Metal inner core, spacer and preparation method for hip joint bone cement spacer

Abstract

The present invention discloses a metal inner core for a hip joint bone cement spacer, a spacer and a preparation method thereof, belonging to the technical field of medical auxiliary appliances. By designing a metal inner core including a frame body and a supporting part in the hip joint bone cement spacer, the strength of the spacer is enhanced; since the metal inner core is in a hollow shape, the antibiotic bone cement can fill the inside of the metal inner core without affecting the antibiotic content in the spacer, effectively controlling infection; the hollow structure endows the spacer with a lighter weight and stronger structural strength, while effectively reducing the material cost; in the preparation method of the hip joint bone cement spacer, the sizes of the spacer and the metal inner core are designed, so that the matching degree of the spacer with the patient's joint is relatively high, reducing the risk of spacer dislocation. The preparation method is simple, the spacer obtained according to the preparation method is smooth enough, and the movement function of the hip joint is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical auxiliary appliances, and particularly relates to a metal inner core for a hip joint bone cement spacer, a spacer and a preparation method thereof. Background Art

[0002] When chronic joint diseases such as severe hip osteoarthritis, hip rheumatoid arthritis, and advanced avascular necrosis of the femoral head, as well as senile femoral neck fractures, which lead to severe pain, dysfunction, and a decline in quality of life, joint replacement surgery is usually required.

[0003] Periprosthetic joint infection after joint replacement is one of the most serious complications of such surgeries. Currently, the treatment options for bone infection mainly include three methods: debridement, one-stage revision, and two-stage revision. One-stage revision means thoroughly debriding and implanting a new prosthesis during the first-stage surgery. Two-stage revision is to thoroughly debride and place a spacer during the first-stage staged surgery, and then remove the spacer during the second-stage surgery after the infection is controlled, and simultaneously perform hip joint prosthesis revision. The effective rate of infection control for this two-stage revision surgery method using an antibiotic bone cement spacer is over 90%, becoming the recognized "gold standard" at home and abroad.

[0004] In the existing hip spacer manufacturing technologies, there are methods such as hand-kneading type antibiotic bone cement spacers, mold pressing type spacers, and perfusion flushing type spacers. The advantages of the hand-kneading type antibiotic bone cement spacer method are: after being left in place, it allows a certain degree of mobility of the affected hip, can restore the length of the lower limb and the tension of the position tissues, and the spacer can be removed during the second-stage revision; the disadvantages are: the shape is difficult to control during the kneading process, the surface is not smooth, and the prosthesis is prone to dislocation. The mold pressing type spacer method has advantages such as simple production, smooth surface, and low cost, and solves some of the deficiencies of the hand-kneading type spacer; however, the specifications of such spacers are limited, generally only having large, medium, and small specifications, and it is difficult to meet the needs of each patient. The advantages of the perfusion flushing type spacer method are: it can maintain the joint function during the period of leaving the joint in place after clearing the joint infection focus; the disadvantages are: the voids in the spacer are easily blocked by blood clots and tissues, affecting the effect and the patient cannot walk while bearing weight.

[0005] In addition, the placeholders made by the above three methods will break when the load exceeds the limit during limb weight-bearing. The existing patent with publication number CN209004338U discloses a new type of antibiotic bone cement placeholder, which includes a placeholder body and a reinforcing skeleton arranged inside the placeholder body. The placeholder body is made of antibiotic bone cement material, and the reinforcing skeleton is a curved metal nail. Scholars such as Thielen measured the ultimate loads that a solid support metal, titanium needles, and titanium plates can withstand at the center of the placeholder by biomechanics, which are 400 - 600N, 1100 - 1300N, and 2380 - 4811N respectively. At the same time, he also proposed that for complete weight-bearing, the diameter of the all-titanium metal inner core should reach 8mm. Although the new type of antibiotic bone cement placeholder disclosed in CN209004338U uses a Steinmann pin with a diameter of 4mm bent at 130° as the reinforcing skeleton to ensure the strength of the placeholder, a placeholder such as the one disclosed in CN209004338U cannot achieve complete weight-bearing, and there is still a risk of fracture when the limb weight-bearing exceeds the load. Further, scholars such as Nobuhiro Kaku believe that increasing the metal diameter to enhance the strength of the placeholder will affect the antibiotic content, and through practice, it is very difficult to bend a thick metal rod during the operation, and thickening the metal rod will directly lead to an increase in weight. Therefore, although the solid support metal, titanium needles, and titanium plates tried in the current existing technology play a certain strengthening role to a certain extent, their respective deficiencies are still obvious.

