Calculation method of model positioning parameters in knee joint prosthesis planning, electronic equipment and storage medium

Abstract

The invention discloses a method for calculating model positioning parameters in knee joint prosthesis planning, electronic equipment and a storage medium. The method comprises the following steps: acquiring a femur model, a first feature point set, a tibia model, a second feature point set, a femur prosthesis model and a tibia prosthesis model; determining a third feature point set based on the femoral prosthesis model; determining a fourth feature point set based on the tibial prosthesis model; moving the femoral prosthesis model to a first target position according to the first control instruction; calculating a first positioning parameter of the femoral prosthesis model according to the coordinates of the feature points of the first feature point set and the third feature point set; moving the tibial prosthesis model to a second target position according to the second control instruction; and calculating a second positioning parameter of the tibial prosthesis model according to the coordinates of the feature points of the second feature point set and the fourth feature point set. The first positioning parameter and the second positioning parameter are calculated according to the coordinates of the feature points in the feature point set, and the positioning parameters of the prosthesis model can be accurately obtained during preoperative planning.

Description

Technical Field

[0001] The present invention relates to the field of medical technology, and in particular to a method for calculating model positioning parameters in knee joint prosthesis planning, electronic equipment and storage medium. Background Art

[0002] Knee replacement surgery is a surgical method used to treat knee joint diseases. In knee replacement surgery, especially in single knee replacement surgery, doctors need to accurately place the knee prosthesis to restore the patient's knee function. Therefore, knee replacement surgery requires extremely high positioning accuracy of the prosthesis, and the success of the operation is highly dependent on the accuracy of the positioning parameters between the prosthesis and the femur and tibia in preoperative planning.

[0003] Currently, before knee replacement surgery, doctors usually determine the relative position and positioning parameters between the prosthesis and the femur and tibia based on experience and visual inspection.

[0004] However, existing surgical planning methods mainly rely on the doctor's experience and visual inspection, and lack accurate calculation methods for positioning parameters, which often leads to low accuracy of positioning parameters and, in turn, low accuracy of knee replacement surgery. Summary of the invention

[0005] In response to the shortcomings of the prior art, the present application provides a method for calculating model positioning parameters in knee prosthesis planning, an electronic device and a storage medium. The first positioning parameters of the femoral prosthesis model are calculated according to the coordinates of the feature points in the first feature point set and the coordinates of the feature points in the third feature point set, and the second positioning parameters of the tibial prosthesis model are calculated according to the coordinates of the feature points in the second feature point set and the coordinates of the feature points in the fourth feature point set. The positioning parameters of the prosthesis model can be accurately obtained during preoperative planning, which is convenient for doctors to judge whether the current preoperative planning is reasonable, thereby providing accurate reference for doctors performing knee replacement surgery and improving the accuracy of the surgery.

[0006] To solve the above problems, the present invention provides the following technical solutions:

[0007] In a first aspect, an embodiment of the present application provides a method for calculating model positioning parameters in knee prosthesis planning, comprising: obtaining a femur model, a first feature point set of the femur model, a tibia model, a second feature point set of the tibia model, a femur prosthesis model, and a tibia prosthesis model;

[0008] Determine a third feature point set of the femoral prosthesis model based on the femoral prosthesis model;

[0009] Determining a fourth feature point set of the tibial prosthesis model based on the tibial prosthesis model;

[0010] receiving a first control instruction, and moving the femoral prosthesis model to a first target position adapted to the femoral model according to the first control instruction;

[0011] Calculating first positioning parameters of the femoral prosthesis model according to the coordinates of the feature points in the first feature point set and the coordinates of the feature points in the third feature point set;

[0012] receiving a second control instruction, and moving the tibial prosthesis model to a second target position adapted to the tibial model according to the second control instruction;

[0013] The second positioning parameters of the tibial prosthesis model are calculated according to the coordinates of the feature points in the second feature point set and the coordinates of the feature points in the fourth feature point set.

[0014] In some embodiments, determining a third feature point set of the femoral prosthesis model based on the femoral prosthesis model includes:

[0015] Selecting a point on the plane where the distal end surface of the femoral prosthesis model is located as the first feature point;

[0016] Determine two end points of the intersection line segment of the posterior inclined surface and the distal surface of the femoral prosthesis model as the second characteristic point and the third characteristic point respectively;

[0017] The bottom center of the first protrusion of the femoral prosthesis model is determined as a fourth feature point, and the bottom center of the second protrusion of the femoral prosthesis model is determined as a fifth feature point;

[0018] The first connecting line between the fourth feature point and the fifth feature point is translated in a plane perpendicular to the posterior inclined plane where the first connecting line is located so that the translated first connecting line is tangent to the curved surface of the femoral prosthesis model, and a tangent point where the translated first connecting line is tangent to the curved surface is determined as a sixth feature point;

[0019] Determine a third feature point set including the first feature point, the second feature point, the third feature point, the fourth feature point, the fifth feature point and the sixth feature point;

[0020] The step of determining a fourth feature point set of the tibial prosthesis model based on the tibial prosthesis model comprises:

[0021] Determine the center of the bottom surface of the first protrusion of the tibial prosthesis model located on the lower surface of the tibial prosthesis model as the seventh feature point;

[0022] A point whose distance from the seventh feature point is equal to the thickness of the tibial prosthesis model, which is far away from the lower surface of the tibial prosthesis model and whose line connecting the seventh feature point and the lower surface is perpendicular to the lower surface is determined as an eighth feature point;

[0023] Select two points on the horizontal line of the rear end surface of the tibial prosthesis model and determine them as the ninth feature point and the tenth feature point respectively;

[0024] A fourth feature point set including the seventh feature point, the eighth feature point, the ninth feature point and the tenth feature point is determined.

[0025] In some embodiments, the first positioning parameter includes a first angle, a second angle, a third angle and a first distance, the first angle represents the angle of anteversion or posterior tilt of the femoral prosthesis model relative to the femoral model, the second angle represents the angle of varus or valgus of the femoral prosthesis model relative to the femoral model, the third angle represents the angle of internal rotation or external rotation of the femoral prosthesis model relative to the femoral model, the first distance represents the distance of the femoral prosthesis model protruding or protruding relative to the femoral model, and the first positioning parameter of the femoral prosthesis model is calculated according to the coordinates of the feature points in the first feature point set and the coordinates of the feature points in the third feature point set, including:

[0026] Determine a third local coordinate system of the femur model according to the coordinates of the feature points in the first feature point set, and determine a first plane where the direction vector of the first coordinate axis and the direction vector of the second coordinate axis of the third local coordinate system are located, a second plane where the direction vector of the first coordinate axis and the direction vector of the third coordinate axis of the third local coordinate system are located, and a third plane where the direction vector of the second coordinate axis and the direction vector of the third coordinate axis of the third local coordinate system are located according to the third local coordinate system;

[0027] Determine a calculation vector corresponding to each of the first positioning parameters according to the coordinates of the feature points in the third feature point set;

[0028] For each first positioning parameter among the first angle, the second angle and the third angle, calculate the angle between the projection vector of the calculation vector corresponding to the first positioning parameter on the first target plane corresponding to the first positioning parameter and the first target axis direction vector corresponding to the first positioning parameter, to obtain the value of each first positioning parameter, wherein the first target plane is the first plane, the second plane or the third plane of the third local coordinate system, and the first target axis direction vector is on the first target plane;

[0029] Calculate a first intersection point set between a straight line where a calculation vector corresponding to the first distance is located and the femur model, and determine an intersection point in the first intersection point set that is closest to a sixth feature point in the third feature point set as a first calculation point;

[0030] taking the magnitude of the direction vector pointing from the sixth feature point to the first calculation point as the value of the first distance;

[0031] The first position state of the femoral prosthesis model relative to the femoral model represented by each of the first positioning parameters is determined according to the calculation vector corresponding to each of the first positioning parameters, wherein the first position state includes the anterior tilt or posterior tilt of the femoral prosthesis model relative to the femoral model, the varus or valgus of the femoral prosthesis model relative to the femoral model, the internal rotation or external rotation of the femoral prosthesis model relative to the femoral model, and the protrusion or protrusion of the femoral prosthesis model relative to the femoral model.

[0032] In some implementations, determining the calculation vector corresponding to each first positioning parameter according to the coordinates of the feature points in the third feature point set includes:

[0033] Before moving the femoral prosthesis model, determining a first local coordinate system of the femoral prosthesis model based on a third feature point set of the femoral prosthesis model;

[0034] Determine an initial calculation vector corresponding to each first positioning parameter based on the coordinates of the feature points in the third feature point set;

[0035] After moving the femoral prosthesis model, determining a first pose matrix based on expressions of direction vectors of all coordinate axes of the first local coordinate system after movement and coordinates of the origin of the first local coordinate system after movement;

[0036] The first posture matrix is ​​multiplied on the left by an initial calculation vector corresponding to each of the first positioning parameters to obtain a final calculation vector corresponding to each of the first positioning parameters.

[0037] In some embodiments, the third feature point set includes a first feature point, a second feature point, a third feature point, a fourth feature point, a fifth feature point, and a sixth feature point, and determining an initial calculation vector corresponding to each first positioning parameter based on the coordinates of the feature points in the third feature point set includes:

[0038] Determine a normal vector of the distal surface passing through the first feature point as an initial calculation vector corresponding to the first angle;

[0039] Determining an initial calculation vector corresponding to the first angle as an initial calculation vector corresponding to the second angle;

[0040] Determine a direction vector pointing from the second feature point to the third feature point as an initial calculation vector corresponding to the third angle;

[0041] Draw a perpendicular line segment through the sixth feature point to the first connecting line of the fourth feature point and the fifth feature point, and determine the foot of the perpendicular line segment as the second calculation point;

[0042] A direction vector pointing from the second calculation point to the sixth feature point is determined as an initial calculation vector corresponding to the first distance.

