamic loading parameters during the treatment process, such as loading frequency, amplitude and duration, which limits its application in personalized treatment and precision medicine. The present application provides a staged dynamic load loading mode and reasonably sets various load waveforms for dynamic stimulation of bone healing simulation; through an intelligent optimization algorithm, the loading parameters are adjusted in real time according to the simulation data to improve the accuracy and reliability of bone healing simulation.

[0042] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0043] Example 1

[0044] See also Figure 1 , is a flow chart of a modeling method for regulating bone healing by dynamic stress stimulation according to Example 1 of the present application; the steps include:

[0045] S1: Establish a geometric model of the fracture site.

[0046] In this embodiment, a DICOM image is obtained by scanning and slicing medical images using CT scans, and then imported into ITK-Snap to extract the required two-dimensional fracture model, that is, to obtain a geometric model of the fracture site.

[0047] S2: Meshing the geometric model to generate a finite element model of the bone and callus.

[0048] In this embodiment, the obtained two-dimensional model is imported into Abaqus software for meshing. Because the model is generally considered to be a two-phase porous medium, the mesh is set to CAX4P units to obtain a finite element model of the fracture site.

[0049] S3: Assign the material properties of the callus at the initial moment.

[0050] In this embodiment, the material properties of the callus at the initial moment are assigned to the material property values ​​of the granulation tissue.

[0051] S4: Applying dynamic load constraints to the top of the cortical bone based on the finite element model to establish a bone healing model.

[0052] In this example, to accurately simulate the physical effects and cellular behavior during fracture healing, external load constraints and fixation constraints were applied. Specifically, an external load caused by an external fixator was applied to the top of the cortical bone. The external fixator stabilized the fracture site and applied the necessary force to promote alignment and healing. A complete fixation constraint was also applied across the fracture gap, restricting movement by fixing both ends of the fracture, thereby supporting the stability and gradual healing of the fracture area.

[0053] Furthermore, because mesenchymal stem cells play an important role in the early stages of fracture healing, changes in tissue concentration in the callus are primarily driven by the biological functions of mesenchymal stem cells; overall cell differentiation is driven by both mechanical and biological stimulation; mesenchymal stem cells, osteocytes, chondrocytes, and fibroblasts form at the fracture healing site. Therefore, the bone healing model is expressed as:

[0054]

[0055] in, is the concentration; is the concentration The rate of change over time t; v f is the velocity vector of the fluid; D β is the diffusion coefficient of cells in callus tissue; is the cell proliferation rate; is the cell death rate; Regulate cell proliferation rate for chemical stimulation; The growth rate regulated by mechanical stimulation; Where n is the power of the stem cell concentration C; β is a coefficient related to the concentration change, which is a constant or a variable that changes with time. In the formula, it represents a factor that affects the stem cell concentration.

[0056] When β = m, the above formula is the formula for changes in the concentration of mesenchymal stem cells; when β = c, the above formula is the formula for changes in the concentration of chondrocytes; when β = b, the above formula is the formula for changes in the concentration of bone cells; when β = fb, the above formula is the formula for changes in the concentration of fibroblasts; wherein m, c, b, and fb are mesenchymal stem cells, chondrocytes, bone cells, and fibroblasts, respectively.

[0057] S5: Calculate the properties of the new material in the tissue cells, and determine whether the properties of the new material meet the preset healing standards through the bone healing model; if the preset healing standards are met, the simulation is completed; otherwise, iterative simulation is performed by dynamically adjusting the mechanical parameters until the preset healing standards are met, and the final bone healing data is output.

[0058] In this embodiment, fracture healing can be viewed as a process in which the concentration states of different tissues within the fracture area change over time and space. In this process, the overall tissue state can be defined as a function T(x, y, z, t) that depends on time and space. This state variable is directly affected by the concentrations of various tissue cells, including the concentration of fibrous connective tissue T fiber (x,y,z,t), the concentration of cartilage tissue T carti (x,y,z,t), the concentration of immature bone tissue T imbone (x,y,z,t), and the concentration of mature bone tissue T mbone(x,y,z,t). In addition, the level of vascular remodeling in the fracture area T blood (x, y, z, t), that is, the level of blood supply restoration, is also a crucial factor in the fracture healing process. The tissue state function T(x, y, z, t) is expressed as:

[0059] where x,y,z∈Ω,t≥0;

[0060] Wherein, Ω is the area to which the callus tissue belongs.

