TWI744626B - The design method and device of patient specific instruments for knee replacement related surgery - Google Patents

Abstract

A method of designing patient specific instrument (PSI) for knee related surgery includes: (1) building 3D digital bone model, which reconstructs the patient’s digital imaging and communications in medicine into a 3D model; (2) setting the anatomical axis, which connects centroids in two different cross section of canal of the bone model; (3) designing the PSI, which has a main body matching with the frontal plane of the bone model, a slot with certain angle relating to the anatomical axis for the clinical needs and at least two fixing ports to hold the PSI; (4) sizing the implant, which measures the antero-posterior and medio-lateral distances of the bone model and compares with those of the commercial implants to select the implant size; (5) setting the anchor points of the PSI, which selects the cutting jig model based on the implant size to simulate the jig on the bone model surface been cut and then sets the corresponding anchor points on the PSI

Description

Design method and device of patient-specific instruments for knee joint replacement related operations

The present invention relates to a patient-specific appliance for surgery, in particular to a method and device for designing a patient-specific appliance for knee replacement surgery.

The knee joint is formed by the combination of the distal end of the femur, the proximal end of the tibia and the patella. The three bones are covered with articular cartilage to make the knee joint easy to move. However, with the aging of the human body, the articular cartilage will gradually degenerate and wear out. In recent years, with the advancement of medical technology and medical materials, for patients with severely degenerative knee joints, total knee arthroplasty (total knee arthroplasty, abbreviated as total knee arthroplasty) TKA) has a considerable therapeutic effect, and total artificial knee replacement surgery is even claimed to be one of the most successful operations in medical history.

Although the amount of TKA surgery continues to increase, about 1%~2% of patients will suffer from infections due to TKA surgery, which reduces the pollution during the operation, such as improving surgical skills, shortening the operation time, and strengthening the operating room. The environmental conditions in China are the only way to reduce surgical infections. Indeed, various artificial joint manufacturers have also designed various surgical jigs or guides for TKA surgery to reduce the skills required for TKA surgery and shorten the operation time.

However, there are still individual differences between each person. General surgical jigs or guides, after all, cannot fully conform to the shape and size of everyone’s knee joint, so the surgeon’s Experience and surgical skills will be related to the effectiveness of the operation. However, with the evolution of technology, patient specific instruments (PSI) have been developed accordingly. For example, the PSI disclosed in US Patent No. 10130378 (filed on May 10, 2012, claiming priority date on May 11, 2011) mainly includes three parts: surgical site model, surgical planning, and PSI design. The surgical site model The surgical site is reconstructed into a 3D model through image scanning; the surgical planning part can display the model of the implant and the model of the surgical site, allowing the user to plan the operation before the operation, such as the position of the implant And the position of the surgical site; and the PSI design part is to allow the operation to be performed in a planned manner during the operation. To achieve this goal, at least one guiding structure must be set up to extend from the implant to the surgical site. At least one guide hole on the PSI is matched with it. Therefore, this patent designs the PSI for implants.

U.S. Patent Application No. 20150182342 (filed on March 12, 2015) mentioned PSI, but did not disclose how to construct PSI. This application was rejected and there was no subsequent reply, which led to rejection. U.S. Patent Application No. 20130001121 (filed on July 1, 2011) discloses a method for patient-specific joint surgery backup kits, including the use of patient-specific joint surgery kits to complete joint surgery database, data The library contains a comparison between the planned implant size before the operation and the actual implant size during the operation, and confirms the degree of deviation between the statistically expected and planned implant size, so as to assemble a set of spare implants. The number and size of the implants in the spare set are determined based on the deviation of the statistically expected implant size. At present, in addition to implants, TKA surgery already requires a large box of tools. If this spare set is added, it will be a heavy burden on the operating room; besides, this patent application does not mention how to design PSI.

