Femoral inverted intramedullary nail entry point guide plate and preparation method thereof

Abstract

The invention discloses a thighbone inverted-hitting intramedullary nail entry point guide plate and a preparation method thereof, and aims to improve the precision and efficiency of a thighbone intramedullary nail operation. The guide plate comprises an attaching plate and a guide column, the attaching plate is provided with an attaching face precisely matched with a femoral intercondylar fossa and an inner side condylar area, it is ensured that the guide plate can be stably attached to the distal end of the femur, and stable support is provided for an operation. One end of the guide column is connected with the pasting plate, the other end of the guide column extends towards the proximal femur, a guide hole is formed in the guide column, the central axis of the guide hole is strictly collinear with a preset needle inserting point at the distal femur, and reliable guidance is provided for accurate insertion of an intramedullary nail. The guide plate can be prepared before an operation, assists a doctor in quickly positioning a needle inserting point during the operation, effectively shortens the operation time, improves the operation efficiency, reduces the operation risk, and provides an efficient and accurate auxiliary tool for the femoral intramedullary nail operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of surgical instruments, and particularly relates to a guide plate for the entry point of a retrograde femoral intramedullary nail and a preparation method thereof. Background Art

[0002] The retrograde femoral intramedullary nail internal fixation technique is an important means for treating distal femoral fractures and C1-type femoral condyle fractures. The accurate placement of the entry point of the intramedullary nail is the key to the success of the surgery. However, at present, the determination of the guide pin position mainly relies on the experience of the doctor during the operation and multiple fluoroscopic adjustments to ensure that the guide pin remains centered in both the coronal and sagittal planes. This uncertainty not only prolongs the operation time but also increases the radiation exposure risk for both the doctor and the patient. Due to the limited surgical field of view at the entry point of the main nail of the retrograde femoral intramedullary nail, the entry point is located 3 - 5 millimeters in front of the intercondylar fossa of the femur.

[0003] Doctors usually visually estimate on the body surface and combine with a honeycomb guide to insert the guide pin under fluoroscopy. However, the fracture displacement makes it difficult for the body surface to provide accurate reference marks, so continuous fluoroscopy is required to adjust the direction of the guide pin. This method usually cannot ensure that the guide pin is centered simultaneously in the femoral coronal and sagittal planes, and often requires multiple adjustments of the guide pin direction through the honeycomb guide, resulting in uncertainty of the entry point and the guide pin direction. The main disadvantages include: 1. The doctor needs to monitor the guide pin under fluoroscopy to ensure that it is centered in the femoral coronal and sagittal planes; 2. If the guide pin is inserted into the wrong bone canal during the operation, since the diameter of the guide pins of domestic and foreign products is 2.5 mm, its elasticity may cause the guide pin to re-enter the wrong bone canal, making it difficult to correct, thus prolonging the operation time and increasing the difficulty of nail placement; 3. The optimal nail placement position and the guide pin direction mainly rely on the experience of the doctor and fluoroscopic judgment, and multiple adjustments are required when the position is not satisfactory.

[0004] Chinese Patent Application: A guide plate for the isthmus of pedicle screw, with the application number 202421955664.9, involves a guide plate for the isthmus of pedicle screw, which is a unilateral split template designed by reverse using the classic anatomical "herringbone ridge" structure. Using this guide plate does not require excessive peeling of the supraspinous and interspinous ligaments to expose the spinous process, and the posterior tension band structure is completely retained, which is beneficial to maintaining the stability of the overall posterior structure; it reduces the peeling and damage of soft tissues such as paravertebral muscles and deep fascia.

[0005] Combined with the above comparison scheme and aiming at the surgical characteristics of the retrograde femoral intramedullary nail surgery, a guide plate for the entry point of a retrograde femoral intramedullary nail is developed. Summary of the Invention

[0006] The purpose of the present invention is to provide a reverse femoral intramedullary nail entry point guide plate and its preparation method, aiming to improve the accuracy and efficiency of femoral intramedullary nail surgery. The guide plate includes an adhering plate and a guiding column. The adhering plate is designed with an adhering surface that precisely fits the intercondylar fossa and the medial condyle region of the femur, ensuring that the guide plate can be firmly attached to the distal femur, providing stable support for the surgery. One end of the guiding column is connected to the adhering plate, and the other end extends towards the proximal femur. A guiding hole is provided on the guiding column, and the central axis of the guiding hole is strictly collinear with the preset entry point on the distal femur, providing reliable guidance for the accurate insertion of the intramedullary nail. The guide plate of the present invention can be prepared before the operation, assisting the doctor to quickly locate the entry point during the operation, effectively reducing the operation time, improving the operation efficiency, and at the same time reducing the operation risk, providing an efficient and accurate auxiliary tool for femoral intramedullary nail surgery.

