Orthopedic internal fixation screw loosening prediction method and system based on finite element analysis

Abstract

The present invention relates to the field of smart medical technology, and specifically to a method and system for predicting loosening of orthopedic internal fixation screws based on finite element analysis, comprising: analyzing bone images of patients during a historical acquisition period, and determining abnormal sub-periods within the historical acquisition period based on the displacement of key nodes of the screws and key nodes of bone tissue; analyzing the number of abnormal sub-periods and the interface slip ratio within the historical acquisition period to identify fastening screws; analyzing the rate of change of the interface slip value of the fastening screws during the historical acquisition period, judging whether the rate of change is uniform, and outputting a predicted time point based on the result of the uniformity judgment of the rate of change; and processing and analyzing to determine the remaining adjustment time based on the predicted time point. By calculating the remaining adjustment time, the present invention allows doctors to choose to retighten or replace the screws according to the specific situation of the patient before the end of the time, thereby providing a clear and scientific time basis for the doctor's clinical decision-making and improving the timeliness and effectiveness of treatment.

Description

Technical Field

[0001] The present invention relates to the field of smart medical technology, and in particular to a method and system for predicting loosening of orthopedic internal fixation screws based on finite element analysis. Background Art

[0002] Orthopedic internal fixation surgery is widely used clinically as an important treatment for orthopedic conditions such as fractures and spinal lesions. The stability of the internal fixation screws plays a crucial role in the effectiveness of surgical treatment. However, screw loosening is a common and troublesome postoperative complication, leading to increased pain and prolonged healing. In severe cases, secondary surgery may be necessary, causing significant pain and financial burden to the patient.

[0003] With the continuous development of finite element analysis technology, its application in the medical field has become increasingly in-depth, providing a new way to predict the loosening of orthopedic internal fixation screws. At present, although the prediction system for orthopedic internal fixation screw loosening based on finite element analysis has made certain progress, it still has many shortcomings. In the analysis and judgment process, the existing system is not accurate enough in quantifying the mechanical changes at the contact interface between the screw and the bone, which makes it difficult to accurately judge the tightness of the screw. Doctors can only rely on experience to make subjective judgments, which increases the risk of misdiagnosis. In terms of data mining, historical data is not fully utilized, and abnormal data cannot be captured in time, missing the best time for intervention. In addition, the existing system does not fully analyze the dynamic changes of screw loosening, cannot effectively judge the characteristics of the rate of change of the interface slip value, and the prediction method is single and inaccurate. It cannot provide doctors with a clear prediction time point and a scientific adjustment remaining time, which greatly limits the scientificity and timeliness of clinical decision-making.

[0004] To this end, we propose a method and system for predicting loosening of orthopedic internal fixation screws based on finite element analysis. Summary of the Invention

[0005] The object of the present invention is to provide a method and system for predicting loosening of orthopedic internal fixation screws based on finite element analysis, so as to solve at least one of the above-mentioned problems in the prior art.

[0006] The present invention provides a method for predicting loosening of orthopedic internal fixation screws based on finite element analysis, comprising:

[0007] Analyze the patient's bone images during the historical acquisition period, and determine abnormal sub-periods within the historical acquisition period based on the displacement of the screw key nodes and the bone tissue key nodes;

[0008] The process of obtaining abnormal sub-periods is as follows:

[0009] Analyze the patient's bone images during the historical acquisition period, output the interface slip value, and calculate the ratio with the interface slip threshold to obtain the interface slip ratio of the contact interface. If the interface slip ratio is greater than or equal to the interface slip ratio threshold, the corresponding acquisition sub-period is recorded as an abnormal sub-period;

[0010] Analyze the number of abnormal sub-periods and interface slip ratio within the historical acquisition period to determine the tightness of orthopedic internal fixation screws and identify the tightening screws among the fixation screws;

[0011] The process of obtaining the tightness of orthopedic internal fixation screws is as follows:

[0012] Analyze the number of abnormal sub-periods and the interface slip ratio within the historical acquisition period, output the abnormal period number ratio and slip degree ratio within the historical acquisition period, and perform product processing to obtain the screw tightness value;

[0013] The process of obtaining the ratio of the number of abnormal periods and the ratio of the slip degree within the historical collection period is as follows:

[0014] Calculate the proportion of abnormal sub-periods within the historical collection period to obtain the abnormal period quantity ratio;

[0015] The interface slip ratio corresponding to the abnormal sub-period is subtracted from the interface slip ratio threshold to obtain the interface slip deviation value. The interface slip deviation values ​​of all abnormal sub-periods are summed and averaged, and then the average value is compared with the interface slip ratio threshold to obtain the slip degree ratio.