[0043] In some embodiments, the second positioning parameter includes a fourth angle, a fifth angle, a sixth angle and a second distance, the fourth angle represents an angle of anterior tilt or posterior tilt of the tibial prosthesis model relative to the tibial model, the fifth angle represents an angle of varus or valgus of the tibial prosthesis model relative to the tibial model, the sixth angle represents an angle of internal rotation or external rotation of the tibial prosthesis model relative to the tibial model, and the second distance represents a distance of protrusion or projection of the tibial prosthesis model relative to the tibial model, and the second positioning parameter of the tibial prosthesis model is calculated according to the coordinates of the feature points in the second feature point set and the coordinates of the feature points in the fourth feature point set, including:

[0044] Determine a fourth local coordinate system of the tibia model according to the coordinates of the feature points in the second feature point set, and determine a first plane where the direction vector of the first coordinate axis and the direction vector of the second coordinate axis of the fourth local coordinate system are located, a second plane where the direction vector of the first coordinate axis and the direction vector of the third coordinate axis of the fourth local coordinate system are located, and a third plane where the direction vector of the second coordinate axis and the direction vector of the third coordinate axis of the fourth local coordinate system are located according to the fourth local coordinate system;

[0045] Determine a calculation vector corresponding to each of the second positioning parameters according to the coordinates of the feature points in the fourth feature point set;

[0046] For each second positioning parameter among the fourth angle, the fifth angle and the sixth angle, calculate the angle between the projection vector of the calculation vector corresponding to the second positioning parameter on the second target plane corresponding to the second positioning parameter and the second target axis direction vector corresponding to the second positioning parameter, to obtain the value of each second positioning parameter, wherein the second target plane is the first plane, the second plane or the third plane of the fourth local coordinate system, and the second target axis direction vector is on the second target plane;

[0047] Calculate a second intersection point set between the straight line where the calculation vector corresponding to the second distance is located and the tibia model, and determine the intersection point in the second intersection point set that is closest to the eighth feature point in the fourth feature point set as a third calculation point;

[0048] taking the magnitude of the direction vector pointing from the third calculation point to the eighth feature point as the value of the second distance;

[0049] The second position state of the tibial prosthesis model relative to the tibial model represented by each of the second positioning parameters is determined according to the calculation vector corresponding to each of the second positioning parameters, wherein the second position state includes the tibial prosthesis model being tilted forward or backward relative to the tibial model, the tibial prosthesis model being varus or valgus relative to the tibial model, the tibial prosthesis model being internally rotated or externally rotated relative to the tibial model, and the tibial prosthesis model being protruded in or out relative to the tibial model.

[0050] In some implementations, determining the calculation vector corresponding to each second positioning parameter according to the coordinates of the feature points in the fourth feature point set includes:

[0051] Before moving the tibial prosthesis model, determining a second local coordinate system of the tibial prosthesis model based on a fourth feature point set of the tibial prosthesis model;

[0052] Determine an initial calculation vector corresponding to each second positioning parameter based on the coordinates of the feature points in the fourth feature point set;

[0053] After moving the tibial prosthesis model, determining a second pose matrix based on expressions of direction vectors of all coordinate axes of a second local coordinate system of the tibial prosthesis model after movement and coordinates of the origin of the second local coordinate system after movement;

[0054] Multiply the second posture matrix on the left by the initial calculation vector corresponding to each of the second positioning parameters to obtain a final calculation vector corresponding to each of the second positioning parameters.

[0055] In some implementations, the fourth feature point set includes a seventh feature point, an eighth feature point, a ninth feature point, and a tenth feature point, and determining an initial calculation vector corresponding to each second positioning parameter based on the coordinates of the feature points in the fourth feature point set includes:

[0056] Determine a normal vector of the lower surface of the tibial prosthesis model passing through the seventh feature point as an initial calculation vector corresponding to the fourth angle;

[0057] Determine the calculation vector corresponding to the fourth angle as the initial calculation vector corresponding to the fifth angle;

[0058] Determine a direction vector pointing from the ninth feature point to the tenth feature point as an initial calculation vector corresponding to the sixth angle;

[0059] The calculation vector corresponding to the fourth angle is determined as an initial calculation vector corresponding to the second distance.

[0060] In a second aspect, an embodiment of the present application provides an electronic device, the electronic device comprising:

[0061] at least one processor; and,

[0062] a memory communicatively connected to the at least one processor; wherein,

[0063] The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method for calculating model positioning parameters in knee prosthesis planning as described in the first aspect.

[0064] In a third aspect, an embodiment of the present application provides a computer-readable storage medium storing an executable program, wherein the executable program is executed by a processor to implement the method for calculating model positioning parameters in knee prosthesis planning as described in the first aspect.

[0065] The present application provides a method for calculating model positioning parameters in knee prosthesis planning, an electronic device and a storage medium. The present application calculates the first positioning parameters of the femoral prosthesis model according to the coordinates of the feature points in the first feature point set and the coordinates of the feature points in the third feature point set, and calculates the second positioning parameters of the tibial prosthesis model according to the coordinates of the feature points in the second feature point set and the coordinates of the feature points in the fourth feature point set. The positioning parameters of the prosthesis model can be accurately obtained during preoperative planning, which is convenient for doctors to judge whether the current preoperative planning is reasonable, thereby providing accurate reference for doctors performing knee replacement surgery and improving the accuracy of the surgery. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 It is a flowchart of a method for calculating model positioning parameters in knee prosthesis planning provided in an embodiment of the present application.

[0067] Figure 2 It is a schematic diagram of the femur model provided in the embodiment of the present application.

[0068] Figure 3 Schematic diagram of the tibia model provided in the embodiment of the present application.

[0069] Figure 4 It is a schematic diagram of the first perspective of the femoral prosthesis model provided in an embodiment of the present application.

[0070] Figure 5 It is a schematic diagram of a second viewing angle of the femoral prosthesis model provided in an embodiment of the present application.

[0071] Figure 6 It is a bottom view schematic diagram of the tibial prosthesis model provided in the embodiment of the present application.

[0072] Figure 7 It is a front view schematic diagram of the tibial prosthesis model provided in the embodiment of the present application.

[0073] Figure 8 yes Figure 1 Detailed flowchart of step S500 in FIG.

[0074] Fig. 9 It is a schematic diagram of the first local coordinate system of the femoral prosthesis model provided in an embodiment of the present application.

[0075] Fig.10 yes Figure 1 Detailed flowchart of step S600 in FIG.

[0076] Fig.11 It is a schematic diagram of the second local coordinate system of the tibial prosthesis model provided in an embodiment of the present application.

[0077] Fig.12 It is a structural schematic diagram of an electronic device provided in an embodiment of the present application.

[0078] Fig.13 It is a structural block diagram of a computer-readable storage medium provided in an embodiment of the present application. DETAILED DESCRIPTION

[0079] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0080] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0081] The present application provides a method for calculating model positioning parameters in knee prosthesis planning, an electronic device and a storage medium. The method calculates the first positioning parameters of a femoral prosthesis model according to the coordinates of feature points in a first feature point set and the coordinates of feature points in a third feature point set, and calculates the second positioning parameters of a tibial prosthesis model according to the coordinates of feature points in a second feature point set and the coordinates of feature points in a fourth feature point set. The positioning parameters of the prosthesis model can be accurately obtained during preoperative planning, which facilitates doctors to judge whether the current preoperative planning is reasonable, thereby providing accurate reference for doctors performing knee replacement surgery and improving the accuracy of the surgery.

[0082] The following will describe in detail the method for calculating model positioning parameters in knee prosthesis planning provided by the present application in conjunction with the accompanying drawings.

[0083] See also Figure 1 , Figure 1 FIG. 1 is a flow chart of a method for calculating model positioning parameters in knee prosthesis planning provided in an embodiment of the present application. Figure 1 As shown, the method for calculating the model positioning parameters in the knee joint prosthesis planning includes: steps S100 to S700.

[0084] Step S100: Acquire a femur model, a first feature point set of the femur model, a tibia model, a second feature point set of the tibia model, a femoral prosthesis model, and a tibia prosthesis model.

[0085] See also Figure 2 , Figure 2 It is a schematic diagram of the femur model provided in the embodiment of the present application. Figure 2 The femur model is taken as the right femur model as an example. Figure 2 As shown, in some embodiments, the feature points in the first feature point set of the femoral model 100 include the lateral femoral condyle point 101, the medial femoral condyle point 102, and the hip joint rotation center point 103. The feature points in the first feature point set are all located on the surface of the femoral model 100.

[0086] See also Figure 3 , Figure 3 Schematic diagram of the tibia model provided in the embodiment of the present application. Figure 3 The tibia model is taken as an example. Figure 3 As shown, in some embodiments, the feature points in the second feature point set of the tibia model 200 include the medial tibial condyle point 201, the lateral tibial condyle point 202, the medial ankle point 203, and the lateral ankle point 204. The feature points in the second feature point set are all located on the surface of the tibia model 200.

[0087] In some embodiments, the femur model and tibia model of the target object are obtained based on the CT image of the target object. When a knee replacement surgery is required for the knee joint on the left side of the target object's body, the femur model is a left femur model, and the tibia model is a left tibia model. When a knee replacement surgery is required for the knee joint on the right side of the target object's body, the femur model is a right femur model, and the tibia model is a right tibia model.

[0088] Optionally, methods for obtaining a femur model and a tibia model of the target object based on a CT image of the target object include a manual segmentation method and an artificial intelligence algorithm.

[0089] Optionally, the artificial intelligence algorithm includes U-Net, a neural network algorithm, and an attention mechanism algorithm, etc.

[0090] In some implementations, the first feature point set and the second feature point set are obtained by manually selecting feature points on the model.

[0091] In some implementations, an artificial intelligence algorithm is used to select feature points on the model to obtain a first feature point set and a second feature point set.

[0092] Step S200: determining a third feature point set of the femoral prosthesis model based on the femoral prosthesis model.

[0093] In some embodiments, step S200 includes steps (200.1) to (200.5).

[0094] (200.1) Select a point on the plane where the distal surface of the femoral prosthesis model is located and use it as the first feature point.

[0095] See also Figure 4 , Figure 4 Schematic diagram of the femoral prosthesis model provided in the embodiment of the present application from the first perspective. Figure 4 As shown, in some embodiments, the femoral prosthesis model 300 includes a distal surface A1 and a posterior inclined surface A2.

[0096] Optionally, on the plane where the distal surface A1 is located, a circumscribed rectangle of the distal surface A1 is constructed, and the center point of the rectangle is used as the first feature point 301 .

