Pelvic bone and femur bone setting evaluation method and system for total hip replacement

Abstract

The invention discloses a pelvic bone and femur bonesetting evaluation method and system for total hip replacement, which provides accurate quantitative calculation of physiological parameters such as hip length difference and eccentricity difference before and after an operation, establishes a unified numerical evaluation standard, replaces traditional qualitative judgment depending on doctor experience, visually displays the improvement degree of an operation effect through difference analysis, and improves the accuracy of bone setting. The reduction precision of an anatomical structure is ensured based on three-dimensional reconstruction of a CT coordinate system, submillimeter-level positioning of a femoral head center point is realized through a least square fitting algorithm, the error of a local coordinate system established through a vector cross method is smaller than 0.5, the operation repeatability and the bonesetting matrix calculation process are ensured through a unified landmark registration method (four-point registration), manual operation differences are reduced, and the precision of bone setting is improved. The mirror image operation design ensures the consistency of bilateral femur treatment, and the evaluation of preoperative planning and postoperative verification is realized.

Description

Technical Field

[0001] The present invention relates to the field of medical imaging, and in particular to a method and system for evaluating pelvic and femoral bone alignment in total hip replacement. Background Art

[0002] The total hip surgical robot uses a high-precision robotic arm and surgical navigation system to achieve precise hip replacement, reduce surgical complications, lower surgical risks, and accelerate postoperative recovery. The original plan made it difficult to formulate a precise surgical plan because the patient's soft tissue condition was unclear, and the preoperative and postoperative effects mostly relied on the doctor's experience and qualitative analysis, lacking quantitative evaluation standards as a reference.

[0003] In summary, a method and system for evaluating the pelvic and femoral bone alignment for total hip replacement is needed to address the deficiencies in the existing technology. Summary of the Invention

[0004] In view of the deficiencies of the existing technology, the present invention provides a method and system for evaluating the pelvic and femoral bone setting for total hip replacement, aiming to solve the above problems.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for evaluating pelvic and femoral bone setting for total hip replacement, comprising the following steps:

[0006] Step S1: Preoperative reconstruction: perform three-dimensional reconstruction on the preoperative CT of the pelvis and femur to obtain a three-dimensional reconstruction model;

[0007] Step S2: Physiological point annotation: annotate the anterior superior iliac spines on both sides of the pelvis and the pelvic center in the 3D reconstructed model, marking the anterior superior iliac spines on both sides as L and R and the pelvic center P. Annotate the femoral head center point, the proximal end point of the femoral mechanical axis, and the distal end point of the femoral mechanical axis in the 3D reconstructed model, marking them as the femoral head center point C, the proximal end point of the femoral mechanical axis E, and the distal end point of the femoral mechanical axis D.

[0008] Step S3: In the CT coordinate system, a local coordinate system is established with the anterior superior iliac spines on both sides and the center point of the pelvis, with P as the origin of the local coordinate system, the line connecting RL as the local coordinate system X-axis, the axis perpendicular to the LRP plane and in the same direction as the positive direction of the CT coordinate system Y-axis as the local coordinate system Y-axis, and the local coordinate axis Z in the same direction as the positive direction of the CT coordinate system Z-axis is solved to establish the pelvic local coordinate system;

[0009] Step S4: Landmark registration is performed between four non-coplanar points in the local coordinate system and four coplanar points in the CT coordinate system to obtain a registration matrix R. The x-coordinate, y-coordinate, and z-coordinate of P are entered into the R matrix to obtain a pelvic bone alignment matrix. The pelvic bone alignment matrix is ​​applied to the pelvic CT scan, bilateral femoral CT scans, pelvic models, and bilateral femoral models.

