Transplanting ligament with indirect dead point and implanting method

Abstract

The invention relates to the technical field of transplanted ligaments, and provides a transplanted ligament with indirect dead points, which comprises a thighbone side direct dead point, a thighbone side indirect dead point, a free fiber segment, a tibia side direct dead point and a tibia side indirect dead point, the free fiber section is located in an articular cavity and does not participate in ligament fixation, and the thighbone side direct dead center and the tibia side direct dead center are connected with the free fiber section; the thighbone side direct dead center and the tibia side direct dead center are fixed in a bone tunnel, the thighbone side indirect dead center and the tibia side indirect dead center are fixed on a bone surface, and the thighbone side indirect dead center and the tibia side indirect dead center exist at the same time or only one exists; the thighbone side indirect dead point is connected with any one of the thighbone side direct dead point and the free fiber section; the tibia side indirect dead center is connected with any one of the tibia side direct dead center and the free fiber segment. And precise bionic adaptation is achieved, and the original movement function of the joint is recovered.

Description

Technical Field

[0001] This invention relates to the technical field of transplanted ligaments, and more particularly to a transplanted ligament with an indirect insertion point and an implantation method thereof. Background Technology

[0002] Ligaments are vital structures connecting the bones on either side of an articular surface, maintaining joint stability. The anterior cruciate ligament (ACL) is one of the most important ligaments in the knee joint. Its macroscopic shape is hourglass-shaped, narrowest in the middle and increasing in cross-sectional area as it approaches the bone surfaces. The location where the ACL connects to the bone is often referred to as the ACL bone insertion point. Based on the direction of the ligament fibers, it can be divided into two regions: direct insertion and indirect insertion. At the direct insertion point, the fibers directly connect to the ligament parenchyma, with the fiber axis approximately perpendicular to the bone surface, and the fiber direction can flexibly change with joint movement. At the indirect insertion point, the fibers extend from the direct insertion point away from the ligament parenchyma, attaching to the bone surface at a smaller angle, nearly parallel to the bone surface, and the fiber direction hardly changes with joint movement. Furthermore, the indirect insertion point occupies a smaller area than the direct insertion point. Research results show that, in terms of mechanical properties, the Young's modulus at the indirect insertion point is significantly greater than that at the direct insertion point; and under gait loads, the indirect insertion point exhibits a higher peak stress. Furthermore, the anisotropy of the bone at indirect insertion points is significantly less than that at direct insertion points, suggesting that indirect insertion points may bear more shear stress in a single direction, while direct insertion points play a more crucial role in restraining joint rotation. Overall, indirect and direct insertion points differ significantly in morphology, structure, and function. Compared to direct insertion points, indirect insertion points also play an irreplaceable role in knee joint movement and the prevention of ACL injuries.

[0003] ACL injury is one of the most common kinesiological injuries. Currently, ACL reconstruction is a mainstream surgical treatment, which involves replacing the damaged ACL with a graft and fixing both ends of the graft into bone tunnels on the femoral and tibial sides, respectively. Based on the origin of the graft, it can be divided into three types: autologous, allogeneic, and artificial ligaments. Regardless of the type, during reconstruction, it is shaped into a cylindrical graft with a relatively constant cross-sectional area and placed in the bone tunnels on both sides using methods such as suspension or compression fixation. Therefore, the graft only simulates the structure of the direct insertion point, i.e., the fiber direction is almost perpendicular to the bone surface and parallel to the bone tunnel, without considering the structure and function of the indirect insertion point. These structural differences between the graft and the native ACL alter the force transmission pattern, leading to osteoarthritis due to abnormal cartilage stress, and problems such as bone tunnel enlargement, graft wear, and fixation failure due to significant relative movement between the graft and bone.

[0004] The following are some patents related to the design of transplanted ligament structures: (1) such as Figure 1As shown, CN102908209B is a double-hole suspension artificial ligament: This ligament design includes six segments, namely, the free fiber section and the braided section in the femoral tunnel, the free fiber section in the joint, the braided section and the free fiber section in the tibial tunnel, and the traction line section. Each end of the bone tunnel has a single hole.

[0005] The purpose of this design is to enhance ligament fixation and increase the contact area with the bone tunnel. However, this structure only reconstructs the structure of the direct insertion point and does not restore the structure and function of the indirect insertion point.