[0061] The concentration ratio relationship of the five tissues is:

[0062] T fiber +T carti +T imbone +T mbone +T blood =1;

[0063] The time partial derivative of the tissue state function is performed to calculate the state change at any moment during fracture healing. This state change expresses the dynamic change of the tissue state at the current moment. The state change is a function of the tissue state T at time i and the environmental variable S, and is expressed as:

[0064]

[0065] in, is the rate of change of tissue state T with time t; f(T, S) is a function of tissue state T and environmental variable S, which captures the complex state of the interaction between tissue state T and environmental variable S, and explains how the tissue state responds to changes in internal biomechanics and external environmental factors at a specific time and space point.

[0066] From Euler integral we can get: The fracture healing process is essentially a time-cyclic progressive process, in which the tissue state variable at the next moment (moment i+1) is obtained by adding the tissue state variable at the current moment (moment i) and the state change caused by cell differentiation in the local environment at moment i.

[0067] Furthermore, if the preset healing criteria are not met, iterative simulation is performed by dynamically adjusting the mechanical parameters. Dynamically adjusting the mechanical parameters specifically includes: first defining the objective function f = w1*bone tissue concentration + w2*cell proliferation rate - w3*healing time, where w1, w2, and w3 are three weight coefficients that determine the degree of influence of each factor in the objective function on the final evaluation result; then initializing a set of candidate values ​​for loading parameters, such as frequency, amplitude, and duration; the loading parameters can be set as initial values ​​based on expert experience or literature data, and simulating the dynamic loading pattern of the foot received by the femoral fracture. This loading pattern is not a fixed simple load superposition, but is divided into different time stages, with a load loading period t1 and a tissue recovery period t2; and different load peaks are set, t2 and t1 as a loading cycle, and t2 is approximately 3t1, to simulate various fracture phenomena and dynamic loading conditions in treatment applications. Through the calculation of the simulation system, the impact of loading parameters on the bone healing process, including changes in bone tissue concentration, cell proliferation and differentiation, is evaluated in real time.

[0068] By simulating the candidate values ​​of the initial loading parameters, the value of the objective function is calculated; the optimal loading parameter combination is selected according to the value of the objective function, and the loading parameters are dynamically adjusted using the particle swarm optimization algorithm; the calculation formula is:

[0069] x i (t+1)=x i (t)+v i (t+1),

[0070] Among them, x i (t+1) is the position of particle i at time t+1; x i (t) is the position of particle i at time t; v i (t+1) is the velocity of the particle at time t+1;

[0071] v i The calculation formula for (t+1) is:

[0072] v i (t+1)=w*v i (t)+c1*r1*(p best，i -x i (t))+c2*r2*(g best，i -

[0073] x i (t)),

[0074] Among them, w is the inertia weight, which is used to control the influence of the previous speed on the current speed; c1 and c2 are learning factors; r1 and r2 are random numbers in the interval [0,1]; p best , iFor particle i to the selected optimal position, g best , i is the global optimal position, that is, the optimal solution among all particles.

[0075] See also Figure 5 、 Figure 6 、 Figure 7 They are respectively a schematic diagram of the change of bone tissue concentration over time, a schematic diagram of the change of cartilage tissue concentration over time, and a schematic diagram of the change of fibrous tissue concentration over time in Example 1 of the present application.

[0076] Based on the dynamic stimulation bone healing simulation process described in this application, the concentration changes of bone, cartilage, and fibrous tissue during the healing process were predicted. Over time, the bone concentration increased while the fibrous tissue concentration decreased. Initially, there was almost no cartilage tissue. As the healing process progressed, secondary fracture healing began, with cartilage tissue continuously converting to bone tissue, ultimately completing fracture healing.

[0077] In the paper by Gries (Geris L, Sloten JV, Van Oosterwyck H. Connecting Biology and Mechanics in Fracture Healing: An Integrated Mathematical Modeling Framework for the Study of Nonunions [J]. Biomech Model Mechanobiol, 2010, 9 (6): 713), the proposed model uses a variable load as the stimulus condition for fracture healing. The model does not distinguish between specific regions. For comparison, this application will combine the tissue distribution of the three regions based on the results of numerical simulation. In the simulation calculation process, Figure 5 Comparisons of the distribution of various tissues over 35 days with Gries data are shown. The model predicts that the proportion of bone within the callus tissue will be approximately 11.36%, 28.41%, and 99.8% on days 7, 14, and 35 after fracture, respectively. During the same periods, the proportions of cartilage tissue were 1%, 30.3%, and 0%, respectively, while fibrous tissue accounted for 76.4%, 44.5%, and 0% of the total area, respectively. These predictions are consistent with the trends in tissue density observed during fracture healing in real experiments and are generally consistent with morphometric measurements.