[0006] Therefore, how to enhance the strength of the placeholder while ensuring the antibiotic content is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0007] In order to solve the technical problems that the existing placeholders are not strong enough and prone to fracture, and the built-in metal of the existing placeholders affects the antibiotic content, the present invention provides a metal inner core for a hip joint bone cement placeholder, a hip joint bone cement placeholder, and a preparation method.

[0008] The technical solution of the present invention is as follows:

[0009] The present invention discloses a metal inner core for a hip joint bone cement placeholder, which includes a frame body and a support part. The support part is arranged inside the frame body, and the support part and the frame body together form a hollow metal inner core. Both the frame body and the support part are made of metal materials.

[0010] Further, the frame body is provided with a number of hollow holes, and the area of each hollow hole ≤ 1.5 square millimeters.

[0011] Further, the support part includes several connecting rods. The center where several said connecting rods intersect forms a support node, and both ends of each connecting rod are fixedly connected to the inner wall of the frame body.

[0012] The present invention discloses a hip joint bone cement spacer, which includes the above-mentioned metal inner core for hip joint bone cement spacer and an antibiotic bone cement outer shell. The antibiotic bone cement outer shell wraps the metal inner core, and the volume of the metal inner core is 50%-80% of the volume of the antibiotic bone cement outer shell.

[0013] The present invention also discloses a preparation method of a hip joint bone cement spacer, which is used to prepare the above-mentioned hip joint bone cement spacer, and includes the following steps:

[0014] S1. Preparation of the spacer model

[0015] Obtain the contour data of the joint prosthesis, perform a 10%-15% reduction adjustment on the contour data of the joint prosthesis to obtain the contour data of the spacer model, and perform 3D printing on the obtained contour data of the spacer model to obtain the spacer model;

[0016] S2. Preparation of the negative mold

[0017] Design the negative mold according to the contour data of the spacer model and obtain the size data of the negative mold. Use ABS resin as the stacking material, and perform 3D printing on the obtained size data of the negative mold to obtain a negative mold including a first mold and a second mold;

[0018] S3. Preparation of the metal inner core

[0019] Perform an 18%-25% reduction adjustment on the contour data of the spacer model to obtain the contour data of the metal inner core, and perform 3D printing on the obtained contour data of the metal inner core to obtain the metal inner core;

[0020] S4. Preparation of the bone cement spacer

[0021] Place the metal inner core into the first mold or the second mold, fill the liquid antibiotic bone cement into the first mold with the metal inner core placed therein or the second mold with the metal inner core placed therein, and the first mold or the second mold without the metal inner core placed therein also needs to be filled with the liquid antibiotic bone cement. Closely fasten the first mold and the second mold, and after waiting for solidification, separate the first mold and the second mold to obtain the bone cement spacer.

[0022] Further, in the step S1, the hip joint prosthesis is divided into a head, a neck and a stem. The contour data of the hip joint prosthesis is obtained. The contour data of the head and the stem of the hip joint prosthesis are reduced and adjusted by 15%, and the contour data of the neck remains unchanged, so as to obtain the contour data of the placeholder model. The data of the placeholder model is obtained for 3D printing to obtain the placeholder model.

[0023] Further, in the step S3, the placeholder model is divided into a head, a neck and a stem. The contour data of the head and the stem of the placeholder model are reduced and adjusted by 20%, and the neck data remains unchanged, so as to obtain the contour data of the metal inner core. The contour data of the metal inner core is obtained for 3D printing to obtain the metal inner core.

[0024] Further, in the step S2, both the first mold and the second mold include a plurality of heat dissipation holes and recesses. The first mold or the second mold is provided with a plurality of connection holes, and the first mold or the second mold is provided with a plurality of connection posts. The connection holes and the connection posts are arranged at the included angle of the first mold or the second mold, and the connection holes and the connection posts are symmetrically arranged. The heat dissipation holes are arranged around the recesses, and the connection posts are detachably installed in the connection holes.