[0016] Analyze the rate of change of the interface slip value of the fastening screw during the historical collection period, judge whether the rate of change is uniform, and output the predicted time point based on the result of the uniformity judgment of the rate of change;

[0017] Based on the forecast period, the analysis is performed to determine the remaining time for adjustment.

[0018] As a further solution of the present invention: the process of obtaining the abnormal sub-period is:

[0019] The patient's bone images in the historical acquisition period are analyzed, the interface slip value is output, and the interface slip ratio is calculated by proportional calculation with the interface slip threshold to obtain the interface slip ratio of the contact interface. If the interface slip ratio is greater than or equal to the interface slip ratio threshold, the corresponding acquisition sub-period is recorded as an abnormal sub-period.

[0020] As a further solution of the present invention: the process of obtaining the interface slip value is:

[0021] The time period between adjacent collection time points in the historical collection period is recorded as a collection sub-period;

[0022] During the acquisition sub-period, the displacements of the screw key nodes and the bone tissue key nodes are measured and deviation processing is performed to obtain the displacement deviation;

[0023] According to the displacement deviation, the interface slip value of the contact interface in the acquisition sub-period is calculated.

[0024] As a further solution of the present invention: the process of obtaining the tightness state of an orthopedic internal fixation screw is as follows:

[0025] The number of abnormal sub-periods and the interface slip ratio within the historical acquisition period are analyzed, and the ratio of the number of abnormal periods and the slip degree ratio within the historical acquisition period are output. The product is processed to obtain the screw tightness value.

[0026] As a further solution of the present invention, the process of obtaining the abnormal period number ratio and slippage degree ratio within the historical collection period is as follows:

[0027] Calculate the proportion of abnormal sub-periods within the historical collection period to obtain the abnormal period quantity ratio;

[0028] The interface slip ratio corresponding to the abnormal sub-period is subtracted from the interface slip ratio threshold to obtain the interface slip deviation value. The interface slip deviation values ​​of all abnormal sub-periods are summed and averaged, and then the average value is compared with the interface slip ratio threshold to obtain the slip degree ratio.

[0029] As a further solution of the present invention: the process of determining whether the rate of change is uniform is as follows:

[0030] The interface slip values ​​within the historical acquisition period are analyzed to obtain the standard deviation and average value of the interface slip value change rate within the historical acquisition period, and the ratio processing is performed to output the coefficient of variation of the change rate; if the coefficient of variation is greater than or equal to the coefficient of variation threshold, it indicates that the change rate within the historical acquisition period is uniform; otherwise, it indicates that the change rate within the historical acquisition period is uneven.

[0031] As a further solution of the present invention: the process of obtaining the standard deviation and average value of the interface slip value change rate during the historical acquisition period is as follows:

[0032] Obtain the interface slip value sequence within the historical acquisition period, calculate the change rate of the interface slip value in the acquisition sub-period and integrate it into a change rate sequence, calculate the average value of the change rate, and then calculate the standard deviation of the change rate.

[0033] As a further solution of the present invention: the acquisition process of adjusting the remaining time is:

[0034] Based on the uneven change rate, the maximum change rate in the change rate sequence table is extracted as the predicted change rate; the interface slip threshold is calculated with the predicted change rate to obtain the predicted time point;

[0035] Based on the uniformity of the change rate, determine whether the change rate of the interface slip value during the historical acquisition period changes linearly;

[0036] Based on linear changes, the interface slip threshold is used as the y input of the fitting straight line equation, and the x value of the predicted time point is output; based on nonlinear changes, a prediction model is constructed, and the trained model is used. The interface slip threshold is used as input and the predicted time point when the interface slip threshold is reached is output; the predicted time point is subtracted from the current time point to obtain the remaining time for adjustment.

[0037] As a further solution of the present invention, the specific process of determining whether the rate of change of the interface slip value during the historical acquisition period is linear is as follows:

[0038] The interface slip value change rate during the historical acquisition period is linearly fitted using the least squares method, and the goodness of fit is calculated. If the goodness of fit is greater than or equal to the goodness of fit threshold, the interface slip value change rate changes linearly during the historical acquisition period; otherwise, it changes nonlinearly.