[0078] As can be seen from the results, within the first 25 days of fracture healing, the formation rate of bone tissue is faster than that of Gries' simulation model. The present application adopts a dynamic loading parameter optimization method based on simulation feedback and uses a reasonable dynamic load to promote the flow of interstitial fluid, thereby enhancing the transport of mesenchymal stem cells and bone growth factors and accelerating the formation of bone tissue. After 25 days, the conversion process of cartilage tissue to bone tissue is strengthened, and the growth rate of bone tissue is significantly improved. Compared with the Gries model, the change trend of cartilage tissue in the present application is basically the same, but the conversion time is delayed by about 2 days. This phenomenon may be due to the fact that under dynamic load, mesenchymal stem cells are more converted into bone cells in the early stage of fracture healing.

[0079] To summarize, this application first establishes a two-dimensional geometric model of the fracture area, imports it into the abaqus software, performs mesh division, and generates a finite element model; assigns materials to the initial properties of the bone area, applies external load constraints to the top of the cortical bone, and stimulates cell tissue differentiation through finite element force stimulation to establish a bone healing model; calculates the material values ​​of each attribute of the bone tissue area at time i to determine whether the preset healing standard is met. If so, healing is completed; otherwise, the mechanical parameters are dynamically adjusted to dynamically change the stress load assignment, frequency, etc.; then enters the next healing moment for iterative simulation until healing is completed and the result is finally achieved.

[0080] Example 2

[0081] See also Figure 9 , is a schematic structural diagram of a modeling system for dynamic stress stimulation regulating bone healing according to Example 2 of the present application; the specific contents include:

[0082] Model building module: establishes a geometric model of the fracture site; meshes the geometric model to generate a finite element model of the bone and callus; assigns material properties at the initial moment in the callus; applies a dynamic load constraint to the top of the cortical bone based on the finite element model to establish a bone healing model;

[0083] Judgment and simulation module: Calculate the properties of the new material in the tissue cells, and judge whether the properties of the new material meet the preset healing standards through the bone healing model; if the preset healing standards are met, the simulation is completed; otherwise, iterative simulation is performed by dynamically adjusting the mechanical parameters until the preset healing standards are met, and the final bone healing data is output.

[0084] Example 3

[0085] See also Figure 9 , which is a schematic diagram of the device structure of Example 3 of the present application. The device 50 includes a processor 51 and a memory 52 coupled to the processor 51.

[0086] The memory 52 stores program instructions for implementing the above-mentioned modeling method for regulating bone healing through dynamic stress stimulation.

[0087] The processor 51 is configured to execute program instructions stored in the memory 52 to implement a modeling method for regulating bone healing through dynamic stress stimulation.

[0088] The processor 51 may also be referred to as a CPU (Central Processing Unit).

[0089] Processor 51 may be an integrated circuit chip with signal processing capabilities. Processor 51 may also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. A general-purpose processor may be a microprocessor or any conventional processor.

[0090] Example 4

[0091] See also Figure 10 , which is a structural diagram of the storage medium of Example 4 of the present application. The storage medium of the embodiment of the present application stores a program file 61 that can implement all the above methods, wherein the program file 61 can be stored in the above storage medium in the form of a software product, including a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) or a processor to execute all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, or a computer, server, mobile phone, tablet and other devices.

[0092] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, apparatus, article, or method comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, apparatus, article, or method. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, apparatus, article, or method comprising the element.

[0093] The above description is only a preferred embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

[0094] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

[0095] Of course, the present invention may have many other implementations. Based on this implementation, other implementations obtained by ordinary technicians in this field without any creative work are all within the scope of protection of the present invention.