U.S. Published Patent Application No. 20150245844 (filed on August 9, 2013) discloses a patient-compliant device, including a body, which has an inner surface that is consistent with the patient’s anatomy; everything The slot is provided on the body; the first wing is extended from the main body; and the second wing is extended from the main body and is separated from the first wing, of which the first wing and the second wing At least one of them contains a tick. The specification of this patent application mentions that the incision is to remove bone from a proximal end of the tibia, but it does not reveal how to set the incision to complete the resection of the proximal tibia in TKA (proximal tibia). resection)? The second embodiment disclosed in the specification is equipped with an alignment checker on the PSI, which is said to allow the surgeon to adjust the lateral alignment of the PSI, such as the posterior tibia slope. ). However, the position of the notch and the back bevel angle to be cut should be set on the PSI, which will be more convenient for the surgeon to use, and there is no need to adjust it again during the operation. And this application was first cited by the examiner in the US Patent Application No. 20090087276, which was rejected as novelty. Although the rights were amended and restrictions were added to only apply to the tibia, the WIPO application No. 2011106400 (filed on February 23, 2011) plus other previous techniques was cited by the examiner to make it clear that the refusal was made. In fact, the WIPO Application No. 2011106400 disclosed the design of the tibial PSI and mentioned that the position of the cutting guide was set to the angle of the anatomical-mechanical axis formed by the patient’s femur and tibia. This is very important, and this kind of PSI will be practical.

U.S. Patent Application No. 20180344335 (filed on August 10, 2018) proposes a device conforming to the patient's femur, including a body with all grooves on the body and a contact surface for the patient, which fits into the patient's trochlear groove (trochlear). groove); the first extension, which is extended from the body, has a contact plate that contacts the patient’s femoral medial condyle; and the second extension, which is extended from the body, has a contact plate Contact with the patient's femoral medial condyle (femoral medial condyle). Similar to this kind of patent application, it looks like There is a large range of rights, but in fact it has not revealed how to design the PSI of the femur, such as how to make the notch so that the distal femoral resection in the TKA procedure can be successfully completed. It is a pity.

U.S. Published Patent Application No. 20160089153 (filed on September 25, 2014), approved as U.S. Patent No. 9924950, discloses a method for creating PSI for joint replacement surgery, which includes: performing at least two directions X-ray scanning, in which the X-ray scanning in two directions is from different angles in a substantially perpendicular manner; the three-dimensional digital model of the bone is generated, which is based on the X-ray scanning in the two directions; the planning of PSI is based on The three-dimensional digital model of bones, including the confirmation of one or more anchor points on the PSI for a specific surface on the bone. The determination of the anchor points is based on the X-ray scanning in two directions. Generate a three-dimensional digital bone model based on its corresponding area, and its corresponding area includes at least one bone surrounding shape; and generate PSI with at least one or more positioning points. The other content of this patent is to disclose how to use PSI to perform TKA surgery. At present, there is PSI of TKA in use, which is the device that can conform to the shape of the patient's bone and is used to make 4 positioning holes. This kind of PSI requires more MRI or CT medical imaging examinations, and then reconstructs the images into a stereo digital bone model, and then designs and manufactures the PSI based on the bone model. A lot of resources are spent, but only to make 4 positioning holes. The benefit of the entire TKA surgery is really limited. No wonder it has not been widely used so far.

From the above review of previous skills in the United States, it is not difficult to find that many previous skills want to set PSI as the martial arts supreme in TKA, and want to complete many surgical operations through PSI, but in the end they only have four positioning holes, so this innovation The idea is great, but it has not been popularized yet.

my country Invention Patent No. I639409 discloses the method of designing surgical instruments and positioning instruments, mainly for knee fractures of the tibial plateau (fracture of tibial plateau). Although the positioning method is mentioned, it is in line with the technical means, functions and functions of the present invention. The results are quite different. The invention patent No. I638634 and the new patent M568688 are for high tibial osteotomy (high tibial osteotomy) and the invention is for knee replacement related operations, and they are completely different in function and results.

my country Invention Patent No. I617282 discloses a bone cutting auxiliary tool used on the femur or tibia and its operation method. The first fixing plate and the second fixing plate can be used to select a combination of designs with different angles, which can be combined into different angles. Bone jigs (jig), in addition, because the fixed plate cannot match the patient's anatomical characteristics, there is a difference from the technical means of the present invention. In addition, my country's TW200920305A public case uses intramedullary positioning rods to determine the position and angle of the distal bone section, and special tools installed on the aforementioned intramedullary positioning rods can be used during surgery to reproduce the reference from the femur and knee joints. The content of the point decision, although medical imaging technology is used, it is not developing PSI.

