Automatic bone cutting planning method and system in unicompartmental knee arthroplasty

Abstract

This invention provides an automated osteotomy planning method and system for unicompartmental knee arthroplasty, comprising: acquiring a first contact point between the femur and tibia on the healthy side of the knee joint, and a second contact point between the femoral prosthesis and tibial prosthesis on the surgical side of the knee joint; generating the postoperative motion trajectory of the femur and tibia based on the first and second contact points; and automatically planning the amount of osteotomy of the femur or tibia on the surgical side of the knee joint based on the motion trajectory of the femur and tibia. This invention solves the problems of traditional manual surgery relying on the surgeon's experience, affecting the surgical outcome, and currently lacking effective intraoperative planning and accurate prediction capabilities. It greatly improves the safety and efficiency of unicompartmental knee arthroplasty, while also improving the surgical outcome, and significantly enhances the intelligence, usability, and reliability of this invention.

Description

Technical Field

[0001] This invention relates to the field of medical technology for unicompartmental knee arthroplasty, specifically to an automated osteotomy planning method and system for unicompartmental knee arthroplasty. Background Technology

[0002] PKA is an important stepwise treatment for knee osteoarthritis. Recent clinical studies have found that in the treatment of medial unicompartment knee joint, compared with total knee arthroplasty (TKA), PKA surgery preserves almost all of the knee joint's biological functions. It has advantages such as shorter operation time, less surgical trauma, and a lower incidence of postoperative complications. Moreover, postoperative functional recovery is also better than that of TKA surgery.

[0003] PKA surgery requires high precision in lower limb alignment, soft tissue balance, and prosthesis placement. Traditional manual surgery relies on the surgeon's experience, which can easily lead to unsatisfactory results. Surgical robots have significant advantages in PKA surgery. During robotic surgery, it is crucial to assess the osteotomy effect and make further adjustments to the plan, including repeating the osteotomy to achieve satisfactory results.

[0004] Because current technologies lack effective automated acquisition methods when using surgical robots for osteotomy, they often rely on complex and imprecise measurement methods, leading to difficulties and inaccuracies in data acquisition. When acquiring contact trajectory data between the femoral head and tibia, existing technologies are limited by various factors, such as errors in manual operation and limitations of measuring tools, making it difficult to achieve ideal accuracy. Therefore, for unicompartmental knee replacement, there is currently a lack of effective intraoperative planning and accurate prediction capabilities, which has a significant impact on surgical outcomes.

[0005] Therefore, existing technologies still need further development. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide an automatic osteotomy planning method and system for unicompartmental knee arthroplasty to solve the problems existing in the prior art.

[0007] To achieve the above-mentioned technical objectives, according to a first aspect of the present invention, the present invention provides an automated osteotomy planning method in unicompartmental knee arthroplasty, comprising: S100. Obtain the first contact point between the femur and tibia on the healthy side of the knee joint, and the second contact point between the femoral prosthesis and tibial prosthesis on the surgical side of the knee joint. S200: Generate the postoperative movement trajectory of the femur and tibia based on the first contact point and the second contact point; S300: Automatically plan the amount of osteotomy of the femur or tibia on the surgical side of the knee joint based on the movement trajectory of the femur and tibia.

[0008] Specifically, S100 includes: S210. Obtain CT images containing the knee joint before surgery, and segment the CT images to obtain a three-dimensional model of the knee joint bone surface in the CT images. S220. Register the CT images to obtain the transformation relationship between the image coordinate system containing the femur and tibia and the patient's spatial coordinate system. S230. Obtain the first contact point between the femur and tibia, and the second contact point between the femoral prosthesis and the tibial prosthesis.

[0009] Specifically, the method for registering the CT images to obtain the transformation relationship between the image coordinate system containing the femur and tibia and the patient's spatial coordinate system includes: Based on the segmented 3D model of the knee joint, the rigid registration algorithm is used to calculate the first registration matrix between the dataset of the surgical area collected in the patient space coordinate system and its corresponding data in the 3D model. Then, the iterative nearest point algorithm is used to calculate the femoral registration matrix of the knee joint in the patient space coordinate system and the tibial registration matrix of the knee joint in the patient space coordinate system.

[0010] Specifically, the method for calculating the femoral registration matrix of the knee joint in the patient space coordinate system and the tibial registration matrix in the patient space coordinate system in the three-dimensional model includes: The registration points of the segmented 3D model of the knee joint are acquired. These registration points are then translated and rotated to obtain the target points in the patient's spatial coordinate system. The specific calculations are as follows: pi' = R*pi + t, Where pi represents the point to be registered, R represents the rotation matrix of the registration matrix, t represents the translation matrix of the registration matrix, and pi' represents the target point; The rotation and translation matrices are converted into homogeneous transformation matrices to obtain the femoral registration matrix and the tibial registration matrix.

[0011] Specifically, S230 includes: A tibial coordinate system is established with the center of the tibial plateau as the origin, where the Z-axis coincides with the mechanical axis of the tibia; the Y-axis coincides with the Akagi line; and the X-axis is perpendicular to both the Y-axis and the Z-axis. Obtain the three-dimensional coordinates of the first contact point between the femoral head and tibia on the healthy side of the knee joint at different flexion angles in the tibial coordinate system, and the three-dimensional coordinates of the second contact point between the femoral prosthesis and tibia prosthesis on the surgical side of the knee joint at different flexion angles in the tibial coordinate system.

[0012] Specifically, the method for obtaining the three-dimensional coordinates of the first contact point between the femoral head and tibia on the healthy side of the knee joint at different flexion angles in the tibial coordinate system includes: Real-time acquisition of the pose matrix of the femoral tracker in the patient space coordinate system , where T represents the transformation matrix, C represents the patient, and F represents the femoral tracker; Calculate the pose matrix of the femoral image coordinates in the patient space coordinate system. The calculation method is as follows: , Where I represents the femur image, Represents the femoral registration matrix; Real-time acquisition of the pose matrix of the tibia tracker in the patient space coordinate system Where C represents the patient and E represents the tibial tracker; Real-time calculation of the pose matrix of the tibia image coordinates in the patient space coordinate system The calculation method is as follows: , Where I2 represents the tibia image, Represents the tibial registration matrix; Calculate the pose matrix of the femoral image coordinates in the tibial coordinate system. The calculation method is as follows: =invert( ) ; Furthermore, the three-dimensional coordinates of the minimum point of the femur on the z-axis of the tibial coordinate system under different flexion angles are used as the three-dimensional coordinates of the first contact point between the femur and the tibia.

[0013] Specifically, the method for obtaining the three-dimensional coordinates of the second contact point of the femoral and tibial prostheses on the surgical side of the knee joint at different flexion angles in the tibial coordinate system includes: Real-time acquisition of the pose matrix of the femoral tracker in the patient space coordinate system , where T represents the transformation matrix, C represents the patient, and F represents the femoral tracker; Calculate the pose matrix of the femoral prosthesis image coordinates in the patient space coordinate system. The calculation method is as follows: , Where I1 represents the femoral prosthesis image, Represents the femoral registration matrix; Real-time acquisition of the pose matrix of the tibia tracker in the patient space coordinate system Where C represents the patient and E represents the tibial tracker; Calculate the pose matrix of the tibial prosthesis image coordinates in the patient space coordinate system. The calculation method is as follows: , Where I3 represents the tibial prosthesis image, Represents the tibial registration matrix; Calculate the pose matrix of the femoral prosthesis image coordinates in the tibial coordinate system. The calculation method is as follows: =invert( ) ; Furthermore, the three-dimensional coordinates of the minimum point of the femoral prosthesis on the z-axis of the tibial coordinate system under different flexion angles are used as the three-dimensional coordinates of the second contact point between the femoral prosthesis and the tibial prosthesis.

