Anatomical meniscus stent and its preparation method

Abstract

The present invention relates to an anatomical meniscus stent and a preparation method thereof. The steps include: obtaining two-dimensional images of the bone tissue and soft tissue of the knee joint on the side of the meniscus injury of the patient, and respectively constructing three-dimensional models of the knee joint bone tissue, the knee joint soft tissue and the meniscus; according to the constructed three-dimensional models, successively determining the positions of the suture straps, the sizes and positions of the bone fixators, the pore diameters and porosity of the meniscus stent, and constructing a three-dimensional model of the suture strap-meniscus-bone fixator; according to the three-dimensional model of the suture strap-meniscus-bone fixator constructed in step S2, importing it into 3D printing software and performing 3D printing to obtain the anatomical meniscus stent. The present invention uses the suture strap for soft fixation with the collateral ligament, and the front and rear corners use the bone fixator to form hard fixation with the bone tissue, providing a stable microenvironment and blood supply basis for meniscus regeneration through the combination of soft and hard fixation.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to an anatomical meniscus stent and a preparation method thereof. Background Art

[0002] The history of meniscus reconstruction can be traced back to 1916. LEXER first attempted to reconstruct the meniscus by transplanting autologous fat during arthroplasty. In many animal experimental models, varying degrees of success have been achieved using a variety of meniscus substitutes. Meniscus substitutes can generally be divided into three categories: allograft (homologous, heterologous), synthetic materials, and tissue engineering (polytetrafluoroethylene resin, carbon fiber, silicone rubber, polyester fiber, and meniscus stents, etc.), and autologous tissue transplantation (fat pad, perichondrium tissue, Achilles tendon, quadriceps tendon, and patellar ligament, etc.). However, in meniscus reconstruction and replacement surgery, currently only methods such as meniscus allograft transplantation, autologous tendon transplantation, and meniscus stents are applied clinically. The meniscus is dense connective tissue with weak immunogenicity and an immune shielding effect, so immune matching is not a determining factor for allogeneic meniscus transplantation. However, allograft transplantation has the possibility of transmitting diseases, and combined with problems such as cost, source, and storage, it limits its clinical application. Accurate graft size matching is crucial for the postoperative effect of meniscus reconstruction. It is difficult to ensure the size matching of allogeneic menisci, and even the sizes of the bilateral menisci of the same person can vary by 2.6 - 6.9 mm. Currently, most scholars use MRI methods to measure the size of the meniscus.

[0003] Transplant fixation techniques can generally be divided into two categories: fixation by bone plugs or bone blocks and soft tissue fixation. Cadaver studies have shown that whether anatomical reconstruction and fixation directly affect the biomechanical properties of the transplanted meniscus. The advantage of soft tissue fixation is that it is easier to match the size of the meniscus, and transplanting menisci of equal size and precise anterior and posterior horns has good clinical effects. Transplant fixation using bone plugs or bone blocks has been reported both in open surgery and arthroscopic surgery. Firm fixation of the anterior and posterior horns of the meniscus is the basis for load bearing. Bone plug fixation has initial stability, but bone plug fixation requires precise graft size, and even a slight error may lead to serious degenerative changes.

[0004] With the development of tissue engineering, people have considered using tissue engineering methods to reconstruct the function of the meniscus. Natural or synthetic biomaterials are used as carriers to implant or not implant cells to reconstruct the meniscus. The implanted seed cells must have strong self-renewal ability and multiple differentiation potentials. The carrier tissue used as the meniscus scaffold should have good biocompatibility, be easily degradable, and harmless to the human body. Moreover, it is required that the proliferation and replacement of the implanted cells be synchronized with the degradation of the carrier. Non-degradable organic materials may induce synovial or fibroblast synthesis of collagenase, which has an adverse effect on the meniscus and cartilage tissues and hinders the transition to clinical application. Some scholars have studied the 2-year follow-up effect of a synthetic collagen scaffold for the implantation and growth of fibrocartilage cells, but there are few reports on the biomechanical properties of the implanted meniscus. So far, there is a lack of artificial meniscus grafts with accurate size matching, firm fixation, and the ability to induce meniscus regeneration for clinical selection. Summary of the Invention