The public case of China CN109363682A uses knee scan, hip scan, foot and ankle scan, data and image collection and processing to prepare for total knee arthroplasty. It is hoped that preoperative evaluation and mechanical alignment analysis can be provided. Develop PSI. The public case of China CN108056800A uses 3D body surface scanning to establish a digital model of the knee joint. It is hoped that the efficiency of modeling can be improved. However, 3D body surface scanning is bound to be carried out during surgery, and it may not be possible to build a complete model. In fact, the current medical imaging The software reconstruction of CT and MRI three-dimensional models has been very fast, so there is no need to worry.

China's CN108040464A public case is also an early public disclosure in the United States 20160346044 The case discloses the preparation and preparation methods for total knee arthroplasty, including generating a three-dimensional model of the patient’s tibia and femur; screening the tibia and femur based on the three-dimensional model to be within a certain range; and based on the three-dimensional model as the Choose an osteotomy tool for each of the tibia and the femur; and package the osteotomy tool, and the developed PSI is basically to locate the hole of the subsequent osteotomy tool. The Chinese CN104970904A public case is similar. It uses 3D printing technology and reverse engineering to design an individualized positioning template for total knee replacement patients based on MRI images. Reconstruction completes the scanning and reconstruction of the corresponding knee joint prosthesis and osteotomy instruments, determines the corresponding reference size of the osteotomy, and determines the position of the nail hole in the femur and tibia positioning template in the reverse engineering processing software", but this public case did not disclose Come up with achievable methods.

In summary, the current PSI for knee-related surgery in the previous art is used to set positioning holes, but the resection surface is not simulated first, but the positioning holes for subsequent jigs are set. The positioning benefits are very limited. However, if you want to simulate the resection surface, you must first set the bone axis. These are not disclosed in the previous art. It is no wonder that the concept of PSI cannot be popularized. Therefore, it is indeed necessary to develop a PSI that can achieve this goal accurately, quickly and conveniently, so as to improve the efficiency of the operation and save the operation time.

The main purpose of the present invention is to develop patient-specific instruments (hereinafter referred to as PSI) for knee joint-related surgery to improve surgical efficiency and save operation time; The femoral and tibial models of the knee joint of the present invention have developed PSI; the other main purpose of the present invention is to design the cut grooves for the proximal tibia resection and the distal femur resection on the computer model, and combine them with the PSI; the main subject of the present invention One is Through the computer model, find out the bone axis (anatomical axis), and eliminate the need to hit the rod to the femur canal to confirm the orientation of the canal (orientation of canal); another object of the present invention is to avoid the positioning Rod to the femoral tube to reduce intraoperative bleeding. Moreover, one of the targets of the present invention is to compare the models of the femur and tibia after resection with the fixture models required for subsequent bone resection, thereby determining the PSI. The positioning holes can quickly locate the solid fixture during the actual operation.