[0014] Specifically, the method for predicting the postoperative movement trajectory of the femur and tibia based on the first contact point and the second contact point includes: The first and second contact points at different flexion angles are projected onto the XY plane of the tibial coordinate system to obtain the movement trajectories of the femur and tibia at different flexion angles.

[0015] Specifically, the method for automatically planning the osteotomy amount of the femur or tibia on the surgical side of the knee joint based on the movement trajectory of the femur and tibia includes: Based on the diameter of the tibia in the Y-axis direction of the tibial coordinate system, a preset safe area is set for the movement trajectory of the femoral prosthesis and the tibial prosthesis in the tibial coordinate system. It is then determined whether the movement trajectory of the femur and the tibia is within the preset safe area, and based on the determination result, it is determined whether the amount of osteotomy of the femur or the tibia needs to be adjusted.

[0016] Specifically, the method for determining whether to adjust the osteotomy amount of the femur or tibia based on the judgment result includes: If the movement trajectory of the femur and tibia is within the preset safe area, the amount of osteotomy of the femur or tibia will not be adjusted. If the movement trajectory of the femur and tibia is not within the preset safe area, the amount of osteotomy of the femur or tibia is adjusted according to the direction in which the movement trajectory exceeds the preset safe area.

[0017] Specifically, adjusting the amount of osteotomy of the femur or tibia according to the direction in which the movement trajectory exceeds the preset safe area includes: If the surgical side of the knee joint is the medial condyle, the direction pointing to the anteromedial side of the knee joint is the positive direction of the Y-axis, and the direction pointing to the posteromedial side is the negative direction of the Y-axis. If the movement trajectory exceeds the preset safety zone in both the positive and negative Y-axis directions of the tibial coordinate system, the amount of osteotomy of the tibia or femur is reduced, or the height of the tibial prosthesis is increased. When the movement trajectory exceeds the preset safety area in the positive Y-axis direction of the tibial coordinate system, the amount of osteotomy of the anteromedial tibia is reduced and the amount of osteotomy of the posteromedial tibia is increased. When the movement trajectory exceeds the preset safety zone in the negative Y-axis direction of the tibial coordinate system, the amount of osteotomy on the anteromedial tibia is increased and the amount of osteotomy on the posteromedial tibia is decreased.

[0018] Specifically, adjusting the osteotomy amount according to the direction of the movement trajectory exceeding the preset safety zone also includes: If the surgical side of the knee joint is the lateral condyle, the direction pointing to the anterolateral aspect of the knee joint is the positive direction of the Y-axis, and the direction pointing to the posterolateral aspect is the negative direction of the Y-axis. If the movement trajectory exceeds the preset safety zone in both the positive and negative Y-axis directions of the tibial coordinate system, the amount of osteotomy of the tibia or femur is reduced, or the height of the tibial prosthesis is increased. When the movement trajectory exceeds the preset safety zone in the positive Y-axis direction of the tibial coordinate system, the amount of osteotomy of the posterolateral tibia is increased. When the movement trajectory exceeds the preset safety zone in the negative Y-axis direction of the tibial coordinate system, the osteotomy amount of the anterolateral tibia is increased and the osteotomy amount of the posterolateral tibia is decreased. When the movement trajectory is concentrated within a preset safe area, the amount of osteotomy of the tibia or femur is increased, or the height of the tibial prosthesis is reduced.

[0019] According to a second aspect of the present invention, an automated osteotomy planning system for unicompartmental knee arthroplasty is provided, comprising: Acquisition module: used to acquire the first contact point between the femur and tibia on the healthy side of the knee joint, and the second contact point between the femoral prosthesis and tibial prosthesis on the surgical side of the knee joint; Control module: used to generate the postoperative movement trajectory of the femur and tibia based on the first contact point and the second contact point; and used to automatically plan the amount of osteotomy of the femur or tibia on the surgical side of the knee joint based on the movement trajectory of the femur and tibia.

[0020] Beneficial effects: This invention obtains the first contact point between the femur and tibia on the healthy side of the knee joint, and the second contact point between the femoral prosthesis and tibial prosthesis on the surgical side of the knee joint; generates the postoperative movement trajectory of the femur and tibia based on the first and second contact points; and automatically plans the amount of osteotomy of the femur or tibia on the surgical side of the knee joint based on the movement trajectory of the femur and tibia. This solves the problems of traditional manual surgery relying on the surgeon's experience, affecting the surgical outcome, and currently lacking effective intraoperative planning and accurate prediction capabilities. It greatly improves the safety and efficiency of unicompartmental knee replacement surgery, further improves the surgical outcome, and significantly enhances the intelligence, usability, and reliability of this invention. Attached Figure Description

[0021] Figure 1 This is a flowchart of the automatic osteotomy planning method in unicompartmental knee arthroplasty provided in a specific embodiment of the present invention; Figure 2 This is a schematic diagram of the composition of the automatic osteotomy planning system in unicompartmental knee arthroplasty provided in a specific embodiment of the present invention; Figure 3 This is a schematic diagram of a unicompartmental femoral prosthesis model provided in a specific embodiment of the present invention; Figure 4 This is a schematic diagram of the unicompartmental tibial plateau model provided in a specific embodiment of the present invention; Figure 5 This is a schematic diagram of the tibial coordinate system provided in a specific embodiment of the present invention; Figure 6 This is a schematic diagram of the position planning of the unicompartmental prosthesis provided in a specific embodiment of the present invention; Figure 7 This is a flowchart of preoperative preparation provided in a specific embodiment of the present invention; Figure 8 This is a flowchart of intraoperative motion pattern acquisition provided in a specific embodiment of the present invention; Figure 9 This is a schematic diagram of the movement trajectory of the femur and tibia provided in a specific embodiment of the present invention; Figure 10 This is a schematic diagram of the inner trajectory within a preset safety area provided in a specific embodiment of the present invention; Figure 11 This is a schematic diagram of the inner trajectory exceeding the preset safety area provided in a specific embodiment of the present invention; Figure 12 This is a schematic diagram showing the inner trajectory extending beyond a preset safety area in a specific embodiment of the present invention; Figure 13 This is a schematic diagram showing the inner trajectory extending beyond a preset safety area in a specific embodiment of the present invention. Figure 14 This is a schematic diagram of the outer trajectory within a preset safety area provided in a specific embodiment of the present invention; Figure 15 This is a schematic diagram of the outer trajectory exceeding the preset safety area provided in a specific embodiment of the present invention; Figure 16 This is a schematic diagram showing the outer trajectory extending beyond a preset safety area in a specific embodiment of the present invention; Figure 17 This is a schematic diagram showing the outer trajectory extending beyond the preset safety area in a specific embodiment of the present invention; Figure 18 This is a schematic diagram showing the outer trajectory concentrated within a preset safety area, provided in a specific embodiment of the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments in this application, other similar embodiments obtained by those skilled in the art without creative effort should all fall within the scope of protection of this application. Furthermore, directional terms mentioned in the following embodiments, such as "up," "down," "left," and "right," are only for reference to the directions in the accompanying drawings; therefore, the directional terms used are for illustrative purposes and not for limiting the invention.