Claims

1. A modeling method for dynamic stress stimulation regulation of bone healing, characterized in that: include: Establish a geometric model of the fracture site; Meshing the geometric model to generate a finite element model of the bone and callus; Assign values ​​to the material properties within the callus at the initial moment; Applying dynamic load constraints to the top of the cortical bone based on the finite element model to establish a bone healing model; Calculate the properties of the new material in the tissue cells and determine whether the properties of the new material meet the preset healing standard through the bone healing model; if the preset healing standard is met, the simulation is completed; otherwise, it is iterated by dynamically adjusting the mechanical parameters until the preset healing standard is met, and the final bone healing data is output; The bone healing model is expressed as follows: ， ， in, is the concentration; is the concentration Over time rate of change; is the velocity vector of the fluid; is the diffusion coefficient of cells in callus tissue; is the cell proliferation rate; is the cell death rate; Regulate cell proliferation rate for chemical stimulation; The growth rate regulated by mechanical stimulation; where n is the power of the stem cell concentration C; is a factor that affects the concentration of stem cells; when The above formula is the formula for the change of mesenchymal stem cell concentration when When the above formula is the formula for changes in chondrocyte concentration; When the above formula is the formula for changes in bone cell concentration; The above formula is the formula for the change of fiber cell concentration; where, They are mesenchymal stem cells, chondrocytes, osteocytes, and fibroblasts; The step of calculating the properties of the new material in the tissue cells and determining whether the properties of the new material meet the preset healing standards through the bone healing model specifically includes the following steps: The tissue state of fracture healing is defined as the tissue state function , the formula is: ,in ; in, is the concentration of fibrous connective tissue; is the concentration of cartilage tissue; is the concentration of immature bone tissue; is the concentration of mature bone tissue; The level of vascular reconstruction in the fracture area, that is, the level of blood supply recovery; The area to which the callus belongs; The concentration ratio relationship of the five tissues is: ； The time partial derivative of the tissue state function is performed to calculate the state change at any moment in the fracture healing process; the state change is The function of the organizational state T and the environmental variable S at the moment is expressed as: ； in, Organizational status Over time rate of change; It is a function of the organizational state T and the environmental variables S.

2. A modeling method for dynamic stress stimulation regulation of bone healing according to claim 1, characterized in that: The step of meshing the geometric model to generate a finite element model of the bone and callus specifically includes the following steps: The geometric model is a two-dimensional model, which is imported into Abaqus software for meshing.

3. A modeling method for dynamic stress stimulation regulation of bone healing according to claim 1, characterized in that: The step of applying a dynamic load constraint to the top of the cortical bone based on the finite element model to establish a bone healing model specifically includes the following steps: On top of the cortical bone, an external load caused by an external fixator is applied, said external fixator being used to stabilize the fracture site; A fixed constraint is applied at the ends of the fracture gap to limit movement by fixing both ends of the fracture.

4. A modeling method for dynamic stress stimulation regulation of bone healing according to claim 1, characterized in that: According to the state change amount, the state change amount at the next moment is obtained by Euler integration; The calculation formula is: The state change at the next moment is given by The organizational status at the moment It is obtained by adding the state changes at each moment.

5. The modeling method for dynamic stress stimulation regulation of bone healing according to claim 1, characterized in that: The dynamic adjustment of mechanical parameters includes: Define the objective function ,by simulating the candidate values ​​of the initialization loading parameters, the value of the objective function is calculated; The optimal loading parameter combination is selected according to the value of the objective function, and the loading parameters are dynamically adjusted using the particle swarm optimization algorithm; the calculation formula is: ， in, For particles In time Position at the moment; For particles In time location; The particle in time speed; The calculation formula is: ， in, is the inertia weight, which is used to control the influence of the previous speed on the current speed; 、 is the learning factor; 、 is a random number in the interval [0,1]; For particles To the optimal position, is the global optimal position, that is, the optimal solution among all particles.

6. A system for a modeling method for regulating bone healing by dynamic stress stimulation according to claim 1, characterized in that: include: Model building module: building a geometric model of the fracture site; meshing the geometric model to generate a finite element model of the bone and callus; Assign values ​​to the material properties within the callus at the initial moment; Applying dynamic load constraints to the top of the cortical bone based on the finite element model to establish a bone healing model; Judgment and simulation module: Calculate the properties of the new material in the tissue cells, and judge whether the properties of the new material meet the preset healing standards through the bone healing model; if the preset healing standards are met, the simulation is completed; otherwise, iterative simulation is performed by dynamically adjusting the mechanical parameters until the preset healing standards are met, and the final bone healing data is output.

7. An electronic device, characterized in that: The electronic device includes a processor and a memory coupled to the processor, wherein the memory stores program instructions for implementing a modeling method for dynamically stress stimulating and regulating bone healing as described in any one of claims 1-5; the processor is used to execute the program instructions stored in the memory to implement a modeling method for dynamically stress stimulating and regulating bone healing.

8. A storage medium, characterized in that: Program instructions executable by a processor are stored, and the program instructions are used to execute the modeling method for regulating bone healing through dynamic stress stimulation according to any one of claims 1 to 5.

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