In order to achieve the above goals, the method of designing PSI in the present invention mainly includes: (1) The establishment of a three-dimensional digital model of bones, using medical images such as Computed Tomography (CT) and Magnetic Resonance Imaging (Magnetic Resonance Imaging) MRI) or ultrasound, etc., to obtain the patient's image data. Among them, the image is preferably finely cut (less than 1mm). The medical image is reconstituted into a three-dimensional digital model of the bone. There are also many software packages such as 3D Slicer, Amira, Mimics, etc. Medical image reorganization can be performed; (2) The bone axis is set. From the proximal and distal cut surfaces of the medullary cavity of the bone model, the centroid position is found, and the connection between the two centroids is used as the bone axis (anatomical axis), of course, the choice of these two cut planes is to make the line of the centroid enough to show the orientation of the bone axis; (3) Design PSI, mark the frontal plane of the bone and indicate the desired fit The surface of the PSI body is designed to conform to the patient’s bone. The design of the groove on the PSI body is based on the thickness of the bone cut and the angle relative to the axis of the bone, and at least two fixations are provided. Use holes to fix the PSI during use; (4) Select the size and model of the implant, and measure the antero-posterior (AP) and the medial-lateral (medio-lateral, abbreviated) on the bone three-dimensional digital model ML), compare the AP and ML of the implant product to select the appropriate implant size; (5) Determine the position of the positioning hole on the resection surface, and simulate the PSI cutting on the bone three-dimensional digital model After the noodles, According to the size and model of the selected implant, select the three-dimensional digital model to be used for the bone cutting jig, and then compare it to set the position of the positioning hole on the resection surface and combine it with the PSI.

Therefore, it can be seen that the PSI designed by the present invention, please refer to the first figure. Since it is designed based on the patient’s bone, the PSI body 1 will have a surface 11 that fits the patient’s specific shape of the bone, so that the PSI Appropriately mounted on the bone to be cut, and the designed PSI will also include a notch 12, at least two fixing holes 13 for fixing the PSI, and an extension extending to the predetermined cutting surface of the bone on both sides of the body The wing 14, and at least two positioning holes 15 (there are four positioning holes in the first figure) for subsequent jigs are set on the extension wing, wherein the cutting groove 12 can accommodate a bone cutting tool to guide bone removal, And according to the bone axis and the amount to be removed to set its position and position; and the setting of the positioning hole is to simulate the surface of the removed bone, and according to the selected implant size model, select its corresponding subsequent bone cutting jig , So as to compare the location of the positioning hole.

Regarding the selection of the size and model of the knee implant, the smallest error method can be used to select the best implant size, that is, the AP and ML values measured on the three-dimensional digital model are subtracted from the implant products. Based on the sum of the squares of the difference between AP and ML, select the one with the smallest error, that is, the one with the closest product size of the implant product to the size of the three-dimensional digital model.

The positioning hole position of the resection surface is determined as shown in the second figure. The surface 211 after the PSI cutting is simulated on the bone three-dimensional digital model 21, and then as shown in the third figure, the bone surface is cut here Above, compare the three-dimensional digital model 31 that will be used for the subsequent bone cutting tool, and the selection of the subsequent bone cutting tool is based on the size and model of the selected implant, so as to set the position of the positioning hole 311 on the resection surface. , And combine this positioning hole position on the PSI to become the positioning hole 15 on the PSI. Among them, the first figure, the second figure, and the third figure are based on the tibia.

The fourth picture shows the femur as an example. The face 221 after cutting with PSI is simulated on the femoral three-dimensional digital model 22; the fifth picture is the bone face after the femur is cut, which will be used to cut the femoral jig after comparison. The three-dimensional digital model 32. It should be emphasized here that the PSI, the tibial fixture (substrate) 31 and the femoral fixture 32 are three-dimensional digital models on the computer, but they are entities in actual use, so the same description codes are used in the specification of the present invention. The sixth figure is a three-dimensional schematic diagram of an embodiment of the femur of a patient-specific appliance for knee joint related surgery designed according to the present invention. There are two positioning holes 15 on the sixth figure.

For the setting of the bone axis, please refer to the tibia model in Figure 7. You can find the position of the proximal and distal section centroid 2311 and 2321 on the proximal section 231 and the distal section 232 of the medullary cavity of the bone model, and then The line 233 between the two centroids is used as the axis of the bone. In practice, a slice can be set in the medullary cavity of the proximal cut surface 231 and the distal cut surface 232, and the coordinates of the geometric center can be calculated as the cut surface. Centroid. The distance between the proximal cut surface 231 and the distal cut surface 232 can be set to be 20 mm to close to the entire length of the bone, generally 50 mm to 300 mm, and the most suitable distance is 100 mm to 250 mm. For the setting of the tibial axis, the proximal cut surface 231 can be set in the medullary cavity near the proximal condyle of the tibia; while the femoral axis can be set, the distal cut surface 232 can be set in the medullary cavity near the condyle of the distal femur.