[0097] Optionally, a point is randomly selected on the distal surface A1 as the first feature point 301 .

[0098] (200.2) The two endpoints of the intersection line segment between the posterior inclined surface and the distal surface of the femoral prosthesis model are respectively determined as the second feature point and the third feature point.

[0099] like Figure 4As shown, in some embodiments, two endpoints of the intersection segment of the rear bevel A2 and the distal surface A1 are respectively determined as the second feature point 302 and the third feature point 303 .

[0100] (200.3) The center of the bottom surface of the first protrusion of the femoral prosthesis model is determined as the fourth feature point, and the center of the bottom surface of the second protrusion of the femoral prosthesis model is determined as the fifth feature point.

[0101] See also Figure 5 , Figure 5 FIG. 2 is a schematic diagram of a second perspective of the femoral prosthesis model provided in an embodiment of the present application. Figure 5 As shown, in some embodiments, the femoral prosthesis model 300 includes a first protrusion 310 and a second protrusion 320 .

[0102] In some embodiments, a cross section of the first protrusion 310 cut by a plane where the distal end surface A1 is located is circular, and the cross section is also the bottom surface of the first protrusion 310 .

[0103] Optionally, the center of the bottom surface of the first protrusion 310 is determined as the fourth feature point 304 .

[0104] In some embodiments, a cross section of the second protrusion 320 cut by a plane where the rear slope A2 is located is circular, and the cross section is also the bottom surface of the second protrusion 320 .

[0105] Optionally, the center of the bottom surface of the second protrusion 320 is determined as the fifth feature point 305 .

[0106] (200.4) The first connecting line between the fourth feature point and the fifth feature point is translated in a plane perpendicular to the posterior inclined plane where the first connecting line is located so that the translated first connecting line is tangent to the curved surface of the femoral prosthesis model, and the tangent point where the translated first connecting line is tangent to the curved surface is determined as the sixth feature point.

[0107] like Figure 5 As shown, in some embodiments, the first connecting line L1 between the fourth feature point 304 and the fifth feature point 305 is determined. The first connecting line L1 is located at the position of the first connecting line L1 and the Figure 4 The first connecting line L2 is translated in a plane perpendicular to the posterior inclined surface A2 in the femoral prosthesis model 300 so that the translated first connecting line L2 is tangent to the curved surface 330 of the femoral prosthesis model 300, and the tangent point where the translated first connecting line L2 is tangent to the curved surface 330 is determined as the sixth feature point 306.

[0108] (200.5) Determine a third feature point set including the first feature point, the second feature point, the third feature point, the fourth feature point, the fifth feature point and the sixth feature point.

[0109] In some embodiments, the third feature point set includes Figure 4The first feature point 301, the second feature point 302, the third feature point 303, Figure 5 The fourth feature point 304, the fifth feature point 305 and the sixth feature point 306 in FIG.

[0110] Step S300: determining a fourth feature point set of the tibial prosthesis model based on the tibial prosthesis model.

[0111] In some embodiments, step S300 includes steps (300.1) to (300.4).

[0112] (300.1) The center of the bottom circle of the first protrusion of the tibial prosthesis model located on the lower surface of the tibial prosthesis model is determined as the seventh feature point.

[0113] See also Figure 6 , Figure 6 FIG. 1 is a bottom view of a tibial prosthesis model provided in an embodiment of the present application. Figure 6 As shown, in some embodiments, the tibial prosthesis model 400 includes a first protrusion 410 and a lower surface A3 of the tibial prosthesis model 400 .

[0114] like Figure 6 As shown, in some embodiments, the cross section of the first protrusion 410 of the tibial prosthesis model 400 cut by the plane where the lower surface A3 is located is circular, and the cross section is also the bottom surface of the first protrusion 410 of the tibial prosthesis model 400.

[0115] Optionally, the center of the bottom surface of the first protrusion 410 of the tibial prosthesis model 400 is determined as the seventh feature point 401 .

[0116] (300.2) A point whose distance from the seventh feature point is the thickness of the tibial prosthesis model, which is far away from the lower surface of the tibial prosthesis model and whose line connecting the seventh feature point and the lower surface is perpendicular to the eighth feature point is determined as the eighth feature point.

[0117] See also Figure 7 , Figure 7 is a front view schematic diagram of the tibial prosthesis model provided in the embodiment of the present application. Figure 7 As shown, in some embodiments, a point that is at a distance from the seventh feature point 401 equal to the thickness of the tibial prosthesis model 400, is far from the lower surface of the tibial prosthesis model 400, and at which a line L3 connecting the seventh feature point 401 and the lower surface is perpendicular is determined as the eighth feature point 402. The eighth feature point 402 may not be on the surface of the tibial prosthesis model 400.

[0118] (300.3) Two points on the horizontal line of the rear end surface of the tibial prosthesis model are selected and determined as the ninth feature point and the tenth feature point respectively.

[0119] like Figure 7 As shown, in some embodiments, the tibial prosthesis model 400 includes a rear end surface A4, and two points on a horizontal line L4 of the rear end surface A4 are selected and determined as a ninth feature point 403 and a tenth feature point 404, respectively.

[0120] like Figure 7 As shown, in some embodiments, the rear end surface A4 is a rectangle, and the horizontal line L4 is the median line of the rear end surface A4 in the horizontal direction.

[0121] like Figure 7 As shown, in some embodiments, the ninth feature point 403 and the tenth feature point 404 are at the same distance from the line L3 connecting the seventh feature point 401 and the eighth feature point 402, so the ninth feature point 403 and the tenth feature point 404 are also at the same distance from the seventh feature point 401. In this way, the subsequent calculation of the second positioning parameter can be facilitated.

[0122] (300.4) Determine a fourth feature point set including the seventh feature point, the eighth feature point, the ninth feature point and the tenth feature point.

[0123] like Figure 7 As shown, in some embodiments, the fourth feature point set includes a seventh feature point 401 , an eighth feature point 402 , a ninth feature point 403 , and a tenth feature point 404 .

[0124] Step S400: receiving a first control instruction, and moving the femoral prosthesis model to a first target position that matches the femoral model according to the first control instruction.

[0125] During knee replacement surgery, the femoral prosthesis needs to be installed on the femur of the target object. Therefore, when planning the knee prosthesis, the doctor moves the femoral prosthesis model to a first target position that matches the femoral model. The first target position is also the installation position of the femoral prosthesis model estimated by the doctor.

[0126] Step S500: Calculate first positioning parameters of the femoral prosthesis model according to the coordinates of the feature points in the first feature point set and the coordinates of the feature points in the third feature point set.

[0127] See also Figure 8 , Figure 8 yes Figure 1 The detailed flow chart of step S500 in FIG. Figure 8 As shown, in some embodiments, step S500 includes steps S510 to S560.

[0128] Step S510: Determine the third local coordinate system of the femoral model according to the coordinates of the feature points in the first feature point set, and determine the first plane where the direction vector of the first coordinate axis and the direction vector of the second coordinate axis of the third local coordinate system are located, the second plane where the direction vector of the first coordinate axis and the direction vector of the third coordinate axis of the third local coordinate system are located, and the third plane where the direction vector of the second coordinate axis and the direction vector of the third coordinate axis of the third local coordinate system are located.

[0129] In some embodiments, determining the third local coordinate system of the femur model according to the coordinates of all feature points in the first feature point set includes steps (510.1) to (510.4).

[0130] (510.1) The midpoint of the line connecting the lateral femoral condyle point and the medial femoral condyle point is determined as the origin of the third local coordinate system.

[0131] like Figure 2 As shown, in some embodiments, the feature points in the first feature point set of the femoral model 100 include a lateral femoral condyle point 101 , a medial femoral condyle point 102 , and a hip joint rotation center point 103 .

[0132] In some embodiments, the midpoint of the line connecting the lateral femoral condyle point 101 and the medial femoral condyle point 102 is determined as the origin O3 of the third local coordinate system.

[0133] (510.2) The direction vector from the origin of the third local coordinate system to the rotation center of the hip joint is used as the direction vector of the first coordinate axis of the third local coordinate system, thereby determining the first coordinate axis of the third local coordinate system.

[0134] like Figure 2 As shown, in some embodiments, the direction vector pointing from the origin O3 of the third local coordinate system to the hip joint rotation center 103 is used as the direction vector of the first coordinate axis Z3 of the third local coordinate system, thereby determining the first coordinate axis Z3 of the third local coordinate system. The first coordinate axis Z3 is also the Z axis of the third local coordinate system.

[0135] (510.3) The direction vector from the hip joint rotation center point to the medial femoral condyle point is cross-multiplied with the direction vector from the hip joint rotation center point to the lateral femoral condyle point to obtain the direction vector of the second coordinate axis of the third local coordinate system, and then the second coordinate axis of the third local coordinate system is determined.

[0136] like Figure 2As shown, in some embodiments, the direction vector pointing from the hip joint rotation center point 103 to the medial femoral condyle point 102 is cross-multiplied by the direction vector pointing from the hip joint rotation center point 103 to the lateral femoral condyle point 101 to obtain the direction vector of the second coordinate axis Y3 of the third local coordinate system, and then determine the second coordinate axis Y3 of the third local coordinate system. The second coordinate axis Y3 of the third local coordinate system is also the Y axis of the third local coordinate system.

[0137] (510.4) The direction vector of the second coordinate axis of the third local coordinate system is cross-multiplied by the direction vector of the first coordinate axis to obtain the direction vector of the third coordinate axis of the third local coordinate system, and then the third coordinate axis of the third local coordinate system is determined.

[0138] like Figure 2 As shown, in some embodiments, the third coordinate axis X3 of the third local coordinate system is also the X-axis of the third local coordinate system.

[0139] In some embodiments, a first transformation matrix from the image coordinate system to the third local coordinate system is determined based on an expression of the direction vector of the first coordinate axis of the third local coordinate system in the image coordinate system, an expression of the direction vector of the second coordinate axis, an expression of the direction vector of the third coordinate axis, and the coordinates of the origin.

[0140] In some implementations, the formula for the first conversion matrix is:

[0141]

[0142] Among them, T 3 represents the first transformation matrix, represents the direction vector of the third coordinate axis of the third local coordinate system, represents the direction vector of the second coordinate axis of the third local coordinate system, represents the direction vector of the first coordinate axis of the third local coordinate system, A vector representing the coordinates of the origin of the third local coordinate system. express The first value of express The first value of express The first value of express , and so on.

