Method and system for measuring stability of internal fixation structure of femoral neck fracture

Abstract

The invention relates to the technical field of bone structure mechanical simulation, in particular to a method and system for measuring the stability of a fixing structure in femoral neck fracture, and the method comprises the steps: respectively collecting a hand bone three-dimensional model and a post-operation X film for a fracture part, and carrying out the registration, so as to respectively determine the spatial position of a fracture feature point and the spatial position of a screw in the bone three-dimensional model; and establishing a postoperative three-dimensional model based on the spatial position of the fracture feature point and the spatial position of the screw for evaluating the structural stability of the fracture part. In order to solve the problem that in the prior art, simulation of a fixing structure in a postoperative skeleton is relatively rough, and postoperative fracture geometrical shape changes and actual screw angles cannot be well reflected, the position of a femoral head and the position of a screw are recognized in an X-ray film after an operation, so that the spatial position of a fracture feature point and the spatial position of the screw are formed; and an accurate postoperative three-dimensional model is constructed, so that a more accurate finite element simulation process can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of bone structure mechanics simulation, and in particular to a method and system for measuring the stability of a femoral neck fracture internal fixation structure. Background Art

[0002] Femoral neck fracture refers to a fracture below the femoral head and above the base of the femoral neck due to direct or indirect violence. It is more common in the elderly, for example, due to falls. For this type of fracture, the existing treatment method is usually internal fixation, where screws are inserted from the intertrochanteric ridge, through the femoral neck and fracture section to the inside of the femoral head, and the screws are used to fix the fracture site and replace the force. Since the mechanical structure of the femoral head and neck has changed after internal fixation, its structural stability will be directly related to the patient's prognosis and efficacy. Therefore, it is usually necessary to evaluate and measure the stability of the internal fixation structure after surgery, so as to provide a basis for doctors to judge the prognosis and efficacy.

[0003] Figure 1 A schematic diagram of a typical internal fixation is shown, showing a cross section of the femoral neck and the screws inserted for the internal fixation. The tail end of the screw is exposed on the outside of the femur, and the head of the screw is provided with a threaded structure, which passes over the fracture section and is fixed at the femoral head.

[0004] In the prior art, a finite element simulation method is usually used to measure the stability of the postoperative femoral neck fracture internal fixation structure.

[0005] For example, Chinese patent CN202310958731.6 discloses a finite element bone strength assessment method under a skeletal internal fixation mode, which detects the edge of the internal fixator on the proximal femur image data based on an edge detection algorithm to obtain the edge contour of the internal fixator; analyzes the fracture site area in the proximal femur image data through the mechanical simulation analysis system; finds the position of the edge contour of the internal fixator in the fracture site area and fills it; performs finite element bone strength calculation on the fracture site area. It is capable of performing internal fixation filling on the proximal femur under a skeletal internal fixation mode, eliminating the penetration effect of the internal fixation in the proximal femur image, and avoiding the internal fixator from causing image influence on the proximal femur fracture site in the proximal femur image data, thereby affecting the bone strength assessment process of the proximal femur fracture site. The internal fixation area in the proximal femur fracture site is filled with a near value, which facilitates the subsequent finite element calculation and assessment of the bone strength of the proximal femur fracture site.

[0006] However, during the actual implementation process, the inventor found that the simulation of the fracture site in the prior art was relatively simple, including a certain simplification of the geometric shape of the fracture ends. At the same time, the setting angle of the screws was usually set parallelly with reference to the clinical guidelines, which led to problems such as poor simulation effect and inability to truly reflect the postoperative situation. Figure 2 A typical finite element model is shown, and it can be seen that it omits the geometric shape of the fracture section and the influence on the position of the femoral head, and the screw positions are also set parallelly according to the clinical guidelines. Summary of the Invention

[0007] In view of the above problems existing in the prior art, a method for measuring the stability of an internal fixation structure for femoral neck fractures is provided;

[0008] On the other hand, a measurement system for implementing the measurement method is also provided.

[0009] The specific technical solutions are as follows:

[0010] A method for measuring the stability of an internal fixation structure for femoral neck fractures includes:

[0011] Step S1: Collect preoperative three-dimensional CT images and postoperative X-rays of the fracture site respectively, and establish a bone three-dimensional model based on the preoperative three-dimensional CT images;

[0012] The fracture site is the femoral neck;

[0013] Step S2: Register the bone three-dimensional model and the postoperative X-ray to respectively determine the spatial positions of the fracture feature points and the screw spatial positions in the bone three-dimensional model;

[0014] Step S3: Establish a postoperative three-dimensional model based on the spatial positions of the fracture feature points and the screw spatial positions;

[0015] The postoperative three-dimensional model is used to evaluate the structural stability of the fracture site.

[0016] On the other hand, the step S2 includes:

[0017] Step S21: Identify the greater trochanter associated with the fracture site from the postoperative X-ray as the first registration mark site, and select the greater trochanter as the second registration mark site from the corresponding perspective of the bone three-dimensional model;

[0018] Step S22: Align the first registration mark site and the second registration mark site, and then register the bone three-dimensional model and the postoperative X-ray;

[0019] Step S23: Determine the fracture site and screw positions from the postoperative X-ray, and generate the spatial positions of the fracture feature points and the screw spatial positions on the bone three-dimensional model.