[0005] An object of the present invention is to provide an anatomical meniscus scaffold and a preparation method thereof in view of the deficiencies in the prior art.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] The first aspect of the present invention is to provide a preparation method of an anatomical meniscus scaffold, and the steps include:

[0008] S1. Obtain two-dimensional images of the bone tissue and soft tissue of the knee joint on the damaged side of the patient's meniscus, and respectively construct three-dimensional models of the knee joint bone tissue, knee joint soft tissue, and meniscus;

[0009] S2. According to the three-dimensional models constructed in step S1, sequentially determine the position of the suture loop, the size and position of the bone fixation member, the pore diameter and porosity of the meniscus scaffold, and construct a three-dimensional model of the suture loop-meniscus-bone fixation member;

[0010] S3. According to the three-dimensional model of the suture loop-meniscus-bone fixation member constructed in step S2, import it into 3D printing software and perform 3D printing to obtain the anatomical meniscus scaffold.

[0011] Preferably, step S2 includes:

[0012] S2-1. Determine the position of the suture loop according to the degree of adhesion between the meniscus and the collateral ligament and joint capsule.

[0013] Preferably, step S2 includes:

[0014] S2-2. According to the three-dimensional models of the knee joint bone tissue and the meniscus constructed in step S1, determine the size and position of the bone fixation member.

[0015] Preferably, step S2 includes:

[0016] S2-3. Determine the pore size and porosity of the meniscus scaffold according to the compressive stress and shear stress when the meniscus contacts the femoral surface and the tibial surface in the involved knee joint compartment.

[0017] The second aspect of the present invention is to provide an anatomical medial meniscus scaffold prepared by the preparation method as described above, comprising: a medial meniscus in a reticular scaffold structure, a pair of bone plugs respectively arranged at both ends of the medial meniscus, and a plurality of medial suture loops arranged at the convex side edge of the medial meniscus;

[0018] Wherein, the medial meniscus includes: a first outer surface, a first upper surface and a first lower surface; the plane where the first lower surface is located is parallel to the horizontal direction, and the curved surface where the first upper surface is located is exponentially concave from outside to inside; the medial meniscus also has a plurality of through pores, and the direction of the pores is from the convex side to the concave side.

[0019] Preferably, the medial meniscus is made of a composite of poly(lactic acid-co-carbonate) copolymer and a vasoactive substance; the bone plug is made of a composite of poly(lactic acid-co-carbonate) copolymer and a calcium phosphate material; the medial suture loop is made of a composite of poly(lactic acid-co-carbonate) copolymer and a vasoactive substance.

[0020] Preferably, 2-3 of the medial suture loops are arranged at the convex side edge of the medial meniscus.

[0021] The third aspect of the present invention is to provide an anatomical lateral meniscus scaffold prepared by the preparation method as described above, comprising: a lateral meniscus in a reticular scaffold structure, bone grooves fixedly connected to both ends of the lateral meniscus at both ends respectively, and a plurality of lateral suture loops arranged at the convex side edge of the lateral meniscus;

[0022] Wherein, the lateral meniscus includes: a second outer surface, a second upper surface and a second lower surface; the plane where the second lower surface is located is parallel to the horizontal direction, and the curved surface where the second upper surface is located is exponentially concave from outside to inside; the lateral meniscus also has a plurality of through pores, and the direction of the pores is from the convex side to the concave side.

[0023] Preferably, the lateral meniscus is made of a composite of poly(lactic acid-co-carbonate) copolymer and a vasoactive substance; the bone groove is made of a composite of poly(lactic acid-co-carbonate) copolymer and a calcium phosphate material; the lateral suture loop is made of a composite of poly(lactic acid-co-carbonate) copolymer and a vasoactive substance.

[0024] Preferably, 2-3 of the lateral suture loops are arranged at the convex side edge of the lateral meniscus.