[0143] In some embodiments, the first plane where the direction vector of the first coordinate axis and the direction vector of the second coordinate axis of the third local coordinate system are located, the second plane where the direction vector of the first coordinate axis and the direction vector of the third coordinate axis of the third local coordinate system are located, and the third plane where the direction vector of the second coordinate axis and the direction vector of the third coordinate axis of the third local coordinate system are located are determined according to the third local coordinate system. The first plane of the third local coordinate system is also the YOZ plane of the third local coordinate system, the second plane of the third local coordinate system is also the XOZ plane of the third local coordinate system, and the third plane of the third local coordinate system is also the XOY plane of the third local coordinate system.

[0144] Step S520: determining a calculation vector corresponding to each first positioning parameter according to the coordinates of the feature points in the third feature point set.

[0145] In some embodiments, step S520 includes steps (520.1) to (520.4).

[0146] (520.1) Before moving the femoral prosthesis model, determine a first local coordinate system of the femoral prosthesis model based on a third feature point set of the femoral prosthesis model.

[0147] In some embodiments, step (520.1) includes steps (520.1.1) to step (520.1.4).

[0148] (520.1.1) The midpoint of the line connecting the second feature point and the third feature point is taken as the origin of the first local coordinate system.

[0149] See also Fig. 9 , Fig. 9 Schematic diagram of the first local coordinate system of the femoral prosthesis model provided in the embodiment of the present application. Fig. 9 As shown, in some embodiments, the first local coordinate system of the femoral prosthesis model 300 includes an origin O1, a coordinate axis X1, a coordinate axis Y1, and a coordinate axis Z1.

[0150] As described above, in some embodiments, the third feature point set includes Figure 4 The first feature point 301, the second feature point 302, the third feature point 303, Figure 5 The fourth feature point 304, the fifth feature point 305 and the sixth feature point 306 in FIG.

[0151] In some implementations, the midpoint of the line connecting the second feature point 302 and the third feature point 303 is the origin O1 of the first local coordinate system.

[0152] (520.1.2) The direction vector pointing from the origin of the first local coordinate system to the third feature point is determined as the direction vector of the first coordinate axis of the first local coordinate system, thereby determining the first coordinate axis of the first local coordinate system.

[0153] like Fig. 9 As shown, in some embodiments, the direction vector pointing from the origin O1 of the first local coordinate system to the third feature point 303 is determined as the direction vector of the first coordinate axis Y1 of the first local coordinate system, thereby determining the first coordinate axis Y1 of the first local coordinate system. The first coordinate axis Y1 of the first local coordinate system is also the Y axis of the first local coordinate system.

[0154] (520.1.3) A direction vector on the plane where the posterior bevel is located, passing through the origin of the first local coordinate system, with its vector direction toward the distal surface of the femoral prosthesis model and perpendicular to the direction vector of the first coordinate axis of the first local coordinate system, is determined as the direction vector of the second coordinate axis of the first local coordinate system, thereby determining the second coordinate axis of the first local coordinate system.

[0155] like Fig. 9 As shown, in some embodiments, Figure 4 On the plane where the back slope A2 is located, through the origin O1 of the first local coordinate system, the vector direction is toward Figure 4 The distal surface A1 in the first local coordinate system and the direction vector perpendicular to the direction vector of the first coordinate axis Y1 of the first local coordinate system are determined as the direction vector of the second coordinate axis X1 of the first local coordinate system, thereby determining the second coordinate axis X1 of the first local coordinate system. The second coordinate axis X1 of the first local coordinate system is also the X axis of the first local coordinate system.

[0156] (520.1.4) The direction vector of the third coordinate axis of the first local coordinate system is obtained by cross-multiplying the direction vector of the second coordinate axis of the first local coordinate system by the direction vector of the first coordinate axis, thereby determining the third coordinate axis of the first local coordinate system.

[0157] like Fig. 9 As shown, in some embodiments, the direction vector of the third coordinate axis Z1 of the first local coordinate system is obtained by cross-multiplying the direction vector of the second coordinate axis X1 of the first local coordinate system by the direction vector of the first coordinate axis Y1, thereby determining the third coordinate axis Z1 of the first local coordinate system. The third coordinate axis Z1 of the first local coordinate system is also the Z axis of the first local coordinate system.

[0158] In some embodiments, a default initial position is set for the femoral prosthesis model 300 so that the first local coordinate system coincides with the image coordinate system, that is, the origin of the first local coordinate system coincides with the origin of the image coordinate system, the X-axis of the first local coordinate system coincides with the X-axis of the image coordinate system, the Y-axis of the first local coordinate system coincides with the Y-axis of the image coordinate system, and the Z-axis of the first local coordinate system coincides with the Z-axis of the image coordinate system.

[0159] (520.2) Determine an initial calculation vector corresponding to each first positioning parameter based on the coordinates of the feature points in the third feature point set.

[0160] As described above, in some embodiments, the third feature point set includes Figure 4 The first feature point 301, the second feature point 302, the third feature point 303, Figure 5 The fourth feature point 304, the fifth feature point 305 and the sixth feature point 306 in FIG.

[0161] In some embodiments, the first positioning parameter includes a first angle, a second angle, a third angle, and a first distance. The first angle represents the angle of anteversion or posterior tilt of the femoral prosthesis model relative to the femoral model, the second angle represents the angle of varus or valgus of the femoral prosthesis model relative to the femoral model, the third angle represents the angle of internal rotation or external rotation of the femoral prosthesis model relative to the femoral model, and the first distance represents the distance of protrusion or protrusion of the femoral prosthesis model relative to the femoral model.

[0162] In some embodiments, step (520.2) includes steps (520.2.1) to step (520.2.5).

[0163] (520.2.1) A normal vector of the distal surface passing through the first feature point is determined as an initial calculation vector corresponding to the first angle.

[0164] In some implementations, a unit normal vector of the distal surface A1 that passes through the first feature point 301 and whose vector direction is a direction away from the curved surface 330 is determined as an initial calculation vector corresponding to the first angle.

[0165] (520.2.2) The initial calculation vector corresponding to the first angle is determined as the initial calculation vector corresponding to the second angle.

[0166] (520.2.3) The direction vector pointing from the second feature point to the third feature point is determined as the initial calculation vector corresponding to the third angle.

[0167] (520.2.4) Draw a perpendicular line segment to the first connecting line of the fourth feature point and the fifth feature point through the sixth feature point, and determine the foot of the perpendicular line segment as the second calculation point.

[0168] like Figure 5 As shown, in some embodiments, a perpendicular line segment L5 of the first connecting line L1 between the fourth feature point 304 and the fifth feature point 305 is drawn through the sixth feature point 306 , and the foot of the perpendicular line segment L5 is determined as the second calculation point 307 .

[0169] (520.2.5) Determine the direction vector pointing from the second calculation point to the sixth feature point as the initial calculation vector corresponding to the first distance.

[0170] In some implementations, the calculation formula for the initial calculation vector corresponding to the first distance is:

[0171]

[0172] Wherein, A represents the coordinates of the fourth feature point, B represents the coordinates of the fifth feature point, P represents the coordinates of the sixth feature point, and C represents the coordinates of the second calculation point. represents the direction vector from the fourth feature point to the fifth feature point, express The normalized vector of represents the direction vector from the fourth feature point to the sixth feature point, represents the direction vector from the fourth feature point to the second calculation point, Represents the direction vector pointing from the second calculated point to the sixth feature point. That is, the initial calculation vector corresponding to the first distance.

[0173] (520.3) After the femoral prosthesis model is moved, the first pose matrix is ​​determined based on the expressions of the direction vectors of all coordinate axes of the first local coordinate system after the movement and the coordinates of the origin of the first local coordinate system after the movement.

[0174] Optionally, before moving the femoral prosthesis model, the first local coordinate system coincides with the image coordinate system. In this case, the formula of the first pose matrix is:

[0175]

[0176] Among them, T 1 represents the first pose matrix, Represents the direction vector of the X-axis of the first local coordinate system after the move in the image coordinate system. Represents the direction vector of the Y axis of the first local coordinate system after the move in the image coordinate system. Represents the direction vector of the Z axis of the first local coordinate system after the move in the image coordinate system. Represents the vector consisting of the coordinates of the origin of the first local coordinate system in the image coordinate system after the movement. express The first value of express The first value of express The first value of express , and so on.

[0177] (520.4) Multiply the first pose matrix by the initial calculation vector corresponding to each first positioning parameter to obtain the final calculation vector corresponding to each first positioning parameter.

[0178] In some embodiments, before the femoral prosthesis model is moved, the first local coordinate system coincides with the image coordinate system. In this case, the formula for calculating the final calculation vector corresponding to the first positioning parameter is:

[0179]

[0180] Among them, x 0 is the coordinate value of the initial calculated vector corresponding to the first positioning parameter on the X axis in the image coordinate system, y 0 is the coordinate value of the initial calculated vector corresponding to the first positioning parameter on the Y axis in the image coordinate system, z 0 is the coordinate value of the initial calculated vector corresponding to the first positioning parameter on the Z axis in the image coordinate system, x 0 ' is the coordinate value of the final calculated vector corresponding to the first positioning parameter in the image coordinate system on the X axis, y 0 ' is the Y-axis coordinate value of the final calculated vector corresponding to the first positioning parameter in the image coordinate system, z 0 ' is the Z-axis coordinate value of the final calculated vector corresponding to the first positioning parameter in the image coordinate system.

[0181] In some embodiments, after moving the femoral prosthesis model, the calculation vector corresponding to each first positioning parameter is determined directly based on the coordinates of the feature points in the third feature point set. The method refers to the above description of determining the initial calculation vector corresponding to each first positioning parameter based on the coordinates of the feature points in the third feature point set.

[0182] Step S530: For each first positioning parameter in the first angle, the second angle and the third angle, calculate the angle between the projection vector of the calculation vector corresponding to the first positioning parameter on the first target plane corresponding to the first positioning parameter and the first target axis direction vector corresponding to the first positioning parameter to obtain the value of each first positioning parameter.