[0010] Step S5: using a fitting ball algorithm to collect and connect the center points of the proximal and distal femurs, and fitting the center points of the femoral heads of the femoral models on both sides;

[0011] Step S6: In the CT coordinate system, a local coordinate system is established with the center point C of the left femoral head, the proximal end point E of the left femoral mechanical axis, and the distal end point D of the femoral mechanical axis. C is used as the origin of the local coordinate system, the line connecting DP is used as the local coordinate system Z axis, the axis perpendicular to the CDE plane and in the same direction as the positive direction of the CT coordinate system Y axis is used as the local coordinate system Y axis, and the local coordinate axis X in the same direction as the positive direction of the CT coordinate system X axis is solved to establish the femoral local coordinate system;

[0012] Step S7: Select four non-coplanar points in the local coordinate system and perform landmark registration with the four coplanar points in the CT coordinate system to obtain the registration matrix R. Fill the x-coordinate, y-coordinate, and z-coordinate of C into the R matrix to obtain the left femur bone matrix. The same is true for the right side. Mirror the left femur CT and left femur model and apply the left femur bone matrix. Apply the right femur CT and right femur model and apply the right femur bone matrix.

[0013] Step S8: After the pelvis and femur are adjusted, the corresponding hip length and eccentricity are calculated to evaluate the adjustment results.

[0014] Optionally, in step S3, the local coordinate axis Z that is in the same direction as the positive direction of the Z axis of the CT coordinate system is solved by the following method:

[0015] With P as the origin of the local coordinate system and the line RL as the X-axis of the local coordinate system, it is written as , the axis perpendicular to the LRP plane and in the same direction as the positive direction of the Y axis of the CT coordinate system is the local coordinate system Y axis, denoted as , let vector PL be , The solution formula for the axis is: = .cross( ), cross is the cross product, the vector cross product is the normal vector, remember the Z axis direction of the local coordinate system , The solution formula for the axis is: = .cross( ).

[0016] Optionally, the landmark registration in steps S4 and S7 is performed in the following manner:

[0017] Select the origin of the local coordinate system and three points on the three coordinate axes with a positive direction and a unit length of 1, a total of four points, recorded as , , , , record the coordinates of the four points in the CT coordinate system as , , , ;

[0018] Select four points in the CT coordinate system, the coordinates are ( , , ),( +1, , ),( , +1, ),( , , +1), denoted as,o,x,y,z;

[0019] remember , , , is the source point set, o, x, y, z is the target point set, and the VTK operation library is used for landmark registration to obtain the registration matrix R.

[0020] Optionally, in step S4, the x-coordinate, y-coordinate, and z-coordinate of P are filled into the R matrix in the following manner:

[0021] Fill the x-coordinate, y-coordinate, and z-coordinate of P into R[0,3], R[1,3], and R[2,3] of the R matrix.

[0022] Optionally, the ball fitting algorithm in step S5 is:

[0023] Assume the equation of the space sphere is: (xa) 2 + (yb) 2 + (zc) 2 =R 2 ,

[0024] Expand to get: x 2 +y 2 +z 2 -2ax-2by-2zc+a 2 +b 2 +c 2 =R 2 ,

[0025] Let D = a 2 +b 2 +c 2 -R 2 ,

[0026] Then x 2 +y 2 +z 2 -Ax-By-Cz+D=0,

[0027] Using the matrix method we get:

[0028] ,

[0029] Multiply both sides by the left get;

[0030] ;

[0031] The solution is:

[0032] ;

[0033] The equation parameters of the ball are obtained as follows: .

[0034] Optionally, in step S6, the local coordinate axis X that is in the same direction as the positive direction of the X axis of the CT coordinate system is solved by the following method:

[0035] With C as the origin of the local coordinate system, the line connecting DE is the z-axis of the local coordinate system, which is expressed as , the axis perpendicular to the CDE plane and in the same direction as the positive direction of the Y axis of the CT coordinate system is the local coordinate system Y axis, denoted as , let vector CE be , The solution formula for the axis is: = .cross( ), cross is the cross product, use the vector cross product to find the normal vector, remember the Z axis direction of the local coordinate system , The solution formula for the axis is: = .cross( ).

[0036] Optionally, the hip length and eccentricity in step S8 are calculated in the following manner:

[0037] Hip length is the distance from the ASIS axis to the lesser trochanter of the femur, hl = b z -c z ;

[0038] Eccentricity is the distance from the mid-axis to the femoral axis, Co = α x -β x ;

[0039] Optionally, the bone setting result is evaluated in step S8 by:

[0040] The pelvic assessment is based on the following criteria: whether the line connecting the two points L and R on the anterior superior iliac spines on both sides is parallel to the X-axis of the pelvic local coordinate system, and whether the plane PLR ​​is perpendicular to the Y-axis of the pelvic local coordinate system;

[0041] The evaluation of the femur is based on whether the line DE is parallel to the Z axis of the pelvic local coordinate system and whether the plane CDE is perpendicular to the Y axis of the pelvic local coordinate system.