[0020] On the other hand, the step S23 includes:

[0021] Step S231: Identify the femoral head region from the postoperative X-ray, and extract the femoral head landmark points from the femoral head region respectively;

[0022] The femoral head landmark points include the center point of the fovea of the femoral head, the first end point on the neck side of the femoral head, and the second end point on the neck side of the femoral head;

[0023] Step S232: Generate the spatial positions of the fracture feature points on the bone three-dimensional model according to the femoral head landmark points, and determine the screw end points according to the enclosed area of the femoral head landmark points;

[0024] Step S233: Determine the screw starting point and screw vector from the postoperative X-ray, and pair the screw starting point and the screw end point based on the screw vector to form screw groups;

[0025] Step S234: Determine the screw spatial positions on the bone three-dimensional model according to the screw groups.

[0026] On the other hand, the step S3 includes:

[0027] Step S31: Adjust the femoral head part of the bone three-dimensional model according to the spatial positions of the fracture feature points to form a first adjusted model;

[0028] Step S32: Modify the cross-sectional geometry in the first adjusted model according to the postoperative X-ray to obtain a second adjusted model;

[0029] Step S33: Endow the second adjusted model with bone material properties according to the CT gray values of the preoperative three-dimensional CT images to obtain a third adjusted model;

[0030] Step S34: Add screw models to the third adjusted model according to the screw spatial positions to obtain the postoperative three-dimensional model.

[0031] On the other hand, after executing the step S3, it further includes:

[0032] Step S4: Perform finite element simulation on the postoperative three-dimensional model to obtain mechanical parameters, and evaluate the structural stability of the fracture site according to the mechanical parameters.

[0033] A measurement system for the structural stability of an internal fixation for femoral neck fractures, used to implement the above measurement method;

[0034] The measurement system includes:

[0035] An acquisition module that acquires pre-operative three-dimensional CT images and post-operative X-rays of the fracture site respectively, and establishes a three-dimensional bone model based on the pre-operative three-dimensional CT images;

[0036] The fracture site is the femoral neck;

[0037] A registration module that is connected to the acquisition module;

[0038] The registration module registers the three-dimensional bone model and the post-operative X-ray to respectively determine the spatial positions of the fracture feature points and the screw positions in the three-dimensional bone model;

[0039] A modeling module that is connected to the registration module;

[0040] The modeling module establishes a post-operative three-dimensional model based on the spatial positions of the fracture feature points and the screw positions;

[0041] The post-operative three-dimensional model is used to evaluate the structural stability of the fracture site.

[0042] On the other hand, the registration module includes:

[0043] A site selection module that identifies the greater trochanter associated with the fracture site from the post-operative X-ray as the first registration landmark site, and selects the greater trochanter as the second registration landmark site from the corresponding perspective of the three-dimensional bone model;

[0044] An alignment module that is connected to the site selection module;

[0045] The alignment module aligns the first registration landmark site and the second registration landmark site, and then registers the three-dimensional bone model and the post-operative X-ray;

[0046] A positioning module that is connected to the alignment module;

[0047] The positioning module determines the fracture site and the screw position from the post-operative X-ray, and generates the spatial positions of the fracture feature points and the screw positions on the three-dimensional bone model.

[0048] On the other hand, the positioning module includes:

[0049] A femoral head recognition module that recognizes the femoral head region from the post-operative X-ray and extracts femoral head landmark points from the femoral head region respectively;

[0050] The femoral head landmark points include the center point of the fovea capitis femoris, the first end point on the femoral neck side of the femoral head, and the second end point on the femoral neck side of the femoral head;

[0051] A femoral head processing module, which is connected to the femoral head recognition module;

[0052] The femoral head processing module generates the spatial positions of the fracture feature points on the bone three-dimensional model according to the femoral head landmark points, and determines the screw end points according to the enclosed area of the femoral head landmark points;

[0053] A screw positioning module, which is connected to the femoral head processing module;

[0054] The screw positioning module determines the screw starting point and the screw vector from the postoperative X-ray film, and pairs the screw starting point and the screw end point based on the screw vector to form screw groups;

[0055] A screw processing module, which is connected to the screw positioning module;

[0056] The screw processing module determines the screw spatial positions on the bone three-dimensional model according to the screw groups.

[0057] On the other hand, the modeling module includes:

[0058] A first adjustment module, which adjusts the femoral head part of the bone three-dimensional model according to the spatial positions of the fracture feature points to form a first adjusted model;

[0059] A second adjustment module, which is connected to the first adjustment module;

[0060] The second adjustment module corrects the cross-sectional geometry in the first adjusted model according to the postoperative X-ray film to obtain a second adjusted model;

[0061] A third adjustment module, which is connected to the second adjustment module;

[0062] The third adjustment module assigns bone material properties to the second adjusted model according to the CT gray values of the preoperative three-dimensional CT images to obtain a third adjusted model;

[0063] A fourth adjustment module, which is connected to the third adjustment module;

[0064] The fourth adjustment module adds screw models to the third adjusted model according to the screw spatial positions to obtain the postoperative three-dimensional model.

[0065] On the other hand, it further includes an evaluation module, which performs finite element simulation on the postoperative three-dimensional model to obtain mechanical parameters, and evaluates the structural stability of the fracture site according to the mechanical parameters.