[0183] The first target plane is the first plane, the second plane or the third plane of the third local coordinate system, and the first target axis direction vector is on the first target plane.

[0184] As described above, in some embodiments, the first plane of the third local coordinate system is also the YOZ plane of the third local coordinate system, the second plane of the third local coordinate system is also the XOZ plane of the third local coordinate system, and the third plane of the third local coordinate system is also the XOY plane of the third local coordinate system.

[0185] In some embodiments, for each first positioning parameter in the first angle, the second angle, and the third angle, the inverse matrix of the first transformation matrix is ​​multiplied on the left by the final calculation vector corresponding to the first positioning parameter, and the expression of the final calculation vector corresponding to the first positioning parameter in the third local coordinate system is obtained, and then the components of the final calculation vector corresponding to the first positioning parameter on each coordinate axis in the third local coordinate system are obtained, so as to further obtain the projection vector of the calculation vector corresponding to the first positioning parameter on the first target plane corresponding to the first positioning parameter. In this way, the amount of calculation can be reduced.

[0186] In some embodiments, the first target plane corresponding to the first angle is the YOZ plane of the third local coordinate system, and the first target axis direction vector corresponding to the first angle is the direction vector of the Z axis of the third local coordinate system.

[0187] Optionally, the calculation formula of the first angle is:

[0188]

[0189] Among them, ∠DOV represents the first angle, V y V represents the component of the projection vector of the calculated vector corresponding to the first angle on the YOZ plane of the third local coordinate system on the Y axis. z Represents the component on the Z axis of the projection vector of the calculated vector corresponding to the first angle on the YOZ plane of the third local coordinate system.

[0190] The following methods for calculating the second angle, the third angle, the fourth angle, the fifth angle and the sixth angle refer to the method for calculating the first angle and are not described in detail.

[0191] In some embodiments, the first target plane corresponding to the second angle is the XOZ plane of the third local coordinate system, and the first target axis direction vector corresponding to the second angle is the direction vector of the Z axis of the third local coordinate system.

[0192] In some embodiments, the first target plane corresponding to the third angle is the XOY plane of the third local coordinate system, and the first target axis direction vector corresponding to the third angle is the direction vector of the X axis of the third local coordinate system.

[0193] Step S540: Calculate a first set of intersections between the straight line where the calculation vector corresponding to the first distance is located and the femur model, and determine the intersection point in the first set of intersections closest to the sixth feature point in the third feature point set as the first calculation point.

[0194] Step S550: taking the magnitude of the direction vector pointing from the sixth feature point to the first calculation point as the value of the first distance.

[0195] Step S560: Determine the first position state of the femoral prosthesis model represented by each first positioning parameter relative to the femoral model according to the calculation vector corresponding to each first positioning parameter.

[0196] Among them, the first position state includes the femoral prosthesis model being tilted forward or backward relative to the femoral model, the femoral prosthesis model being varus or valgus relative to the femoral model, the femoral prosthesis model being internally rotated or externally rotated relative to the femoral model, and the femoral prosthesis model being protruded or protruded relative to the femoral model.

[0197] In some embodiments, when the femoral model is a right femoral model, when the component of the projection vector of the calculated vector corresponding to the first angle on the YOZ plane of the third local coordinate system on the Y-axis is greater than 0, the first angle indicates that the femoral prosthesis model is tilted forward relative to the femoral model, otherwise it indicates that the femoral prosthesis model is tilted backward relative to the femoral model.

[0198] In some embodiments, when the femoral model is a left femoral model, when the component of the projection vector of the calculated vector corresponding to the first angle on the YOZ plane of the third local coordinate system on the Y-axis is greater than 0, the first angle indicates that the femoral prosthesis model is tilted backward relative to the femoral model, otherwise it indicates that the femoral prosthesis model is tilted forward relative to the femoral model.

[0199] In some embodiments, when the femoral model is a right femoral model, when the component of the projection vector of the calculated vector corresponding to the second angle on the XOZ plane of the third local coordinate system on the Z-axis is greater than 0, the second angle indicates that the femoral prosthesis model is valgus relative to the femoral model, otherwise it indicates that the femoral prosthesis model is varus relative to the femoral model.

[0200] In some embodiments, when the femoral model is a left femoral model, when the component of the projection vector of the calculated vector corresponding to the second angle on the XOZ plane of the third local coordinate system on the Z-axis is greater than 0, the second angle indicates that the femoral prosthesis model is inverted relative to the femoral model, otherwise it indicates that the femoral prosthesis model is inverted relative to the femoral model.

[0201] In some embodiments, when the femoral model is a right femoral model, when the component of the projection vector of the calculated vector corresponding to the third angle on the XOY plane of the third local coordinate system on the X-axis is greater than 0, the third angle indicates that the femoral prosthesis model is internally rotated relative to the femoral model, otherwise it indicates that the femoral prosthesis model is externally rotated relative to the femoral model.

[0202] In some embodiments, when the femoral model is a left femoral model, when the component of the projection vector of the calculated vector corresponding to the third angle on the XOY plane of the third local coordinate system on the X-axis is greater than 0, the third angle indicates that the femoral prosthesis model is externally rotated relative to the femoral model, otherwise it indicates that the femoral prosthesis model is internally rotated relative to the femoral model.

[0203] In some embodiments, regardless of whether the femoral model is a left femoral model or a right femoral model, when the calculation vector corresponding to the first distance is in the same direction as the direction vector pointing from the sixth feature point to the first calculation point, the first distance indicates that the femoral prosthesis model protrudes relative to the femoral model, otherwise it indicates that the femoral prosthesis model protrudes relative to the femoral model.

[0204] Step S600: receiving a second control instruction, and moving the tibial prosthesis model to a second target position adapted to the tibial model according to the second control instruction.

[0205] During knee replacement surgery, the tibial prosthesis needs to be installed on the tibia of the target object. Therefore, when planning the knee prosthesis, the doctor moves the tibial prosthesis model to a second target position that matches the tibial model. The second target position is also the installation position of the tibial prosthesis model estimated by the doctor.

[0206] Step S700: Calculating second positioning parameters of the tibial prosthesis model according to the coordinates of the feature points in the second feature point set and the coordinates of the feature points in the fourth feature point set.

[0207] See also Fig.10 , Fig.10 yes Figure 1 The detailed flow chart of step S600 in FIG. Fig.10 As shown, in some embodiments, step S600 includes steps S610 to S660.

[0208] Step S610: Determine the fourth local coordinate system of the tibial model according to the coordinates of the feature points in the second feature point set, and determine the first plane where the direction vector of the first coordinate axis and the direction vector of the second coordinate axis of the fourth local coordinate system are located, the second plane where the direction vector of the first coordinate axis and the direction vector of the third coordinate axis of the fourth local coordinate system are located, and the third plane where the direction vector of the second coordinate axis and the direction vector of the third coordinate axis of the fourth local coordinate system are located.

[0209] In some embodiments, determining a fourth local coordinate system of the tibia model according to the coordinates of all feature points in the second feature point set includes steps (610.1) to (610.4).

[0210] (610.1) The midpoint of the line connecting the medial tibial condyle point and the lateral tibial condyle point is determined as the origin of the fourth local coordinate system.

[0211] like Figure 3 As shown, in some embodiments, the feature points in the second feature point set of the tibial model 200 include a medial tibial condyle point 201 , a lateral tibial condyle point 202 , a medial ankle point 203 , and a lateral ankle point 204 .

[0212] In some embodiments, the midpoint of the line connecting the medial tibial condyle point 201 and the lateral tibial condyle point 202 is determined as the origin of the fourth local coordinate system.

[0213] (610.2) The direction vector from the origin of the fourth local coordinate system to the midpoint of the line connecting the medial ankle point and the lateral ankle point is used as the direction vector of the first coordinate axis of the fourth local coordinate system, thereby determining the first coordinate axis of the fourth local coordinate system.

[0214] like Figure 3 As shown, in some embodiments, the direction vector from the origin of the fourth local coordinate system to the midpoint of the line connecting the medial ankle point 203 and the lateral ankle point 204 is used as the direction vector of the first coordinate axis Z4 of the fourth local coordinate system, thereby determining the first coordinate axis Z4 of the fourth local coordinate system. The first coordinate axis Z4 of the fourth local coordinate system is also the Z axis of the fourth local coordinate system.

[0215] (610.3) The direction vector from the origin of the fourth local coordinate system to the lateral tibial condyle is cross-multiplied with the direction vector from the origin of the fourth local coordinate system to the medial tibial condyle to obtain the direction vector of the second coordinate axis of the fourth local coordinate system, thereby determining the second coordinate axis of the fourth local coordinate system.

[0216] like Figure 3 As shown, in some embodiments, the direction vector from the origin of the fourth local coordinate system to the lateral tibial condyle point 202 is cross-multiplied with the direction vector from the origin of the fourth local coordinate system to the medial tibial condyle point 201 to obtain the direction vector of the second coordinate axis Y4 of the fourth local coordinate system, thereby determining the second coordinate axis Y4 of the fourth local coordinate system. The second coordinate axis Y4 of the fourth local coordinate system is also the Y axis of the fourth local coordinate system.

[0217] (610.4) The direction vector of the second coordinate axis of the fourth local coordinate system is cross-multiplied by the direction vector of the first coordinate axis of the fourth local coordinate system to obtain the direction vector of the third coordinate axis of the fourth local coordinate system, thereby determining the third coordinate axis of the fourth local coordinate system.

[0218] like Figure 3 As shown, in some embodiments, the third coordinate axis X4 of the fourth local coordinate system is also the X axis of the fourth local coordinate system.

[0219] In some embodiments, a second transformation matrix from the image coordinate system to the fourth local coordinate system is determined based on an expression of the direction vector of the first coordinate axis of the fourth local coordinate system in the image coordinate system, an expression of the direction vector of the second coordinate axis, an expression of the direction vector of the third coordinate axis, and the coordinates of the origin.

[0220] In some implementations, the formula for the second transformation matrix is:

[0221]

[0222] Among them, T 4 represents the second transformation matrix, represents the direction vector of the third coordinate axis of the fourth local coordinate system, represents the direction vector of the second coordinate axis of the fourth local coordinate system, represents the direction vector of the first coordinate axis of the fourth local coordinate system, A vector consisting of the coordinates of the origin of the fourth local coordinate system. express The first value of express The first value of express The first value of express , and so on.