[0007] To achieve the above object, the technical solution of the present invention is to design a reverse femoral intramedullary nail entry point guide plate, including an adhering plate and a guiding column; the adhering surface of the adhering plate fits the intercondylar fossa and the medial condyle region of the femur; one end of the guiding column is connected to the adhering plate, and the other end of the guiding column extends towards the proximal femur; a guiding hole is provided on the guiding column, and the central axis of the guiding hole is collinear with the preset entry point on the distal femur.

[0008] In a possible implementation manner, the guiding hole is a single channel, and its axis is collinear with the defined entry point on the distal femur.

[0009] In a possible implementation manner, when the adhering surface of the adhering plate adheres to the intercondylar fossa and the medial condyle region of the femur, when the adhering plate adheres to the intercondylar fossa and the medial condyle of the femur, the central axis of the guiding hole passes through the lowest point of the intercondylar fossa in the sagittal plane and is offset forward by 3 - 5 mm.

[0010] In a possible implementation manner, the midline of the guiding hole coincides with the center of the mechanical axis of the femur in the coronal plane and is offset forward by 3 - 5 mm from the lowest point of the intercondylar fossa in the sagittal plane.

[0011] In a possible implementation manner, according to the preparation method of the above reverse femoral intramedullary nail entry point guide plate, it includes the following steps: Step 1: Perform a computed tomography scan on the patient's femur, reconstruct a three-dimensional model containing only the bone structure, and obtain the reconstructed femur model; Step 2: Simulate fracture reduction on the reconstructed femur model. Based on the anatomical landmarks of the intercondylar fossa and the medial condyle of the distal femur, determine the position of the entry point by the intercondylar fossa projection method, and generate a design drawing scheme of the matching entry point guide plate; Step 3: Export the drawing file of the design drawing scheme, and after manufacturing a physical guide plate by machine tool processing, perform cleaning and sterilization treatment on the physical guide plate; Step 4. After cleaning and sterilizing the physical guide plate, use the physical guide plate for the treatment of the patient during the operation.

[0012] In a possible implementation manner, the specific process of determining the needle insertion point position by the intercondylar fossa projection method in Step 2 includes: Step 2.1. Establish a femoral mechanical axis coordinate system in the three-dimensional model, with the center of the femoral head as the origin, the femoral mechanical axis as the Z-axis, the coronal plane as the X-Z plane, and the sagittal plane as the Y-Z plane; Step 2.2. Locate the lowest point of the intercondylar fossa on the sagittal plane and extract its three-dimensional coordinates; Step 2.3. Generate an offset point according to a preset forward offset amount, and the offset point is forward offset relative to the lowest point of the intercondylar fossa along the Y-axis direction of the sagittal plane; Step 2.4. Project the offset point onto the center line of the femoral mechanical axis on the coronal plane and calculate the deviation in the X direction; Step 2.5. When the deviation in the X direction exceeds the preset threshold, automatically correct the X coordinate of the offset point to the center line of the mechanical axis to ensure that the center line of the guiding hole coincides with the mechanical axis on the coronal plane.

[0013] In a possible implementation manner, when generating the guide plate design drawing in Step 2: Step 2.6. Extract the surface curvature data of the medial condyle of the distal femur and generate a matching curvature for the inner surface of the attachment plate, and the deviation between the matching curvature and the surface curvature of the medial condyle is controlled within a preset range; Step 2.7. Fit the three-dimensional surface of the attachment surface based on the anatomical landmark point cloud data of the medial condyle, and the surface fitting error does not exceed the preset accuracy; Step 2.8. Calculate the inclination angle of the guiding column according to the spatial geometric relationship between the axis of the guiding hole and the femoral mechanical axis, and the error of the inclination angle is controlled within a preset angle range.

[0014] In a possible implementation manner, the verification of the guide plate design parameters in Step 2 includes: Step 2.9. Establish a guide plate-femur contact stress model to verify whether the contact area of the attachment surface reaches a preset ratio; Step 2.10. Simulate the spatial deviation between the axis of the guiding hole and the preset needle insertion point so that the deviations in the X / Y / Z three directions do not exceed the preset tolerance range.