[0066] The above technical solution has the following advantages or beneficial effects:

[0067] Aiming at the problem that the simulation of the internal fixation structure of bones after surgery in the prior art is relatively rough and cannot well reflect the change of the fracture geometry and the actual angle of the screws after surgery, in this solution, the positions of the femoral head and the screws are identified in the postoperative X-ray film, so as to form the spatial positions of the fracture feature points and the screw spatial positions, and then an accurate postoperative three-dimensional model is constructed, which can realize a more accurate finite element simulation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Referring to the accompanying drawings, the embodiments of the present invention will be described more fully. However, the accompanying drawings are only for illustration and explanation and do not constitute a limitation on the scope of the present invention.

[0069] Figure 1 It is a schematic diagram of postoperative modeling in the ideal state expected by the present invention;

[0070] Figure 2 It is a typical modeling schematic diagram in the prior art;

[0071] Figure 3 It is a schematic diagram of the method in the embodiment of the present invention;

[0072] Figure 4 It is a schematic diagram of step S2 in the embodiment of the present invention;

[0073] Figure 5 It is a schematic diagram of step S23 in the embodiment of the present invention;

[0074] Figure 6 It is a schematic diagram of step S3 in the embodiment of the present invention;

[0075] Figure 7 It is a schematic diagram of step S4 in the embodiment of the present invention;

[0076] Figure 8 It is a schematic diagram of the system in the embodiment of the present invention;

[0077] Figure 9 It is a schematic diagram of the registration module in the embodiment of the present invention;

[0078] Figure 10 It is a schematic diagram of the positioning module in the embodiment of the present invention;

[0079] Figure 11 It is a schematic diagram of the modeling module in the embodiment of the present invention;

[0080] Figure 12 Schematic diagram of the evaluation module in the embodiments of the present invention. Specific implementation manners

[0081] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0082] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0083] Some of the block diagrams shown in the drawings are functional entities, which do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in the form of software, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0084] Next, the present invention will be further described in conjunction with the accompanying drawings and specific embodiments, but it is not a limitation of the present invention.

[0085] The present invention includes:

[0086] A method for measuring the stability of an internal fixation structure for femoral neck fractures, as Figure 3 shown, includes:

[0087] Step S1: Collect preoperative three-dimensional CT images and postoperative X-rays of the fracture site respectively, and establish a bone three-dimensional model based on the preoperative three-dimensional CT images;

[0088] The fracture site is the femoral neck;

[0089] Step S2: Register the bone three-dimensional model and the postoperative X-ray to respectively determine the spatial positions of the fracture feature points and the screw in the bone three-dimensional model;

[0090] Step S3: Establish a postoperative three-dimensional model based on the spatial positions of the fracture feature points and the screw;

[0091] The postoperative three-dimensional model is used to evaluate the structural stability of the fracture site.

[0092] Specifically, in view of the relatively rough simulation of the internal fixation structure in the bone after surgery in the prior art, which cannot well reflect the change of the fracture geometry and the actual angle of the screws after surgery, in this solution, the positions of the femoral head and the screws are identified in the postoperative X-ray film, so as to form the spatial positions of the fracture feature points and the screw spatial positions, and then an accurate postoperative three-dimensional model is constructed, which can realize a more accurate finite element simulation process.

[0093] Specifically, before the surgery, first, the bone three-dimensional CT images of the hip joint part of the patient are taken, and the bone part can be modeled based on the three-dimensional CT images to obtain the bone three-dimensional model.

[0094] The postoperative X-ray film is the X-ray film taken again of the patient's hip joint after the internal fixation surgery. To facilitate the effective evaluation of the cross-section and the screw position on the three-dimensional level, usually, X-ray films at multiple angles are collected for subsequent processing.

[0095] The spatial position of the fracture feature points refers to the three-dimensional coordinate positions mapped from the corresponding points on the postoperative X-ray film in the coordinate system of the bone three-dimensional model, which includes the positions of multiple feature points and can realize the characterization of the spatial pose change of the fractured femoral head area.

[0096] The screw spatial position is the three-dimensional spatial pose information calculated separately for each screw and can be used to construct the correct position relationship of the screw modeling.

[0097] Based on the spatial position of the fracture feature points and the screw spatial position, the corresponding areas in the bone three-dimensional model can be corrected to form the correct geometric cross-section relationship and the screw spatial position relationship, thereby improving the accuracy of the simulation.

[0098] In one embodiment, as Figure 4 shown, step S2 includes:

[0099] Step S21: Identify the greater trochanter associated with the fracture site as the first registration landmark site from the postoperative X-ray film, and select the greater trochanter as the second registration landmark site from the corresponding perspective of the bone three-dimensional model.

[0100] Step S22: Align the first registration landmark site and the second registration landmark site, and then register the bone three-dimensional model and the postoperative X-ray film.

[0101] Step S23: Determine the fracture site and the screw position from the postoperative X-ray film, and generate the spatial position of the fracture feature points and the screw spatial position on the bone three-dimensional model.

[0102] Specifically, to implement the process of transferring the spatial features of the fracture site from the postoperative X-ray to the three-dimensional model, in this embodiment, the greater trochanter of the fractured femur is selected as the registration landmark. The greater trochanter is anatomically a part at the top of the femur opposite to the femoral head, connected to the femoral neck and located on the outside.