[0025] Further, in the step S4, before filling the liquid antibiotic bone cement into the first mold containing the metal inner core or the second mold containing the metal inner core, a layer of vaseline is first applied in the first mold and the second mold.

[0026] Further, in the step S4, the liquid antibiotic bone cement includes bone cement powder, bone cement monomer liquid and antibiotic. Among them, the weight ratio of the bone cement powder, the bone cement monomer liquid to the antibiotic is 100:50:9, and it is stirred for 60 s to make it fully mixed.

[0027] The beneficial effects of the present invention are as follows:

[0028] By designing a metal inner core including a frame body and a support part in the hip joint bone cement spacer, the strength of the spacer is enhanced; further, since the metal inner core is in a hollow shape, on the one hand, the antibiotic bone cement can fill the inside of the metal inner core without affecting the antibiotic content in the spacer, effectively controlling the infection; on the other hand, the hollow structure endows the spacer with a lighter weight and stronger structural strength, while effectively reducing the material cost; the preparation method includes the preparation of the spacer model, the preparation of the reverse mold, the preparation of the metal inner core and the preparation of the hip joint bone cement spacer. In the preparation method of the hip joint bone cement spacer, the sizes of the spacer and the metal inner core are designed, so that the matching degree between the spacer and the patient's joint is relatively high, reducing the risk of spacer dislocation. The preparation method is simple. The spacer obtained according to this preparation method is smooth enough and improves the movement function of the hip joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 FIG. is an exploded structural schematic diagram of a metal inner core for a hip joint bone cement spacer of the present invention;

[0030] Figure 2 FIG. is a sectional view of the head, neck and stem of a metal inner core for a hip joint bone cement spacer of the present invention;

[0031] Figure 3 FIG. is a rear three-dimensional structural schematic diagram of a metal inner core for a hip joint bone cement spacer, the bone cement spacer and the preparation method of the present invention;

[0032] Figure 4 FIG. is a plan structural schematic diagram of a reverse mold for placing a preparation method of a hip joint bone cement spacer of the present invention;

[0033] Figure 5 FIG. is an X-ray diagram during actual use of the hip joint bone cement spacer of the present invention.

[0034] Reference numerals: 1. Frame body, 11. Hollow hole, 2. Support part, 21. Connecting rod, 22. Support node, 3. Antibiotic bone cement shell, 4. Reverse mold, 41. First mold, 42. Second mold, 43. Heat dissipation hole, 44. Depression, 45. Connecting hole, 46. Connecting column, 5. Head, 6. Neck, 7. Stem. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] Please refer to Figure 1 and Figure 2, the present invention provides a metal inner core for a hip joint bone cement spacer, comprising a frame body 1 and a support portion 2. The support portion 2 is disposed inside the frame body 1. The support portion 2 and the frame body 1 together form a hollow metal inner core. Both the frame body 1 and the support portion 2 are made of metal materials. The hollow structure endows the spacer with a lighter weight and stronger structural strength, and at the same time effectively reduces the material cost.

[0037] Further, the frame body 1 is provided with a plurality of hollow holes 11, and the area of each hollow hole 11 ≤ 1.5 square millimeters. Limiting the area of the hollow holes 11 can increase the hardness of the overall structure on the one hand, and facilitate the filling of bone cement inside the metal inner core on the other hand.

[0038] Refer to Figure 1 , the support portion 2 includes a plurality of connecting rods 21. The center where the plurality of connecting rods 21 intersect forms a support node 22. Both ends of the connecting rods 21 are fixedly connected to the inner wall of the frame body 1. By providing the connecting rods 21, the hardness of the metal inner core is enhanced, preventing the spacer with the metal inner core from breaking after being installed by the patient.

[0039] Refer to Figure 2 , the frame body 1 is divided into a head, a neck and a stem. The outer contour of the frame body 1 is femoral-shaped. The head is circular, the neck is columnar, and the stem is frustum-shaped or conical.