[0006] (2) such as Figure 2 As shown, CN102908210B describes a single-hole suspension artificial ligament, comprising a femoral tunnel section, an intra-articular free fiber section, a tibial tunnel braided section, and a traction suture section connected in sequence, wherein the femoral tunnel section has a single hole. This patent simply changes the double-hole design to a single-hole design based on the aforementioned patent, and still only reconstructs the structure of the direct insertion point.

[0007] (3) such as Figure 3 As shown in CN102871775B, a foldable suspension artificial ligament and its preparation method include a first traction line section (11), a first tibial tunnel braid section (21), a first intra-articular free fiber section (31), a femoral tunnel braid section (4), a second intra-articular free fiber section (32), a second tibial tunnel braid section (22), and a second traction line section (12) connected in sequence. It is folded into a U-shape during use. This structure is suitable for suspension fixation methods; the folding method enhances the stability of the fixation and increases the contact area. This patent proposes a method for using a foldable artificial ligament to create suspension holes, but its effect still only reconstructs the structure of the direct insertion point.

[0008] (4) such as Figure 4 As shown in CN112515813B, an artificial ligament is described: by setting a degradable protective layer, the hydrophilicity of the transplanted ligament is increased, promoting osseointegration while preventing debris from ligament wear from entering the joint space and causing synovitis. This invention represents an innovation in ligament materials and inner and outer layer structures; however, the post-transplant effect still only simulates the structure of the direct insertion point.

[0009] (5) such as Figure 5 As shown in CN106726006B, the biomimetic ligament and biomimetic ligament system are innovative in terms of the material and surface biomembrane of the ligament, without any related design of the ligament structure.

[0010] A comprehensive analysis of the above patents reveals that existing ligament transplant designs only consider the characteristics of reconstructing the direct insertion point, without incorporating indirect insertion point structures to simulate the actual ACL insertion point structure and corresponding functions.

[0011] Existing columnar ligament grafts are fixed to the femur and tibia via bone tunnels, only reconstructing the direct insertion characteristics of the original ACL. This may lead to the following biomechanical problems and related complications: (1) Due to the lack of indirect attachment point constraint, the joint is not sufficiently constrained in certain directions, resulting in abnormal joint kinematic changes, such as rotational instability, which in turn leads to osteoarthritis due to abnormal cartilage stress; at the same time, it may lead to abnormal stress distribution at the bone attachment point, which may then develop into local bone destruction or bone resorption.

[0012] (2) Due to the lack of indirect anchor point constraint, while the direct fibers can slide freely in the bone tunnel, a large relative movement between the graft and bone is generated under high tension, which manifests as a longitudinal (along the long axis of the bone tunnel) "bungee effect" and a transverse "windshield wiper effect" (most obvious at the tunnel entrance), causing clinical complications such as bone tunnel enlargement, graft ligament wear or even rupture.

[0013] (3) Due to the lack of indirect stop point constraint, the tension is entirely borne by the direct stop point, and the direct fiber is fixed to the bone tunnel through the fixation device only within a limited length at both ends, which makes the fixation point a stress concentration point and causes fixation failure. Summary of the Invention

[0014] To address the aforementioned problems, the present invention aims to provide a ligament graft with indirect insertion points and its implantation method. By adding indirect insertion points to the graft structure, the morphology and function of the original ACL-bone interface can be simulated to a greater extent, increasing the contact area and connection morphology between the graft and bone. This better restores joint kinematics to avoid osteoarthritis, improves fixation stability to reduce relative movement between the graft and bone (such as bungee jumping effect, windshield wiper effect), bone tunnel enlargement, graft wear, and even rupture. At the same time, it reduces the stress at the direct fiber fixation site to reduce the risk of postoperative fixation failure.

[0015] The above-mentioned objective of this invention is achieved through the following technical solutions: A grafted ligament with indirect insertion includes a femoral direct insertion, a femoral indirect insertion, a free fibrous segment, a tibial direct insertion, and a tibial indirect insertion. The free fiber segment is located within the joint cavity and does not participate in ligament fixation. The direct insertion point on the femoral side and the direct insertion point on the tibia side are connected to the free fiber segment. The direct femoral insertion point and the direct tibial insertion point are fixed within the bone tunnel, while the indirect femoral insertion point and the indirect tibial insertion point are fixed on the bone surface. The indirect femoral insertion point and the indirect tibial insertion point may exist simultaneously or only one of them may exist. The indirect femoral insertion point is connected to either the direct femoral insertion point or the free fibrous segment. When the indirect femoral insertion point is connected to the direct femoral insertion point but not directly connected to the free fibrous segment, the two have a common femoral root. The tibial indirect insertion point is connected to either the tibial direct insertion point or the free fiber segment. When the tibial indirect insertion point is connected to the tibial direct insertion point but not directly connected to the free fiber segment, the two have a common tibial root.