[0103] After the operation, at least one angle of postoperative X-ray of the patient needs to be collected. Then, according to the relevant parameters during X-ray collection, the collection angle of each postoperative X-ray can be determined. Then, a single-angle picture in the corresponding direction can be intercepted from the pre-established bone three-dimensional model.

[0104] For the corresponding-angle pictures of the postoperative X-ray and the bone three-dimensional model, an identification model can be used for processing respectively, including binarizing the pictures, region recognition, etc., so as to mark the greater trochanter in the image, and then form the first registration landmark part and the second registration landmark part.

[0105] Subsequently, in the three-dimensional coordinate system where the bone three-dimensional model is located, the postoperative X-rays at each angle are aligned according to the corresponding relationship between the first registration landmark part and the second registration landmark part. This alignment process can be an alignment process based on edge detection or a point cloud matching process after point cloud sampling.

[0106] Correspondingly, after registering the first registration landmark part and the second registration landmark part, each part on the postoperative X-ray, including the femoral stem, femoral neck and other parts, generally also has a roughly corresponding positional relationship with the bone three-dimensional model.

[0107] Subsequently, the femoral head and screw parts are identified from the registered postoperative X-ray to form the fracture site and the screw position. For these two, the spatial position coordinates are extracted respectively and mapped to the bone three-dimensional model to form the spatial position of the fracture feature points and the spatial position of the screw. Among them, the spatial position of the fracture feature points also includes the position of the corresponding points on the bone three-dimensional model, that is, the specific points on the preoperatively established bone three-dimensional model, such as the center point of the fovea of the femoral head, the first end point on the femoral neck side and the second end point on the femoral neck side, and the mapping relationship with the corresponding positions in the postoperative X-ray.

[0108] In one embodiment, as Figure 5 shown, step S23 includes:

[0109] Step S231: Identify the femoral head region from the postoperative X-ray and extract the femoral head landmark points from the femoral head region respectively;

[0110] The femoral head landmark points include the center point of the fovea of the femoral head, the first end point on the femoral neck side of the femoral head and the second end point on the femoral neck side of the femoral head;

[0111] Step S232: Generate the spatial positions of the fracture feature points on the bone three-dimensional model based on the femoral head landmark points, and determine the screw end points according to the enclosed area of the femoral head landmark points;

[0112] Step S233: Determine the screw start points and screw vectors from the postoperative X-rays, and form screw groups by pairing the screw start points and screw end points based on the screw vectors;

[0113] Step S234: Determine the screw spatial positions on the bone three-dimensional model according to the screw groups.

[0114] Specifically, to achieve a better mapping relationship of the spatial positions of the feature points, in this embodiment, after registering the postoperative X-rays, an image recognition model is used to perform recognition processing on the postoperative X-rays at each angle. The image recognition model is trained using a dataset with pre-annotated femoral head regions during the training process, and can recognize and annotate the femoral head region from the input image, thereby reducing the data volume for subsequent multi-modal recognition and processing.

[0115] Subsequently, for the selected femoral head region, the edge part is extracted and matched with relevant morphological templates as the input of multi-modal, so that the multi-modal model can comprehensively obtain the selected femoral head landmark points from the postoperative X-rays at each angle, including the center point of the fovea of the femoral head, the first end point on the femoral neck side of the femoral head, and the second end point on the femoral neck side of the femoral head.

[0116] Meanwhile, in combination with the angles at which the postoperative X-rays are collected, the coordinate ranges of each landmark point can be mapped in the coordinate system of the bone three-dimensional model, thereby forming the spatial positions of the fracture feature points.

[0117] Subsequently, a combination of enclosed areas is formed according to the spatial positions of the fracture feature points, the postoperative X-rays are intercepted, and then the screw end points are determined in the intercepted enclosed area by means of gray value recognition.

[0118] Then, an image recognition model is used to recognize the registered multiple postoperative X-rays to determine the screw end points on the lateral side of the femur. The screw end points usually include a region, including the screw end points and a partial extension part. The center line can be extracted based on the extension part to construct the screw vector.

[0119] Map the screw vectors of the multiple postoperative X-rays in the coordinate system of the bone three-dimensional model, thereby constructing the three-dimensional spatial vectors of the screws, find the paired screw end points based on the three-dimensional spatial vectors, and finally obtain the screw groups.

[0120] Finally, determine the screw spatial positions on the bone three-dimensional model according to the screw groups.

[0121] In one embodiment, as Figure 6As shown, step S3 includes:

[0122] Step S31: Adjust the femoral head part of the bone three-dimensional model according to the spatial position of the fracture feature points to form a first adjusted model;

[0123] Step S32: Modify the cross-sectional geometric shape in the first adjusted model according to the postoperative X-ray film to obtain a second adjusted model;

[0124] Step S33: Assign bone material properties to the second adjusted model according to the CT gray value of the preoperative three-dimensional CT image to obtain a third adjusted model;

[0125] Step S34: Add a screw model to the third adjusted model according to the screw spatial position to obtain a postoperative three-dimensional model.