[0023] The present invention will be further described below with reference to the accompanying drawings and preferred embodiments.

[0024] Please see Figure 1 This embodiment provides an automated osteotomy planning method in unicompartmental knee arthroplasty, including: S100. Obtain the first contact point between the femur and tibia on the healthy side of the knee joint, and the second contact point between the femoral prosthesis and tibial prosthesis on the surgical side of the knee joint. It should be noted that a preset safety area is set before step S100. This invention does not limit the specific range of the preset safety area, as long as it can be applied to the automatic osteotomy planning method in unicompartmental knee arthroplasty proposed in this invention. See Figure 6 , Figure 6 The image shows the installation of knee joint prostheses on the tibia and femur. The left image is a front view of the knee joint, and the right image is a side view of the knee joint. The femur is above and the tibia is below. The blue part above is the femoral prosthesis, and the blue ring below is the tibial prosthesis, which is placed on the tibial platform. The red line represents the mechanical axis of the femur, which passes vertically through the center of the femur.

[0025] The yellow dots mark the contact points between the femoral and tibial prostheses. The blue area represents the operated side and the unaffected side. Specifically, S100 includes: S210. Obtain CT images containing the knee joint before surgery, and segment the CT images to obtain a three-dimensional model of the knee joint bone surface in the CT images. In some specific embodiments, a high-resolution CT scanning device is used to acquire detailed tomographic images containing the knee joint. Image processing algorithms (such as thresholding, region growing, etc.) are applied to segment the CT images, extracting the bone surface contours of the femur and tibia. Three-dimensional reconstruction software is then used to convert the segmented two-dimensional image data into an accurate three-dimensional model. For example, Figure 3 This is a unicompartmental femoral prosthesis model. Figure 4 This unicompartmental tibial plateau model provides high-precision anatomical information of the knee joint for subsequent registration and analysis. The 3D model helps to intuitively display the complex geometry of the knee joint, facilitating detailed surgical planning by doctors.

[0026] S220. Register the CT images to obtain the transformation relationship between the image coordinate system containing the femur and tibia and the patient's spatial coordinate system. In some specific embodiments, a rigid registration algorithm can be used to align the segmented 3D model with the standard anatomical model or real-time intraoperative navigation data, calculate and determine the transformation matrix from the image coordinate system to the patient's spatial coordinate system, ensure that the model can be accurately converted between different coordinate systems, improve the reliability of surgical navigation, and improve the accuracy and safety of the surgery.

[0027] S230. Obtain the first contact point between the femur and tibia, and the second contact point between the femoral prosthesis and the tibial prosthesis.

[0028] Specifically, the method for registering the CT images to obtain the transformation relationship between the image coordinate system containing the femur and tibia and the patient's spatial coordinate system includes: Based on the segmented 3D model of the knee joint, the rigid registration algorithm is used to calculate the first registration matrix between the dataset of the surgical area collected in the patient space coordinate system and its corresponding data in the 3D model. Then, the iterative nearest point algorithm is used to calculate the femoral registration matrix of the knee joint in the patient space coordinate system and the tibial registration matrix of the knee joint in the patient space coordinate system.

[0029] In some specific embodiments, the segmented 3D model of the knee joint (including the femur and tibia) and the actual dataset in the patient spatial coordinate system acquired by the navigation device in the surgical area can be initially aligned with the data in the patient spatial coordinate system using a rigid registration algorithm (such as feature point matching, mutual information, etc.). By comparing the key anatomical landmarks (such as bone surface feature points) of the 3D model with the data points acquired in the patient spatial coordinate system, an initial rigid transformation matrix (i.e., the first registration matrix) is calculated. This matrix is ​​used to initially align the 3D model to the patient spatial coordinate system.

[0030] Furthermore, the Iterative Closest Point (ICP) algorithm is used to further optimize the registration accuracy. The ICP algorithm improves the registration results step by step by repeatedly finding the closest point pairs and minimizing the distance between them. For the femur part in the 3D model, the ICP algorithm is used to iteratively calculate the final registration matrix of the femur in the patient space coordinate system, i.e., the femur registration matrix. This matrix accurately describes the transformation relationship of the femur from the image coordinate system to the patient space coordinate system. Similarly, for the tibia part, the ICP algorithm is also used to calculate the final registration matrix of the tibia in the patient space coordinate system (i.e., the tibia registration matrix). This ensures that the registration accuracy of the tibia matches that of the femur.

[0031] By combining rigid registration and the ICP algorithm, high-precision registration was achieved, ensuring a high degree of consistency between the 3D model and the actual anatomical structure. Accurate registration allows doctors to track the position of the femur and tibia in real time during surgery, reducing surgical errors and improving the safety and success rate of the operation.

[0032] Specifically, the method for calculating the femoral registration matrix of the knee joint in the patient space coordinate system and the tibial registration matrix in the patient space coordinate system in the three-dimensional model includes: The registration points of the segmented 3D model of the knee joint are acquired. These registration points are then translated and rotated to obtain the target points in the patient's spatial coordinate system. The specific calculations are as follows: pi' = R*pi + t, Where pi represents the point to be registered, R represents the rotation matrix of the registration matrix, t represents the translation matrix of the registration matrix, and pi' represents the target point; The rotation and translation matrices are converted into homogeneous transformation matrices to obtain the femoral registration matrix and the tibial registration matrix.

[0033] Understandably, optimization algorithms such as the Iterative Closest Point (ICP) algorithm are used to solve for the optimal rotation matrix (R) and translation matrix (t) by minimizing the distance error between all registration points. The rotation and translation matrices for the femur and tibia are calculated separately to ensure accurate registration. The calculated rotation matrix (R) and translation matrix (t) are combined into a 4x4 homogeneous transformation matrix (T) to obtain the femur registration matrix and tibia registration matrix, which respectively describe the complete transformation relationship of the femur and tibia from the image coordinate system to the patient's spatial coordinate system.

[0034] Specifically, S230 includes: A tibial coordinate system is established with the center of the tibial plateau as the origin, where the Z-axis coincides with the mechanical axis of the tibia; the Y-axis coincides with the Akagi line; and the X-axis is perpendicular to both the Y-axis and the Z-axis. Obtain the three-dimensional coordinates of the first contact point between the femoral head and tibia on the healthy side of the knee joint at different flexion angles in the tibial coordinate system, and the three-dimensional coordinates of the second contact point between the femoral prosthesis and tibia prosthesis on the surgical side of the knee joint at different flexion angles in the tibial coordinate system.

[0035] See Figure 5 In this embodiment, the center of the tibial plateau is selected as the origin of the coordinate system. The Z-axis coincides with the mechanical axis of the tibia, that is, the direction from the center of the tibial plateau (proximal end) to the center of the ankle joint (distal end). The Y-axis coincides with the Akag line. According to anatomical convention, it is assumed that the positive direction of the Y-axis points to the front of the knee joint, and the negative direction of the Y-axis points to the back of the knee joint. According to the right-hand rule, the X-axis is perpendicular to the Y-axis and Z-axis to ensure that an orthogonal three-dimensional coordinate system is formed.