[0025] The present invention adopts the above technical solutions, and compared with the prior art, has the following technical effects:

[0026] The anatomical meniscus stent of the present invention is reconstructed based on the CT / MRI scan data of the patient, with accurate dimensions and matching morphology; it uses suture loops to suture and fix with the collateral ligament (i.e., soft fixation), and the anterior and posterior horns use bone plugs or bone grooves to form a firm fixation with bone tissue (i.e., hard fixation). Through the dual soft and hard fixation, the meniscus is firmly fixed, thereby providing a stable microenvironment and blood supply foundation for meniscus regeneration; the material of the meniscus stent is degradable and can induce tissue regeneration, and the material of the bone plug or bone groove is degradable and can induce bone tissue regeneration, thereby realizing the degradation of the meniscus stent to induce the regeneration of the meniscus. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic structural diagram of the anatomical medial meniscus stent of the present invention;

[0028] Figure 2 is a schematic structural diagram of the anatomical lateral meniscus stent of the present invention;

[0029] Figure 3 is a physical diagram of the anatomical medial meniscus stent of the present invention;

[0030] Figure 4 is a physical diagram of the anatomical lateral meniscus stent of the present invention;

[0031] Among them, the reference numerals include: medial meniscus 11; bone plug 12; medial suture loop 13; lateral meniscus 21; bone groove 22; lateral suture loop 23. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0034] The following further illustrates the present invention with reference to the accompanying drawings and specific embodiments, but is not intended to limit the present invention.

[0035] Embodiment 1

[0036] This embodiment provides a preparation method for an anatomical meniscus stent, and the steps include:

[0037] S1. After obtaining the two-dimensional images of the bone tissue (CT) and soft tissue (MRI) of the knee joint on the damaged side of the patient's meniscus, import them into the reverse image software Simpleware respectively to construct the three-dimensional models of the knee joint bone tissue, knee joint soft tissue and meniscus;

[0038] S2-1. According to the degree of adhesion between the meniscus and the collateral ligament and joint capsule, the number of connection parts between the meniscus and the collateral ligament and joint capsule can be determined, and then 2-3 suture button fixation points can be determined in the convex edge area of the meniscus; combined with the artificial intelligence algorithm, optimize the surface curve of the three-dimensional model of the meniscus to improve its surface smoothness, and determine the suture button according to the suture fixation points;

[0039] S2-2. Combine the three-dimensional models of the knee joint bone tissue, soft tissue and meniscus constructed in step S1 to verify the size of the meniscus; determine the size and position of the bone fixation piece according to the positions of the anterior and posterior corners of the meniscus in the knee joint soft tissue model and the three-dimensional bone morphology at the corresponding positions in the knee joint bone tissue model;

[0040] S2-3. Analyze the compression stress and shear stress parameters when the meniscus contacts the femoral surface and tibial surface in the knee joint compartment of the affected side, and import them into the corresponding meniscus simulation modeling model to determine the pore diameter and porosity of the meniscus stent;

[0041] S3. Import the constructed three-dimensional model of the suture button-meniscus-bone fixation piece into the 3D printing software and perform 3D printing with a transparent material to obtain the anatomical meniscus stent.

[0042] Example 2

[0043] As Figure 1 shown, this example provides an anatomical medial meniscus stent prepared by the preparation method described in Example 1, including: a medial meniscus 11 with a reticular stent structure, a pair of bone plugs 12 respectively arranged at both ends of the medial meniscus 11, and 2-3 medial suture buttons 13 arranged on the convex edge of the medial meniscus 11;

[0044] Among them, the medial meniscus 11 includes: a first outer surface, a first upper surface and a first lower surface; the plane where the first lower surface is located is parallel to the horizontal direction, and the curved surface where the first upper surface is located is exponentially recessed from the outside to the inside; there are also several through pores on the medial meniscus 11, and the direction of the pores is from the convex side to the concave side;

[0045] Among them, the medial meniscus 11 is made of a composite of poly(lactic acid-co-carbonate) copolymer and a vasoactive substance; the bone plug 12 is made of a composite of poly(lactic acid-co-carbonate) copolymer and a calcium phosphate material; the medial suture button 13 is made of a composite of poly(lactic acid-co-carbonate) copolymer and a vasoactive substance.