[0126] Specifically, based on the above calculation process, the correction of the femoral head part of the bone three-dimensional model can be realized. Specifically, according to the spatial position of the fracture feature points and the cross-section reflected in the postoperative X-ray film, the spatial pose of the femoral head part beyond the cross-section in the bone three-dimensional model can be adjusted three-dimensionally to form a first adjusted model;

[0127] Subsequently, based on the first adjusted model, the fracture cross-section part is extracted based on the postoperative X-ray films at various angles, and then three-dimensional cross-section reconstruction is performed to obtain the cross-sectional geometric shape and add it to the cross-section part of the first adjusted model to form a second adjusted model;

[0128] Then, the bone density and other information of the patient are measured according to the CT gray value of the preoperative three-dimensional CT image, and bone material properties are assigned to obtain a third adjusted model;

[0129] Finally, a screw model is added to the third adjusted model according to the screw spatial position to obtain a postoperative three-dimensional model.

[0130] In one embodiment, as Figure 7 shown, after executing step S3, it further includes:

[0131] Step S4: Perform finite element simulation on the postoperative three-dimensional model to obtain mechanical parameters, and evaluate the structural stability of the fracture site according to the mechanical parameters.

[0132] Specifically, to achieve a better evaluation effect, after modeling, the postoperative three-dimensional model can be imported into calculation software such as Abaqus / Ansys for finite element simulation calculation, so as to obtain mechanical parameters, including structural stiffness, stress, strain, displacement, and relative displacement of the fracture ends. These parameters are comprehensively analyzed according to the entropy value scoring method to obtain the entropy value score as the stability index of the femoral neck fracture internal fixation structure. It is convenient for doctors to further estimate the prognosis and curative effect.

[0133] A measurement system for the stability of the internal fixation structure of femoral neck fractures, which is used to implement the above-mentioned measurement method;

[0134] As Figure 8 shown, the measurement system includes:

[0135] An acquisition module 1, which acquires the preoperative three-dimensional CT images and postoperative X-rays of the fracture site respectively, and establishes a bone three-dimensional model based on the preoperative three-dimensional CT images;

[0136] The fracture site is the femoral neck;

[0137] A registration module 2, which is connected to the acquisition module 1;

[0138] The registration module 2 registers the bone three-dimensional model and the postoperative X-ray to respectively determine the spatial positions of the fracture feature points and the screw positions in the bone three-dimensional model;

[0139] A modeling module 3, which is connected to the registration module 2;

[0140] The modeling module 3 establishes a postoperative three-dimensional model based on the spatial positions of the fracture feature points and the screw positions;

[0141] The postoperative three-dimensional model is used to evaluate the structural stability of the fracture site.

[0142] Specifically, aiming at the problem that the simulation of the postoperative skeletal internal fixation structure in the prior art is relatively rough and cannot well reflect the postoperative fracture geometry change and the actual angle of the screw, in this solution, the positions of the femoral head and the screw are identified in the postoperative X-ray, so as to form the spatial positions of the fracture feature points and the screw positions, and then an accurate postoperative three-dimensional model is constructed, which can realize a more accurate finite element simulation process.

[0143] Specifically, before the operation, first the acquisition module 1 takes the three-dimensional CT images of the hip joint part of the patient, and the bone part can be modeled based on the three-dimensional CT images to obtain the bone three-dimensional model.

[0144] The postoperative X-ray is an X-ray taken of the patient's hip joint again after the internal fixation operation. To facilitate the effective evaluation of the cross-section and screw position at the three-dimensional level, usually X-rays at multiple angles are collected for the subsequent processing of the registration module 2.

[0145] The spatial position of the fracture feature points refers to the three-dimensional coordinate position mapped from the corresponding points on the postoperative X-ray in the coordinate system of the bone three-dimensional model, which includes the positions of multiple feature points and can realize the characterization of the spatial pose change of the fractured femoral head area;

[0146] The spatial position of the screw is the three-dimensional spatial pose information calculated separately for each screw, which can be used to construct the correct positional relationship for screw modeling.

[0147] Based on the spatial positions of the fracture feature points and the screws, the modeling module 3 can correct the corresponding regions in the bone three-dimensional model to form the correct geometric section relationship and screw spatial position relationship, thereby improving the accuracy of the simulation.

[0148] In one embodiment, as Figure 9 shown, the registration module 2 includes:

[0149] A part selection module 21, which identifies the greater trochanter associated with the fracture site from the postoperative X-ray film as the first registration landmark site, and selects the greater trochanter as the second registration landmark site from the corresponding perspective of the bone three-dimensional model;

[0150] An alignment module 22, which is connected to the part selection module 21;

[0151] The alignment module 22 aligns the first registration landmark site and the second registration landmark site, and then registers the bone three-dimensional model and the postoperative X-ray film;

[0152] A positioning module 23, which is connected to the alignment module 22;

[0153] The positioning module 23 determines the fracture site and the screw position from the postoperative X-ray film, and generates the spatial positions of the fracture feature points and the screws on the bone three-dimensional model.

[0154] Specifically, to realize the process of transferring the spatial features of the fracture site from the postoperative X-ray film to the three-dimensional model, in this embodiment, the greater trochanter part of the fractured femur is selected as the registration landmark point. The greater trochanter part is an anatomical part at the top of the femur opposite to the femoral head, connected to the femoral neck and located on the outside.

[0155] After the operation, at least one angle of postoperative X-ray film needs to be collected from the patient. Then, according to the relevant parameters during X-ray collection, the collection angle of each postoperative X-ray film can be determined. Then, a single-angle picture in the corresponding direction can be intercepted from the pre-established bone three-dimensional model;

[0156] The part selection module 21 can process the postoperative X-ray film and the corresponding-angle picture of the bone three-dimensional model respectively using an identification model, including binarizing the picture, region identification, etc., so as to mark the greater trochanter part in the image, and then form the first registration landmark site and the second registration landmark site.