[0036] Then, the natural contact points between the femoral head and tibia at different flexion angles (e.g., 0°, 30°, 60°, 90°, etc.) are obtained. The coordinates of the contact points at each flexion angle are transformed into the tibial coordinate system using a registration matrix, and the three-dimensional coordinates of the first and second contact points at each flexion angle in the tibial coordinate system are saved. Through coordinate transformation, the accurate representation of the contact points in the tibial coordinate system is ensured. Accurate contact point coordinates help generate the postoperative movement trajectory of the femur and tibia, thereby optimizing the amount of osteotomy and the prosthesis placement.

[0037] Specifically, the method for obtaining the three-dimensional coordinates of the first contact point between the femoral head and tibia on the healthy side of the knee joint at different flexion angles in the tibial coordinate system includes: Real-time acquisition of the pose matrix of the femoral tracker in the patient space coordinate system , where T represents the transformation matrix, C represents the patient, and F represents the femoral tracker; Calculate the pose matrix of the femoral image coordinates in the patient space coordinate system. The calculation method is as follows: , Where I represents the femur image, Represents the femoral registration matrix; Real-time acquisition of the tibial tracker's pose matrix in the patient coordinate system Where C represents the patient and E represents the tibial tracker; Calculate the pose matrix of the tibial image coordinates in the patient space coordinate system. The calculation method is as follows: , Where I2 represents the tibia image, Represents the tibial registration matrix; Calculate the pose matrix of the femoral image coordinates in the tibial coordinate system. The calculation method is as follows: =invert( ) ; Furthermore, the three-dimensional coordinates of the minimum point of the femur on the z-axis of the tibial coordinate system under different flexion angles are used as the three-dimensional coordinates of the first contact point between the femur and the tibia.

[0038] Specifically, the method for obtaining the three-dimensional coordinates of the second contact point of the femoral and tibial prostheses on the surgical side of the knee joint at different flexion angles in the tibial coordinate system includes: Real-time acquisition of the pose matrix of the femoral tracker in the patient space coordinate system , where T represents the transformation matrix, C represents the patient, and F represents the femoral tracker; Calculate the pose matrix of the femoral prosthesis image coordinates in the patient space coordinate system. The calculation method is as follows: , Where I1 represents the femoral prosthesis image, Represents the femoral registration matrix; Real-time acquisition of the pose matrix of the tibia tracker in the patient space coordinate system Where C represents the patient and E represents the tibial tracker; Calculate the pose matrix of the tibial prosthesis image coordinates in the patient space coordinate system. The calculation method is as follows: , Where I3 represents the tibial prosthesis image, Represents the tibial registration matrix; Calculate the pose matrix of the femoral prosthesis image coordinates in the tibial coordinate system. The calculation method is as follows: =invert( ) ; Furthermore, the three-dimensional coordinates of the minimum point of the femoral prosthesis on the z-axis of the tibial coordinate system under different flexion angles are used as the three-dimensional coordinates of the second contact point between the femoral prosthesis and the tibial prosthesis.

[0039] It should be noted that high-precision femoral and tibial trackers are used to acquire the pose matrices of the femoral and tibial images of the healthy side of the knee joint, respectively. These data reflect the position and orientation of the femur and tibia in space. Based on the femoral and tibial registration matrices, the poses of the femoral and tibial images are transformed from the tracker coordinate system to the patient's spatial coordinate system. For each different flexion angle, the minimum point of the femur on the Z-axis in the tibial coordinate system is found. This usually means the point where the femoral head and tibia are closest, i.e., the contact point. The three-dimensional coordinates of this point in the tibial coordinate system are saved as the three-dimensional coordinates of the first contact point between the femur and tibia.

[0040] Similarly, the pose matrices of the femoral and tibial prostheses on the operated side of the knee joint are obtained and transformed into the patient space coordinate system through a registration matrix. The poses of the femoral and tibial prostheses in the patient space coordinate system are further transformed into the tibial coordinate system. For each different flexion angle, the minimum point of the femoral prosthesis on the Z-axis in the tibial coordinate system is found. This represents the point where the femoral and tibial prostheses are closest, i.e., the contact point, and serves as the three-dimensional coordinate of the second contact point between the femoral and tibial prostheses, ensuring the precise position of the femur and femoral prosthesis in the patient space coordinate system.

[0041] S200: Generate postoperative femoral and tibia movement based on the first and second contact points.

[0042] Specifically, the method for predicting the postoperative movement trajectory of the femur and tibia based on the first contact point and the second contact point includes: The first and second contact points at different flexion angles are projected onto the XY plane of the tibial coordinate system to obtain the movement trajectories of the femur and tibia at different flexion angles.

[0043] In some specific embodiments, for each flexion angle, the corresponding first and second contact points are projected onto the XY plane of the tibial coordinate system. This step is achieved by ignoring the Z-axis coordinate value, because the Z-axis represents the height perpendicular to the XY plane, while this invention focuses on the relative positional changes in the XY plane. Therefore, for each flexion angle, two two-dimensional coordinates are obtained: the coordinates of the first contact point after projection and the coordinates of the second contact point after projection. Using the flexion angle as a parameter, all projected coordinate points are connected to determine the movement trajectory of the femur (or femoral prosthesis) and tibia (or tibial prosthesis) in the XY plane as the flexion angle changes. Through the above method, the postoperative movement trajectory of the femur and tibia can be effectively predicted, improving the accuracy of the surgery.

[0044] S300: Automatically plan the amount of osteotomy of the femur or tibia on the surgical side of the knee joint based on the movement trajectory of the femur and tibia.

[0045] Specifically, the method for automatically planning the osteotomy amount of the femur or tibia on the surgical side of the knee joint based on the movement trajectory of the femur and tibia includes: Based on the diameter of the tibia in the Y-axis direction of the tibial coordinate system, a preset safe area is set for the movement trajectory of the femoral prosthesis and the tibial prosthesis in the tibial coordinate system. It is then determined whether the movement trajectory of the femur and the tibia is within the preset safe area, and based on the determination result, it is determined whether the amount of osteotomy of the femur or the tibia needs to be adjusted.

[0046] Specifically, the method for determining whether to adjust the osteotomy amount of the femur or tibia based on the judgment result includes: If the movement trajectory of the femur and tibia is within the preset safe area, the amount of osteotomy of the femur or tibia will not be adjusted. If the movement trajectory of the femur and tibia is not within the preset safe area, the amount of osteotomy of the femur or tibia is adjusted according to the direction in which the movement trajectory exceeds the preset safe area.

[0047] Preferably, a preset safety zone is reasonably set according to the diameter of the tibia in the Y-axis direction of the tibial coordinate system. Theoretically, the contact point between the femoral prosthesis and the tibial prosthesis at different flexion angles should be located within the preset safety zone, thereby ensuring that the safety requirements are met throughout the entire range of motion. If the movement trajectory exceeds the preset safety zone, it may be due to unreasonable osteotomy of the femur or tibia, or incorrect installation position of the prosthesis, etc. According to the specific situation of exceeding the safety zone, the osteotomy amount is re-planned to bring the movement trajectory back to the safety zone.