[0042] A pelvic and femoral bone setting assessment system for total hip replacement adopts a pelvic and femoral bone setting assessment method for total hip replacement, including: a bone model import module, a physiological point annotation module, a coordinate system establishment module, a landmark registration module, a femoral fitting module, and a parameter calculation and evaluation module;

[0043] A bone model import module is used to import CT images of the pelvis, left femur, and right femur in the CT coordinate system, perform three-dimensional reconstruction, and mark them as the pelvic part, left femur part, and right femur part;

[0044] Physiological point marking module, used to mark the two points of the anterior superior iliac spine on both sides of the pelvis and the pelvic center point (P), as well as the femoral head center point, the proximal end point of the mechanical axis, and the distal end point of the mechanical axis;

[0045] A coordinate system establishment module is used to establish the pelvic local coordinate system and the femur local coordinate system, and perform coordinate system conversion calculations;

[0046] Landmark registration module, used to calculate the registration matrix using the Landmark registration algorithm and generate the bone matrix;

[0047] Femoral fitting module, used for femoral head surface acquisition, adopts the least squares sphere fitting algorithm to calculate the center point, acquire the proximal and distal center points of the femur, and perform mechanical axis fitting;

[0048] The parameter calculation and evaluation module is used to evaluate the pelvis and femur of the osteopathic results.

[0049] Beneficial effects of the present invention:

[0050] 1. The present invention provides accurate quantitative calculation of physiological parameters such as preoperative and postoperative hip length difference and eccentricity difference, establishes a unified numerical evaluation standard, replaces the traditional qualitative judgment that relies on the doctor's experience, and intuitively displays the degree of improvement in surgical results through difference analysis.

[0051] 2. In the present invention, three-dimensional reconstruction based on the CT coordinate system ensures the accuracy of anatomical structure restoration, the least squares fitting algorithm achieves submillimeter positioning of the femoral head center point, and the local coordinate system established by the vector cross multiplication method has a small error.

[0052] 3. In the present invention, a unified landmark registration method (four-point registration) ensures the repeatability of the operation, the orthopedic matrix calculation process is streamlined, reducing the differences in human operations, and the mirror operation design ensures the consistency of bilateral femoral treatment, realizing the evaluation of preoperative planning and postoperative verification. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 The present invention is a flow chart of a method.

[0054] Figure 2 This is a pelvic physiological point marking diagram of the present invention.

[0055] Figure 3 This is a local coordinate system diagram of the pelvis of the present invention.

[0056] Figure 4 This is a method of selecting surface points and fitting a center point graph.

[0057] Figure 5 This is a femoral physiological point marking diagram of the present invention.

[0058] Figure 6 This is a local coordinate system diagram of the femur of the present invention.

[0059] Figure 7 This is a schematic diagram of hip length calculation according to the present invention.

[0060] Figure 8 This is a schematic diagram of eccentricity calculation according to the present invention. DETAILED DESCRIPTION

[0061] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0062] like Figures 1 to 8 As shown, a method for evaluating pelvic and femoral bone alignment for total hip replacement includes step S1: preoperative reconstruction, performing three-dimensional reconstruction on preoperative CT scans of the pelvis and femur to obtain a three-dimensional reconstruction model marked as a pelvic part, a left femoral part, and a right femoral part;

[0063] Step S2: Physiological point annotation: annotate the anterior superior iliac spines on both sides of the pelvis and the pelvic center in the 3D reconstructed model, marking the anterior superior iliac spines on both sides as L and R and the pelvic center P. Annotate the femoral head center point, the proximal end point of the femoral mechanical axis, and the distal end point of the femoral mechanical axis in the 3D reconstructed model, marking them as the femoral head center point C, the proximal end point of the femoral mechanical axis E, and the distal end point of the femoral mechanical axis D.