[0157] Subsequently, in the three-dimensional coordinate system where the bone three-dimensional model is located, the alignment module 22 aligns the postoperative X-rays at each angle according to the corresponding relationship between the first registration mark part and the second registration mark part. This alignment process can be an alignment process based on edge detection or a point cloud matching process after point cloud sampling.

[0158] Correspondingly, after registering the first registration mark part and the second registration mark part, each part on the postoperative X-ray, including parts such as the femoral stem and femoral neck, generally also has a roughly corresponding positional relationship with the bone three-dimensional model.

[0159] Subsequently, the positioning module 23 identifies the femoral head and screw parts on the registered postoperative X-ray to form the fracture site and screw position. For these two, the spatial position coordinates are extracted respectively and mapped to the bone three-dimensional model to form the spatial position of the fracture feature points and the spatial position of the screws. Among them, the spatial position of the fracture feature points also includes the position of the corresponding points on the bone three-dimensional model, that is, the specific points on the bone three-dimensional model established preoperatively, such as the center point of the femoral head fovea, the first end point on the side of the femoral head and neck, and the mapping relationship with the corresponding positions in the postoperative X-ray.

[0160] In one embodiment, as Figure 10 shown, the positioning module 23 includes:

[0161] The femoral head recognition module 231, which recognizes the femoral head area from the postoperative X-ray and extracts the femoral head mark points from the femoral head area respectively;

[0162] The femoral head mark points include the center point of the femoral head fovea, the first end point on the side of the femoral head and neck, and the second end point on the side of the femoral head and neck;

[0163] The femoral head processing module 232, which is connected to the femoral head recognition module 231;

[0164] The femoral head processing module 232 generates the spatial position of the fracture feature points on the bone three-dimensional model according to the femoral head mark points, and determines the screw end point according to the enclosed area of the femoral head mark points;

[0165] The screw positioning module 233, which is connected to the femoral head processing module 232;

[0166] The screw positioning module 233 determines the screw start point and screw vector from the postoperative X-ray, and pairs the screw start point and screw end point based on the screw vector to form screw groups;

[0167] The screw processing module 234, which is connected to the screw positioning module 233;

[0168] The screw processing module 234 determines the screw spatial positions on the bone three-dimensional model according to the screw grouping.

[0169] Specifically, to achieve a better mapping relationship of the spatial positions of the feature points, in this embodiment, after registering the postoperative X-ray films, the femoral head recognition module 231 uses an image recognition model to perform recognition processing on the postoperative X-ray films at each angle. This image recognition model is trained using a dataset with pre-annotated femoral head regions during the training process, and can identify and label the femoral head region from the input image, thereby reducing the amount of data for subsequent multi-modal recognition and processing.

[0170] Subsequently, the femoral head processing module 232 extracts the edge part for the selected femoral head region, and performs matching in combination with relevant morphological templates as the input of multi-modal, so that the multi-modal model can comprehensively obtain the selected femoral head landmark points from the postoperative X-ray films at each angle, including the center point of the fovea of the femoral head, the first end point on the femoral neck side of the femoral head, and the second end point on the femoral neck side of the femoral head.

[0171] Meanwhile, in combination with the angles at which the postoperative X-ray films are collected, the coordinate ranges of each landmark point can be mapped in the coordinate system of the bone three-dimensional model, thereby forming the spatial positions of the fracture feature points.

[0172] Subsequently, a set of enclosed areas are formed according to the spatial positions of the fracture feature points, the postoperative X-ray films are intercepted, and then the screw end points are determined in the intercepted enclosed areas by means of gray value recognition.

[0173] Then, the screw positioning module 233 uses an image recognition model to recognize the registered multiple postoperative X-ray films to determine the screw end points on the lateral side of the femur. This screw end point usually includes a region, including the screw end point and a partial extension part, and the center line can be extracted based on the extension part to construct a screw vector.

[0174] The screw processing module 234 maps the screw vectors of the multiple postoperative X-ray films in the coordinate system of the bone three-dimensional model, thereby constructing the three-dimensional space vector of the screw, finding the paired screw end points based on the three-dimensional space vector, and finally obtaining the screw grouping.

[0175] Finally, the screw spatial positions are determined on the bone three-dimensional model according to the screw grouping.

[0176] In one embodiment, as Figure 11 shown, the modeling module 3 includes:

[0177] The first adjustment module 31, and the first adjustment module 31 adjusts the femoral head part of the bone three-dimensional model according to the spatial positions of the fracture feature points to form a first adjustment model;

[0178] The second adjustment module 32, and the second adjustment module 32 is connected to the first adjustment module 31;

[0179] The second adjustment module 32 modifies the cross-sectional geometry in the first adjustment model according to the postoperative X-ray to obtain a second adjustment model;

[0180] The third adjustment module 33, and the third adjustment module 33 is connected to the second adjustment module 32;

[0181] The third adjustment module 33 assigns bone material properties to the second adjustment model according to the CT gray value of the preoperative three-dimensional CT image to obtain a third adjustment model;

[0182] The fourth adjustment module 34, and the fourth adjustment module 34 is connected to the third adjustment module 33;

[0183] The fourth adjustment module 34 adds a screw model to the third adjustment model according to the screw spatial position to obtain a postoperative three-dimensional model.