[0223] In some embodiments, a first plane where the direction vector of the first coordinate axis and the direction vector of the second coordinate axis of the fourth local coordinate system are located, a second plane where the direction vector of the first coordinate axis and the direction vector of the third coordinate axis of the fourth local coordinate system are located, and a third plane where the direction vector of the second coordinate axis and the direction vector of the third coordinate axis of the fourth local coordinate system are located are determined according to the fourth local coordinate system. The first plane of the fourth local coordinate system is also the YOZ plane of the fourth local coordinate system, the second plane of the fourth local coordinate system is also the XOZ plane of the fourth local coordinate system, and the third plane of the fourth local coordinate system is also the XOY plane of the fourth local coordinate system.

[0224] Step S620: determining a calculation vector corresponding to each second positioning parameter according to the coordinates of the feature points in the fourth feature point set.

[0225] In some embodiments, step S620 includes steps (620.1) to (620.4).

[0226] (620.1) Before moving the tibial prosthesis model, determine a second local coordinate system of the tibial prosthesis model based on a fourth feature point set of the tibial prosthesis model.

[0227] In some embodiments, step (620.1) includes steps (620.1.1) to step (620.1.4).

[0228] (620.1.1) Determine the seventh feature point as the origin of the second local coordinate system.

[0229] See also Fig.11 , Fig.11 Schematic diagram of the second local coordinate system of the tibial prosthesis model provided in the embodiment of the present application. Fig.11 As shown, in some embodiments, the second local coordinate system of the tibial prosthesis model 400 includes a coordinate axis X2, a coordinate axis Y2, and a coordinate axis Z2.

[0230] like Figure 7 As shown, in some embodiments, the fourth feature point set includes a seventh feature point 401 , an eighth feature point 402 , a ninth feature point 403 , and a tenth feature point 404 .

[0231] In some implementations, the seventh feature point 401 is determined as the origin of the second local coordinate system.

[0232] (620.1.2) The direction vector pointing from the seventh feature point to the projection point of the midpoint between the ninth feature point and the tenth feature point on the lower surface is determined as the direction vector of the first coordinate axis of the second local coordinate system, thereby determining the first coordinate axis of the second local coordinate system.

[0233] The intersection point between the vertical line of the lower surface where the midpoint between the ninth feature point and the tenth feature point is located and the lower surface is taken as the projection point of the midpoint.

[0234] In some embodiments, when Figure 7 When the ninth feature point 403 and the tenth feature point 404 are at the same distance from the seventh feature point 401, the direction vector from the seventh feature point 401 to the projection point of the midpoint between the ninth feature point 403 and the tenth feature point 404 on the lower surface is determined as Fig.11The direction vector of the first coordinate axis Y2 of the second local coordinate system in the θ is used to determine the first coordinate axis Y2 of the second local coordinate system. The first coordinate axis Y2 of the second local coordinate system is also the Y axis of the second local coordinate system.

[0235] (620.1.3) A direction vector which is perpendicular to the lower surface of the tibial prosthesis model, whose starting point is the seventh feature point and whose direction is away from the lower surface is determined as the direction vector of the second coordinate axis of the second local coordinate system, thereby determining the second coordinate axis of the second local coordinate system.

[0236] In some embodiments, a direction vector which is perpendicular to the lower surface A3 of the tibial prosthesis model 400, whose vector starting point is the seventh feature point 401 and whose vector direction is away from the lower surface A3 is determined as the direction vector of the second coordinate axis Z2 of the second local coordinate system, thereby determining the second coordinate axis Z2 of the second local coordinate system. The second coordinate axis Z2 of the second local coordinate system is also the Z axis of the second local coordinate system.

[0237] (620.1.4) The direction vector of the third coordinate axis of the second local coordinate system is obtained by cross-multiplying the direction vector of the first coordinate axis of the second local coordinate system by the direction vector of the second coordinate axis of the second local coordinate system, thereby determining the third coordinate axis of the second local coordinate system.

[0238] like Fig.11 As shown, in some embodiments, the direction vector of the third coordinate axis X2 of the second local coordinate system is obtained by cross-multiplying the direction vector of the first coordinate axis Y2 of the second local coordinate system by the direction vector of the second coordinate axis Z2, thereby determining the third coordinate axis X2 of the second local coordinate system. The third coordinate axis X2 of the second local coordinate system is also the X axis of the second local coordinate system.

[0239] In some embodiments, a default initial position is set for the tibial prosthesis model 400 so that the second local coordinate system coincides with the image coordinate system, that is, the origin of the second local coordinate system coincides with the origin of the image coordinate system, the X-axis of the second local coordinate system coincides with the X-axis of the image coordinate system, the Y-axis of the second local coordinate system coincides with the Y-axis of the image coordinate system, and the Z-axis of the second local coordinate system coincides with the Z-axis of the image coordinate system.

[0240] (620.2) Determine an initial calculation vector corresponding to each second positioning parameter based on the coordinates of the feature points in the fourth feature point set.

[0241] like Figure 7 As shown, in some embodiments, the fourth feature point set includes a seventh feature point 401 , an eighth feature point 402 , a ninth feature point 403 , and a tenth feature point 404 .

[0242] In some embodiments, the second positioning parameter includes a fourth angle, a fifth angle, a sixth angle, and a second distance. The fourth angle represents the angle of the tibial prosthesis model relative to the tibial model in forward or backward tilt, the fifth angle represents the angle of the tibial prosthesis model relative to the tibial model in inversion or valgus, the sixth angle represents the angle of the tibial prosthesis model relative to the tibial model in internal rotation or external rotation, and the second distance represents the distance of the tibial prosthesis model protruding or protruding relative to the tibial model.

[0243] In some embodiments, step (620.2) includes steps (620.2.1) to (620.2.5).

[0244] (620.2.1) A normal vector of the lower surface of the tibial prosthesis model passing through the seventh feature point is determined as an initial calculation vector corresponding to the fourth angle.

[0245] In some implementations, a unit normal vector of the lower surface A3 that passes through the seventh feature point 401 and whose vector direction is away from the upper surface opposite to the lower surface A3 is determined as the initial calculation vector corresponding to the fourth angle.

[0246] (620.2.2) The calculation vector corresponding to the fourth angle is determined as the initial calculation vector corresponding to the fifth angle.

[0247] (620.2.3) The direction vector pointing from the ninth feature point to the tenth feature point is determined as the initial calculation vector corresponding to the sixth angle.

[0248] (620.2.4) Determine the initial calculation vector corresponding to the fourth angle as the initial calculation vector corresponding to the second distance.

[0249] (620.3) After moving the tibial prosthesis model, a second pose matrix is ​​determined based on the expressions of the direction vectors of all coordinate axes of the second local coordinate system of the tibial prosthesis model after the movement, the initial coordinates of the origin of the second local coordinate system, and the coordinates after the movement.

[0250] Optionally, before moving the tibial prosthesis model, the second local coordinate system coincides with the image coordinate system. In this case, the formula of the second pose matrix is:

[0251]

[0252] Among them, T 2 represents the second pose matrix, Represents the direction vector of the X-axis of the moved second local coordinate system in the image coordinate system. Represents the direction vector of the Y axis of the second local coordinate system in the image coordinate system after the movement. Represents the direction vector of the Z axis of the second local coordinate system in the image coordinate system after the movement. Represents the vector formed by the coordinates of the origin of the second local coordinate system in the image coordinate system after the movement. express The first value of express The first value of express The first value of express , and so on.

[0253] (620.4) Multiply the second posture matrix by the initial calculation vector corresponding to each second positioning parameter to obtain the final calculation vector corresponding to each second positioning parameter.

[0254] In some embodiments, before the tibial prosthesis model is moved, the second local coordinate system coincides with the image coordinate system. In this case, the method for calculating the final calculation vector corresponding to the second positioning parameter refers to the method for calculating the final calculation vector corresponding to the first positioning parameter.

[0255] In some embodiments, after moving the tibial prosthesis model, the calculation vector corresponding to each second positioning parameter is determined directly based on the coordinates of the feature points in the fourth feature point set, and the method refers to the above description of determining the initial calculation vector corresponding to each second positioning parameter based on the coordinates of the feature points in the fourth feature point set.

[0256] Step S630: For each second positioning parameter in the fourth angle, the fifth angle and the sixth angle, calculate the angle between the projection vector of the calculation vector corresponding to the second positioning parameter on the second target plane corresponding to the second positioning parameter and the second target axis direction vector corresponding to the second positioning parameter to obtain the value of each second positioning parameter.

[0257] The second target plane is the first plane, the second plane or the third plane of the fourth local coordinate system, and the second target axis direction vector is on the second target plane.

[0258] As described above, in some embodiments, the first plane of the fourth local coordinate system is also the YOZ plane of the fourth local coordinate system, the second plane of the fourth local coordinate system is also the XOZ plane of the fourth local coordinate system, and the third plane of the fourth local coordinate system is also the XOY plane of the fourth local coordinate system.

[0259] In some embodiments, for each second positioning parameter in the fourth angle, the fifth angle, and the sixth angle, the inverse matrix of the second transformation matrix is ​​left-multiplied by the final calculation vector corresponding to the second positioning parameter to obtain an expression of the final calculation vector corresponding to the second positioning parameter in the fourth local coordinate system, and then the components of the final calculation vector corresponding to the second positioning parameter on each coordinate axis in the fourth local coordinate system are obtained, thereby further obtaining the projection vector of the calculation vector corresponding to the second positioning parameter on the second target plane corresponding to the second positioning parameter. In this way, the amount of calculation can be reduced.

[0260] In some embodiments, the second target plane corresponding to the fourth angle is the YOZ plane of the fourth local coordinate system, and the second target axis direction vector corresponding to the second angle is the direction vector of the Z axis of the fourth local coordinate system.

[0261] In some embodiments, the second target plane corresponding to the fifth angle is the XOZ plane of the fourth local coordinate system, and the second target axis direction vector corresponding to the second angle is the direction vector of the Z axis of the fourth local coordinate system.