[0040] Please refer to Figure 3 , the present invention discloses a hip joint bone cement spacer, comprising the above-mentioned metal inner core for a hip joint bone cement spacer and an antibiotic bone cement outer shell 21. The antibiotic bone cement outer shell 21 wraps the metal inner core. The volume of the metal inner core is 50%-80% of the volume of the antibiotic bone cement outer shell 21. The hip joint bone cement spacer with a femoral shape also includes a head, a neck and a stem. The outer contour of the head is circular, the outer contour of the neck is columnar, and the outer contour of the stem is frustum-shaped or conical, which is a little larger than the size of the metal inner core.

[0041] The present invention also discloses a preparation method for a hip joint bone cement spacer, which is used to prepare the above-mentioned hip joint bone cement spacer, and comprises the following steps:

[0042] S1. Preparation of the spacer model

[0043] Obtain the contour data of the joint prosthesis, perform a 10%-15% reduction adjustment on the contour data of the joint prosthesis to obtain the contour data of the spacer model, and perform 3D printing on the obtained contour data of the spacer model to obtain the spacer model;

[0044] Specifically, taking the femoral head replacement surgery as an example, the method for obtaining the contour data of the joint prosthesis is:

[0045] CT scan the hip joint data of the patient, and import the hip joint data into Mimics modeling software. Through morphological processing, a visual three-dimensional model of the hip joint is generated. Mesh optimization is performed on the three-dimensional model of the hip joint in Geomagic software to obtain a solid model of the hip joint. Since thorough debridement and implantation of a new prosthesis are completed during the first-stage surgery, a solid model of the femoral prosthesis can also be obtained. According to the solid model of the femoral prosthesis, its contour data is obtained.

[0046] Moreover, the reduction ratio of 10%-15% mentioned above is the result of actual verification. On the one hand, reducing the size is more convenient for implantation surgery; on the other hand, it can ensure that the placeholder is not easily detached.

[0047] S2. Preparation of the reverse mold

[0048] Design the reverse mold according to the contour data of the placeholder model, and obtain the size data of the reverse mold. Use ABS resin as the stacking material, and perform 3D printing based on the obtained size data of the reverse mold to obtain a reverse mold including a first mold and a second mold;

[0049] Specifically, taking the reverse mold of the femoral prosthesis as an example, the specific sub-steps of reverse mold preparation are as follows:

[0050] S2-1. Design the model: Input the contour data of the placeholder model into CAD software to design a three-dimensional model of the reverse mold structure;

[0051] S2-2. Slicing process: Use slicing software to cut the three-dimensional model into thin layers and generate a G-code file suitable for 3D printer printing;

[0052] S2-3. Set printing parameters: Set the printing parameters obtained according to the size data of the reverse mold on the 3D printer, where the printing material is ABS resin;

[0053] S2-4. Print the model: Load the G-code file into the 3D printer and start printing the solid structure model of the reverse mold;

[0054] S2-5. Monitor the printing process: Regularly check the printing progress to ensure that the printing process proceeds normally and avoid problems;

[0055] S2-6. Wait for printing to complete: Wait for the 3D printer to complete the printing of the solid structure.

[0056] S2-7. Take out the model: After printing is completed, take out the model and remove the support structure.

[0057] S2-8. Post-processing: Perform post-processing work as needed, such as surface treatment, polishing, painting, etc., to make the reverse mold reach the final appearance and texture.

[0058] S3. Preparation of the metal inner core

[0059] Shrink and adjust the contour data of the placeholder model by 18%-25% to obtain the contour data of the metal inner core, and obtain the contour data of the metal inner core for 3D printing to obtain the metal inner core;

[0060] Specifically, taking the metal inner core in the shape of a femoral prosthesis as an example, the specific sub-steps of 3D printing the metal inner core are as follows:

[0061] S3-1. Design the model: Input the contour data of the metal inner core into CAD software to design a three-dimensional model of the metal inner core;

[0062] S3-2. Design of adding the support part 2: To maintain the stability of the metal inner core, add the support part 2 to prevent tilting or collapsing during the printing process;

[0063] S3-3. Slicing process: Use slicing software to cut the three-dimensional model of the metal inner core into thin layers suitable for printing to generate a G-code file;