[0039] The present invention provides an orthopedic internal fixation screw loosening prediction system based on finite element analysis, comprising:

[0040] Abnormality analysis module: Analyzes the patient's bone images during the historical acquisition period and determines abnormal sub-periods within the historical acquisition period based on the displacement of the screw key nodes and the bone tissue key nodes;

[0041] The process of obtaining abnormal sub-periods is as follows:

[0042] Analyze the patient's bone images during the historical acquisition period, output the interface slip value, and calculate the ratio with the interface slip threshold to obtain the interface slip ratio of the contact interface. If the interface slip ratio is greater than or equal to the interface slip ratio threshold, the corresponding acquisition sub-period is recorded as an abnormal sub-period;

[0043] Tightness judgment module: Analyzes the number of abnormal sub-periods and the interface slip ratio within the historical acquisition period to determine the tightness of orthopedic internal fixation screws and identify the tightening screws among the fixation screws;

[0044] The process of obtaining the tightness of orthopedic internal fixation screws is as follows:

[0045] Analyze the number of abnormal sub-periods and the interface slip ratio within the historical acquisition period, output the abnormal period number ratio and slip degree ratio within the historical acquisition period, and perform product processing to obtain the screw tightness value;

[0046] The process of obtaining the ratio of the number of abnormal periods and the ratio of the slip degree within the historical collection period is as follows:

[0047] Calculate the proportion of abnormal sub-periods within the historical collection period to obtain the abnormal period quantity ratio;

[0048] The interface slip ratio corresponding to the abnormal sub-period is subtracted from the interface slip ratio threshold to obtain the interface slip deviation value. The interface slip deviation values ​​of all abnormal sub-periods are summed and averaged, and then the average value is compared with the interface slip ratio threshold to obtain the slip degree ratio.

[0049] Change uniformity analysis module: Analyzes the change rate of the interface slip value of the fastening screw during the historical acquisition period, judges whether the change rate is uniform, and outputs the predicted time point based on the change rate uniformity judgment result;

[0050] Adjustment remaining time determination module: Based on the forecast period, process and analyze to determine the adjustment remaining time.

[0051] Beneficial effects of the present invention:

[0052] 1. The present invention determines abnormal sub-periods within the historical acquisition period by analyzing the patient's bone images during the historical acquisition period; analyzes the number of abnormal sub-periods and the interface slip ratio within the historical acquisition period to judge the tightness of orthopedic internal fixation screws; measures the displacement of key nodes of the screw and key nodes of the bone tissue, and calculates the displacement deviation and interface slip value, thereby accurately quantifying the slip of the contact interface, making the analysis result more accurate, facilitating the effective judgment of the tightness of orthopedic internal fixation screws, and providing doctors with a clear basis for decision-making. Based on the historical orthopedic internal fixation screw loosening change data, comprehensive analysis and processing are performed to timely discover abnormal sub-periods within the historical acquisition period, thereby promptly detecting possible loosening of the screw, helping doctors to take timely measures to avoid adverse consequences caused by screw loosening, thereby improving treatment effects and patient safety.

[0053] 2. The present invention judges whether the change rate is uniform by analyzing the change rate of the interface slip value of the fastening screw during the historical acquisition period; outputs the predicted time point according to the judgment result of whether the change rate of the interface slip value is uniform during the historical acquisition period; and processes and analyzes to determine the adjustment remaining time according to the predicted time point; the present invention can accurately judge whether the change rate of the interface slip value is uniform during the historical acquisition period by calculating the change rate of the interface slip value, so as to clearly grasp its change state, which is helpful to deeply understand the interface slip characteristics of the fastening screw during the historical acquisition period. When the change rate of the interface slip value is uneven, the maximum change rate is used as the predicted change rate to calculate the predicted time point, which can minimize the risk caused by loosening of orthopedic internal fixation screws when the screw loosening rate is the fastest. The risk of interface slippage can be estimated by the medical staff, so that they can evaluate the time point when the interface slippage value reaches the threshold value and take measures in advance to avoid loosening of the fixation screws in patients and promote their recovery. When the interface slippage value changes at a uniform rate, the least squares method is used for linear fitting and the change type is judged by the goodness of fit. If it is a linear change, the time point is predicted based on the fitted straight line equation; if it is a nonlinear change, an LSTM neural network prediction model is constructed for prediction, and then the time point when the interface slippage value reaches the interface slippage threshold is accurately predicted. The remaining adjustment time is calculated based on the predicted time point. The doctor can choose to retighten or replace the screw according to the patient's specific situation before the end of the time, which provides a clear and scientific time basis for the doctor's clinical decision-making and improves the timeliness and effectiveness of treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0055] Figure 1 This is a flow chart of a method for predicting loosening of orthopedic internal fixation screws based on finite element analysis according to an embodiment of the present invention;