[0262] In some embodiments, the second target plane corresponding to the sixth angle is the XOY plane of the fourth local coordinate system, and the second target axis direction vector corresponding to the sixth angle is the direction vector of the X axis of the fourth local coordinate system.

[0263] Step S640: Calculate a second intersection point set between the straight line where the calculation vector corresponding to the second distance is located and the tibia model, and determine the intersection point in the second intersection point set closest to the eighth feature point in the fourth feature point set as the third calculation point.

[0264] Step S650: taking the magnitude of the direction vector pointing from the third calculation point to the eighth feature point as the value of the second distance.

[0265] Step S660: Determine the second position state of the tibial prosthesis model represented by each second positioning parameter relative to the tibial model according to the calculation vector corresponding to each second positioning parameter.

[0266] Among them, the second position state includes the tibial prosthesis model leaning forward or backward relative to the tibial model, the tibial prosthesis model being inverted or everted relative to the tibial model, the tibial prosthesis model being internally rotated or externally rotated relative to the tibial model, and the tibial prosthesis model being protruded or protruded relative to the tibial model.

[0267] In some embodiments, when the tibial model is a right tibial model, when the component of the projection vector of the calculated vector corresponding to the fourth angle on the YOZ plane of the fourth local coordinate system on the Z-axis is greater than 0, the fourth angle indicates that the tibial prosthesis model is tilted forward relative to the tibial model, otherwise it indicates that the tibial prosthesis model is tilted backward relative to the tibial model.

[0268] In some embodiments, when the tibial model is a left tibial model, when the component of the projection vector of the calculated vector corresponding to the fourth angle on the YOZ plane of the fourth local coordinate system on the Z-axis is greater than 0, the fourth angle indicates that the tibial prosthesis model is tilted posteriorly relative to the tibial model, otherwise it indicates that the tibial prosthesis model is tilted anteriorly relative to the tibial model.

[0269] In some embodiments, when the tibial model is a right tibial model, when the component of the projection vector of the calculated vector corresponding to the fifth angle on the XOZ plane of the fourth local coordinate system on the Z-axis is greater than 0, the fifth angle indicates that the tibial prosthesis model is everted relative to the tibial model, otherwise it indicates that the tibial prosthesis model is everted relative to the tibial model.

[0270] In some embodiments, when the tibial model is a left tibial model, when the component of the projection vector of the calculated vector corresponding to the fifth angle on the XOZ plane of the fourth local coordinate system on the Z-axis is greater than 0, the fifth angle indicates that the tibial prosthesis model is inverted relative to the tibial model, otherwise it indicates that the tibial prosthesis model is everted relative to the tibial model.

[0271] In some embodiments, when the tibial model is a right tibial model, when the component of the projection vector of the calculated vector corresponding to the sixth angle on the XOY plane of the fourth local coordinate system on the X-axis is greater than 0, the sixth angle indicates that the tibial prosthesis model is internally rotated relative to the tibial model, otherwise it indicates that the tibial prosthesis model is externally rotated relative to the tibial model.

[0272] In some embodiments, when the tibial model is a left tibial model, when the component of the projection vector of the calculated vector corresponding to the sixth angle on the XOY plane of the fourth local coordinate system on the X-axis is greater than 0, the sixth angle indicates that the tibial prosthesis model is externally rotated relative to the tibial model, otherwise it indicates that the tibial prosthesis model is internally rotated relative to the tibial model.

[0273] In some embodiments, regardless of whether the tibial model is a left tibial model or a right tibial model, when the calculated vector corresponding to the second distance has the same direction as the calculated vector corresponding to the first distance, the first distance indicates that the tibial prosthesis model protrudes relative to the tibial model, otherwise it indicates that the tibial prosthesis model protrudes relative to the tibial model.

[0274] In summary, the method for calculating model positioning parameters in knee prosthesis planning provided by the embodiment of the present application has the following advantages:

[0275] 1. By calculating the first positioning parameters of the femoral prosthesis model according to the coordinates of the feature points in the first feature point set and the coordinates of the feature points in the third feature point set, and calculating the second positioning parameters of the tibial prosthesis model according to the coordinates of the feature points in the second feature point set and the coordinates of the feature points in the fourth feature point set, the positioning parameters of the prosthesis model can be accurately obtained during preoperative planning, which is convenient for doctors to judge whether the current preoperative planning is reasonable, thereby providing accurate reference for doctors performing knee replacement surgery and improving the accuracy of the surgery.

[0276] 2. By converting the expression of the calculation vector corresponding to the positioning parameter into the local coordinate system, it is easy to calculate the projection vector of the calculation vector corresponding to the positioning parameter on the target plane, and it is easy to calculate the angle between the projection vector and the target axis direction vector, thereby reducing the amount of calculation.

[0277] See also Fig.12 , Fig.12 Schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Fig.12 As shown, the electronic device 600 includes: one or more processors 610 and a memory 620, Fig.12 A processor 610 is taken as an example.

[0278] In some implementations, the processor 610 and the memory 620 may be connected via a bus or other means. Fig.12 The example of connecting through bus is taken in the following.

[0279] In some embodiments, the processor 610 is used to obtain a femoral model, a first feature point set of the femoral model, a tibial model, a second feature point set of the tibial model, a femoral prosthesis model, and a tibial prosthesis model; determine a third feature point set of the femoral prosthesis model based on the femoral prosthesis model; determine a fourth feature point set of the tibial prosthesis model based on the tibial prosthesis model; receive a first control instruction, and move the femoral prosthesis model to a first target position that matches the femoral model according to the first control instruction; calculate a first positioning parameter of the femoral prosthesis model according to the coordinates of the feature points in the first feature point set and the coordinates of the feature points in the third feature point set; receive a second control instruction, and move the tibial prosthesis model to a second target position that matches the tibial model according to the second control instruction; calculate a second positioning parameter of the tibial prosthesis model according to the coordinates of the feature points in the second feature point set and the coordinates of the feature points in the fourth feature point set.

[0280] In some embodiments, the memory 620, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer executable programs and modules, such as the program instructions / modules of the method for calculating the positioning parameters of the model in the knee prosthesis planning in the embodiment of the present application. The processor 610 executes various functional applications and data processing of the electronic device 600 by running the non-volatile software programs, instructions and modules stored in the memory 620, that is, the method for calculating the positioning parameters of the model in the knee prosthesis planning in the above method embodiment is implemented.

[0281] In some embodiments, the memory 620 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created according to the use of the electronic device 600, etc. In addition, the memory 620 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 620 may optionally include a memory remotely arranged relative to the processor 610, and these remote memories may be connected to the controller via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0282] In some embodiments, one or more modules are stored in the memory 620, and when executed by one or more processors 610, the calculation method of the model positioning parameters in the knee prosthesis planning in any of the above method embodiments is executed, for example, the calculation method described above is executed. Figure 1 The method comprises steps S100 to S700.

[0283] Please refer to Fig.13 , Fig.13 The computer-readable storage medium 700 stores a program code 710, which can be called by a processor to execute the method for calculating the model positioning parameters in the knee joint prosthesis planning described in the above method embodiment.

[0284] The computer-readable storage medium 700 can be an electronic memory such as a flash memory, an EEPROM (electrically erasable programmable read-only memory), an EPROM, a hard disk or a ROM. Optionally, the computer-readable storage medium includes a non-volatile computer-readable medium (non transitory computer readable storage medium). The computer-readable storage medium 700 has a storage space for program codes of any method steps in the calculation method of model positioning parameters in the above-mentioned knee prosthesis planning. These program codes can be read from or written into one or more computer program products. The program code can be compressed, for example, in an appropriate form.

[0285] In summary, the present application provides a method for calculating model positioning parameters in knee prosthesis planning, an electronic device and a storage medium. The method for calculating model positioning parameters in knee prosthesis planning includes obtaining a femoral model, a first feature point set of the femoral model, a tibial model, a second feature point set of the tibial model, a femoral prosthesis model and a tibial prosthesis model; determining a third feature point set of the femoral prosthesis model based on the femoral prosthesis model; determining a fourth feature point set of the tibial prosthesis model based on the tibial prosthesis model; receiving a first control instruction, and moving the femoral prosthesis model to a first target position that matches the femoral model according to the first control instruction; calculating the first positioning parameters of the femoral prosthesis model according to the coordinates of the feature points in the first feature point set and the coordinates of the feature points in the third feature point set; receiving a second control instruction, and moving the tibial prosthesis model to a second target position that matches the tibial model according to the second control instruction; and calculating the second positioning parameters of the tibial prosthesis model according to the coordinates of the feature points in the second feature point set and the coordinates of the feature points in the fourth feature point set. The present application calculates the first positioning parameters of the femoral prosthesis model according to the coordinates of the feature points in the first feature point set and the coordinates of the feature points in the third feature point set, and calculates the second positioning parameters of the tibial prosthesis model according to the coordinates of the feature points in the second feature point set and the coordinates of the feature points in the fourth feature point set. By accurately obtaining the positioning parameters of the prosthesis model during preoperative planning, the doctor can judge whether the current preoperative planning is reasonable, thereby providing an accurate reference for the doctor to perform knee replacement surgery and improving the accuracy of the surgery.

[0286] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for calculating model positioning parameters in knee prosthesis planning, characterized in that: include: Acquire a femur model, a first feature point set of the femur model, a tibia model, a second feature point set of the tibia model, a femur prosthesis model, and a tibia prosthesis model; Determine a third feature point set of the femoral prosthesis model based on the femoral prosthesis model; Determining a fourth feature point set of the tibial prosthesis model based on the tibial prosthesis model; receiving a first control instruction, and moving the femoral prosthesis model to a first target position adapted to the femoral model according to the first control instruction; Calculating first positioning parameters of the femoral prosthesis model according to the coordinates of the feature points in the first feature point set and the coordinates of the feature points in the third feature point set; receiving a second control instruction, and moving the tibial prosthesis model to a second target position adapted to the tibial model according to the second control instruction; The second positioning parameters of the tibial prosthesis model are calculated according to the coordinates of the feature points in the second feature point set and the coordinates of the feature points in the fourth feature point set.