[0064] Step S3: In the CT coordinate system, establish a local coordinate system before rotation based on the anterior superior iliac spines on both sides and the center of the pelvis, with P as the origin of the local coordinate system and the line connecting RL as the X axis of the local coordinate system, denoted as , the axis perpendicular to the LRP plane and in the same direction as the positive direction of the Y axis of the CT coordinate system is the local coordinate system Y axis, denoted as , let vector PL be , The solution formula for the axis is: = .cross( ), cross is the cross product. The principle used is to find the normal vector by vector cross product, and the Z axis direction of the local coordinate system is recorded. , The solution formula for the axis is: = .cross( ), solve the local coordinate system Z axis which is in the same direction as the positive direction of the CT coordinate system Z axis, and take P as the origin. , , , respectively as the X-axis, Y-axis, and Z-axis to establish the local coordinate system of the pelvis before rotation;

[0065] Step S4: Select four non-coplanar points in the local coordinate system and perform landmark registration with the four co-coordinate points in the CT coordinate system.

[0066] Select the origin of the local coordinate system and three points on the three coordinate axes with a positive direction and a unit length of 1, a total of four points, recorded as , , , , record the coordinates of the four points in the CT coordinate system as , , , .

[0067] Select four points in the CT coordinate system, the coordinates are ( , , ),( +1, , ),( , +1, ),( , , +1), denoted as,o,x,y,z;

[0068] remember , , , The source point set and o, x, y, z are the target point set for landmark registration. The specific process of the classic algorithm is not involved in this patent and will not be described in detail. The operation library in VTK is used to obtain the registration matrix R. The x-coordinate, y-coordinate and z-coordinate of P are filled into R[0,3], R[1,3] and R[2,3] of the R matrix. The filled matrix is ​​the pelvic bone matrix. This matrix is ​​applied to the pelvic model and the femoral models on both sides.

[0069] Step S5: using a fitting ball algorithm to collect and connect the center points of the proximal and distal femurs, and fitting the center points of the femoral heads of the femoral models on both sides;

[0070] Algorithm for fitting multiple points into a sphere: the least squares method is used:

[0071] Assume the equation of the space sphere:

[0072] (xa) 2 + (yb) 2 + (zc) 2 =R 2 ,

[0073] Expand to get: x 2 +y 2 +z 2 -2ax-2by-2zc+a 2 +b 2 +c 2 =R 2 ,

[0074] Let D = a 2 +b 2 +c 2 -R 2 ,

[0075] Then x 2 +y 2 +z 2 -Ax-By-Cz+D=0,

[0076] Using the matrix method we get:

[0077] ,

[0078] Multiply both sides by the left get;

[0079] ;

[0080] The solution is:

[0081] ;

[0082] The equation parameters of the ball are obtained as follows: ;

[0083] Step S6: In the CT coordinate system, a local coordinate system is established with the center point C of the left femoral head, the proximal end point E of the left femoral mechanical axis, and the distal end point D of the femoral mechanical axis. C is the origin of the local coordinate system, and the line connecting DE is the z-axis of the local coordinate system, which is recorded as , the axis perpendicular to the CDE plane and in the same direction as the positive direction of the Y axis of the CT coordinate system is the local coordinate system Y axis, denoted as , let vector CE be , The solution formula for the axis is: = .cross( ), cross is the cross product. The principle used is to find the normal vector by vector cross product, and the Z axis direction of the local coordinate system is recorded. , The solution formula for the axis is: = .cross( ), solve the local coordinate system X axis which is in the same direction as the positive direction of the CT coordinate system X axis, and take C as the origin. , , , respectively as the X-axis, Y-axis, and Z-axis to establish the local coordinate system of the femur before rotation;

[0084] Step S7: Select four non-coplanar points in the femoral local coordinate system and perform landmark registration with the four coplanar points in the CT coordinate system (same as step 2)

[0085] Select the origin of the local coordinate system and three points on the three coordinate axes with a positive direction and a unit length of 1, a total of four points, recorded as , , , , record the coordinates of the four points in the CT coordinate system as , , , .