1. The main body of patient-specific equipment

11‧‧‧A face that conforms to the patient's specific shape of bone

12‧‧‧Grooving

13‧‧‧Fixed hole

14‧‧‧Extension Wing

15‧‧‧Locating hole

21‧‧‧Tibia

211‧‧‧The face after resection of the proximal tibia

22‧‧‧Femur

221‧‧‧Face after removal of distal femur

231‧‧‧Proximal section

2311‧‧‧Proximal section centroid

232‧‧‧Distal section

2321‧‧‧Distal section centroid

233‧‧‧Central Connection

31‧‧‧Tibia fixture (base plate)

311‧‧‧Tibia Fixture Positioning Hole

32‧‧‧Femur Fixture

321‧‧‧Femur fixture positioning hole

The first figure is a three-dimensional schematic diagram of a patient-specific device for knee-related surgery designed according to the present invention.

The second figure is a schematic diagram of the three-dimensional digital model of tibia of the present invention after cutting, and the third figure is a comparison of the tibia after cutting the three-dimensional digital model of the present invention. A schematic diagram of a three-dimensional digital model of a bone fixture.

The fourth figure is a schematic diagram of the three-dimensional digital model of the femur of the present invention after cutting, and the fifth figure is a schematic diagram of the three-dimensional digital model of the subsequent femoral bone cutting jig after cutting the three-dimensional digital model of the present invention.

The sixth figure is a three-dimensional schematic diagram of another embodiment of the patient-specific appliance for knee joint-related surgery designed according to the present invention.

The seventh figure is a schematic diagram of setting the bone axis of the present invention.

The present invention provides examples of proximal tibial resection and distal femoral resection respectively. The PSI for proximal tibial resection is: (1) The establishment of a three-dimensional digital model of the tibial head, which uses medical imaging such as CT to obtain imaging data of the patient’s lower limbs. Among them, the image should be finely cut (less than 1mm), and reconstruct the tibia 3D digital model through medical imaging software; (2) The tibia axis is set from the proximal and distal medullary cavity of the tibia 3D digital model to find out The position of the centroid is to use the line of the two centroids as the tibial axis. (3) Design PSI. On the front face of the tibia, mark the surface to be fitted with the PSI body, so as to design the PSI body 1, PSI that conforms to the patient’s tibia. The body 1 will have a surface 11 that will fit the patient’s specific shape of the bone. The cut 12 on the PSI body is designed to cut 0~2mm from the inside of the tibia. The cut can be designed to be perpendicular to the axis of the tibia. Or the included angle of 92~88, but it should be noted that the outside of the tibia cannot be cut more than 12~13mm, and the design of the groove can also provide posterior tibia slope, the posterior tibia slope can be 0~15 degrees , Usually use 4~6 degrees. In order to make the PSI have a better fixation effect, at least fixation holes 13 will be provided on the PSI body, and then, both sides of the PSI body are provided with medial condyles extending to the tibia and The extension wing 14 on the lateral condyle allows the PSI to be more firmly erected on the patient’s tibia, and for proximal tibial resection, the extension wing 14 and It can provide the design of the positioning holes needed in the future; (4) Select the size and model of the implant, take the AP and ML values of the tibia measured on the 3D digital model, and subtract the AP and ML of the implant product respectively, and use it The sum of the squares of the difference is used to select the implant product whose size is closest to the size of the tibia 3D digital model; (5) Determine the position of the positioning hole of the resection surface, and simulate the surface after the patient’s proximal tibia is removed. 211 , Compare with the tibial base plate 31 in the computer. The size of the base plate is selected according to the size and model of the implant. During the comparison, the suitability of the size selected in step 4 can also be checked, and then the base plate can be determined. Then, according to the positioning hole 311 on the base plate 31, design the corresponding positioning hole 15 on the PSI extension wing at the proper position and orientation on the tibial surface. In the neck bone resection operation, the extension wing 14 can be used first. The positioning hole 15 is marked with a marking hole. After the proximal tibia is removed, the marking hole can be referred to. The subsequent tibial base plate 31 can be quickly erected. The blue dye) will be marked again, and the location of the positioning hole on the proximal tibia resection surface will be more obvious during the operation.