[0015] In a possible implementation manner, when machining and manufacturing by the machine tool in Step 3: Step 3.1. Based on the matching curvature of the inner surface of the attachment plate and the inclination angle of the guiding column, adjust the smooth transition parameters of the machining tool path so that the curvature transition deviation between the attachment surface and the femoral surface does not exceed the preset curvature tolerance; Step 3.2: Set the simultaneous machining parameters of the multi-axis machine tool according to the inclination angle of the guide post and the spatial relationship of the axis of the guiding hole, ensuring that the spatial angle deviation between the axis of the guiding hole and the preset needle insertion point does not exceed the preset angle tolerance.

[0016] In a possible implementation, before the operation, the solid guide plate in step 4 is used: Step 4.1: Obtain the actual curvature data of the attachment surface of the solid guide plate through a three-dimensional scanner, compare the deviation with the matching curvature in the design drawing, and reprocess if the deviation exceeds the preset threshold; Step 4.2: Attach the guide plate to the patient's femur model, detect the contact surface gap after applying the preset pressing force, and correct the curvature of the attachment surface if the gap distribution exceeds the preset density.

[0017] The advantages and beneficial effects of the present invention are as follows: improving the accuracy and efficiency of femoral intramedullary nail surgery. The guide plate includes two parts, an attachment plate and a guide post. The attachment plate is designed with an attachment surface that precisely fits the intercondylar fossa and the medial condyle region of the femur, ensuring that the guide plate can be firmly attached to the distal end of the femur and providing stable support for the operation. One end of the guide post is connected to the attachment plate, and the other end extends towards the proximal end of the femur. A guiding hole is provided thereon, and the central axis of the guiding hole is strictly collinear with the preset needle insertion point at the distal end of the femur, providing reliable guidance for the accurate insertion of the intramedullary nail. The guide plate of the present invention can be prepared before the operation, assist the doctor in quickly positioning the needle insertion point during the operation, effectively reduce the operation time, improve the operation efficiency, and at the same time reduce the operation risk, providing an efficient and accurate auxiliary tool for femoral intramedullary nail surgery. Brief Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the first angle of the present invention.

[0019] Figure 2 It is a schematic diagram of the second angle of the present invention.

[0020] Figure 3 It is a schematic diagram of the usage state of the present invention.

[0021] Figure 4 It is a CT scan diagram of a case.

[0022] Figure 5 It is a schematic diagram of the computer simulation of the surgical plan in the coronal plane.

[0023] Figure 6 It is a schematic diagram of the computer simulation of the surgical plan in the sagittal plane.

[0024] Figure 7 It is a verification schematic diagram of the actual needle insertion point and the standard needle insertion point.

[0025] Among them, attachment plate 1, guide post 2, guiding hole 3, Kirschner wire 4, femur B. Detailed Embodiments

[0026] The following will further describe the specific implementation manners of the present invention in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.

[0027] As Figure 1 and Figure 2 shown, this reverse femoral intramedullary nail entry point guide plate is composed of an adhering plate 1 and a guiding column 2. The adhering plate 1 is a plate-like structure designed based on the anatomical landmarks of the femoral intercondylar fossa and the medial condyle. To accurately guide the entry point, its adhering surface must highly coincide with the femoral intercondylar fossa and the medial condyle area. This requires the aid of advanced medical imaging and three-dimensional modeling techniques. Before surgery, the patient will be subjected to CT and MRI examinations. For CT, the thickness of each layer is required to be no more than 1.5 mm, and the data format is dicom; for MRI, the thickness of each layer is required to be no more than 5 mm, and the data format is also dicom. Such detailed scanning requirements are to completely and accurately obtain various subtle structural information of the femur, such as the depression depth of the intercondylar fossa, the specific shape and curvature changes of the medial condyle, etc.

[0028] The obtained CT and MRI image data are imported into professional three-dimensional modeling software, and the noise and irrelevant information are removed, and only the bone structure is retained, thereby reconstructing a three-dimensional model containing only the bone. On this three-dimensional model, the anatomical features of the femoral intercondylar fossa and the medial condyle can be accurately analyzed, including the curvature sizes of different parts, the specific numerical values of various angles, etc. Based on these analysis results, the shape and size of the adhering plate 1 are designed. The material is usually selected from medical materials with good biocompatibility, such as titanium alloy or medical plastics. Titanium alloy has high strength and corrosion resistance, which can ensure the stability of the guide plate during the operation; medical plastics are light in weight, low in cost, and can also meet the basic use requirements. At the same time, they have less adverse effects on the human body.