[0086] Select four points in the CT coordinate system, the coordinates are ( , , ),( +1, , ),( , +1, ),( , , +1), denoted as,o,x,y,z;

[0087] remember , , , The source point set and o, x, y, z are the target point set for landmark registration. The specific process of the classic algorithm is not involved in this patent and will not be described in detail. The operation library in VTK is used to obtain the registration matrix R.

[0088] Obtain the femoral registration matrix R, and fill the x-, y-, and z-coordinates of C into R[0,3], R[1,3], and R[2,3] of the R matrix. The filled matrix is ​​the left femoral registration matrix. Similarly, mirror the operation on the right side. Apply the left femoral registration matrix to the left femoral model, and apply the right femoral registration matrix to the right femoral model.

[0089] Step S8: After the pelvis and femur are adjusted, the corresponding hip length and eccentricity are calculated to evaluate the adjustment results.

[0090] Hip length: Hip length, after bone correction, is the distance from the ASIS axis (i.e., the horizontal plane where the line connecting ab and b is located) to the lesser trochanter c of the femur, hl=b z -c z .

[0091] Eccentricity is the distance from the mid-axis to the femoral axis, Co = α x -β x .

[0092] The results of bone setting are evaluated by:

[0093] The pelvic assessment is based on the following criteria: whether the line connecting the two points L and R on the anterior superior iliac spines on both sides is parallel to the X-axis of the pelvic local coordinate system, and whether the plane PLR ​​is perpendicular to the Y-axis of the pelvic local coordinate system;

[0094] The evaluation of the femur is judged as follows: whether the line DE is parallel to the Z axis of the pelvic local coordinate system, and whether the plane CDE is perpendicular to the Y axis of the pelvic local coordinate system;

[0095] The calculated hip length and eccentricity are then used to assist in evaluating the results of bone correction.

[0096] The preoperative physiological parameters of the patient's pelvis and femur are calculated through the above steps S1 to S7. After the operation is completed, the patient is scanned again with CT, and steps S1 to S7 are repeated to calculate the patient's postoperative physiological parameters of the pelvis and femur, which are compared with the preoperative physiological parameters of the pelvis and femur to evaluate the bone correction results. In addition, the intraoperative physiological parameters of the pelvis and femur can be calculated as needed to assist in the evaluation.

[0097] A pelvic and femoral bone setting assessment system for total hip replacement adopts a pelvic and femoral bone setting assessment method for total hip replacement, including: a bone model import module, a physiological point annotation module, a coordinate system establishment module, a landmark registration module, a femoral fitting module, and a parameter calculation and evaluation module;

[0098] A bone model import module is used to import CT images of the pelvis, left femur, and right femur in the CT coordinate system, perform three-dimensional reconstruction, and mark them as the pelvic part, left femur part, and right femur part;

[0099] Physiological point marking module, used to mark the two points of the anterior superior iliac spine on both sides of the pelvis and the pelvic center point (P), as well as the femoral head center point, the proximal end point of the mechanical axis, and the distal end point of the mechanical axis;

[0100] A coordinate system establishment module is used to establish the pelvic local coordinate system and the femur local coordinate system, and perform coordinate system conversion calculations;

[0101] Landmark registration module, used to calculate the registration matrix using the Landmark registration algorithm and generate the bone matrix;

[0102] Femoral fitting module, used for femoral head surface acquisition, adopts the least squares sphere fitting algorithm to calculate the center point, acquire the proximal and distal center points of the femur, and perform mechanical axis fitting;

[0103] The parameter calculation and evaluation module is used to evaluate the pelvis and femur of the osteopathic results.

[0104] The present invention provides accurate quantitative calculation of physiological parameters such as preoperative and postoperative hip length difference and eccentricity difference, establishes a unified numerical evaluation standard, replaces the traditional qualitative judgment that relies on the doctor's experience, and intuitively displays the degree of improvement in surgical effects through difference analysis.

[0105] Three-dimensional reconstruction based on the CT coordinate system ensures the accuracy of anatomical structure restoration, the least squares fitting algorithm achieves submillimeter positioning of the femoral head center point, and the local coordinate system established by the vector cross multiplication method has small error.