[0048] Specifically, adjusting the amount of osteotomy of the femur or tibia according to the direction in which the movement trajectory exceeds the preset safe area includes: If the surgical side of the knee joint is the medial condyle, the direction pointing to the anteromedial side of the knee joint is the positive direction of the Y-axis, and the direction pointing to the posteromedial side is the negative direction of the Y-axis. If the movement trajectory exceeds the preset safety zone in both the positive and negative Y-axis directions of the tibial coordinate system, the amount of osteotomy of the tibia or femur is reduced, or the height of the tibial prosthesis is increased. When the movement trajectory exceeds the preset safety area in the positive Y-axis direction of the tibial coordinate system, the amount of osteotomy of the anteromedial tibia is reduced and the amount of osteotomy of the posteromedial tibia is increased. When the movement trajectory exceeds the preset safety zone in the negative Y-axis direction of the tibial coordinate system, the amount of osteotomy on the anteromedial tibia is increased and the amount of osteotomy on the posteromedial tibia is decreased.

[0049] Specifically, adjusting the osteotomy amount according to the direction of the movement trajectory exceeding the preset safety zone also includes: If the surgical side of the knee joint is the lateral condyle, the direction pointing to the anterolateral aspect of the knee joint is the positive direction of the Y-axis, and the direction pointing to the posterolateral aspect is the negative direction of the Y-axis. If the movement trajectory exceeds the preset safety zone in both the positive and negative Y-axis directions of the tibial coordinate system, the amount of osteotomy of the tibia or femur is reduced, or the height of the tibial prosthesis is increased. When the movement trajectory exceeds the preset safety zone in the positive Y-axis direction of the tibial coordinate system, the amount of osteotomy of the posterolateral tibia is increased. When the movement trajectory exceeds the preset safety zone in the negative Y-axis direction of the tibial coordinate system, the osteotomy amount of the anterolateral tibia is increased and the osteotomy amount of the posterolateral tibia is decreased. When the movement trajectory is concentrated within a preset safe area, the amount of osteotomy of the tibia or femur is increased, or the height of the tibial prosthesis is reduced.

[0050] It should be further explained that the osteotomy plan is divided into medial condyle surgery and lateral condyle surgery. This is mainly because the medial and lateral condyles of the knee joint have significant differences in anatomical structure, biomechanical characteristics, and movement patterns. The medial and lateral condyles of the knee joint have obvious differences in morphology. The medial condyle is wider and differs from the lateral condyle in the shape, curvature of the articular surface, and the way it connects with surrounding tissues (such as ligaments and menisci). The lateral condyle is relatively smaller and more rounded. This difference in morphology leads to different mechanical characteristics and movement patterns of the medial and lateral condyles during knee joint movement. Due to the different morphologies of the medial and lateral condyles, the stress distribution they generate when bearing body weight and during movement is also different. During normal standing and walking, the medial condyle often bears more weight load, and its stress distribution is relatively concentrated in a specific area. The lateral condyle bears a relatively small load, but during certain movements (such as torsional movements), the stress on the lateral condyle changes, and its stress distribution pattern is quite different from that of the medial condyle.

[0051] Preferably, in medial condyle surgery, the preset safety zone is set as an elliptical region at the center of the medial tibial plateau, with its major axis being 1 / 3 of the diameter of the tibia in the Y-axis direction of the tibial coordinate system. When the movement trajectory exceeds the preset safety zone in different directions of the Y-axis of the tibial coordinate system, the amount of osteotomy is adjusted based on the anatomical structure and mechanical properties of the medial condyle. For example, when the movement trajectory exceeds the preset safety zone in the positive Y-axis direction, the amount of osteotomy on the anteromedial tibia is reduced, and the amount of osteotomy on the posteromedial tibia is increased. Increasing the amount of osteotomy is to reduce the contact gap between the femur and tibia. Increasing or decreasing soft tissue tension can cause the movement area to become too concentrated if the gap is too small (too much tension). Conversely, if the gap is too large (too little tension), the movement area will exceed the normal trajectory range. For cases where the movement area exceeds the trajectory range, the local gap can be adjusted. The gap can be adjusted by adjusting the thickness of the pad (tibial prosthesis) or by adjusting the amount of femoral and tibial osteotomy. However, the range of femoral and tibial osteotomy is limited, and too much or too little osteotomy cannot be performed. Doctors need to consider many factors. Preferably, in lateral condyle surgery, the pre-defined safe zone is set as an elliptical region at the center of the lateral tibial plateau, with its major axis being 2 / 3 of the diameter of the tibia in the Y-axis direction of the tibial coordinate system. The amount of osteotomy is adjusted based on whether the movement trajectory exceeds the pre-defined safe zone in the Y-axis direction of the tibial coordinate system. For example, when the movement trajectory exceeds the pre-defined safe zone in the positive Y-axis direction, the amount of osteotomy on the posterolateral tibia is increased. Increasing the amount of osteotomy can alter the structure of the posterolateral tibia, thereby adjusting the movement trajectory. Unlike the medial condyle, the structure and biomechanical characteristics of the lateral condyle dictate that when the movement trajectory exceeds the safe zone, the amount of osteotomy needs to be adjusted according to the anatomical and functional characteristics of the lateral condyle itself to ensure normal knee joint function and stability. In addition, compared with the medial condyle, the lateral condyle bears a smaller load. If the movement trajectory is too concentrated in the safe area, that is, the gap is too small (the tension is too large), the movement area will be too concentrated. Therefore, lateral condyle surgery needs to take into account the situation where the movement trajectory is too concentrated. The dispersion of the movement trajectory can be preset to evaluate whether it is too concentrated in the safe area. The range of dispersion values ​​can be set by the doctor according to the actual situation.

[0052] Dividing osteotomy planning into medial condyle surgery and lateral condyle surgery allows for personalized surgical plans. Each patient's medial and lateral condyles may differ, including anatomical structure, lesion severity, and exercise needs. By developing separate osteotomy plans for the medial and lateral condyles, we can better adapt to the specific circumstances of different patients, improve the success rate of surgery, and enhance the recovery of knee joint function after surgery.

[0053] Please see Figures 3-18 The working principle of this invention will be illustrated below with specific examples: This example demonstrates a robot-assisted total hip replacement surgery. A virtual 3D reconstruction of the patient's original knee joint anatomy is created using CT scans. Prosthesis planning is performed based on this 3D model. Intraoperative registration is executed, mapping the patient's skeletal anatomy onto a general virtual model of the knee joint. Optical motion capture technology is used to acquire the relative positions of the femur and tibia. The contact point trajectories of the femur and tibia are calculated based on their motion trajectories. Intraoperative adjustments and planning are then performed using a surgical navigation system for knee replacement. a. Real-time display of the contact point trajectory between the femoral head (femoral prosthesis) and the tibia (plate) during the flexion and extension process of the knee joint in the surgical compartment; b. Real-time display of the contact point trajectory between the femoral head and tibia during the flexion and extension of the knee joint in the healthy compartment; c. Adjust the planning according to the contact point trajectory to improve the stability of the prosthesis after surgery.