[0016] Furthermore, the cross-sections of the femoral direct insertion point, the femoral indirect insertion point, the tibial direct insertion point, and the tibial indirect insertion point can be any shape including circles, semicircles, ellipses, rectangles, and round rectangles, or can simulate the shape of the original anterior cruciate ligament (ACL) insertion point. The cross-sectional area can be constant as a cylinder or vary irregularly.

[0017] Furthermore, on the femoral side, the femoral indirect insertion point is located posterior to and closer to the proximal end of the femoral direct insertion point; on the tibia side, the tibia indirect insertion point is located anterior to the tibia direct insertion point.

[0018] Furthermore, the connection method between the direct femoral insertion point and the indirect femoral insertion point, and between the direct tibial insertion point and the indirect tibial insertion point, can be any connection method including V-shaped connection or U-shaped connection. Simultaneous connection can be achieved through integrated weaving, integrated printing, or additional devices.

[0019] Furthermore, the bone tunnel and bone fixation of the femoral direct insertion point and the tibial direct insertion point are performed by methods including suspension fixation, compression fixation or hydrogel filling fixation. When compression fixation is used, the ends of the femoral direct insertion point and the tibial direct insertion point have traction structures; when suspension fixation is used, the ends of the femoral direct insertion point and the tibial direct insertion point have extension sections, and the extension sections have holes in the middle for connecting with the suspension fixation device.

[0020] Furthermore, when fixing the femoral side indirect insertion point and the tibial side indirect insertion point to the bone surface, no bone tunnel is drilled, and the fixation device includes a staple structure design or suture anchors. The staple structure is designed as a two-pronged structure, a four-pronged structure, or any other structural form that can produce a fixing effect, and the staple structure design has at least one spike structure for improving pull-out resistance. The suture anchors are fixed using suture techniques including single-row suture, double-row suture, or suture bridge suture.

[0021] Furthermore, the material of the transplanted ligament is one or more combinations including polyester fiber, ultra-high molecular weight polyethylene fiber, polypropylene fiber, collagen, and silk fibroin, or one or more combinations including autologous ligament, autologous tendon, allogeneic ligament, and allogeneic tendon.

[0022] Furthermore, the surface of the transplanted ligament is provided with a coating that promotes osseointegration, and the coating material is a calcium phosphate compound or a biodegradable polymer material.

[0023] Furthermore, the processing method of the transplanted ligament includes weaving, composite material lamination, collagen and silk fibroin self-assembly, or reshaping after taking materials from autologous ligaments, autologous tendons, allogeneic ligaments, or allogeneic tendons.

[0024] A method for implanting a grafted ligament with an indirect insertion point, as described above, includes the following steps: S1: The transplanted ligament is introduced into the joint cavity through a tibial tunnel, a femoral tunnel, or other joint approach; S2: The femoral direct insertion point is fixed in the femoral bone tunnel; S3: The femoral indirect insertion point is fixed on the femoral bone surface; S4: The tibial direct insertion point is fixed in the tibial bone tunnel; S5: The tibial indirect insertion point is fixed on the tibial bone surface; The order of S2 and S3, the order of S4 and S5, and the fixing order of the femoral direct insertion point, the femoral indirect insertion point, the tibial direct insertion point, and the tibial indirect insertion point can be adjusted according to the actual situation.

[0025] Compared with the prior art, the present invention has at least one of the following beneficial effects: (1) Precise biomimetic adaptation to restore the original joint movement function: This invention innovatively adds femoral and tibial indirect insertion points to the transplanted ligament, and combines a synergistic structure of "direct insertion point + indirect insertion point" (e.g., the femoral indirect insertion point is located behind the direct insertion point and closer to the proximal end, and the tibial indirect insertion point is located in front of the direct insertion point, with each sharing a root with the corresponding direct insertion point), to precisely replicate the morphology and spatial position characteristics of the original ACL-bone interface, maximizing the restoration of the physiological structure of the original ACL. This design can effectively restore the normal kinematic laws of the knee joint, avoid abnormal movements such as joint rotational instability caused by incomplete structural replication, and thus prevent uneven stress on the cartilage, thereby reducing the risk of postoperative osteoarthritis from the root.