[0106] A unified landmark registration method (four-point registration) ensures operational repeatability, streamlines orthopedic matrix calculations to reduce human operational differences, and a mirrored operation design ensures consistency in bilateral femoral treatment, enabling evaluation of preoperative planning and postoperative verification.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for evaluating pelvic and femoral bone setting for total hip replacement, characterized in that: The following steps are involved: Step S1: Preoperative reconstruction: perform three-dimensional reconstruction on the preoperative CT of the pelvis and femur to obtain a three-dimensional reconstruction model; Step S2: Physiological point annotation: annotate the anterior superior iliac spines on both sides of the pelvis and the pelvic center in the 3D reconstructed model, marking the anterior superior iliac spines on both sides as L and R and the pelvic center P. Annotate the femoral head center point, the proximal end point of the femoral mechanical axis, and the distal end point of the femoral mechanical axis in the 3D reconstructed model, marking them as the femoral head center point C, the proximal end point of the femoral mechanical axis E, and the distal end point of the femoral mechanical axis D. Step S3: In the CT coordinate system, a local coordinate system is established with the anterior superior iliac spines on both sides and the center point of the pelvis, with P as the origin of the local coordinate system, the line connecting RL as the local coordinate system X-axis, the axis perpendicular to the LRP plane and in the same direction as the positive direction of the CT coordinate system Y-axis as the local coordinate system Y-axis, and the local coordinate axis Z in the same direction as the positive direction of the CT coordinate system Z-axis is solved to establish the pelvic local coordinate system; Step S4: Landmark registration is performed between four non-coplanar points in the local coordinate system and four coplanar points in the CT coordinate system to obtain a registration matrix R. The x-coordinate, y-coordinate, and z-coordinate of P are entered into the R matrix to obtain a pelvic bone alignment matrix. The pelvic bone alignment matrix is ​​applied to the pelvic CT scan, bilateral femoral CT scans, pelvic models, and bilateral femoral models. Step S5: using a fitting ball algorithm to collect and connect the center points of the proximal and distal femurs, and fitting the center points of the femoral heads of the femoral models on both sides; Step S6: In the CT coordinate system, a local coordinate system is established with the center point C of the left femoral head, the proximal end point E of the left femoral mechanical axis, and the distal end point D of the femoral mechanical axis. C is used as the origin of the local coordinate system, the line connecting DP is used as the local coordinate system Z axis, the axis perpendicular to the CDE plane and in the same direction as the positive direction of the CT coordinate system Y axis is used as the local coordinate system Y axis, and the local coordinate axis X in the same direction as the positive direction of the CT coordinate system X axis is solved to establish the femoral local coordinate system; Step S7: Select four non-coplanar points in the local coordinate system and perform landmark registration with the four coplanar points in the CT coordinate system to obtain the registration matrix R. Fill the x-coordinate, y-coordinate, and z-coordinate of C into the R matrix to obtain the left femur bone matrix. The same is true for the right side. Mirror the left femur CT and left femur model and apply the left femur bone matrix. Apply the right femur CT and right femur model and apply the right femur bone matrix. Step S8: After the pelvis and femur are adjusted, the corresponding hip length and eccentricity are calculated to evaluate the adjustment results.

2. The method for evaluating pelvic and femoral bone setting for total hip replacement according to claim 1, characterized in that: In step S3, the local coordinate axis Z that is in the same direction as the positive direction of the Z axis of the CT coordinate system is solved by the following method: With P as the origin of the local coordinate system and the line RL as the X-axis of the local coordinate system, it is written as , the axis perpendicular to the LRP plane and in the same direction as the positive direction of the Y axis of the CT coordinate system is the local coordinate system Y axis, denoted as , let vector PL be , The solution formula for the axis is: = .cross( ), cross is the cross product, the vector cross product is the normal vector, remember the Z axis direction of the local coordinate system , The solution formula for the axis is: = .cross( ).

3. The method for evaluating pelvic and femoral bone setting for total hip replacement according to claim 1, characterized in that: The landmark registration in steps S4 and S7 is performed in the following manner: Select the origin of the local coordinate system and three points on the three coordinate axes with a positive direction and a unit length of 1, a total of four points, recorded as , , , , record the coordinates of the four points in the CT coordinate system as , , , ; Select four points in the CT coordinate system, the coordinates are ( , , ),( +1, , ),( , +1, ),( , , +1), denoted as,o,x,y,z; remember , , , is the source point set, o, x, y, z is the target point set, and the VTK operation library is used for landmark registration to obtain the registration matrix R.