[0054] The specific steps of the above work process are as follows: Step 1: Preoperative preparation, see Figure 7 The main processes include: (1) Obtain CT image data containing the knee joint, femoral head and ankle joint; (2) Segment CT image data to obtain a three-dimensional model of the bone surface for display planning; (2) Bony reference points, including the femoral head center, femoral condyle center, medial / lateral lowest point of the distal femur, tibial plateau center, tibial plateau osteotomy reference point, and ankle center. The femoral mechanical axis is determined by the femoral head center and femoral condyle center; the tibial mechanical axis is determined by the tibial plateau center and ankle center, with the tibial plateau center being the proximal endpoint of the tibial mechanical axis. (4) Perform initial prosthesis adjustments and obtain unicompartmental planning data until the doctor's requirements are met.

[0055] Step 2: Intraoperative motion trajectory acquisition, see Figure 8 The main process is as follows: (1) Register the tibia and femur images: Coarse registration calculation: Based on the planned coarse registration points, the patient's coarse registration points are collected. Based on the planned coarse registration points, the positions of the corresponding planned coarse registration points in the camera coordinate system are collected by probes. The preoperative segmented 3D data is used for calculation. Through the rigid registration algorithm, the matrix with the smallest error between the collected patient coarse registration points and the planned coarse registration bone points is obtained, which is used as the original registration matrix, i.e., the first registration matrix. Precise registration calculation: Several points (20-50 points) are selected on the bone surface of the surgical area of ​​the patient using a probe. The acquisition points should be as dispersed as possible. Using the preoperative segmented 3D region data, the iterative closest point (ICP) algorithm is used to calculate the precise registration matrix. The formula pi' = R*pi + t is used, where pi is the acquired registration point, R is the rotation matrix of the registration matrix, and t is the translation matrix of the registration matrix. The rotation matrix R and the translation matrix t constitute the registration matrix. Transforming the acquired registration point pi yields the new point cloud target point pi'. The registration matrix is ​​then converted into a 4*4 homogeneous transformation matrix to obtain the femoral registration matrix. Where T represents the transformation matrix, F represents the femoral tracker, and I represents the femoral image, i.e., the pose of the femoral image in the patient's spatial coordinate system; the tibial registration matrix is ​​obtained as follows. , where T represents the transformation matrix, E represents the tibia tracker, and I2 represents the tibia image, i.e., the pose of the tibia image in the patient's spatial coordinate system.

[0056] (2) Obtain the contact point. The specific process is as follows: For the surgical compartment: The contact points between the femoral and tibial prostheses are collected, and the motion of the femoral prosthesis in the tibial coordinate system is calculated. Contact points between the femoral and tibial prostheses at different flexion angles of the femur and tibia are collected. The lowest points (minimum z-axis value) of the medial and lateral condyles in the tibial coordinate system are used as the contact points. The calculation steps are as follows: Real-time acquisition of the pose matrix of the femoral tracker , where T represents the transformation matrix, C represents the patient, and F represents the femoral tracker, that is, the pose of the femoral tracker in the patient coordinate system; Using formula ⋅ = The femoral image is obtained in the patient coordinate system. Simultaneously, the pose matrix of the tibia tracker is obtained. ,Will ⋅ = The pose matrix of the tibial image coordinates in the patient coordinate system is obtained. ; via invert ( )⋅ Obtain the transformation matrix Where T represents the transformation matrix, I3 represents the tibial prosthesis image, and I1 represents the femoral prosthesis image, i.e., the pose of the femoral prosthesis image in the tibial coordinate system. Then, the minimum point of the z-axis on the femoral condyle in the tibial coordinate system is taken as the second contact point between the femoral prosthesis and the tibial prosthesis.

[0057] For the healthy compartment: The contact points between the femur and tibia are collected, and the movement of the femur in the tibial coordinate system is calculated. The contact points between the femoral head and the tibial plateau at different flexion angles of the femur and tibia are collected. The lowest point of the healthy femoral condyle in the tibial coordinate system is used as the contact point. The calculation process is as follows: Real-time acquisition of femoral pose matrix , where T represents the transformation matrix, C represents the patient, and F represents the femoral tracker, that is, the pose of the femoral tracker in the patient coordinate system; Using formula ⋅ = That is, the pose of the femoral image in a coordinate system based on the patient's coordinates. ; Simultaneously acquire the pose matrix of the tibia tracker. ,according to ⋅ = The pose matrix of the tibial image coordinates in the patient coordinate system is obtained. ; via invert ( )⋅ Obtain the transformation matrix , where T represents the transformation matrix, I2 represents the tibia image, and I represents the femur image, that is, the pose of the femur image in the coordinate system based on the tibia coordinates. Then, the minimum point of the z-axis on the femur in the coordinate system based on the tibia coordinates is taken as the first contact point between the femoral head and the tibia.

[0058] (3) Map the contact points to obtain their trajectories. The specific process is as follows: like Figure 5 As shown, a tibial coordinate system is established, with the Z-axis coinciding with the tibial mechanical axis; the Y-axis coinciding with the Akagi line; and the X-axis perpendicular to both the Y-axis and the Z-axis. The origin is located at the proximal end of the tibial mechanical axis, i.e., the center of the tibial plateau. The contact point between the femoral prosthesis and the tibia is projected onto the XY plane of the tibial coordinate system to obtain a trajectory at a flexion angle.

[0059] The trajectory points are acquired in real time at different flexion angles, with the femoral and tibial flexion angles ranging from -20° to 160°, and plotted as follows: Figure 9 The contact point trajectory diagram shown uses different colors to represent different buckling angles. For example, blue represents smaller buckling angles (such as 0°, 10°, etc.), green represents medium buckling angles (such as 30°, 50°, etc.), and other colors represent larger buckling angles (such as 70°, 90°, etc.). Two regions are marked in the diagram: the M side is the inner region, and the L side is the outer region.

[0060] Step 3: Adjust the osteotomy amount according to the contact point trajectory, see [link / reference]. Figures 10-18The main process is as follows: Based on the distribution of contact point trajectories, planning suggestions are provided for medial condyle surgery (most unicompartmental surgeries involve medial compartment replacement): See Figure 10 The medial movement trajectory is within the preset safe area, which is an elliptical area at the center of the medial tibial plateau. The long axis is recommended to be 1 / 3 of the anterior and posterior diameter of the tibia (the size of the area can be set), and no adjustment is required. See Figure 11 If the medial movement trajectory exceeds the preset safe zone, it is recommended to reduce the amount of medial osteotomy (tibial reduction or femoral reduction) or increase the height of the pad (tibia); See Figure 12 If the medial movement trajectory exceeds the preset safety area on the anterior side, it is recommended to reduce the osteotomy amount of the anteromedial tibia and increase the osteotomy amount of the posteromedial tibia. See Figure 13 If the medial movement trajectory exceeds the preset safety zone, it is recommended to increase the osteotomy amount of the anteromedial tibia and decrease the osteotomy amount of the posteromedial tibia.