2. The method for calculating model positioning parameters in knee joint prosthesis planning according to claim 1, characterized in that: The step of determining a third feature point set of the femoral prosthesis model based on the femoral prosthesis model comprises: Selecting a point on the plane where the distal end surface of the femoral prosthesis model is located as the first feature point; Determine two end points of the intersection line segment of the posterior inclined surface and the distal surface of the femoral prosthesis model as the second characteristic point and the third characteristic point respectively; The bottom center of the first protrusion of the femoral prosthesis model is determined as a fourth feature point, and the bottom center of the second protrusion of the femoral prosthesis model is determined as a fifth feature point; The first connecting line between the fourth feature point and the fifth feature point is translated in a plane perpendicular to the posterior inclined plane where the first connecting line is located so that the translated first connecting line is tangent to the curved surface of the femoral prosthesis model, and a tangent point where the translated first connecting line is tangent to the curved surface is determined as a sixth feature point; Determine a third feature point set including the first feature point, the second feature point, the third feature point, the fourth feature point, the fifth feature point and the sixth feature point; The step of determining a fourth feature point set of the tibial prosthesis model based on the tibial prosthesis model comprises: Determine the center of the bottom surface of the first protrusion of the tibial prosthesis model located on the lower surface of the tibial prosthesis model as the seventh feature point; A point whose distance from the seventh feature point is equal to the thickness of the tibial prosthesis model, which is far away from the lower surface of the tibial prosthesis model and whose line connecting the seventh feature point and the lower surface is perpendicular to the lower surface is determined as an eighth feature point; Select two points on the horizontal line of the rear end surface of the tibial prosthesis model and determine them as the ninth feature point and the tenth feature point respectively; A fourth feature point set including the seventh feature point, the eighth feature point, the ninth feature point and the tenth feature point is determined.

3. The method for calculating model positioning parameters in knee joint prosthesis planning according to claim 1 or 2, characterized in that: The first positioning parameter includes a first angle, a second angle, a third angle and a first distance, wherein the first angle represents an angle of anteversion or posterior tilt of the femoral prosthesis model relative to the femoral model, the second angle represents an angle of varus or valgus of the femoral prosthesis model relative to the femoral model, the third angle represents an angle of internal rotation or external rotation of the femoral prosthesis model relative to the femoral model, and the first distance represents a distance by which the femoral prosthesis model protrudes into or out of the femoral model. The first positioning parameter of the femoral prosthesis model is calculated according to the coordinates of the feature points in the first feature point set and the coordinates of the feature points in the third feature point set, including: Determine a third local coordinate system of the femur model according to the coordinates of the feature points in the first feature point set, and determine a first plane where the direction vector of the first coordinate axis and the direction vector of the second coordinate axis of the third local coordinate system are located, a second plane where the direction vector of the first coordinate axis and the direction vector of the third coordinate axis of the third local coordinate system are located, and a third plane where the direction vector of the second coordinate axis and the direction vector of the third coordinate axis of the third local coordinate system are located according to the third local coordinate system; Determine a calculation vector corresponding to each of the first positioning parameters according to the coordinates of the feature points in the third feature point set; For each first positioning parameter among the first angle, the second angle and the third angle, calculate the angle between the projection vector of the calculation vector corresponding to the first positioning parameter on the first target plane corresponding to the first positioning parameter and the first target axis direction vector corresponding to the first positioning parameter, to obtain the value of each first positioning parameter, wherein the first target plane is the first plane, the second plane or the third plane of the third local coordinate system, and the first target axis direction vector is on the first target plane; Calculate a first intersection point set between a straight line where a calculation vector corresponding to the first distance is located and the femur model, and determine an intersection point in the first intersection point set that is closest to a sixth feature point in the third feature point set as a first calculation point; taking the magnitude of the direction vector pointing from the sixth feature point to the first calculation point as the value of the first distance; The first position state of the femoral prosthesis model relative to the femoral model represented by each of the first positioning parameters is determined according to the calculation vector corresponding to each of the first positioning parameters, wherein the first position state includes the anterior tilt or posterior tilt of the femoral prosthesis model relative to the femoral model, the varus or valgus of the femoral prosthesis model relative to the femoral model, the internal rotation or external rotation of the femoral prosthesis model relative to the femoral model, and the protrusion or protrusion of the femoral prosthesis model relative to the femoral model.

4. The method for calculating model positioning parameters in knee joint prosthesis planning according to claim 3, characterized in that: The determining, according to the coordinates of the feature points in the third feature point set, a calculation vector corresponding to each of the first positioning parameters comprises: Before moving the femoral prosthesis model, determining a first local coordinate system of the femoral prosthesis model based on a third feature point set of the femoral prosthesis model; Determine an initial calculation vector corresponding to each first positioning parameter based on the coordinates of the feature points in the third feature point set; After moving the femoral prosthesis model, determining a first pose matrix based on expressions of direction vectors of all coordinate axes of the first local coordinate system after movement and coordinates of the origin of the first local coordinate system after movement; Multiply the first posture matrix on the left by the initial calculation vector corresponding to each of the first positioning parameters to obtain a final calculation vector corresponding to each of the first positioning parameters.

5. The method for calculating model positioning parameters in knee joint prosthesis planning according to claim 4, characterized in that: The third feature point set includes a first feature point, a second feature point, a third feature point, a fourth feature point, a fifth feature point and a sixth feature point, and determining an initial calculation vector corresponding to each first positioning parameter based on the coordinates of the feature points in the third feature point set includes: Determine a normal vector of a distal surface passing through the first feature point as an initial calculation vector corresponding to the first angle; Determining an initial calculation vector corresponding to the first angle as an initial calculation vector corresponding to the second angle; Determine a direction vector pointing from the second feature point to the third feature point as an initial calculation vector corresponding to the third angle; Draw a perpendicular line segment through the sixth feature point to the first connecting line of the fourth feature point and the fifth feature point, and determine the foot of the perpendicular line segment as the second calculation point; A direction vector pointing from the second calculation point to the sixth feature point is determined as an initial calculation vector corresponding to the first distance.

6. The method for calculating model positioning parameters in knee joint prosthesis planning according to claim 1 or 2, characterized in that: The second positioning parameters include a fourth angle, a fifth angle, a sixth angle and a second distance, the fourth angle represents an angle of anterior tilt or posterior tilt of the tibial prosthesis model relative to the tibial model, the fifth angle represents an angle of varus or valgus of the tibial prosthesis model relative to the tibial model, the sixth angle represents an angle of internal rotation or external rotation of the tibial prosthesis model relative to the tibial model, the second distance represents a distance of protrusion or projection of the tibial prosthesis model relative to the tibial model, and the second positioning parameters of the tibial prosthesis model are calculated according to the coordinates of the feature points in the second feature point set and the coordinates of the feature points in the fourth feature point set, including: Determine a fourth local coordinate system of the tibia model according to the coordinates of the feature points in the second feature point set, and determine a first plane where the direction vector of the first coordinate axis and the direction vector of the second coordinate axis of the fourth local coordinate system are located, a second plane where the direction vector of the first coordinate axis and the direction vector of the third coordinate axis of the fourth local coordinate system are located, and a third plane where the direction vector of the second coordinate axis and the direction vector of the third coordinate axis of the fourth local coordinate system are located according to the fourth local coordinate system; Determine a calculation vector corresponding to each of the second positioning parameters according to the coordinates of the feature points in the fourth feature point set; For each second positioning parameter among the fourth angle, the fifth angle and the sixth angle, calculate the angle between the projection vector of the calculation vector corresponding to the second positioning parameter on the second target plane corresponding to the second positioning parameter and the second target axis direction vector corresponding to the second positioning parameter, to obtain the value of each second positioning parameter, wherein the second target plane is the first plane, the second plane or the third plane of the fourth local coordinate system, and the second target axis direction vector is on the second target plane; Calculate a second intersection point set between the straight line where the calculation vector corresponding to the second distance is located and the tibia model, and determine the intersection point in the second intersection point set that is closest to the eighth feature point in the fourth feature point set as a third calculation point; taking the magnitude of the direction vector pointing from the third calculation point to the eighth feature point as the value of the second distance; The second position state of the tibial prosthesis model relative to the tibial model represented by each of the second positioning parameters is determined according to the calculation vector corresponding to each of the second positioning parameters, wherein the second position state includes the tibial prosthesis model being tilted forward or backward relative to the tibial model, the tibial prosthesis model being varus or valgus relative to the tibial model, the tibial prosthesis model being internally rotated or externally rotated relative to the tibial model, and the tibial prosthesis model being protruded in or out relative to the tibial model.

7. The method for calculating model positioning parameters in knee joint prosthesis planning according to claim 6, characterized in that: The determining, according to the coordinates of the feature points in the fourth feature point set, a calculation vector corresponding to each of the second positioning parameters comprises: Before moving the tibial prosthesis model, determining a second local coordinate system of the tibial prosthesis model based on a fourth feature point set of the tibial prosthesis model; Determine an initial calculation vector corresponding to each second positioning parameter based on the coordinates of the feature points in the fourth feature point set; After moving the tibial prosthesis model, determining a second pose matrix based on expressions of direction vectors of all coordinate axes of a second local coordinate system of the tibial prosthesis model after movement and coordinates of the origin of the second local coordinate system after movement; Multiply the second posture matrix on the left by the initial calculation vector corresponding to each of the second positioning parameters to obtain a final calculation vector corresponding to each of the second positioning parameters.

8. The method for calculating model positioning parameters in knee joint prosthesis planning according to claim 7, characterized in that: The fourth feature point set includes a seventh feature point, an eighth feature point, a ninth feature point and a tenth feature point, and determining an initial calculation vector corresponding to each second positioning parameter based on the coordinates of the feature points in the fourth feature point set includes: Determine a normal vector of the lower surface of the tibial prosthesis model passing through the seventh feature point as an initial calculation vector corresponding to the fourth angle; Determine the calculation vector corresponding to the fourth angle as the initial calculation vector corresponding to the fifth angle; Determine a direction vector pointing from the ninth feature point to the tenth feature point as an initial calculation vector corresponding to the sixth angle; The calculation vector corresponding to the fourth angle is determined as an initial calculation vector corresponding to the second distance.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method for calculating model positioning parameters in knee prosthesis planning as described in any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores an executable program, and the executable program is executed by a processor to implement the method for calculating model positioning parameters in knee prosthesis planning as described in any one of claims 1 to 8.

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