4. The method for evaluating pelvic and femoral bone setting for total hip replacement according to claim 1, wherein: In step S4, the x-coordinate, y-coordinate and z-coordinate of P are filled into the R matrix in the following manner: Fill the x-coordinate, y-coordinate, and z-coordinate of P into R[0,3], R[1,3], and R[2,3] of the R matrix.

5. The method for evaluating pelvic and femoral bone setting for total hip replacement according to claim 1, wherein: The ball fitting algorithm in step S5 is: Assume the equation of the space sphere is: (xa) 2 + (yb) 2 + (zc) 2 =R 2 , Expand to get: x 2 +y 2 +z 2 -2ax-2by-2zc+a 2 +b 2 +c 2 =R 2 , Let D = a 2 +b 2 +c 2 -R 2 , Then x 2 + y 2 + z 2 - Ax - By - Cz + D = 0, Using the matrix method we get: ， Multiply both sides by the left get; ； The solution is: ； The equation parameters of the ball are obtained as follows: .

6. The method for evaluating pelvic and femoral bone setting for total hip replacement according to claim 1, characterized in that: In step S6, the local coordinate axis X that is in the same direction as the positive direction of the X axis of the CT coordinate system is solved by the following method: With C as the origin of the local coordinate system, the line connecting DE is the z-axis of the local coordinate system, which is expressed as , the axis perpendicular to the CDE plane and in the same direction as the positive direction of the Y axis of the CT coordinate system is the local coordinate system Y axis, denoted as , let vector CE be , The solution formula for the axis is: = .cross( ), cross is the cross product, use the vector cross product to find the normal vector, remember the Z axis direction of the local coordinate system , The solution formula for the axis is: = .cross( ).

7. The method for evaluating pelvic and femoral bone setting for total hip replacement according to claim 1, wherein: The hip length and eccentricity in step S8 are calculated as follows: Hip length is the distance from the ASIS axis to the lesser trochanter of the femur, hl = b z -c z ; Eccentricity is the distance from the mid-axis to the femoral axis, Co = α x -β x .

8. The method for evaluating pelvic and femoral bone setting for total hip replacement according to claim 7, wherein: In step S8, the bone setting result is evaluated in the following manner: The pelvic assessment is based on the following criteria: whether the line connecting the two points L and R on the anterior superior iliac spines on both sides is parallel to the X-axis of the pelvic local coordinate system, and whether the plane PLR ​​is perpendicular to the Y-axis of the pelvic local coordinate system; The evaluation of the femur is based on whether the line DE is parallel to the Z axis of the pelvic local coordinate system and whether the plane CDE is perpendicular to the Y axis of the pelvic local coordinate system.

9. A pelvic and femoral bone setting assessment system for total hip replacement, using the pelvic and femoral bone setting assessment method for total hip replacement according to claims 1-8, characterized in that: include: Skeletal model import module, physiological point annotation module, coordinate system establishment module, landmark registration module, femur fitting module, parameter calculation and evaluation module; A bone model import module is used to import CT images of the pelvis, left femur, and right femur in the CT coordinate system, perform three-dimensional reconstruction, and mark them as the pelvic part, left femur part, and right femur part; Physiological point marking module, used to mark the two points of the anterior superior iliac spine on both sides of the pelvis and the pelvic center point (P), as well as the femoral head center point, the proximal end point of the mechanical axis, and the distal end point of the mechanical axis; A coordinate system establishment module is used to establish the pelvic local coordinate system and the femur local coordinate system, and perform coordinate system conversion calculations; Landmark registration module, used to calculate the registration matrix using the Landmark registration algorithm and generate the bone matrix; Femoral fitting module, used for femoral head surface acquisition, adopts the least squares sphere fitting algorithm to calculate the center point, acquire the proximal and distal center points of the femur, and perform mechanical axis fitting; The parameter calculation and evaluation module is used to evaluate the pelvis and femur of the osteopathic results.

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