[0061] For lateral condyle surgery: The preset safe area is an elliptical region in the center of the lateral tibial plateau, and the long axis is recommended to be 2 / 3 of the anterior and posterior diameter of the tibia (the size of the area can be set). See Figure 14 The outer movement trajectory is within the preset safe area, and no adjustment to the plan is required; See Figure 15 If the lateral movement trajectory exceeds the preset safe area, it is recommended to reduce the amount of osteotomy (tibial reduction or femoral reduction) or increase the height of the pad. See Figure 16 The lateral movement trajectory extends beyond the preset safety zone, increasing the amount of osteotomy on the posterolateral tibia; See Figure 17 If the lateral movement trajectory exceeds the preset safety zone, it is recommended to increase the osteotomy amount of the anterolateral tibia and decrease the osteotomy amount of the posterolateral tibia. See Figure 18 If the lateral movement trajectory is concentrated within the preset safe area, it is recommended to increase the amount of osteotomy (femoral or tibial increase) or reduce the height of the spacer (tibial prosthesis).

[0062] After adjustments, if the doctor's requirements are met, osteotomy is performed; if not, adjustments are made based on the contact point trajectory, and the above process is repeated until the doctor's requirements are met.

[0063] It should be noted that this embodiment provides an automatic osteotomy planning method in unicompartmental knee arthroplasty. By acquiring the first contact point between the femur and tibia on the healthy side of the knee joint, and the second contact point between the femoral prosthesis and tibial prosthesis on the operated side of the knee joint, the method generates the postoperative movement trajectory of the femur and tibia based on the first and second contact points. The method automatically plans the amount of osteotomy to be performed on the operated side of the knee joint based on the movement trajectory of the femur and tibia. This solves the problems of traditional manual surgery relying on the surgeon's experience, which affects the surgical outcome, and the current lack of effective intraoperative planning and accurate prediction capabilities. It greatly improves the safety and efficiency of unicompartmental knee arthroplasty, further enhancing the surgical outcome and significantly improving the intelligence, usability, and reliability of this invention.

[0064] Please see Figure 2 This embodiment provides an automated osteotomy planning system for unicompartmental knee arthroplasty, the system comprising: Acquisition module 100: used to acquire the first contact point between the femur and tibia on the healthy side of the knee joint, and the second contact point between the femoral prosthesis and tibial prosthesis on the surgical side of the knee joint. Control module 200: is used to generate the postoperative movement trajectory of the femur and tibia based on the first contact point and the second contact point; and is used to automatically plan the amount of osteotomy of the femur or tibia on the surgical side of the knee joint based on the movement trajectory of the femur and tibia.

[0065] It should be noted that this embodiment provides an automatic osteotomy planning system for unicompartmental knee arthroplasty. By acquiring the first contact point between the femur and tibia on the healthy side of the knee joint, and the second contact point between the femoral prosthesis and tibial prosthesis on the operated side of the knee joint, the system generates the postoperative motion trajectory of the femur and tibia based on the first and second contact points. It automatically plans the amount of osteotomy to be performed on the operated side of the knee joint based on the motion trajectory of the femur and tibia. This solves the problems of traditional manual surgery relying on the surgeon's experience, which affects the surgical outcome, and the current lack of effective intraoperative planning and accurate prediction capabilities. It greatly improves the safety and efficiency of unicompartmental knee arthroplasty, further enhancing the surgical outcome and significantly improving the intelligence, usability, and reliability of this invention.

[0066] In a preferred embodiment, this application also provides an electronic device, the electronic device comprising: The computer device includes a memory and a processor, wherein the memory stores computer-readable instructions that, when executed by the processor, implement the automated osteotomy planning method in unicompartmental knee arthroplasty. The computer device can be broadly categorized as a server, terminal, or any other electronic device with the necessary computing and / or processing capabilities. In one embodiment, the computer device may include a processor, memory, network interface, communication interface, etc., connected via a system bus. The processor of the computer device can be used to provide the necessary computing, processing, and / or control capabilities. The memory of the computer device may include a non-volatile storage medium and internal memory. The non-volatile storage medium may store an operating system, computer programs, etc. The internal memory can provide an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The network interface and communication interface of the computer device can be used to connect and communicate with external devices via a network. When the computer program is executed by the processor, it performs the steps of the method of the present invention.

[0067] It should be noted that this invention obtains the first contact point between the femur and tibia on the healthy side of the knee joint, and the second contact point between the femoral prosthesis and tibial prosthesis on the surgical side of the knee joint; generates the postoperative movement trajectory of the femur and tibia based on the first and second contact points; and automatically plans the amount of osteotomy of the femur or tibia on the surgical side of the knee joint based on the movement trajectory of the femur and tibia. This solves the problems of traditional manual surgery relying on the surgeon's experience, affecting the surgical outcome, and currently lacking effective intraoperative planning and accurate prediction capabilities. It greatly improves the safety and efficiency of unicompartmental knee replacement surgery, further improves the surgical outcome, and significantly enhances the intelligence, usability, and reliability of this invention.

[0068] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0069] The technical features described above can be combined arbitrarily. Although not all possible combinations of these technical features are described, any combination of these technical features should be considered to be covered by this specification, provided that such combination does not contain contradictions.

[0070] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An automated osteotomy planning method in unicompartmental knee arthroplasty, characterized in that, include: S100. Obtain the first contact point between the femur and tibia on the healthy side of the knee joint, and the second contact point between the femoral prosthesis and tibial prosthesis on the surgical side of the knee joint. S200: Generate the postoperative movement trajectory of the femur and tibia based on the first contact point and the second contact point; S300: Automatically plan the amount of osteotomy of the femur or tibia on the surgical side of the knee joint based on the movement trajectory of the femur and tibia.

2. The automatic osteotomy planning method in unicompartmental knee arthroplasty according to claim 1, characterized in that, The S100 includes: S210. Obtain CT images containing the knee joint before surgery, and segment the CT images to obtain a three-dimensional model of the knee joint bone surface in the CT images. S220. Register the CT images to obtain the transformation relationship between the image coordinate system containing the femur and tibia and the patient's spatial coordinate system. S230. Obtain the first contact point between the femur and tibia, and the second contact point between the femoral prosthesis and the tibial prosthesis.

3. The automatic osteotomy planning method in unicompartmental knee arthroplasty according to claim 2, characterized in that, A method for registering the CT images to obtain the transformation relationship between the image coordinate system containing the femur and tibia and the patient's spatial coordinate system includes: Based on the segmented 3D model of the knee joint, the rigid registration algorithm is used to calculate the first registration matrix between the dataset of the surgical area collected in the patient space coordinate system and its corresponding data in the 3D model. Then, the iterative nearest point algorithm is used to calculate the femoral registration matrix of the knee joint in the patient space coordinate system and the tibial registration matrix of the knee joint in the patient space coordinate system.

4. The automatic osteotomy planning method in unicompartmental knee arthroplasty according to claim 3, characterized in that, The method for calculating the femoral registration matrix and the tibial registration matrix of the knee joint in the patient spatial coordinate system in the three-dimensional model includes: The registration points of the segmented 3D model of the knee joint are acquired. These registration points are then translated and rotated to obtain the target points in the patient's spatial coordinate system. The specific calculations are as follows: pi' = R*pi + t, Where pi represents the point to be registered, R represents the rotation matrix of the registration matrix, t represents the translation matrix of the registration matrix, and pi' represents the target point; The rotation and translation matrices are converted into homogeneous transformation matrices to obtain the femoral registration matrix and the tibial registration matrix.