[0029] One end of the guiding column 2 is connected to the adhering plate 1, and the connection method can be welding or integral molding, etc., to ensure the firmness of the connection. The other end of the guiding column 2 extends upward above the distal femur, and a guiding hole 3 collinear with the entry point of the distal femur is provided at this end. The guiding hole 3 is the core part of the guiding column 2, and its function is to guide instruments such as Kirschner wires to accurately enter the entry point of the femur. The guiding hole 3 is a single channel, and its axis is collinear with the defined entry point of the distal femur. This design can ensure that the Kirschner wire advances strictly along the preset path during insertion, improving the accuracy of needle insertion. To ensure the accuracy of the guiding hole 3, high-precision processing equipment and processes are used during processing. For example, a numerically controlled machine tool is used for drilling, and the movement trajectory and depth of the drill bit are controlled through precise programming, so that the axis of the guiding hole 3 is precisely collinear with the preset entry point.

[0030] The determination of the position of the guiding hole 3 is a key step in the design of the guide plate. When the adhering surface of the adhering plate 1 adheres to the intercondylar fossa and the medial condyle of the femur, the central axis of the guiding hole 3 passes through the lowest point of the intercondylar fossa on the sagittal plane and is offset forward by 3 - 5 mm. On the coronal plane, the midline of the guiding hole 3 coincides with the center of the mechanical axis of the femur. To accurately determine the position of the guiding hole 3, the intercondylar fossa projection method is used. First, a mechanical axis coordinate system of the femur is established in the three-dimensional model, with the center of the femoral head as the origin, the mechanical axis of the femur as the Z-axis, the coronal plane as the X-Z plane, and the sagittal plane as the Y-Z plane. This coordinate system provides an accurate reference framework for subsequent position determination. Then, the lowest point of the intercondylar fossa is located on the sagittal plane, and its three-dimensional coordinates are extracted. This requires using the measurement function of the three-dimensional modeling software to accurately find the lowest point of the intercondylar fossa and record its coordinate values. Then, an offset point is generated according to the preset forward offset amount. This offset point is offset forward by 3 - 5 mm along the Y-axis direction of the sagittal plane relative to the lowest point of the intercondylar fossa. This offset amount is the optimal value obtained through a large number of clinical studies and practical verifications. After that, the offset point is projected onto the center line of the mechanical axis of the femur on the coronal plane, and the deviation in the X direction is calculated to determine the positional relationship between the offset point and the mechanical axis of the femur on the coronal plane. When the deviation in the X direction exceeds the preset threshold, the X coordinate of the offset point is automatically corrected to the center line of the mechanical axis to ensure that the midline of the guiding hole 3 coincides with the mechanical axis on the coronal plane and guarantee the accuracy of the position of the guiding hole 3 on the coronal plane.

[0031] The preparation method of the guide plate includes multiple steps. The first step is to perform CT and MRI scans on the patient's femur. After obtaining detailed data, a three-dimensional model containing only the bone structure is reconstructed to obtain the reconstructed femur model, which is the basis for subsequent designs. The second step is to simulate fracture reduction on the reconstructed femur model. According to the patient's specific condition and fracture type, the doctor uses the operation function of the three-dimensional modeling software to perform reduction simulation on the fracture site. By simulating the reduction, the optimal fracture reduction position is determined, providing a basis for determining the needle insertion point. Based on the anatomical landmarks of the intercondylar fossa and the medial condyle of the distal femur, the position of the needle insertion point is determined by the intercondylar fossa projection method. The specific process is the same as the intercondylar fossa projection method when determining the position of the guiding hole 3. After determining the position of the needle insertion point, a design drawing scheme of the matching needle insertion point guide plate is generated. Specifically, it includes extracting the surface curvature data of the medial condyle of the distal femur and generating a matching curvature for the inner surface of the attaching plate 1. When extracting the curvature data, the measurement function of the three-dimensional modeling software is used to measure the curvature of each point on the surface of the medial condyle of the distal femur, and then the matching curvature of the inner surface of the attaching plate 1 is generated according to the measurement data. To ensure the attachment effect, the deviation between the matching curvature and the surface curvature of the medial condyle is controlled within a preset range. Based on the anatomical landmark point cloud data of the medial condyle, a three-dimensional curved surface of the attaching surface is fitted, and the surface fitting error does not exceed the preset accuracy, which can ensure the fitting degree between the attaching plate 1 and the femur surface. According to the spatial geometric relationship between the axis of the guiding hole 3 and the mechanical axis of the femur, the inclination angle of the guiding column 2 is calculated, and the error of the inclination angle is controlled within a preset angle range to ensure that the inclination angle of the guiding column 2 meets the design requirements. The design parameters of the guide plate also need to be verified. A guide plate-femur contact stress model is established to verify whether the contact area of the attaching surface reaches the preset ratio. By simulating the stress distribution when the guide plate contacts the femur through this model, it is ensured that the attaching surface has sufficient contact area to ensure the stability of the guide plate. Simulate the spatial deviation between the axis of the guiding hole 3 and the preset needle insertion point, so that the deviations in the X / Y / Z three directions do not exceed the preset tolerance range, ensuring that the guide plate can accurately guide the needle insertion during actual use.