[0064] S3-4. Set the printing parameters: Set the printing parameters obtained according to the contour data of the metal inner core on the 3D printer. Among them, the printing material is metal, specifically it can be titanium, and in the printing density, the area of each hollow hole 11 is set to ≤1.5 square millimeters;

[0065] S3-5. Print the internal structure: Print the support part 2, referring to Figure 1 , the support part 2 at the head of the metal inner core is in the shape of a "cross", which is formed by multiple connecting rods 21 crossing each other. The center where several connecting rods 21 cross forms a support node 22. The support part 2 at the neck and the stem of the metal inner core is a connecting rod 21 connected end to end. Both ends of the connecting rod 21 are fixedly connected to the inner wall of the frame body 1. Of course, it can also be designed as multiple "cross" shapes formed by multiple connecting rods 21 crossing each other;

[0066] S3-6. Print the frame body 1: Build the outer shape of the metal inner core around the printed support part 2;

[0067] S3-7. Cleaning and post-processing: After waiting for the printing to be completed, perform necessary surface treatments such as polishing and painting to make the metal inner core present the final appearance.

[0068] The above shrinkage ratio of 18%-25% is for the bone cement to completely wrap the metal inner core.

[0069] S4. Preparation of the bone cement placeholder

[0070] Place the metal inner core into the first mold or the second mold. Fill the first mold with the metal inner core or the second mold with the metal inner core with liquid antibiotic bone cement. Moreover, the first mold or the second mold without the metal inner core placed needs to be filled with liquid antibiotic bone cement. Scrape the antibiotic bone cement in the first mold and the second mold flat. Then, closely fasten the first mold and the second mold. After waiting for it to solidify, separate the first mold and the second mold to obtain the bone cement spacer.

[0071] Further, in the step S1, the hip joint prosthesis is divided into a head, a neck, and a stem. Obtain the prosthesis contour data of the hip joint. Reduce the head contour data and the stem contour data of the hip joint prosthesis by 15% for adjustment, and keep the neck contour data unchanged to obtain the contour data of the spacer model. Obtain the contour data of the spacer model and perform 3D printing to obtain the spacer model.

[0072] Further, in the step S3, the spacer model is divided into a head, a neck, and a stem. Reduce the head contour data and the stem contour data of the spacer model by 20% for adjustment, while keeping the neck contour data unchanged to obtain the contour data of the metal inner core. Obtain the contour data of the metal inner core and perform 3D printing to obtain the metal inner core.

[0073] The reason for keeping the neck contour data unchanged is that keeping the neck contour data unchanged can maintain the offset of the spacer without change, so that joint dislocation is not likely to occur after the spacer is implanted.

[0074] Further, in the step S2, both the first mold and the second mold include a number of heat dissipation holes and recesses. The recess is the position for placing the bone cement. The recess also has a head, a neck, and a stem. The heat dissipation holes are used for cavity flow to assist the bone cement in solidifying. The first mold or the second mold is provided with a number of connecting holes, and the first mold or the second mold is provided with a number of connecting columns. The connecting holes and the connecting columns are arranged at the included angle of the first mold or the second mold, and the connecting holes and the connecting columns are symmetrically arranged. The heat dissipation holes are arranged around the recess. The connecting columns are detachably installed in the connecting holes. Through the structural setting of the connecting columns and the connecting holes, it is more convenient and rapid to realize the combination and separation between the first mold and the second mold. Therefore, the above-mentioned reverse mold dimension data includes the shape of the reverse mold, the contour length of the reverse mold, the contour thickness of the reverse mold, the contour height of the reverse mold, the diameter of the heat dissipation holes in the reverse mold, the head diameter of the recess in the reverse mold, the length and width of the neck of the recess in the reverse mold, and the upper and lower bottoms (i.e., the bilateral lengths) of the stem of the recess in the reverse mold.

[0075] Further, in step S4, before filling the liquid antibiotic bone cement into the first mold with a metal inner core or the second mold with a metal inner core, a layer of vaseline is first applied inside the first mold and the second mold, and applying vaseline facilitates the removal of the spacer after the bone cement solidifies.

