Individualized tibia defect repairing type knee joint prosthesis

Abstract

The invention provides an individualized tibia defect repairing type knee joint prosthesis, and belongs to the technical field of orthopedic implants. The device is formed by assembling a femoral condyle, a femoral bone marrow needle, a plateau pad, a tibia plateau, a restoration body and a tibia bone marrow needle. Wherein the tibia platform and the restoration body are matched through metal-metal threads and are assisted by bone cement to achieve anti-rotation locking, the restoration body adopts a 3D printing individualized bone trabecula structure and is compounded with an HA coating to promote bone ingrowth, the tibia bone marrow needle and the platform are connected through a standard taper connector, inventory and individualization compatibility is achieved, and the bone marrow needle and the platform are connected through a standard taper connector. The defects that an existing prosthesis is large in bone mass loss, unattractive in reconstruction, free of bone ingrowth function, high in processing cost and the like are overcome, and the postoperative function of a tibia defect patient and the long-term stability of the prosthesis can be remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of orthopedic implant technology, specifically relating to a knee joint prosthesis for individualized repair of tibial defects. Background Technology

[0002] The knee joint is one of the most complex and weight-bearing joints in the human body. Due to its unique anatomical location and biomechanical environment, the proximal tibia is a common site for primary or metastatic bone tumors, and also an area where severe bone defects frequently occur during knee revision surgery. For large-segment tibial bone defects caused by tumor resection, prosthesis loosening, or infection, effectively restoring skeletal continuity, restoring knee joint stability, and achieving long-term stability is a major challenge in orthopedics.

[0003] While traditional modular prostheses offer a degree of flexibility in assembly, their shape does not match the patient's skeletal anatomy well, making it difficult to achieve precise anatomical reconstruction. This can easily lead to problems such as poor soft tissue balance and stress concentration around the prosthesis, affecting postoperative functional recovery and long-term prosthesis stability. In contrast, early customized individualized prostheses can achieve morphological matching, but they are usually manufactured over a long period of time and are very expensive. Furthermore, there is still room for optimization in terms of fixation methods and bone ingrowth induction. Summary of the Invention

[0004] The purpose of this invention is to provide an individualized knee joint prosthesis for repairing tibial defects. It aims to address the problems of traditional modular prostheses in the prior art, which, although they have a certain degree of assembly flexibility, have poor matching with the patient's skeletal anatomy, making it difficult to achieve precise anatomical reconstruction. This can easily lead to problems such as poor soft tissue balance and stress concentration around the prosthesis, affecting postoperative functional recovery and long-term stability of the prosthesis. While early customized individualized prostheses can achieve morphological matching, they are usually long in manufacturing cycle and expensive, and there is still room for optimization in terms of fixation method and bone ingrowth induction.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A personalized knee prosthesis for repairing tibial defects includes: Femoral condyle; A femoral bone marrow needle, which is fixedly connected to the femoral condyle; A platform pad that matches the articular surface of the femoral condyle; The tibial plateau includes a plateau surface, a support body, and a cone head. The plateau surface is provided with a buckle and a plateau pad for locking. The support body has external threads on its outer periphery. The cone head has a standard taper structure. The prosthesis includes a solid region and a porous region. The solid region has an internal thread that engages with the external thread of the support. The porous region has a porous structure with a pore diameter of 300-1000 μm, a wire diameter of 300-800 μm, and a porosity of 50-80%, and is coated with an HA coating. The prosthesis has an internal conical hole. The tibial bone marrow needle includes a bone marrow needle osteotomy segment, a bone marrow needle body, and a bone marrow needle conical hole. The bone marrow needle conical hole is connected to the conical head. The surface of the bone marrow needle body is coated with a Ti plus HA double coating. The Ti plus HA double coating on the surface of the bone marrow needle body fits with the conical hole, and a gap is reserved between the two for filling bone cement.

[0006] In a preferred embodiment of the present invention, the solid area and the porous area of ​​the prosthesis are integrally printed, with the porous area located on the side away from the knee joint and the solid area located on the side closer to the knee joint.

[0007] As a preferred embodiment of the present invention, bone cement is applied between the external thread of the support and the internal thread of the repair body.

[0008] As a preferred embodiment of the present invention, the anti-loosening structure of the tibial bone marrow needle is a Mohs taper of 1:10-1:20.

