Establishment Of Coupled Mechanobioregulatory Fracture Healing Model And Analysis Of Factors Affecting Fracture Healing

Fracture,as a high-risk orthopedic traumatic disease,poses a serious burden on patients' lives,work and economy.Fixing the fracture region with a fracture fixation is a commonly used fracture treatment method in clinical practice.However,this treatment method strictly relies on the doctor's experience and skill,so it is inevitable that delayed fracture healing or even nonunion of the fracture may occur due to lack of experience of the doctor,human error and the like.In addition,there are often more than one type of fracture treatments in the same patient.Due to the lack of objective evaluation methods,doctors can only choose treatment options based on their experience.This may also delay the fracture healing due to missed optimal fracture treatment.With the rapid development of the computer industry and the cross-integration among various disciplines,computer simulation technology is used to make bold predictions of life activities,which is very important for medical clinical research,selecting the best surgical treatment plan,postoperative rehabilitation and reducing medical costs.Using computer simulation technology to simulate the fracture healing process,not only can objectively evaluate a variety of possible fracture treatment options,but also optimize the determined fracture treatment plan.Through the prediction and evaluation of the fracture healing outcomes,the fracture healing simulation model can assist the doctor to select the best fracture treatment plan.In addition,computer simulation technology can also make bold assumptions and guesses on the unresolved mechanism problems in the fracture healing process.By analyzing the correctness of the hypothesis through the simulation results,the simulation model can provide important guidance on the problems explored for the fracture healing mechanism.The fracture healing process is complex and long,and is also affected by many factors.Therefore,how to describe the fracture healing process as well as its relationship with the influencing factors is an important challenge in fracture healing simulation.Different from the previous research models,based on the biological process of fracture healing,this paper uses a mechanical-biological regulation method to simulate the dynamic process of the fracture healing.With the computational model,the effects of mechanical environment and biological factors on healing process are studied.A computational model of dynamic process of fracture healing regulated by mechanical stimulation is established.A two-dimensional finite element analysis model of sheep tibia is established by using the osteotomy fracture of the tibia of sheep as a research model.Through the finite element analysis,dilatational strain and distortional strain are obtained.The fracture healing process is simulated by fuzzy logic control method.The dynamic simulation model of fracture healing regulated by mechanical stimulation is realized by constructing the fuzzy logic control rules of 7 input variables and 3 output variables.The established mechanoregulatory fracture healing model is verified with animal experiments and human tibia fracture.The study object is sheep transverse fracture.The simulation model is used to simulate the fracture healing process in the stable group A with a fracture gap size of 2 mm and an interfragmentary movement of 0.25 mm and an unstable group B with a fracture gap size of 3 mm and an interfragmentary movement of 1.25 mm.The change of interfragmentary movement at the fracture gap with time are obtained.Taking human tibia fractures as the research object,the healing process of tibia fractures in a patient was tracked and X-ray images of the fracture sites were obtained.The human transverse fracture model is established.The established model is used to simulate the healing process of the tibia fracture.The relationship between the interfragmentary movement at the fracture gap and time and the spatiotemporal distribution of the bone tissue is obtained.By analyzing the change of interfragmentary movement with time,the correctness of the established model in the simulation of human fracture healing process is preliminarily proved.By comparing the temporal and spatial distribution of bone tissue with the X-ray image of the fracture region,the correctness of the established model in human fracture healing simulation is proved.The established mechanoregulatory fracture healing model is used to study the effect of mechanical stimulation on fracture healing process.By analyzing the relationship between mechanical stimulation and the formation of various tissues,it is concluded that the smaller fracture gap size and interfragmentary value are beneficial to the fracture healing.The effects of flexible fixation,rigid fixation and variable stiffness on the fracture healing process are simulated.It is concluded that rigid fixation is still the most effective fracture fixation method.The partial differential equation is used to simulate the biological activities of chondrogenic growth factor and osteogenic growth factor during fracture healing.The chondrogenic growth factor and osteogenic growth factor concentration are used as input variables to the established simulation model regulated by mechanical stimulation,and the computational model of dynamic process of fracture healing regulated by both mechanical stimuli and biological factors is realized.The effects of different osteogenic growth factor sustained release time on the fracture healing process are analyzed and it is concluded that the long-term and stable sustained release time of bone growth factor contributes to the smooth progress of the fracture healing process.The effects of different osteogenic growth factor production rates on the fracture healing process are analyzed and it is concluded that the faster rate of bone growth factor production contributes to the fracture healing process,especially to the cartilage ossification process at the fracture gap.