[0076] Further, in step S4, the liquid antibiotic bone cement includes bone cement powder, bone cement monomer liquid, and an antibiotic. Among them, the weight ratio of the bone cement powder, the bone cement monomer liquid, and the antibiotic is 100:50:9. Stir for 60 s to fully mix them. Specifically, for a femur with a normal shape, the bone cement powder is 40 g, the bone cement monomer liquid is 20 ml, and the antibiotic is 3.6 g. Mix them according to the ratio. It is considered that adding at least 3.6 g of antibiotic to every 40 g of bone cement can achieve a good antibacterial effect on muscle and bone infections and can maintain the sustained release of the antibiotic.

[0077] The above-mentioned contour data includes shape, the diameter, length, width, side length, etc. that make up the contour.

[0078] The following are the clinical data:

[0079] From January 2018 to June 2023, a total of 18 patients (18 hips) diagnosed with periprosthetic joint infection after artificial hemi / total hip arthroplasty were included. After thorough debridement, antibiotic-loaded bone cement spacers with metal inner cores were implanted. There were 8 male patients and 10 female patients, aged from 49 to 88 years old, with an average age of (72.5±6.5) years. Clinical efficacy analysis was performed on the wound healing of the patients, hip X-ray examination, blood white blood cells, erythrocyte sedimentation rate, high-sensitivity C-reactive protein, and Harris hip score at different time points (2 weeks, 1, 3, and 6 months after surgery) during the use of the spacer after the implantation of the antibiotic-loaded bone cement spacer with a metal inner core.

[0080] Results: All patients had their wounds healed 2 weeks after surgery, and there was no residual sinus tract opening. At the 6-week postoperative review, the blood white blood cells, erythrocyte sedimentation rate, and high-sensitivity C-reactive protein were all within the normal range, and the hip function Harris score (see Table 1); it increased from (40.0±3.6) points before surgery to (80.6±4.5) points at 6 months after surgery. Follow-up X-rays showed no dislocation, fracture, subsidence, or penetration of the acetabulum of the spacer. 12 patients successfully underwent hip revision surgery, and the postoperative function recovered well. For the other 6 patients who were older, in poor physical condition, and feared revision surgery, this spacer was used as the final treatment. At the last follow-up, there was no dislocation, fracture, subsidence, or penetration of the acetabulum of the spacer, and the hip joint function was good.

[0081] Table 1 Comparison of Harris scores at different times

[0082]

[0083] In summary, the bone cement spacer of the present invention can effectively resist infection, restore hip function, and achieve good clinical results. It can also be used as the ultimate treatment for some patients with older age, poor physical condition, and fear of revision surgery.

[0084] The above-described embodiments merely represent one implementation manner of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. A metal inner core for a hip joint bone cement spacer, characterized in that: The invention comprises a frame body (1) and a support part (2), wherein the support part (2) is arranged inside the frame body (1), and the support part (2) and the frame body (1) as a whole form a hollow metal inner core, and the frame body (1) and the support part (2) are both made of metal material, and the support part (2) comprises a plurality of connecting rods (21), and the center of the plurality of connecting rods (21) cross-arranged forms a support node (22), and both ends of the connecting rods (21) are fixedly connected to the inner wall of the frame body (1); the frame body (1) is divided into a head, a neck and a handle, and the outer contour of the frame body (1) is a pseudo-femur shape, the head is circular, the neck is columnar, and the handle is truncated cone or conical, and the frame body (1) is the outer shape of the metal inner core constructed around the printed support part (2).

2. The metal inner core for a hip joint bone cement spacer according to claim 1, characterized in that: The frame body (1) is provided with a plurality of hollow holes (11), and the area of ​​each hollow hole (11) is ≤1.5 square millimeters.

3. A hip joint bone cement spacer, characterized in that: It comprises a metal inner core for a hip joint bone cement spacer as claimed in claim 1 or claim 2 and an antibiotic bone cement shell (21), wherein the antibiotic bone cement shell (21) wraps the metal inner core, and the volume of the metal inner core is 50%-80% of the volume of the antibiotic bone cement shell (21).