[0026] (2) Improve fixation stability and reduce graft-bone related complications: In terms of fixation methods, this invention provides multiple adaptation schemes for direct insertion points, such as suspension fixation (end extension with connecting hole), compression fixation (end with traction structure), and hydrogel filling fixation, to ensure a stable connection with the bone tunnel; for indirect insertion points, boneless tunnel fixation methods are adopted (such as two- or four-pronged staples with barbed structures, single- or double-row / suture bridge technology suture anchors), which can improve pull-out resistance through the barbed structure of the staples and enhance the fit with the bone surface through the suture anchors. The synergistic fixation of dual insertion points can significantly increase the contact area between the grafted ligament and the bone, inhibit the generation of "bungee jumping effect" (longitudinal sliding) and "windshield wiper effect" (lateral wear) under high tension, and effectively reduce common clinical complications such as bone tunnel enlargement, grafted ligament wear, and even rupture.

[0027] (3) Optimize stress distribution and reduce the risk of fixation failure: In existing technologies, the tension of the transplanted ligament is entirely borne by the direct fixation point, which easily leads to stress concentration and failure at the fixation site. This invention achieves a reasonable distribution of tension between the "direct fixation point + indirect fixation point" by having the indirect fixation point bear part of the shear tension (matching the mechanical function of the original indirect fixation point), which greatly reduces the load on the direct fixation device. At the same time, the V-shaped / U-shaped connection (or integrated braiding / printing) between the direct and indirect fixation points further improves the continuity of force transmission, avoids sudden changes in local stress, and significantly reduces the probability of postoperative fixation failure.

[0028] (4) Strong adaptability and integration, aiding postoperative recovery: In terms of material selection, this invention covers synthetic materials (polyester fiber, ultra-high molecular weight polyethylene fiber, etc.) and biological tissues (autologous / allogeneic ligaments, tendons), which can be flexibly adapted according to the patient's age, degree of injury, and clinical needs; the calcium phosphate compound or biodegradable polymer coating on the surface of the transplanted ligament can actively promote osseointegration, accelerate the healing process of the transplant and bone tissue, and shorten the postoperative recovery period. In addition, various processing methods (weaving, composite material lamination, collagen-silk fibroin self-assembly, and biological tissue shaping) can ensure structural precision and further improve the stability and reliability of the transplant effect.

[0029] (5) Wide clinical applicability and adaptability to diverse surgical scenarios: The design of "indirect insertion points can exist simultaneously or only one" in this invention, the flexible fixation sequence (the fixation sequence of the femoral side and tibial side insertion points can be adjusted) and the multiple approach implantation scheme (tibial side tunnel, femoral side tunnel or other joint approach) can adapt to the differences in anatomical structure and surgical operation habits of different patients, reduce the difficulty of surgical operation, provide clinicians with more personalized choices, and have broad clinical promotion value. Attached Figure Description

[0030] Figure 1This is a schematic diagram of the structure of the double-hole suspension artificial ligament in the prior art (CN102908209B). Figure 2 This is a structural schematic diagram of the single-hole suspension artificial ligament in the prior art, CN102908210B. Figure 3 This is a schematic diagram of the structure of the folded suspension artificial ligament and its preparation method in the prior art (CN102871775B). Figure 4 This is a schematic diagram of the structure of an artificial ligament as described in CN112515813B of the prior art; Figure 5 This is a structural schematic diagram of the biomimetic ligament and biomimetic ligament system in the prior art, CN106726006B. Figure 6 This is a two-dimensional structural diagram of the transplanted ligament of the present invention; Figure 7 This is a schematic diagram of the cross-sectional shape of the simulated native ACL endpoint in this invention; Figure 8 This is a schematic diagram illustrating the connection method between the direct insertion point and the indirect insertion point on the femoral side in this invention; Figure 9 This is a schematic diagram of the method of bone fixation through bone tunnels at the femoral and tibial direct insertion points of the present invention. The left side is a schematic diagram of the end structure suitable for compression fixation; the right side is a schematic diagram of the end structure suitable for suspension fixation. Figure 10 This is a schematic diagram of the femoral lateral indirect insertion point, the tibial lateral indirect insertion point, and the fixation to the bone surface in this invention. The left side shows the fixation method using a staple; the right side shows the fixation method using suture anchors. Figure 11 This is a schematic diagram of the two-pronged (left) and four-pronged (right) structure of the staple of the present invention; Figure 12 This is a postoperative schematic diagram of the transplanted ligament with indirect insertion structures on both sides according to the present invention.