[0056] Figure 2 This is a system block diagram of an orthopedic internal fixation screw loosening prediction system based on finite element analysis according to an embodiment of the present invention. DETAILED DESCRIPTION

[0057] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0058] Example 1 Figure 1 As shown, the method for predicting loosening of orthopedic internal fixation screws based on finite element analysis provided by an embodiment of the present invention specifically includes:

[0059] Step 1: Analyze the patient's bone images during the historical acquisition period and determine the abnormal sub-periods within the historical acquisition period;

[0060] A historical acquisition period was set, and several acquisition time points with equal time intervals were set within the historical acquisition period. The patient's bone images were acquired using a spiral CT scanner. A 3D model of the bone fixation screw and surrounding bone was created using the 3D modeling software SolidWorks. The model was imported into the finite element analysis software ANSYS. Material properties were defined, and parameters such as the elastic modulus and Poisson's ratio were assigned to the screw and bone. Meshing was performed, with a finer mesh used for the screw and key bone locations to improve calculation accuracy. Boundary conditions and loads were applied to simulate the stress conditions of the bone fixation screw under actual working conditions.

[0061] It should be noted that the historical collection period includes but is not limited to 10 days, 20 days, and 30 days;

[0062] The stress distribution of the model was calculated using the finite element software solver. The stress values ​​of various parts of the screw were extracted from the post-processing module. The nodes associated with the contact element were selected using the ESLN command using the ANSYS CONTACT unit and recorded as the screw key nodes. The bone surface nodes in contact with the screw were recorded as the bone tissue key nodes.

[0063] It should be noted that there is a one-to-one correspondence between the screw key nodes and the bone surface nodes;

[0064] Generate a displacement cloud map through NODAL SOLUTION→U-Total, and record the time period between adjacent acquisition time points as the acquisition sub-period;

[0065] During the acquisition sub-period, the displacement of the key nodes of the screw is measured and recorded as the screw node displacement ; Measure the displacement of key nodes of bone tissue, recorded as bone tissue node displacement ;

[0066] Calculate screw node displacement Displacement with bone tissue nodes Displacement deviation , the specific calculation formula is:

[0067]

[0068] Then calculate the interface slip value d of the contact interface in the acquisition sub-period, i=1,2,…,n, where n represents the total number of key nodes of the screw. The specific calculation formula is:

[0069]

[0070] Setting an interface slip threshold, wherein the interface slip threshold is set by a person skilled in the art based on historical orthopedic internal fixation screw loosening change data;

[0071] The interface slip value is ratioed to the interface slip threshold to obtain the interface slip ratio of the contact interface;

[0072] In some embodiments, the interface slip ratio is compared with an interface slip ratio threshold, and the specific comparison process is:

[0073] If the interface slip ratio is greater than or equal to the interface slip ratio threshold, the corresponding acquisition sub-period is recorded as an abnormal sub-period;

[0074] If the interface slip ratio is less than the interface slip ratio threshold, the corresponding acquisition sub-period is recorded as a normal sub-period;

[0075] Step 2: Analyze the number of abnormal sub-periods and the interface slip ratio within the historical acquisition period to determine the tightness of the orthopedic internal fixation screws;

[0076] Count the number of abnormal sub-periods in the historical collection period, and perform ratio processing on the total number of collection sub-periods in the historical collection period to obtain the ratio of the number of abnormal periods in the historical collection period;

[0077] The interface slip ratio corresponding to the abnormal sub-period is extracted and subtracted from the interface slip ratio threshold to obtain the interface slip deviation value. The interface slip deviation values ​​corresponding to all abnormal sub-periods are summed and averaged to obtain the interface slip deviation mean. The interface slip deviation mean is then compared with the interface slip ratio threshold to obtain the slip degree ratio of the contact interface during the historical acquisition period.