4. A method for preparing a hip joint bone cement spacer, characterized in that: The method is used to prepare the hip joint bone cement spacer according to claim 3, comprising the following steps: S1. Placeholder Model Preparation Acquire contour data of a hip joint prosthesis, reduce the contour data of the hip joint prosthesis by 10%-15%, obtain contour data of a placeholder model, obtain the contour data of the placeholder model for 3D printing, and obtain the placeholder model; S2. Reverse mold preparation Performing reverse mold design according to the contour data of the placeholder model and obtaining dimension data of the reverse mold, using ABS resin as a buildup material, obtaining the dimension data of the reverse mold for 3D printing, and obtaining a reverse mold including a first mold and a second mold; S3. Preparation of metal core The contour data of the placeholder model is reduced by 18%-25% to obtain the contour data of the metal inner core. The contour data of the metal inner core is obtained for 3D printing to obtain the metal inner core. The specific sub-steps of the 3D printing of the metal inner core are as follows: S3-1. Design model: Input the contour data of the metal inner core into the CAD software to design a three-dimensional model of the metal inner core; S3-2, add support part design; S3-3, Slicing processing: Use slicing software to cut the three-dimensional model of the metal core into thin layers suitable for printing and generate a G-code file; S3-4, setting printing parameters: setting printing parameters obtained according to the contour data of the metal inner core on the 3D printer, wherein the printing material is metal, and the area of ​​each hollow hole in the printing density is set to ≤1.5 square millimeters; S3-5, printing the internal structure: printing the support part, the support part of the head of the metal inner core is in the shape of a "M", which is cross-arranged by multiple connecting rods, and the center of the cross-arranged connecting rods forms a support node, and the support parts of the neck and handle of the metal inner core are connecting rods connected end to end, and both ends of the connecting rods are fixedly connected to the inner wall of the frame body; S3-6, printing frame body: constructing the outer shape of the metal core around the printed support part; S3-7, cleaning and post-processing: After the printing is completed, surface treatment is performed to give the metal core its final appearance; S4. Preparation of bone cement spacer Place the metal inner core in the first mold or the second mold, fill the liquid antibiotic bone cement in the first mold with the metal inner core or the second mold with the metal inner core, and the first mold without the metal inner core or the second mold without the metal inner core must be filled with liquid antibiotic bone cement, tightly fit the first mold and the second mold, wait for solidification, and then separate the first mold and the second mold to obtain a bone cement placeholder.

5. The method for preparing a hip joint bone cement spacer according to claim 4, characterized in that: In step S1, the hip joint prosthesis is divided into a head, a neck and a handle, the contour data of the hip joint prosthesis is obtained, the contour data of the head and the handle of the hip joint prosthesis are reduced by 15%, and the neck contour data remains unchanged, and the contour data of the placeholder model is obtained. The contour data of the placeholder model is obtained for 3D printing to obtain the placeholder model.

6. The method for preparing a hip joint bone cement spacer according to claim 5, characterized in that: In step S3, the placeholder model is also divided into a head, a neck and a handle. The head contour data and the handle contour data of the placeholder model are reduced by 20%, and the neck data remains unchanged to obtain the contour data of the metal inner core. The contour data of the metal inner core is obtained for 3D printing to obtain the metal inner core.

7. The method for preparing a bone cement spacer according to claim 4, characterized in that: In step S2, the first mold and the second mold both include a plurality of heat dissipation holes and recessed positions, the first mold or the second mold is provided with a plurality of connection holes, the first mold or the second mold is provided with a plurality of connection columns, the connection holes and the connection columns are provided at the angle between the first mold or the second mold, and the connection holes and the connection columns are symmetrically arranged, the heat dissipation holes are provided around the recessed positions, and the connection columns are detachably installed in the connection holes.

8. The method for preparing a hip joint bone cement spacer according to claim 7, characterized in that: In step S4, before filling the liquid antibiotic bone cement into the first mold with the metal inner core or the second mold with the metal inner core, a layer of vaseline is first applied to the first mold and the second mold.

9. The method for preparing a hip joint bone cement spacer according to claim 8, characterized in that: In the step S4, the liquid antibiotic bone cement includes bone cement powder, bone cement monomer liquid and antibiotics, wherein the weight ratio of bone cement powder, bone cement monomer liquid and antibiotics is 100:50:9, and the mixture is stirred for 60 seconds to be fully mixed.

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