[0032] The third step is to export the drawing file of the design drawing scheme and manufacture a physical guide plate through machine tool processing. Based on the matching curvature of the inner surface of the attaching plate 1 and the inclination angle of the guiding column 2, the smooth transition parameters of the machining tool path are adjusted so that the curvature transition deviation between the attaching surface and the femur surface does not exceed the preset curvature tolerance, ensuring the smoothness and fitting degree of the attaching surface. According to the inclination angle of the guiding column 2 and the spatial relationship of the axis of the guiding hole 3, the linkage machining parameters of the multi-axis machine tool are set to ensure that the spatial angle deviation between the axis of the guiding hole 3 and the preset needle insertion point does not exceed the preset angle tolerance, ensuring the accuracy of the guiding hole 3. After processing, the physical guide plate is cleaned and sterilized to remove impurities and bacteria on the surface of the guide plate, ensuring that the guide plate meets the requirements for surgical use.

[0033] Step 4: After cleaning and sterilizing the physical guide plate, use the physical guide plate for the treatment of the patient during the operation. Before the operation, obtain the actual curvature data of the adhering surface of the physical guide plate through a three-dimensional scanner, and compare the deviation with the matching curvature in the design drawing. If the deviation exceeds the preset threshold, reprocess it to ensure that the curvature of the adhering surface of the guide plate meets the design requirements. Affix the guide plate to the patient's femur model, and detect the contact surface gap after applying the preset pressing force. If the gap distribution exceeds the preset density, correct the curvature of the adhering surface to ensure a tight fit between the guide plate and the femur. During the operation, as Figure 3 shown, affix the adhering surface of the adhering plate 1 to the intercondylar fossa and the medial condyle area of the femur B. At this time, the guiding hole 3 is collinear with the needle insertion point at the distal end of the femur, and then insert the Kirschner wire 4 along the guiding hole 3, pass through the adhering plate 1 and enter the needle insertion point of the femur. However, as Figure 7 shown, due to the slight deformation of the guide plate material during the disinfection process, even when using the guide plate for needle insertion during the operation, slight errors will still occur. Therefore, it is necessary to simulate the data before and after the operation to confirm the offset data between the standard needle insertion point and the actual needle insertion point, and ensure that the offset data is within the allowable error range. When the patient undergoes CT and MRI examinations before the operation, as Figure 4 shown, the coronal plane and sagittal plane images as shown in Figure 5 , Figure 6 shown can be obtained respectively. Doctors can use these images to further analyze the patient's condition, including the location and type of the fracture and the condition of the surrounding tissues, so as to formulate a more accurate surgical plan.

[0034] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A femoral retrograde intramedullary nail entry point guide plate, characterized in that: It includes a covering plate and a guiding column; the covering surface of the covering plate conforms to the intercondylar fossa of the femur and the medial condyle region; one end of the guiding column is connected to the covering plate, and the other end of the guiding column extends towards the proximal femur; a guiding hole is provided on the guiding column, and the central axis of the guiding hole is collinear with the preset needle insertion point at the distal femur.

2. The femoral retrograde intramedullary nail insertion point guide plate according to claim 1, characterized in that: The guiding hole is a single channel, and its axis is collinear with the defined needle insertion point at the distal femur.

3. The femoral retrograde intramedullary nail entry point guide plate according to claim 1, characterized in that: When the covering surface of the covering plate covers the intercondylar fossa of the femur and the medial condyle region, when the covering plate covers the intercondylar fossa and the medial condyle of the femur, the central axis of the guiding hole passes through the lowest point of the intercondylar fossa in the sagittal plane and is offset forward by 3 - 5 mm.