[0078] The screw tightness value is obtained by multiplying the ratio of the number of abnormal periods in the historical acquisition period by the ratio of the slip degree of the contact interface in the historical acquisition period.

[0079] In some embodiments, a screw tightness threshold is set, and the screw tightness value is compared with the screw tightness threshold. The specific comparison process is:

[0080] If the screw tightness value is greater than or equal to the screw tightness threshold, the fixed screw is recorded as a loose screw, and the doctor can choose to retighten the screw or replace the screw according to the patient's specific situation;

[0081] If the screw tightness value is less than the screw tightness threshold, the fixed screw is recorded as a tightening screw;

[0082] The technical solution of this embodiment is: analyzing the bone images of the patient during the historical acquisition period to determine the abnormal sub-periods within the historical acquisition period; analyzing the number of abnormal sub-periods and the interface slip ratio within the historical acquisition period to judge the tightness of the orthopedic internal fixation screw; the present invention can accurately quantify the slip of the contact interface by measuring the displacement of the key nodes of the screw and the key nodes of the bone tissue, and calculating the displacement deviation and the interface slip value, so as to make the analysis result more accurate, which is conducive to effectively judging the tightness of the orthopedic internal fixation screw and providing doctors with a clear decision-making basis. Based on the historical orthopedic internal fixation screw loosening change data, comprehensive analysis and processing are carried out, which can timely discover the abnormal sub-periods within the historical acquisition period, thereby timely detecting the possible loosening of the screw, helping doctors to take timely measures to avoid the adverse consequences caused by screw loosening, and improve treatment effects and patient safety.

[0083] Example 2 Figure 1 As shown, the method for predicting loosening of orthopedic internal fixation screws based on finite element analysis provided by an embodiment of the present invention specifically includes:

[0084] Step 3: Analyze the rate of change of the interface slip value of the fastening screw during the historical collection period and determine whether the rate of change is uniform;

[0085] In some embodiments, all acquisition sub-periods are combined into an acquisition sub-period sequence. , j = 1, 2, ..., m, where m represents the number of acquisition sub-periods, and the interface slip value sequence within the historical acquisition period is obtained ,in, represents the displacement corresponding to the jth acquisition sub-period;

[0086] By formula: Calculate the change rate of the jth acquisition sub-period ;

[0087] Integrate the change rates of the interface slip values ​​of all acquisition sub-periods into a change rate sequence ;

[0088] Extract the change rate of the interface slip value in the change rate sequence table and calculate the average change rate of the interface slip value during the historical acquisition period , the specific calculation formula is:

[0089]

[0090] Then calculate the standard deviation of the interface slip value change rate during the historical acquisition period , the specific calculation formula is:

[0091]

[0092] The standard deviation of the interface slip value change rate during the historical acquisition period The average value of the interface slip value change rate during the historical acquisition period Perform ratio processing to obtain the coefficient of variation of the interface slip value change rate during the historical acquisition period;

[0093] In some embodiments, the coefficient of variation of the interface slip value change rate within the historical acquisition period is compared with a threshold value of the coefficient of variation of the interface slip value change rate within the historical acquisition period;

[0094] If the coefficient of variation of the interface slip value change rate during the historical acquisition period is greater than or equal to the threshold value of the coefficient of variation of the interface slip value change rate during the historical acquisition period, it indicates that the interface slip value change rate during the historical acquisition period is uniform;

[0095] If the coefficient of variation of the interface slip value change rate during the historical acquisition period is less than the threshold value of the coefficient of variation of the interface slip value change rate during the historical acquisition period, it indicates that the interface slip value change rate during the historical acquisition period is uneven;

[0096] It should be noted that the purpose of obtaining the coefficient of variation of the interface slip value change rate during the historical acquisition period is as follows:

[0097] Function 1: By comparing and judging the coefficient of variation of the interface slip value change rate during the historical collection period, it is helpful to analyze whether the interface slip value change rate during the historical collection period is uniform, and then to understand the change state of the interface slip value change rate during the historical collection period;

[0098] Function 2: By comparing and judging the coefficient of variation of the interface slip value change rate during the historical collection period, it is helpful to analyze whether the interface slip value change rate during the historical collection period is uniform, and to facilitate the subsequent adjustment of the remaining time based on whether the interface slip value change rate during the historical collection period is uniform;