An example of distal femoral resection, where the PSI of proximal tibial resection is: (1) The establishment of a three-dimensional digital model of the femur, and the imaging data of the patient’s lower limbs are obtained by medical imaging such as CT, where the image is finely cut (less than 1mm) Good, reconstitute a three-dimensional digital model of tibia through medical imaging software; (2) Set the axis of the femur, from the proximal and distal sections of the medullary cavity of the three-dimensional digital model of femur, find out its centroid position. Connect the line as the femoral axis (3) Design PSI. On the front face of the femur, mark the face to be matched with the PSI body, so as to design the PSI body 1 that conforms to the patient's tibia. The face 11 of the bone with a specific shape, and the design of the groove 12 on the PSI body is designed to match the amount of removal of the distal femur, which is generally the thickness of the distal femoral condyle of the prosthesis. , Plus the thickness of the cartilage (about 0.5mm~2mm). Furthermore, the design of the groove 12 also takes into account the valgus angle of the knee joint (valgus angle), because knee surgery aims to restore the patient’s mechanical axis to a neutral state. The most effective way to achieve this is to design a neutral at the distal femur and proximal tibia. The mechanical axis, in practice, is to make a line from the center of the hip joint to the center of the ankle joint as the mechanical axis, and then make a vertical line on the knee joint for the distal femoral resection. However, the use of mechanical axis requires imaging information of the hip joint. Generally, there are difficulties during surgery. The alternative method is to refer to the femoral axis and define the angle between the femoral axis and the mechanical axis as the valgus angle. The valgus angle can be used. It ranges from 2.6 degrees to 11.4 degrees. Generally, 3 to 10 degrees are used. The best angle is 5 to 9 degrees. That is to say, the incision is designed to be 90 degrees outside the femoral axis minus the outer angle. Flip angle (2.6 degrees to 11.4 degrees), the integer value is between 87 degrees and 78 degrees, and then, on both sides of the PSI body are provided with extension wings 14 extending to the medial and lateral condyles of the femur to make the PSI It can be more stably erected on the patient’s femur, and the distal femur resection can be performed. The wings 14 are extended and the design of the positioning holes required for the follow-up can be provided. When the PSI is designed, it can be scanned from the hip joint to the patient’s CT image. For the ankle joint, the joint center line is used as the mechanical axis; or if a photo includes X-rays from the hip joint to the ankle joint, the patient’s mechanical axis can also be known to set the valgus angle; (4) Select implantation The size and model of the object, take the AP and ML values of the femur measured on the three-dimensional digital model, subtract the AP and ML of the implant product, and use the square sum of the difference to select the size of the implant product and the femur The three-dimensional digital model has the closest size; (5) Determine the position of the positioning hole of the resection surface, and simulate the surface 221 after the patient’s distal femur is resected, and compare it with the subsequent femoral jig model 32 in the computer. Follow-up The selection of the size and model of the femoral jig is based on the size and model of the implant. During the comparison, the suitability of the size selected in step 4 can also be checked, and then the appropriate position and orientation of the jig model on the femoral surface can be determined. The positioning hole 321 on the femoral jig model 32 is designed with the corresponding positioning hole 15 on the PSI extension wing. During the femoral resection operation, you can first A marking hole is punched from the positioning hole 15 on the extension wing 14. After the distal femur is removed, the marking hole can be referred to, and the subsequent femoral jig 32 can be quickly erected. The marking of the positioning hole can be further treated with dye, etc. It will be more obvious during surgery.