[0009] As a preferred embodiment of the present invention, the platform pad and the platform surface are locked together by a one-time snap-fit, and the snap-fit ​​release force is ≥150N.

[0010] As a preferred embodiment of the present invention, the thickness of the HA coating in the porous region of the repair body is 50-100 μm.

[0011] As a preferred embodiment of the present invention, the length of the intramedullary fixation segment of the tibial bone marrow needle can be selected and configured between 60mm and 140mm according to the remaining medullary cavity length.

[0012] As a preferred embodiment of the present invention, the prosthesis is reverse-engineered using the patient's CT data before surgery and manufactured using EBM or SLM metal 3D printing technology.

[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. By reverse engineering the patient's preoperative CT data, the prosthesis is manufactured in one piece using EBM or SLM metal 3D printing technology. This ensures that the prosthesis closely matches the anatomical structure of the tibial defect area, effectively restoring the biomechanical alignment of the knee joint and the soft tissue attachment conditions. At the same time, the tibial plateau, the prosthesis, and the tibial bone marrow nail are firmly bonded together through a triple fixation method of "threaded connection + tapered fit + bone cement reinforcement". This significantly enhances the prosthesis's anti-rotation and anti-subsidence capabilities and reduces the risk of failure due to mechanical loosening after surgery.

[0014] 2. The prosthesis features a dedicated porous region with pore size, wire diameter, and porosity strictly controlled to facilitate bone ingrowth: pore size 300–1000 μm, wire diameter 300–800 μm, and porosity 50%–80%. A 50–100 μm thick hydroxyapatite coating is also applied to the surface. This structure provides an ideal osteogenic microenvironment for host bone ingrowth. Combined with the Ti+HA dual-coating treatment on the tibial bone marrow needle surface, it guides bone tissue ingrowth into the prosthesis and its interface, achieving a smooth transition from mechanical fixation to biological fixation and significantly improving the long-term stability of the prosthesis.

[0015] 3. The prosthesis adopts a modular assembly design. The length of the intramedullary fixation segment of the tibial spinal cord needle can be flexibly selected within the range of 60–140 mm according to the actual length of the patient's medullary cavity, which enhances the surgical adaptability. The tibial plateau and the spinal cord needle adopt a standard tapered interface, which can realize mass production and inventory management, effectively reducing manufacturing costs and delivery cycle. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the structure in this invention; Figure 3 This is a schematic diagram of the structure in this invention; Figure 4 This is a schematic diagram of the structure in this invention; In the diagram: 1. Femoral bone marrow needle; 2. Femoral condyle; 3. Plateau pad; 4. Tibial plateau; 401. Plateau; 402. Support; 403. Cone; 5. Prosthesis; 501. Solid area; 502. Thread; 503. Porous area; 504. Internal conical foramen; 6. Tibial bone marrow needle; 601. Osteotomy segment of the bone marrow needle; 602. Bone marrow needle; 603. Conical foramen of the bone marrow needle. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1

[0019] Please see Figures 1-4 The present invention provides the following technical solutions: A personalized knee prosthesis for repairing tibial defects includes: Femoral condyle 2; Femoral bone marrow needle 1 is fixedly connected to the femoral condyle 2; Platform pad 3, which matches the articular surface of femoral condyle 2; Tibial plateau 4 includes a plateau surface 401, a support body 402 and a cone head 403. The plateau surface 401 is provided with a buckle and locked to the plateau pad 3. The support body 402 is provided with external threads on its outer periphery. The cone head 403 has a standard taper structure. The restoration 5 includes a solid region 501 and a porous region 503. The solid region 501 has an internal thread 502 that engages with the external thread of the support 402. The porous region 503 has a porous structure with a pore diameter of 300-1000 μm, a wire diameter of 300-800 μm, and a porosity of 50-80%, and is coated with an HA coating. The restoration 5 has an internal conical hole 504. Tibial bone marrow needle 6, which includes bone marrow needle osteotomy segment 601, bone marrow needle body 602 and bone marrow needle conical hole 603. The bone marrow needle conical hole 603 is connected to the conical head 403. The surface of the bone marrow needle body 602 is provided with Ti plus HA double coating. The surface of the bone marrow needle body 602 is provided with Ti plus HA double coating and fits with the conical hole 504. A gap is reserved between the two for filling bone cement.