[0099] Step 4: Output the predicted time point based on the judgment result of whether the interface slip value change rate is uniform during the historical acquisition period;

[0100] S41, based on the uneven change rate of the interface slip value during the historical acquisition period, continue to monitor the subsequent interface slip values, obtain the maximum change rate in the change rate sequence table, and use the maximum change rate as the predicted change rate;

[0101] Calculate the ratio of the interface slip threshold to the predicted change rate to obtain the predicted time point;

[0102] It should be noted that the purpose of using the maximum value of the change rate as the predicted change rate is to minimize the risk caused by the loosening of the orthopedic internal fixation screws when the loosening rate of the orthopedic internal fixation screws is the fastest, which is beneficial for medical personnel to assess the time point when the interface slip value reaches the interface slip threshold. Therefore, medical personnel can choose to retighten the screws or replace the screws according to the specific situation of the orthopedic patient before the interface slip value reaches the interface slip threshold, thereby avoiding the loosening of the fixation screws in the orthopedic patient and facilitating the patient's recovery.

[0103] S42, based on the uniformity of the change rate of the interface slip value during the historical acquisition period, determining whether the change rate of the interface slip value during the historical acquisition period changes linearly;

[0104] The interface slip value change rate during the historical acquisition period is linearly fitted using the least squares method, where the fitting line equation is: ;

[0105] Calculate goodness of fit , the specific calculation formula is:

[0106]

[0107] Where l represents the total number of data points for linear fitting, is the kth actual value, represents the k-th predicted value, Indicates the average of actual values;

[0108] Set the goodness of fit threshold and compare the goodness of fit with the goodness of fit threshold. The specific comparison process is:

[0109] If the goodness of fit is greater than or equal to the goodness of fit threshold, it means that the degree of fit between the interface slip value change rate and the fitting straight line is high, and the interface slip value change rate changes linearly during the historical acquisition period;

[0110] If the goodness of fit is less than the goodness of fit threshold, it means that the degree of fit between the interface slip value change rate and the fitting straight line is low, and the interface slip value change rate changes nonlinearly during the historical acquisition period;

[0111] Based on linear changes, according to the fitting straight line equation Predict the time point when the interface slip value reaches the interface slip threshold, take the interface slip threshold as the y input, and output the x value, which is the predicted time point;

[0112] Based on nonlinear changes and LSTM neural network, a prediction model is constructed;

[0113] After normalizing the interface slip value change rate during the historical acquisition period, the data is converted into a format suitable for LSTM model input [number of samples, time step, number of features]; and divided into training set, validation set, and test set in a ratio of 8:1:1;

[0114] Use the training set to train the model, monitor the performance of the model through the validation set during the training process, and use the test set to evaluate the performance of the model. The specific evaluation indicators are:

[0115] Calculate the mean square error. The specific calculation formula is:

[0116]

[0117] in, represents the actual observation value of the cth sample, represents the predicted value (model output value) of the cth sample, and N represents the total number of samples;

[0118] Then the loss function in the model training process is obtained as:

[0119]

[0120] Where d represents the time step, T represents the total number of time steps in the time series, represents the mean square error of the dth time step;

[0121] Use the trained model, take the interface slip threshold as input, and output the predicted time point when the interface slip threshold is reached;

[0122] Step 5: Based on the forecast period, process and analyze to determine the remaining time for adjustment;

[0123] Based on the predicted time point, the predicted time point is subtracted from the current time point to obtain the remaining adjustment time. The doctor needs to choose to retighten the screw or replace the screw according to the patient's specific situation before the remaining adjustment time ends;

[0124] The technical solution of this embodiment is: analyzing the rate of change of the interface slip value of the fastening screw during the historical acquisition period, and judging whether the rate of change is uniform; outputting a predicted time point according to the judgment result of whether the rate of change of the interface slip value is uniform during the historical acquisition period; processing and analyzing to determine the adjustment remaining time according to the predicted time point; the present invention can accurately judge whether the rate of change of the interface slip value is uniform during the historical acquisition period by calculating the rate of change of the interface slip value, so as to clearly grasp its change state, which is helpful to deeply understand the interface slip characteristics of the fastening screw during the historical acquisition period; when the rate of change of the interface slip value is uneven, the maximum value of the rate of change is used as the predicted rate of change to calculate the predicted time point, which can minimize the loosening of the orthopedic internal fixation screw when the screw loosening rate is the fastest. The risks brought about by this can enable medical staff to evaluate the time point when the interface slip value reaches the threshold and take measures in advance to avoid loosening of the fixation screws in patients and promote their recovery. When the interface slip value changes at a uniform rate, the least squares method is used for linear fitting and the change type is judged by the goodness of fit. If it is a linear change, the time point is predicted based on the fitted straight line equation; if it is a nonlinear change, an LSTM neural network prediction model is constructed for prediction, and then the time point when the interface slip value reaches the interface slip threshold is accurately predicted. The remaining adjustment time is calculated based on the predicted time point. The doctor can choose to retighten or replace the screws according to the patient's specific situation before the end of the time, which provides a clear and scientific time basis for the doctor's clinical decision-making and improves the timeliness and effectiveness of treatment.