[0046] Example 3

[0047] As Figure 2 shown, this embodiment provides an anatomical lateral meniscus scaffold prepared by the preparation method described in Example 1, including: a lateral meniscus 21 in a reticular scaffold structure, bone grooves 22 fixedly connected to both ends of the lateral meniscus 21 respectively, and 2-3 lateral suture straps 23 arranged on the convex edge of the lateral meniscus 21;

[0048] Among them, the lateral meniscus 21 includes: a second outer surface, a second upper surface, and a second lower surface; the plane where the second lower surface is located is parallel to the horizontal direction, and the curved surface where the second upper surface is located is exponentially recessed from the outside to the inside; the lateral meniscus 21 also has a number of through pores, and the direction of the pores is from the convex side to the concave side;

[0049] Among them, the lateral meniscus 21 is made of a composite of a polylactic acid - polycarbonate copolymer and a vasoactive substance; the bone groove 22 is made of a composite of a polylactic acid - polycarbonate copolymer and a calcium phosphate material; the lateral suture strap 23 is made of a composite of a polylactic acid - polycarbonate copolymer and a vasoactive substance.

[0050] Example 4

[0051] Using a CT instrument (model GE1600C), according to the following parameters: baseline: the lower edge of the patella, angle: 0°, voltage: 120 kV, current: 60 mA, slice thickness: 5 mm, slice interval: 5 mm, perform a CT scan on the affected knee joint (left knee) to obtain a two - dimensional image of the bone tissue of the affected knee;

[0052] Using a United Imaging 1.5T permanent magnetic MRI scanner, using a head - neck coil, SE sequence: T1WI TR / TE = 500 ms / 18 - 30 ms; T2WI TR / TE - 1800 - 2000 ms / 80 - 90 ms, slice thickness 7 mm, 4 - time average, FOV256, perform conventional sagittal, coronal, and axial scans on the affected knee joint (left knee) to obtain a two - dimensional image of the soft tissue of the affected knee;

[0053] Import the two - dimensional images (dicom format) of the bone tissue and soft tissue of the affected knee into the reverse image software Simpleware respectively, use the ScanIP module to construct a three - dimensional model of the knee joint soft tissue, and then perform image segmentation processing to obtain a three - dimensional model of the medial meniscus;

[0054] According to the degree of adhesion between the meniscus, the collateral ligament and the joint capsule, the number of connection sites between the meniscus, the collateral ligament and the joint capsule can be determined. Three suture button fixation points are determined in the convex edge area of the meniscus. In the Simpleware software, suture buttons are designed according to the determined suture fixation points. Using the FE module and combining with artificial intelligence algorithms, the surface of the three-dimensional model of the meniscus is meshed and the curved surface lines are optimized to improve its surface smoothness;

[0055] Using the Simpleware software, a three-dimensional model of the knee joint bone tissue is constructed. Using the CAD module, the model of the medial meniscus is imported into the three-dimensional model of the knee joint bone tissue to evaluate and verify the size of the meniscus; According to the positions of the anterior and posterior corners of the meniscus in the knee joint soft tissue model and the three-dimensional bone morphology at the corresponding positions in the knee joint bone tissue model, the size and position of the bone plugs are determined, and models of two bone plugs are designed respectively before and after the three-dimensional model of the meniscus;

[0056] According to the compression stress and shear stress parameters when the medial meniscus of the knee joint contacts the femoral surface and the tibial surface reported in the literature, the modeling parameters of the Simpleware software are designed and determined, and the corresponding parameter values are given to the meniscus model. Through model simulation, the pore size and porosity of the meniscus scaffold are determined;

[0057] Using a regenovo 3D printer, the three-dimensional model of the suture button-medial meniscus-bone plug is run using the Bio-Architect software. Using poly(lactic acid carbonate) copolymer (PDT) as the raw material, 3D printing is carried out. The obtained transparent anatomical medial meniscus scaffold is as Figure 3 shown.