The only ones mentioned are only examples of preferred embodiments of the present invention. When they cannot be used to limit the scope of implementation of the present invention, that is, all equal changes and modifications made in accordance with the scope of the patent application of the present invention should still belong to the present invention. The scope covered by the patents, I would like to ask your reviewer to express and pray for the approval.

1. The main body of patient-specific equipment

11‧‧‧A face that conforms to the patient's specific shape of bone

12‧‧‧Grooving

13‧‧‧Fixed hole

14‧‧‧Extension Wing

15‧‧‧Locating hole

Claims (10)

A method for designing a patient-specific instrument for knee joint surgery, and the steps include: (1) obtaining medical image data of the patient, and reconstructing the medical image into a three-dimensional digital model of the bone; (2) building the bone model from the bone model The proximal and distal sections of the medullary cavity, find out the position of the centroid, and use the line of the two centroids as the axis of the bone; (3) On the front face of the bone, mark the specific patient-specific The surface of the body of the sex device is designed to fit the patient’s bones. The notch on the body is designed to cut the bone out of the thickness of the implant, plus the thickness of the cartilage, and the notch is designed to It forms 90 degrees with the axis of the bone on the outside minus the valgus angle, and is provided with at least two fixing holes for fixing in use; (4) Measure the front and back sides of the bones and the inner and outer sides of the bone on the three-dimensional digital model of the bone Distance, compare the distance between the front and back side of the implant product and the inner and outer side, so as to select the size and model of the implant; (5) Simulate the face after cutting with the patient-specific tool on the three-dimensional digital model of the bone, Compare it with the three-dimensional digital model of the bone cutting jig to be used later. The choice of the bone cutting jig is based on the size and model of the selected implant, so as to set the positioning hole on the resection surface and set it To the patient's specific device. The method for designing patient-specific instruments for knee surgery as described in item 1 of the scope of the patent application, wherein the medical image refers to a computed tomography, magnetic resonance imaging, or ultrasound. The method for designing patient-specific instruments for knee surgery as described in item 1 of the scope of patent application, wherein the bone refers to the femur. The method of designing patient-specific equipment for knee surgery as described in item 1 of the scope of patent application Method, wherein the valgus angle is 3 degrees to 12 degrees. The method for designing patient-specific instruments for knee surgery as described in item 1 of the scope of patent application, wherein the valgus angle refers to CT or X-ray images, and the mechanical axis connecting the center of the hip joint to the ankle joint and The angle between the axis of the bone. A patient-specific appliance for knee joint surgery, which includes: a body with a surface conforming to the specific shape of the patient's bone, so that it can be installed on the bone to be cut; all grooves are provided on the body The groove guides the removal of the bone, which can accommodate a bone cutting tool. The groove is designed to cut the bone out of the thickness of the implant, plus the thickness of the cartilage, and the groove is designed to be consistent with The axis of the bone forms 90 degrees on the outside minus the valgus angle; two fixing holes are provided under the cut groove of the body to fix the body when the bone is removed; the extension wings extend from the body to the desired The surface of the bone is cut, and a surface conforming to the specific shape of the bone of the patient is provided, which can fit the surface of the bone to be cut; two positioning holes are provided on the extension wing, which are connected to the simulated resection The bone model is compared with the three-dimensional digital model to be used for the subsequent bone cutting jig, so as to set the position of the positioning hole, so that the bone cutting jig can be positioned after the bone is resected. For the patient-specific appliance described in item 6 of the scope of patent application, the system uses medical images to reconstruct the three-dimensional digital model of the bone, and the front side is designed to match its appearance. The patient-specific sex device described in item 6 of the scope of patent application, wherein the bone refers to the femur. Such as the patient-specific appliance described in item 6 of the scope of patent application, where the valgus angle refers to CT or X-ray image, the obtained angle between the mechanical axis connecting the hip joint to the ankle joint center and the bone axis. The patient-specific appliance described in item 6 of the scope of patent application, wherein the valgus angle is 3 degrees to 12 degrees.

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