[0125] Example 3 Figure 2 As shown, the orthopedic internal fixation screw loosening prediction system based on finite element analysis provided by the embodiment of the present invention specifically includes:

[0126] Abnormality analysis module: Analyzes the patient's bone images during the historical acquisition period and determines abnormal sub-periods within the historical acquisition period based on the displacement of the screw key nodes and the bone tissue key nodes;

[0127] Tightness judgment module: Analyzes the number of abnormal sub-periods and the interface slip ratio within the historical acquisition period to determine the tightness of orthopedic internal fixation screws and identify the tightening screws among the fixation screws;

[0128] Change uniformity analysis module: Analyzes the change rate of the interface slip value of the fastening screw during the historical collection period and determines whether the change rate is uniform;

[0129] Prediction time point output module: judge the result uniformly according to the change rate and output the predicted time point;

[0130] Adjustment remaining time determination module: Based on the forecast period, process and analyze to determine the adjustment remaining time.

[0131] The above formulas are all dimensionless and numerical calculations. The formulas are obtained by collecting a large amount of data and performing software simulation to obtain the most recent real situation. The preset parameters in the formulas are set by technicians in this field according to actual conditions.

[0132] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for predicting loosening of orthopedic internal fixation screws based on finite element analysis, characterized in that: include: Analyze the patient's bone images during the historical acquisition period, and determine abnormal sub-periods within the historical acquisition period based on the displacement of the screw key nodes and the bone tissue key nodes; The process of obtaining abnormal sub-periods is as follows: Analyze the patient's bone images during the historical acquisition period, output the interface slip value, and calculate the ratio with the interface slip threshold to obtain the interface slip ratio of the contact interface. If the interface slip ratio is greater than or equal to the interface slip ratio threshold, the corresponding acquisition sub-period is recorded as an abnormal sub-period; Analyze the number of abnormal sub-periods and interface slip ratio within the historical acquisition period to determine the tightness of orthopedic internal fixation screws and identify the tightening screws among the fixation screws; The process of obtaining the tightness of orthopedic internal fixation screws is as follows: Analyze the number of abnormal sub-periods and the interface slip ratio within the historical acquisition period, output the abnormal period number ratio and slip degree ratio within the historical acquisition period, and perform product processing to obtain the screw tightness value; The process of obtaining the ratio of the number of abnormal periods and the ratio of the slip degree within the historical collection period is as follows: Calculate the proportion of abnormal sub-periods within the historical collection period to obtain the abnormal period number ratio; The interface slip ratio corresponding to the abnormal sub-period is subtracted from the interface slip ratio threshold to obtain the interface slip deviation value. The interface slip deviation values ​​of all abnormal sub-periods are summed and averaged, and then the average value is compared with the interface slip ratio threshold to obtain the slip degree ratio. Analyze the rate of change of the interface slip value of the fastening screw during the historical collection period, judge whether the rate of change is uniform, and output the predicted time point based on the result of the uniformity judgment of the rate of change; Based on the forecast period, the analysis is performed to determine the remaining time for adjustment.

2. The method for predicting loosening of orthopedic internal fixation screws based on finite element analysis according to claim 1, characterized in that: The process of obtaining the interface slip value is as follows: The time period between adjacent collection time points in the historical collection period is recorded as a collection sub-period; During the acquisition sub-period, the displacements of the screw key nodes and the bone tissue key nodes are measured and deviation processing is performed to obtain the displacement deviation; According to the displacement deviation, the interface slip value of the contact interface in the acquisition sub-period is calculated.