[0058] Example 5

[0059] Using a CT instrument (model GE1600C), according to the following parameters: baseline: the lower edge of the patella, angle: 0°, voltage: 120 kV, current: 60 mA, slice thickness: 5 mm, slice interval: 5 mm, the affected knee joint (left knee) is scanned by CT to obtain two-dimensional images of the bone tissue of the affected knee;

[0060] Using a United Imaging 1.5T permanent magnetic MRI scanner, using a head and neck coil, SE sequence: T1WI TR / TE = 500 ms / 18 - 30 ms; T2WI TR / TE - 1800 - 2000 ms / 80 - 90 ms, slice thickness 7 mm, 4 times average, FOV256, routine sagittal, coronal, and axial scans, the affected knee joint (left knee) is scanned by MRI to obtain two-dimensional images of the soft tissues of the affected knee;

[0061] Import the two-dimensional images (DICOM format) of the bone tissue and soft tissue of the affected knee into the reverse image software Simpleware. Use the ScanIP module to construct a three-dimensional model of the knee joint soft tissue, and then perform image segmentation to obtain a three-dimensional model of the lateral meniscus.

[0062] According to the degree of adhesion between the lateral meniscus and the lateral collateral ligament and joint capsule, the number of connection sites between the lateral meniscus and the collateral ligament and joint capsule can be determined. Determine 2 suture button fixation points in the convex edge area of the meniscus. In the Simpleware software, design suture buttons according to the determined suture fixation points. Use the FE module and combine with artificial intelligence algorithms to perform meshing on the surface of the three-dimensional model of the meniscus and optimize the curved surface lines to improve its surface smoothness.

[0063] Use the Simpleware software to construct a three-dimensional model of the knee joint bone tissue. Use the CAD module to import the model of the lateral meniscus into the three-dimensional model of the knee joint bone tissue to evaluate and verify the size of the meniscus. According to the positions of the anterior and posterior horns of the lateral meniscus in the knee joint soft tissue model and the three-dimensional bone morphology at the corresponding positions in the knee joint bone tissue model, determine the size and position of the bone groove, and design a model of the bone groove between the anterior and posterior horns of the three-dimensional model of the meniscus.

[0064] According to the compression stress and shear stress parameters when the lateral meniscus of the knee joint contacts the femoral surface and tibial surface reported in the literature, design and determine the modeling parameters of the Simpleware software, assign corresponding parameter values to the meniscus model, and determine the pore size and porosity of the meniscus stent through model simulation.

[0065] Use a regenovo 3D printer to run the three-dimensional models of the suture button - lateral meniscus - bone groove using Bio-Architect software. Use polylactic acid (PLLA) as the raw material for 3D printing. The obtained transparent anatomical lateral meniscus stent is as Figure 4 shown.

[0066] In summary, the anatomical meniscus stent of the present invention is reconstructed based on the CT / MRI scan data of the patient, with accurate size and morphological matching. It uses suture buttons to suture and fix with the collateral ligament (i.e., soft fixation), and the anterior and posterior horns use bone plugs or bone grooves to form firm fixation with bone tissue (i.e., hard fixation). The firm fixation of the meniscus is achieved through soft and hard double fixation, thereby providing a stable microenvironment and blood supply basis for meniscus regeneration. The material of the meniscus stent is biodegradable and can induce tissue regeneration, and the material of the bone plug or bone groove is biodegradable and can induce bone tissue regeneration, thereby realizing the degradation of the meniscus stent to induce the regeneration of the meniscus.

[0067] The above are only the preferred embodiments of the present invention, and do not limit the implementation manners and protection scope of the present invention. For those skilled in the art, it should be realized that all the equivalent substitutions and obvious changes made by using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. An anatomical medial meniscus stent, and the preparation steps of the anatomical medial meniscus stent include: S1. Obtain two-dimensional images of the bone tissue and soft tissue of the knee joint on the side of the patient with meniscus injury, and respectively construct three-dimensional models of the knee joint bone tissue, knee joint soft tissue, and meniscus; S2. According to the three-dimensional models constructed in step S1, sequentially determine the positions of the suture loops, the sizes and positions of the bone fixators, the pore diameters and porosities of the meniscus stent, and construct a three-dimensional model of the suture loop-meniscus-bone fixator; S3. Import the three-dimensional model of the suture loop-meniscus-bone fixator constructed in step S2 into 3D printing software and perform 3D printing to obtain the anatomical meniscus stent; It is characterized in that it includes: a medial meniscus (11) in a reticular stent structure, a pair of bone plugs (12) respectively arranged at both ends of the medial meniscus (11), and a plurality of medial suture loops (13) arranged on the convex side edge of the medial meniscus (11); Wherein, the medial meniscus (11) includes: a first outer surface, a first upper surface, and a first lower surface; the plane where the first lower surface is located is parallel to the horizontal direction, and the curved surface where the first upper surface is located is exponentially recessed from the outside to the inside; the medial meniscus (11) also has a plurality of through pores, and the direction of the pores is from the convex side to the concave side.