[0031] Figure Labels 11: Direct insertion point on the femoral side; 12: Indirect insertion point on the femoral side; 13: Femoral root; 14: Direct insertion point on the tibia; 15: Indirect insertion point on the tibia; 16: Tibial root; 17: Overall structure of the direct insertion point on the tibia; 18: Overall structure of the direct insertion point on the femoral side. 111: Traction structure; 112: Extension section; 113: Hole; 2: Free fiber segments; 21: bifurcated structure; 23: thorn structure. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0034] Currently, the ligaments used in anterior cruciate ligament reconstruction (ACLR) are fibrous tissue (autologous) or fibrous materials (artificial) with a relatively constant cross-sectional area. The two ends of the transplanted ligament are inserted into cylindrical bone tunnels on the femoral and tibial sides, respectively, and fixed using suspension fixation or interfacial compression screws. This approach primarily replicates the connection between the ligament fibers and bone at the direct bone insertion point, without fully considering the actual ligament-bone connection, particularly omitting the structure of indirect bone insertion points. Therefore, it alters the biomechanical function of the original ligament-bone interface, leading to a series of postoperative complications, mainly including joint kinematic abnormalities, arthritis caused by abnormal cartilage stress, and problems such as bone tunnel enlargement, ligament wear, and fixation failure due to significant relative movement between the transplanted ligament and bone.

[0035] To address the above issues, this invention proposes a ligament graft structure design with indirect insertion points and a corresponding fixation method. This design aims to better simulate the morphology of the original ACL-bone interface, increase the contact area and connection morphology between the grafted ligament and bone, better restore joint kinematics, and prevent osteoarthritis. It also improves fixation stability, reduces relative movement between the grafted ligament and bone (such as bungee jumping or windshield wiper effects), reduces stress concentration at the bone tunnel opening and on the grafted ligament, and minimizes bone tunnel enlargement, graft wear, and even rupture. Furthermore, it reduces stress at the direct fiber fixation site, lowering the risk of postoperative fixation failure.

[0036] The following is an illustration through specific examples: First Embodiment like Figure 6 As shown, this embodiment provides a transplanted ligament with indirect insertion points, including a femoral direct insertion point 11, a femoral indirect insertion point 12, a free fiber segment 2, a tibial direct insertion point 14, and a tibial indirect insertion point 15. The free fiber segment 2 is located within the joint cavity and does not participate in ligament fixation. The femoral side direct insertion point 11 and the tibial side direct insertion point 14 are connected to the free fiber segment 2. The direct femoral insertion point 11 and the direct tibial insertion point 14 are fixed within the bone tunnel, while the indirect femoral insertion point 12 and the indirect tibial insertion point 15 are fixed to the bone surface. The indirect femoral insertion point 12 and the indirect tibial insertion point 15 may exist simultaneously or only one of them may exist. Figure 6 The left-hand diagram shows a schematic representation of a joint insertion point on the femoral side (12) and the tibial side (15), as follows. Figure 6 The middle diagram shows only the indirect insertion point 12 on the femoral side, while the tibial side shows the overall structure 17 of the direct insertion point on the tibial side. Figure 6 The diagram on the right shows only the indirect insertion point on the tibial side 15, while the femoral side shows the overall structure of the direct insertion point on the femoral side 18.

[0037] The indirect femoral insertion point 12 is connected to either the direct femoral insertion point 11 or the free fibrous segment 2. When the indirect femoral insertion point 12 is connected to the direct femoral insertion point 11 but not directly connected to the free fibrous segment 2, the two have a common femoral root 13, the length of which is 0-10 mm. The tibial indirect insertion point 15 is connected to either the tibial direct insertion point 14 or the free fiber segment 2. When the tibial indirect insertion point 15 is connected to the tibial direct insertion point 14 but not directly connected to the free fiber segment 2, the two have a common tibial root 16, the length of which is 0-10 mm.

[0038] The length of the free fiber segment 2 is 5-30mm, the length of the femoral direct insertion point 11 and the tibial direct insertion point 14 is 5-50mm, and the length of the femoral indirect insertion point 12 and the tibial indirect insertion point 15 is 2-30mm. The lengths of the femoral direct insertion point 11, the femoral indirect insertion point 12, the tibial direct insertion point 14, and the tibial indirect insertion point 15 can be shortened according to the actual situation during use.