[0184] Specifically, based on the above calculation process, the partial correction of the femoral head of the bone three-dimensional model can be realized. Specifically, according to the spatial position of the fracture feature points and the cross-section reflected in the postoperative X-ray, the first adjustment module 31 can adjust the three-dimensional spatial pose of the part of the femoral head that crosses the cross-section in the bone three-dimensional model to form a first adjustment model;

[0185] Subsequently, on the basis of the first adjustment model, the second adjustment module 32 extracts the fracture cross-section part based on the postoperative X-rays at various angles, then performs three-dimensional cross-section reconstruction, obtains the cross-sectional geometry and adds it to the cross-section part of the first adjustment model to form a second adjustment model;

[0186] Then, the third adjustment module 33 measures information such as the bone density of the patient according to the CT gray value of the preoperative three-dimensional CT image, and assigns bone material properties to obtain a third adjustment model;

[0187] Finally, the fourth adjustment module 34 adds a screw model to the third adjustment model according to the screw spatial position to obtain a postoperative three-dimensional model.

[0188] In one embodiment, as Figure 12 shown, it further includes an evaluation module 4. The evaluation module 4 performs finite element simulation on the postoperative three-dimensional model to obtain mechanical parameters, and evaluates the structural stability of the fracture site according to the mechanical parameters.

[0189] Specifically, to achieve better evaluation results, after modeling, the evaluation module 4 imports the postoperative three-dimensional model into calculation software such as Abaqus / Ansys for finite element simulation calculation, so as to obtain mechanical parameters, including structural stiffness, stress, strain, displacement, and relative displacement of the fracture ends. These parameters are comprehensively analyzed according to the entropy value scoring method to obtain the entropy value score as the stability index of the internal fixation structure for femoral neck fractures, which is convenient for doctors to further estimate the prognosis and curative effect.

[0190] Those of ordinary skill in the art will understand that various aspects of the present invention, or possible implementations of various aspects, can be specifically implemented as a system, a method, or a computer program product. Therefore, various aspects of the present invention, or possible implementations of various aspects, can take the form of a complete hardware embodiment, a complete software embodiment (including firmware, resident software, etc.), or a form combining software and hardware embodiments, which are collectively referred to as "circuits", "modules", or "systems" here. In addition, various aspects of the present invention, or possible implementations of various aspects, can take the form of a computer program product, which refers to computer instructions stored in a memory.

[0191] The memory can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium includes, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or apparatuses, or any suitable combination of the foregoing, such as random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable read-only memory (CD-ROM).

[0192] The processor in the computer reads the computer instructions stored in the memory, enabling the processor to perform the functional actions specified in each step, or combinations of steps, in the flowchart; generating a device for performing the functional actions specified in each block, or combinations of blocks, in the block diagram.

[0193] It should be understood that the processor in the computer can be understood as being implemented by one or more application-specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), complex programmable logic devices (CPLDs), field-programmable gate arrays (FPGAs), general-purpose processors, controllers, microcontrollers (MCUs), microprocessors (Microprocessors), or other electronic components for executing the aforementioned computer instructions.

[0194] Computer instructions can be executed entirely on the user's local computer, partially on the user's local computer, as a separate software package, partially on the user's local computer and partially on a remote computer, or entirely on a remote computer or server. It should also be noted that in certain alternative embodiments, the functions noted in each step of the flowchart or each block of the block diagram may not occur in the order noted in the figure. For example, depending on the functions involved, two consecutive steps or two blocks shown may actually be executed substantially simultaneously, or these blocks may sometimes be executed in the reverse order.

[0195] Of course, in actual application, the various components in the computer system are coupled together through a bus system. It can be understood that the bus system is used to achieve connection and communication between these components. In addition to the data bus, the bus system also includes a power bus, a control bus, and a status signal bus.

[0196] The above are only the preferred embodiments of the present invention, and do not limit the implementation manners and protection scope of the present invention. For those skilled in the art, it should be able to realize that all the equivalent replacements and obvious changes made by using the specification and illustrated content of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for measuring the stability of the internal fixation structure of femoral neck fracture, characterized in that: include: Step S1: collecting three-dimensional CT images before surgery and X-rays after surgery for the fracture site, and establishing a three-dimensional bone model based on the three-dimensional CT images before surgery; The fracture site is the femoral neck; Step S2: registering the three-dimensional bone model with the post-operative X-ray film to respectively determine the spatial position of the fracture feature point and the spatial position of the screw in the three-dimensional bone model; Step S3: establishing a postoperative three-dimensional model based on the spatial position of the fracture feature point and the spatial position of the screw; The postoperative three-dimensional model is used to evaluate the structural stability of the fracture site.

2. The measuring method according to claim 1, characterized in that: The step S2 comprises: Step S21: identifying the greater trochanter associated with the fracture site in the postoperative X-ray as a first registration landmark, and selecting the greater trochanter from a corresponding viewing angle of the three-dimensional bone model as a second registration landmark; Step S22: aligning the first registration mark portion and the second registration mark portion, and then registering the three-dimensional bone model and the postoperative X-ray film; Step S23: determining the fracture site and screw position from the post-operative X-ray, and generating the fracture feature point spatial position and the screw spatial position on the bone three-dimensional model.