2. The anatomical medial meniscus stent according to claim 1, characterized in that, The medial meniscus (11) is made of a composite of poly(lactic acid-co-carbonate) and a vasoactive substance; the bone plug (12) is made of a composite of poly(lactic acid-co-carbonate) and a calcium phosphate material; the medial suture loop (13) is made of a composite of poly(lactic acid-co-carbonate) and a vasoactive substance.

3. The anatomical medial meniscus stent according to claim 1, characterized in that, There are 2-3 medial suture loops (13) arranged on the convex side edge of the medial meniscus (11).

4. An anatomical lateral meniscus stent, and the preparation steps of the anatomical lateral meniscus stent include: S1. Obtain two-dimensional images of the bone tissue and soft tissue of the knee joint on the side of the patient with meniscus injury, and respectively construct three-dimensional models of the knee joint bone tissue, knee joint soft tissue, and meniscus; S2. According to the three-dimensional models constructed in step S1, sequentially determine the positions of the suture loops, the sizes and positions of the bone fixators, the pore diameters and porosities of the meniscus stent, and construct a three-dimensional model of the suture loop-meniscus-bone fixator; S3. Import the three-dimensional model of the suture loop-meniscus-bone fixator constructed in step S2 into 3D printing software and perform 3D printing to obtain the anatomical meniscus stent; It is characterized in that it includes: a lateral meniscus (21) in a reticular stent structure, bone grooves (22) fixedly connected to both ends of the lateral meniscus (21) at both ends, and a plurality of lateral suture loops (23) arranged on the convex side edge of the lateral meniscus (21); Wherein, the lateral meniscus (21) includes: a second outer surface, a second upper surface, and a second lower surface; the plane where the second lower surface is located is parallel to the horizontal direction, and the curved surface where the second upper surface is located is exponentially recessed from the outside to the inside; the lateral meniscus (21) also has a plurality of through pores, and the direction of the pores is from the convex side to the concave side.

5. The anatomical lateral meniscus stent according to claim 4, wherein The outer meniscus (21) is made of a composite of a polylactic acid - polycarbonate copolymer and a vasoactive substance; the bone groove (22) is made of a composite of a polylactic acid - polycarbonate copolymer and a calcium phosphate material; the outer suture loop (23) is made of a composite of a polylactic acid - polycarbonate copolymer and a vasoactive substance.

6. The anatomical lateral meniscus stent according to claim 4, wherein There are 2 - 3 of the outer suture loops (23) provided on the convex side edge of the outer meniscus (21).

7. The anatomical medial meniscus stent according to claim 1 or the anatomical lateral meniscus stent according to claim 4, characterized in that, Step S2 includes: S2 - 1. Determine the position of the suture loop according to the degree of adhesion between the meniscus and the collateral ligament and the joint capsule.

8. The anatomical medial meniscus stent according to claim 1 or the anatomical lateral meniscus stent according to claim 4, characterized in that, Step S2 includes: S2 - 2. Determine the size and position of the bone fixator according to the three - dimensional models of the knee joint bone tissue and the meniscus constructed in step S1.

9. The anatomical medial meniscus stent according to claim 1 or the anatomical lateral meniscus stent according to claim 4, characterized in that, Step S2 includes: S2 - 3. Determine the pore diameter and porosity of the meniscus scaffold according to the compressive stress and shear stress when the meniscus contacts the femoral surface and the tibial surface in the knee joint compartment of the affected side.

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