3. The method for predicting loosening of orthopedic internal fixation screws based on finite element analysis according to claim 1, characterized in that: The process of judging whether the rate of change is uniform is as follows: Analyze the interface slip values ​​within the historical acquisition period to obtain the standard deviation and average value of the interface slip value change rate within the historical acquisition period, perform ratio processing, and output the coefficient of variation of the change rate; If the coefficient of variation is greater than or equal to the coefficient of variation threshold, it indicates that the rate of change within the historical collection period is uniform; otherwise, it indicates that the rate of change within the historical collection period is uneven.

4. The method for predicting loosening of orthopedic internal fixation screws based on finite element analysis according to claim 1, characterized in that: The process of obtaining the standard deviation and average value of the interface slip value change rate during the historical acquisition period is as follows: Obtain the interface slip value sequence within the historical acquisition period, calculate the change rate of the interface slip value in the acquisition sub-period and integrate it into a change rate sequence, calculate the average value of the change rate, and then calculate the standard deviation of the change rate.

5. The method for predicting loosening of orthopedic internal fixation screws based on finite element analysis according to claim 4, characterized in that: The process of obtaining the adjusted remaining time is as follows: Based on the uneven change rate, the maximum change rate in the change rate sequence table is extracted as the predicted change rate; the interface slip threshold is calculated with the predicted change rate to obtain the predicted time point; Based on the uniformity of the change rate, determine whether the change rate of the interface slip value during the historical acquisition period changes linearly; Based on linear changes, the interface slip threshold is used as the y input of the fitting straight line equation, and the x value of the predicted time point is output; based on nonlinear changes, a prediction model is constructed, and the trained model is used. The interface slip threshold is used as input and the predicted time point when the interface slip threshold is reached is output; the predicted time point is subtracted from the current time point to obtain the remaining time for adjustment.

6. The method for predicting loosening of orthopedic internal fixation screws based on finite element analysis according to claim 5, characterized in that: The specific process of judging whether the rate of change of the interface slip value during the historical acquisition period is linear is as follows: The interface slip value change rate during the historical acquisition period is linearly fitted using the least squares method, and the goodness of fit is calculated. If the goodness of fit is greater than or equal to the goodness of fit threshold, the interface slip value change rate changes linearly during the historical acquisition period; otherwise, it changes nonlinearly.

7. A system for predicting loosening of orthopedic internal fixation screws based on finite element analysis, the system implementing the method for predicting loosening of orthopedic internal fixation screws based on finite element analysis according to any one of claims 1 to 6, characterized in that: include: Abnormality analysis module: Analyzes the patient's bone images during the historical acquisition period and determines abnormal sub-periods within the historical acquisition period based on the displacement of the screw key nodes and the bone tissue key nodes; The process of obtaining abnormal sub-periods is as follows: Analyze the patient's bone images during the historical acquisition period, output the interface slip value, and calculate the ratio with the interface slip threshold to obtain the interface slip ratio of the contact interface. If the interface slip ratio is greater than or equal to the interface slip ratio threshold, the corresponding acquisition sub-period is recorded as an abnormal sub-period; Tightness judgment module: Analyzes the number of abnormal sub-periods and the interface slip ratio within the historical acquisition period to determine the tightness of orthopedic internal fixation screws and identify the tightening screws among the fixation screws; The process of obtaining the tightness of orthopedic internal fixation screws is as follows: Analyze the number of abnormal sub-periods and the interface slip ratio within the historical acquisition period, output the abnormal period number ratio and slip degree ratio within the historical acquisition period, and perform product processing to obtain the screw tightness value; The process of obtaining the ratio of the number of abnormal periods and the ratio of the slip degree within the historical collection period is as follows: Calculate the proportion of abnormal sub-periods within the historical collection period to obtain the abnormal period number ratio; The interface slip ratio corresponding to the abnormal sub-period is subtracted from the interface slip ratio threshold to obtain the interface slip deviation value. The interface slip deviation values ​​of all abnormal sub-periods are summed and averaged, and then the average value is compared with the interface slip ratio threshold to obtain the slip degree ratio. Change uniformity analysis module: Analyzes the change rate of the interface slip value of the fastening screw during the historical acquisition period, judges whether the change rate is uniform, and outputs the predicted time point based on the change rate uniformity judgment result; Adjustment remaining time determination module: Based on the forecast period, process and analyze to determine the adjustment remaining time.

Images