3. The measuring method according to claim 2, characterized in that: The step S23 comprises: Step S231: identifying a femoral head region from the post-operative X-ray, and extracting femoral head landmarks from the femoral head region; The femoral head landmarks include the center point of the femoral head fossa, the first endpoint on the femoral head and neck side, and the second endpoint on the femoral head and neck side; Step S232: generating the spatial position of the fracture feature point on the three-dimensional bone model according to the femoral head landmarks, and determining the screw end point according to the enclosed area of ​​the femoral head landmarks; Step S233: determining a screw starting point and a screw vector from the postoperative X-ray, and pairing the screw starting point and the screw end point based on the screw vector to form a screw group; Step S234: determining the spatial position of the screws on the three-dimensional bone model according to the screw grouping.

4. The measuring method according to claim 1, characterized in that: The step S3 comprises: Step S31: adjusting the femoral head part of the three-dimensional bone model according to the spatial position of the fracture feature point to form a first adjusted model; Step S32: modifying the cross-sectional geometry of the first adjustment model according to the post-operative X-ray to obtain a second adjustment model; Step S33: assigning bone material properties to the second adjustment model according to the CT grayscale value of the pre-operative 3D CT image to obtain a third adjustment model; Step S34: adding a screw model to the third adjustment model according to the screw spatial position to obtain the postoperative three-dimensional model.

5. The measuring method according to claim 1, characterized in that: After executing step S3, the method further includes: Step S4: performing finite element simulation on the postoperative three-dimensional model to obtain mechanical parameters, and evaluating the structural stability of the fracture site according to the mechanical parameters.

6. A system for measuring the stability of the internal fixation structure of femoral neck fracture, characterized in that: Used to implement the measurement method according to any one of claims 1 to 5; The measurement system comprises: An acquisition module, wherein the acquisition module acquires pre-operative 3D CT images and post-operative X-rays of the fracture site, and establishes a bone 3D model according to the pre-operative 3D CT images; The fracture site is the femoral neck; A registration module, the registration module is connected to the acquisition module; The registration module registers the three-dimensional bone model and the post-operative X-ray film to respectively determine the spatial position of the fracture feature point and the spatial position of the screw in the three-dimensional bone model; A modeling module, the modeling module is connected to the registration module; The modeling module establishes a postoperative three-dimensional model based on the spatial position of the fracture feature point and the spatial position of the screw; The postoperative three-dimensional model is used to evaluate the structural stability of the fracture site.

7. The measuring system according to claim 6, characterized in that The registration module comprises: A site selection module, wherein the site selection module identifies the greater trochanter associated with the fracture site from the post-operative X-ray as a first registration landmark site, and selects the greater trochanter from a corresponding viewing angle of the three-dimensional bone model as a second registration landmark site; An alignment module, the alignment module is connected to the part selection module; The alignment module aligns the first registration mark part and the second registration mark part, and then aligns the three-dimensional bone model and the post-operative X-ray film; A positioning module, the positioning module is connected to the alignment module; The positioning module determines the fracture site and the screw position from the post-operative X-ray, and generates the fracture feature point spatial position and the screw spatial position on the bone three-dimensional model.

8. The measuring system according to claim 7, characterized in that The positioning module comprises: A femoral head recognition module, wherein the femoral head recognition module recognizes a femoral head region from the post-operative X-ray film and extracts femoral head landmark points from the femoral head region; The femoral head landmarks include the center point of the femoral head fossa, the first endpoint on the femoral head and neck side, and the second endpoint on the femoral head and neck side; A femoral head processing module, wherein the femoral head processing module is connected to the femoral head identification module; The femoral head processing module generates the spatial position of the fracture feature point on the three-dimensional bone model according to the femoral head landmark points, and determines the screw end point according to the enclosed area of ​​the femoral head landmark points; A screw positioning module, the screw positioning module is connected to the femoral head processing module; The screw positioning module determines the screw starting point and the screw vector from the postoperative X-ray, and pairs the screw starting point and the screw end point based on the screw vector to form a screw group; A screw processing module, the screw processing module is connected to the screw positioning module; The screw processing module determines the spatial position of the screws on the bone three-dimensional model according to the screw grouping.

9. The measuring system according to claim 6, characterized in that The modeling module includes: A first adjustment module, which adjusts the femoral head part of the three-dimensional bone model according to the spatial position of the fracture feature point to form a first adjustment model; a second adjustment module, the second adjustment module being connected to the first adjustment module; The second adjustment module corrects the cross-sectional geometry of the first adjustment model according to the post-operative X-ray to obtain a second adjustment model; a third adjustment module, the third adjustment module being connected to the second adjustment module; The third adjustment module assigns bone material properties to the second adjustment model according to the CT grayscale value of the pre-operative three-dimensional CT image to obtain a third adjustment model; a fourth adjustment module, the fourth adjustment module being connected to the third adjustment module; The fourth adjustment module adds the screw model to the third adjustment model according to the screw spatial position to obtain the postoperative three-dimensional model.

10. The measuring system according to claim 6, characterized in that Also includes assessment modules, The evaluation module performs finite element simulation on the postoperative three-dimensional model to obtain mechanical parameters, The structural stability of the fracture site is evaluated based on the mechanical parameters.

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