[0039] The grafted ligament with indirect insertion provided in this embodiment is a biomimetic structure designed to meet the needs of anterior cruciate ligament reconstruction (ACLR). Its overall composition and functional adaptation logic can be combined. Figure 6 The three structural diagrams are shown below for clear understanding: From a core compositional perspective, this transplanted ligament comprises five key parts: femoral direct insertion 11, femoral indirect insertion 12, free fibrous segment 2, tibial direct insertion 14, and tibial indirect insertion 15. The position, function, and connection relationships of each part exhibit clear physiological adaptability. Free fibrous segment 2 is a "connecting transition segment" existing only within the joint cavity; it does not participate in any fixation procedures and only serves to connect femoral direct insertion 11 and tibial direct insertion 14, mimicking the central fibrous structure of the original anterior cruciate ligament (ACL) within the joint cavity. The core functions of fixation and force transmission are undertaken by the combination of "direct insertion + indirect insertion," with fundamentally different fixation positions: femoral direct insertion 11 and tibial direct insertion 14 need to be implanted and fixed within pre-prepared bone tunnels in the femur and tibia, serving as the primary force transmission carriers; femoral indirect insertion 12 and tibial indirect insertion 15 do not require bone tunnels and are directly adhered to the bone surfaces of the femur and tibia, used to supplement constraint and distribute stress.

[0040] To accommodate the differences in anatomical structure and surgical needs of different patients, the indirect insertion points of this transplanted ligament are designed with flexible combinations, corresponding to... Figure 6 The three scenarios presented are: first, "bilateral indirect stop point" ( Figure 6 The left image shows that both the femoral side indirect insertion point 12 and the tibial side indirect insertion point 15 are preserved simultaneously, which is suitable for situations where the original ACL insertion point function needs to be maximized; the second is "femoral side indirect insertion point only" ( Figure 6 (middle image), at this time, only the overall structure of the tibial direct insertion point 17 is retained on the tibial side, and no indirect insertion point 15 is set on the tibial side, which is suitable for scenarios where the bone surface conditions on the tibial side are limited; the third is "only the indirect insertion point on the tibial side" ( Figure 6 (See right figure). In this case, only the overall structure 18 of the direct insertion point of the femur is retained on the femoral side, and the indirect insertion point 12 of the femur is not set. This is suitable for scenarios where the femoral bone surface conditions are limited.

[0041] In terms of structural connection details, the transplanted ligament strictly follows the "bionic adaptation" principle: the femoral side indirect insertion point 12 is not directly connected to the free fiber segment 2, but shares a "femoral side root 13" with the femoral side direct insertion point 11. The length of this root can be adjusted within the range of 0-10mm to ensure continuous force transmission between the indirect and direct insertion points; similarly, the tibial side indirect insertion point 15 is not directly connected to the free fiber segment 2, but shares a "tibial side root 16" with the tibial side direct insertion point 14. The root length is also 0-10mm to avoid structural dislocation when the indirect insertion point is under stress.

[0042] Furthermore, the length design of each part takes into account both universality and personalized needs: the length of the free fiber segment 2 is 5-30mm, which can adapt to different knee joint cavity sizes; the lengths of the femoral direct insertion point 11 and the tibial direct insertion point 14 are 5-50mm, which can match bone tunnels of different depths; the lengths of the femoral indirect insertion point 12 and the tibial indirect insertion point 15 are 2-30mm, which can adapt to bone surface fixation areas of different areas; and the lengths of all the above insertion points and free fiber segments can be shortened and adjusted during the surgical procedure according to the patient's actual anatomical data (such as bone tunnel depth, bone surface area, and joint cavity size), further improving surgical adaptability.

[0043] Furthermore, the cross-sections of the femoral direct insertion point 11, the femoral indirect insertion point 12, the tibial direct insertion point 14, and the tibial indirect insertion point 15 are any one of the following shapes: circular, semi-circular, elliptical, rectangular, or rounded rectangle. Figure 7 The shape of the simulated native anterior cruciate ligament (ACL) insertion point is shown. The cross-sectional area can be constant as a cylinder or vary irregularly, ranging from 0 to 600 mm. 2 between.

[0044] Furthermore, on the femoral side, the femoral side indirect insertion point 12 is located posterior to and closer to the proximal end of the femoral side direct insertion point 11; on the tibial side, the tibial side indirect insertion point 15 is located anterior to the tibial side direct insertion point 14.