4. A femoral retrograde intramedullary nail entry point guide plate according to claim 1, characterized in that: The midline of the guiding hole coincides with the center of the mechanical axis of the femur in the coronal plane and is offset forward by 3 - 5 mm from the lowest point of the intercondylar fossa in the sagittal plane.

5. The preparation method of the femoral retrograde intramedullary nail entry point guide plate according to any one of claims 1 to 4, characterized in that, It includes the following steps: Step 1: Perform a computed tomography scan on the patient's femur, reconstruct a three-dimensional model containing only the bone structure, and obtain the reconstructed femur model. Step 2: Simulate fracture reduction on the reconstructed femur model. Based on the anatomical landmarks of the intercondylar fossa and the medial condyle at the distal femur, determine the position of the needle insertion point by the intercondylar fossa projection method, and generate a design drawing plan of a matching needle insertion point guide plate. Step 3: Export the drawing file of the design drawing plan, and after machining and manufacturing a physical guide plate by a machine tool, perform cleaning and sterilization treatment on the physical guide plate. Step 4: After completing the cleaning and sterilization treatment of the physical guide plate, use the physical guide plate for the treatment of the patient during the operation.

6. The preparation method according to claim 5, characterized in that, The specific process of determining the position of the needle insertion point by the intercondylar fossa projection method in Step 2 includes: Step 2.1: Establish a mechanical axis coordinate system of the femur in the three-dimensional model, with the center of the femoral head as the origin, the mechanical axis of the femur as the Z-axis, the coronal plane as the X-Z plane, and the sagittal plane as the Y-Z plane. Step 2.2: Locate the lowest point of the intercondylar fossa in the sagittal plane and extract its three-dimensional coordinates. Step 2.3: Generate an offset point according to the preset forward offset amount, and the offset point is offset forward along the Y-axis direction of the sagittal plane relative to the lowest point of the intercondylar fossa. Step 2.4: Project the offset point onto the center line of the mechanical axis of the femur in the coronal plane and calculate the deviation in the X direction. Step 2.5: When the deviation in the X direction exceeds the preset threshold, automatically correct the X coordinate of the offset point to the center line of the mechanical axis to ensure that the midline of the guiding hole coincides with the mechanical axis in the coronal plane.

7. The preparation method according to claim 5, characterized in that When generating the design drawing of the guide plate in Step 2: Step 2.6: Extract the surface curvature data of the medial condyle at the distal femur, generate a matching curvature for the inner surface of the covering plate, and control the deviation between the matching curvature and the surface curvature of the medial condyle within a preset range. Step 2.7: Fit the three-dimensional surface of the covering surface based on the anatomical landmark point cloud data of the medial condyle, and the surface fitting error does not exceed the preset accuracy. Step 2.8: Calculate the inclination angle of the guiding column according to the spatial geometric relationship between the axis of the guiding hole and the mechanical axis of the femur, and control the error of the inclination angle within a preset angular range.

8. The preparation method according to claim 5, characterized in that, The verification of the guide plate design parameters in Step 2 includes: Step 2.9: Establish a guide plate-femur contact stress model to verify whether the contact area of the covering surface reaches a preset ratio. Step 2.10: Simulate the spatial deviation between the axis of the guiding hole and the preset needle insertion point so that the deviations in the X / Y / Z directions do not exceed the preset tolerance range.

9. The preparation method according to claim 5, characterized in that, During the machining and manufacturing of the machine tool in Step 3: Step 3.1: Based on the matching curvature of the inner surface of the cladding plate and the inclination angle of the guiding column, adjust the smooth transition parameters of the machining tool path so that the curvature transition deviation between the cladding surface and the femoral surface does not exceed the preset curvature tolerance. Step 3.2: According to the spatial relationship between the inclination angle of the guiding column and the axis of the guiding hole, set the linkage machining parameters of the multi-axis machine tool to ensure that the spatial angle deviation between the axis of the guiding hole and the preset needle insertion point does not exceed the preset angle tolerance.

10. The preparation method according to claim 5, characterized in that, The solid guide plate in Step 4 is used before the operation: Step 4.1: Obtain the actual curvature data of the cladding surface of the solid guide plate through a 3D scanner, compare the deviation with the matching curvature in the design drawing, and reprocess if the deviation exceeds the preset threshold. Step 4.2: Attach the guide plate to the patient's femoral model, detect the contact surface gap after applying the preset pressing force, and correct the curvature of the cladding surface if the gap distribution exceeds the preset density.

Images