5. The automatic osteotomy planning method in unicompartmental knee arthroplasty according to claim 3, characterized in that, S230 includes: A tibial coordinate system is established with the center of the tibial plateau as the origin, where the Z-axis coincides with the mechanical axis of the tibia; the Y-axis coincides with the Akagi line; and the X-axis is perpendicular to both the Y-axis and the Z-axis. Obtain the three-dimensional coordinates of the first contact point between the femoral head and tibia on the healthy side of the knee joint at different flexion angles in the tibial coordinate system, and the three-dimensional coordinates of the second contact point between the femoral prosthesis and tibia prosthesis on the surgical side of the knee joint at different flexion angles in the tibial coordinate system.

6. The automatic osteotomy planning method in unicompartmental knee arthroplasty according to claim 5, characterized in that, The method for obtaining the three-dimensional coordinates of the first contact point between the femoral head and tibia on the healthy side of the knee joint at different flexion angles in the tibial coordinate system includes: Real-time acquisition of the pose matrix of the femoral tracker in the patient space coordinate system , where T represents the transformation matrix, C represents the patient, and F represents the femoral tracker; Calculate the pose matrix of the femoral image coordinates in the patient space coordinate system. The calculation method is as follows: ， Where I represents the femur image, Represents the femoral registration matrix; Real-time acquisition of the tibial tracker's pose matrix in the patient coordinate system Where C represents the patient and E represents the tibial tracker; Calculate the pose matrix of the tibial image coordinates in the patient space coordinate system. The calculation method is as follows: ， Where I2 represents the tibia image, Represents the tibial registration matrix; Calculate the pose matrix of the femoral image coordinates in the tibial coordinate system. The calculation method is as follows: =invert( ) ; Furthermore, the three-dimensional coordinates of the minimum point of the femur on the z-axis of the tibial coordinate system under different flexion angles are used as the three-dimensional coordinates of the first contact point between the femur and the tibia.

7. The automatic osteotomy planning method in unicompartmental knee arthroplasty according to claim 5, characterized in that, The method for obtaining the three-dimensional coordinates of the second contact points of the femoral and tibial prostheses on the surgical side of the knee joint at different flexion angles in the tibial coordinate system includes: Real-time acquisition of the pose matrix of the femoral tracker in the patient space coordinate system , where T represents the transformation matrix, C represents the patient, and F represents the femoral tracker; Calculate the pose matrix of the femoral prosthesis image coordinates in the patient space coordinate system. The calculation method is as follows: ， Where I1 represents the femoral prosthesis image, Represents the femoral registration matrix; Real-time acquisition of the pose matrix of the tibia tracker in the patient space coordinate system Where C represents the patient and E represents the tibial tracker; Calculate the pose matrix of the tibial prosthesis image coordinates in the patient space coordinate system. The calculation method is as follows: ， Where I3 represents the tibial prosthesis image, Represents the tibial registration matrix; Calculate the pose matrix of the femoral prosthesis image coordinates in the tibial coordinate system. The calculation method is as follows: =invert( ) ; Furthermore, the three-dimensional coordinates of the minimum point of the femoral prosthesis on the z-axis of the tibial coordinate system under different flexion angles are used as the three-dimensional coordinates of the second contact point between the femoral prosthesis and the tibial prosthesis.

8. The automatic osteotomy planning method in unicompartmental knee arthroplasty according to claim 5, characterized in that, The method for predicting the postoperative movement trajectory of the femur and tibia based on the first contact point and the second contact point includes: The first and second contact points at different flexion angles are projected onto the XY plane of the tibial coordinate system to obtain the movement trajectories of the femur and tibia at different flexion angles.

9. The automatic osteotomy planning method in unicompartmental knee arthroplasty according to claim 8, characterized in that, The method for automatically planning the amount of osteotomy of the femur or tibia on the surgical side of the knee joint based on the movement trajectory of the femur and tibia includes: Based on the diameter of the tibia in the Y-axis direction of the tibial coordinate system, a preset safe area is set for the movement trajectory of the femoral prosthesis and the tibial prosthesis in the tibial coordinate system. It is then determined whether the movement trajectory of the femur and the tibia is within the preset safe area, and based on the determination result, it is determined whether the amount of osteotomy of the femur or the tibia needs to be adjusted.

10. The automatic osteotomy planning method in unicompartmental knee arthroplasty according to claim 9, characterized in that, The method for determining whether to adjust the osteotomy amount of the femur or tibia based on the judgment result includes: If the movement trajectory of the femur and tibia is within the preset safe area, the amount of osteotomy of the femur or tibia will not be adjusted. If the movement trajectory of the femur and tibia is not within the preset safe area, the amount of osteotomy of the femur or tibia is adjusted according to the direction in which the movement trajectory exceeds the preset safe area.

11. The automatic osteotomy planning method in unicompartmental knee arthroplasty according to claim 10, characterized in that, The adjustment of the osteotomy amount of the femur or tibia according to the direction of the movement trajectory exceeding the preset safety zone includes: If the surgical side of the knee joint is the medial condyle, the direction pointing to the anteromedial side of the knee joint is the positive direction of the Y-axis, and the direction pointing to the posteromedial side is the negative direction of the Y-axis. If the movement trajectory exceeds the preset safety zone in both the positive and negative Y-axis directions of the tibial coordinate system, the amount of osteotomy of the tibia or femur is reduced, or the height of the tibial prosthesis is increased. When the movement trajectory exceeds the preset safety area in the positive Y-axis direction of the tibial coordinate system, the amount of osteotomy of the anteromedial tibia is reduced and the amount of osteotomy of the posteromedial tibia is increased. When the movement trajectory exceeds the preset safety zone in the negative Y-axis direction of the tibial coordinate system, the amount of osteotomy on the anteromedial tibia is increased and the amount of osteotomy on the posteromedial tibia is decreased.

12. The automatic osteotomy planning method in unicompartmental knee arthroplasty according to claim 10, characterized in that, The method of adjusting the osteotomy amount according to the direction of the movement trajectory exceeding the preset safety zone also includes: If the surgical side of the knee joint is the lateral condyle, the direction pointing to the anterolateral aspect of the knee joint is the positive direction of the Y-axis, and the direction pointing to the posterolateral aspect is the negative direction of the Y-axis. If the movement trajectory exceeds the preset safety zone in both the positive and negative Y-axis directions of the tibial coordinate system, the amount of osteotomy of the tibia or femur is reduced, or the height of the tibial prosthesis is increased. When the movement trajectory exceeds the preset safety zone in the positive Y-axis direction of the tibial coordinate system, the amount of osteotomy of the posterolateral tibia is increased. When the movement trajectory exceeds the preset safety zone in the negative Y-axis direction of the tibial coordinate system, the osteotomy amount of the anterolateral tibia is increased and the osteotomy amount of the posterolateral tibia is decreased. When the movement trajectory is concentrated within a preset safe area, the amount of osteotomy of the tibia or femur is increased, or the height of the tibial prosthesis is reduced.

13. An automated osteotomy planning system for unicompartmental knee arthroplasty, characterized in that, include: Acquisition module: used to acquire the first contact point between the femur and tibia on the healthy side of the knee joint, and the second contact point between the femoral prosthesis and tibial prosthesis on the surgical side of the knee joint; Control module: used to generate the postoperative movement trajectory of the femur and tibia based on the first contact point and the second contact point; and used to automatically plan the amount of osteotomy of the femur or tibia on the surgical side of the knee joint based on the movement trajectory of the femur and tibia.

Images