[0045] This placement design is based on the anatomy of the knee joint and the physiological characteristics of the original anterior cruciate ligament (ACL) insertion points: "Posterior" on the femoral side refers to the side closer to the popliteal fossa of the knee joint, and "proximal" refers to the side closer to the hip joint; therefore, indirect insertion point 12 is posterior to direct insertion point 11 and closer to the hip joint. "Anterior" on the tibial side refers to the side closer to the patella of the knee joint; therefore, indirect insertion point 15 is anterior to direct insertion point 14. This design precisely replicates the spatial distribution of the original ACL insertion points, conforms to the biomechanical requirements of the knee joint, avoids interference between the transplanted ligament and other joint structures, and simultaneously assists the direct insertion point in constraining joint movement and optimizing stress distribution.

[0046] Furthermore, such as Figure 8 As shown, the connection between the femoral direct insertion point 11 and the femoral indirect insertion point 12, and between the tibial direct insertion point 14 and the tibial indirect insertion point 15, can be any connection method including V-shaped connection or U-shaped connection; at the same time, the connection can be achieved through integrated weaving, integrated printing or additional devices.

[0047] Furthermore, the femoral direct insertion point 11 and the tibial direct insertion point 14 are fixed to the bone through the bone tunnel in a manner including suspension fixation, compression fixation or hydrogel filling fixation. like Figure 9 As shown on the left, when compression fixation is used, the ends of the femoral direct insertion point 11 and the tibial direct insertion point 14 have traction structures 111; as shown on the left. Figure 9 As shown on the right, when suspension fixation is used, the ends of the femoral side direct insertion point 11 and the tibial side direct insertion point 14 have extension sections 112, and the extension sections 112 have holes 113 in the middle for connecting with the suspension fixation device.

[0048] Furthermore, when fixing the femoral side indirect insertion point 12 and the tibial side indirect insertion point 15 to the bone surface, no bone tunnel is drilled. The fixation device includes a staple structure design or suture anchors, such as... Figure 10 As shown; The staple structure is designed as a two-pronged structure or a four-pronged structure (such as...). Figure 11 (As shown) or any other structural form capable of providing a fixing effect, i.e., the forked structure 21 has two or four branches respectively. Furthermore, the staple structure design has at least one spike structure 23 for improving pull-out resistance; The suture anchors are fixed using suture techniques including single-row suture, double-row suture, or suture bridge suture.

[0049] Furthermore, the material of the transplanted ligament is one or more combinations including polyester fiber, ultra-high molecular weight polyethylene fiber, polypropylene fiber, collagen, and silk fibroin, or one or more combinations including autologous ligament, autologous tendon, allogeneic ligament, and allogeneic tendon.

[0050] Furthermore, the surface of the transplanted ligament is provided with a coating that promotes osseointegration, and the coating material is a calcium phosphate compound or a biodegradable polymer material.

[0051] Furthermore, the processing method of the transplanted ligament includes weaving, composite material lamination, collagen and silk fibroin self-assembly, or reshaping after taking materials from autologous ligaments, autologous tendons, allogeneic ligaments, or allogeneic tendons.

[0052] Second Embodiment This embodiment provides a method for implanting a transplanted ligament with an indirect insertion point based on the first embodiment, including the following steps: S1: The transplanted ligament is introduced into the joint cavity through a tibial tunnel, a femoral tunnel, or other joint approach; S2: The femoral direct insertion point 11 is fixed within the femoral bone tunnel; S3: The femoral indirect insertion point 12 is fixed onto the femoral bone surface; S4: The tibial direct insertion point 14 is fixed within the tibial bone tunnel; S5: The tibial indirect insertion point 15 is fixed onto the tibial bone surface; The order of S2 and S3, the order of S4 and S5, and the fixing order of the femoral direct insertion point, the femoral indirect insertion point, the tibial direct insertion point, and the tibial indirect insertion point can be adjusted according to the actual situation. Figure 12 The image shows a postoperative schematic of a transplanted ligament with indirect insertion structures on both sides.

[0053] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

[0054] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A transplanted ligament with an indirect stop point, characterized in that, The direct femoral insertion, the indirect femoral insertion, the free fiber segment, the direct tibial insertion, and the indirect tibial insertion; The free fiber segment is located in the joint cavity and does not participate in the fixation of the ligament, and the direct femoral insertion and the direct tibial insertion are connected with the free fiber segment; The direct femoral insertion and the direct tibial insertion are fixed in the bone tunnel, and the indirect femoral insertion and the indirect tibial insertion are fixed on the bone surface, and the indirect femoral insertion and the indirect tibial insertion exist simultaneously or only one of them exists; The indirect femoral insertion is connected with any one of the direct femoral insertion and the free fiber segment, and when the indirect femoral insertion is connected with the direct femoral insertion and not directly connected with the free fiber segment, the two have a common femoral root; The indirect tibial insertion is connected with any one of the direct tibial insertion and the free fiber segment, and when the indirect tibial insertion is connected with the direct tibial insertion and not directly connected with the free fiber segment, the two have a common tibial root.

2. The graft ligament with indirect stop point of claim 1, wherein, The cross section of the direct femoral insertion, the indirect femoral insertion, the direct tibial insertion, and the indirect tibial insertion is any one of a circle, a semicircle, an ellipse, a rectangle, a circular rectangle, or a shape simulating the original anterior cruciate ligament (ACL) insertion. The cross-sectional area can be constant as a cylinder or change as an irregular body.

3. The graft ligament with indirect fixation points of claim 1, wherein, On the femoral side, the indirect femoral insertion is located posterior to the direct femoral insertion and closer to the proximal end; on the tibial side, the indirect tibial insertion is located anterior to the direct tibial insertion.

4. The graft ligament with indirect fixation points of claim 1, wherein, The connection mode between the direct femoral insertion and the indirect femoral insertion, and between the direct tibial insertion and the indirect tibial insertion, is any one of a V-shaped connection or a U-shaped connection. Simultaneous connection can be achieved by integrated knitting, integrated printing, or additional devices.

5. The graft ligament with indirect fixation points of claim 1 wherein, The fixation mode of the direct femoral insertion and the direct tibial insertion into the bone tunnel and the bone is any one of hanging fixation, extrusion fixation, or hydrogel filling fixation. When extrusion fixation is used, the end of the direct femoral insertion and the direct tibial insertion has a traction structure; when hanging fixation is used, the end of the direct femoral insertion and the direct tibial insertion has an extension segment, and a hole is formed in the middle of the extension segment for connecting with the hanging fixation device.

6. The graft ligament with indirect fixation points of claim 1 wherein, When the indirect femoral insertion and the indirect tibial insertion are fixed to the bone surface, no bone tunnel is formed, and the fixation device includes a staple structure design or a suture anchor; The staple structure design is a two-prong structure, a four-prong structure, or any other structure that can produce a fixing effect, and the staple structure design has at least one spike structure for improving the pull-out resistance; The fixation mode of the suture anchor is any one of single-row suture, double-row suture, or suture bridge suture.

7. The graft ligament with indirect fixation points of claim 1 wherein, The material of the transplanted ligament is one or more of the following: polyester fiber, ultra-high molecular weight polyethylene fiber, polypropylene fiber, collagen, silk fibroin, etc., or one or more of the following: autologous ligament, autologous tendon, allogeneic ligament, allogeneic tendon, etc.

8. The graft ligament with indirect fixation points of claim 1 wherein, The surface of the transplanted ligament is coated with a material that promotes osseointegration, and the material of the coating is a calcium phosphate compound or a biodegradable polymer.

9. The graft ligament with indirect fixation points of claim 1 wherein, The processing methods for the transplanted ligaments include weaving, composite material lamination, and self-assembly of collagen and silk fibroin, or reshaping methods after taking materials from autologous ligaments, autologous tendons, allogeneic ligaments, or allogeneic tendons.

10. A method of implanting a ligament graft with an indirect stop point according to any one of claims 1-9, characterized in that, Includes the following steps: S1: The transplanted ligament is introduced into the joint cavity through a tibial tunnel, a femoral tunnel, or other joint approach; S2: Fix the direct insertion point on the femoral side into the femoral side bone tunnel; S3: Fix the femoral side indirect insertion point to the femoral side bone surface; S4: Fix the tibial direct insertion point into the tibial bone tunnel; S5: Fix the tibial side indirect insertion point to the tibial side bone surface; The order of S2 and S3, the order of S4 and S5, and the order of fixing the femoral direct insertion point, femoral indirect insertion point and tibial direct insertion point, tibial indirect insertion point can be adjusted according to the actual situation.

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