[0020] In a specific embodiment of the present invention, the femoral condyle 2 is a standard knee joint prosthesis component, matching the anatomical shape of the patient's femoral condyle. The femoral medullary needle 1 is fixedly connected to the femoral condyle 2 by tapering, riveting, or bolting. The platform pad 3 matches the articular surface of the femoral condyle 2 and is locked to the tibial plateau by a snap-fit ​​structure. The platform surface 401 is provided with a snap-fit ​​structure for quick locking of the platform pad 3. The support body 402 has external threads on its outer periphery. The cone head 403 has a standard tapered structure for connecting with the tibial medullary needle 6. The prosthesis 5 is an individualized component 3D printed based on the patient's CT data. The solid area 501 has internal threads 502 that engage with the external threads of the support body 402. The porous area 503 has a pore diameter of 300–1000 μm and a wire diameter of 300–800 μm. The prosthesis features a trabecular bone structure with a micrometer diameter and a porosity of 50–80%, coated with an HA layer. An inner conical hole 504 is used for taper fitting with the root of the tibial medullary needle 6. The head of the prosthesis tapers with the conical head 403 of the tibial plateau 4, and the distal end is embedded in the remaining medullary cavity. The surface has a Ti+HA double coating, and the root features a taper-based anti-dislodgement structure corresponding to the inner conical hole 504 of the prosthesis 5. The prosthesis 5 is customized based on the patient's osteotomy area CT data to achieve anatomical reconstruction of the osteotomy area and reduce soft tissue irritation. The tibial plateau 4, medullary needle 6, and prosthesis 5 are triple-fixed using a combination of threaded joints, taper fitting, and bone cement to prevent rotation. The trabecular bone region features a 503 HA coating to provide a bone ingrowth channel, enhancing long-term biological fixation strength. The tibial plateau 4 and medullary nail 6 utilize a standard tapered interface, enabling mass production and inventory management to reduce costs. The prosthesis 5 is 3D printed for lightweight design, reducing the amount of femoral osteotomy. The modular structure allows for flexible adjustment of length and angle during surgery, effectively addressing the shortcomings of existing technologies. It boasts advantages such as high shape matching, good stability, promotion of bone ingrowth, and reduced costs, significantly improving postoperative function and long-term prosthesis stability in patients with tibial defects, and increasing surgical success rates.

[0021] Please refer to the details. Figure 3 The solid region 501 and the porous region 503 of the prosthesis 5 are printed as a single unit. The porous region 503 is located on the side away from the knee joint, and the solid region 501 is located on the side closer to the knee joint.

[0022] In this embodiment, the prosthesis consists of a solid region 501 and a porous region 503, and these two parts are integrally printed. The porous region 503 is located on the side away from the knee joint, and the solid region 501 is located on the side closer to the knee joint. This design allows the porous region to better contact the host bone, promote bone ingrowth, and at the same time ensure the strength and stability of the solid region.

[0023] Please refer to the details. Figure 1 Bone cement is applied between the external thread of the support 402 and the internal thread 502 of the repair 5.

[0024] In this embodiment, bone cement is applied between the external thread of the support 402 and the internal thread 502 of the prosthesis 5 to enhance the connection strength between the prosthesis and the support, prevent rotation and loosening, and improve the stability of the prosthesis.

[0025] Please refer to the details. Figure 2 The anti-loosening structure of the tibial bone marrow needle 6 is a Mohs taper of 1:10-1:20.

[0026] In this embodiment, the anti-dislodgement structure of the tibial bone marrow needle 6 is a Mohs taper of 1:10-1:20, which prevents the tibial bone marrow needle 6 from falling out of the medullary cavity and improves the safety of the prosthesis.

[0027] Please refer to the details. Figure 1 The platform pad 3 and the platform surface 401 are locked together by a one-time snap-fit, and the snap-fit ​​release force is ≥150N.

[0028] In this embodiment, the platform pad 3 and the platform surface 401 are locked together by a one-time snap fastener with a release force of ≥150N, which can make the connection between the platform pad 3 and the platform surface 401 firm, prevent loosening, and facilitate surgical operation.

[0029] Please refer to the details. Figure 1 The thickness of the HA coating in the porous region 503 of the repair body 5 is 50-100μm.

[0030] In this embodiment, the HA coating thickness of the porous region 503 of the prosthesis is 50-100μm to ensure the quality and effect of the HA coating and promote bone ingrowth.

[0031] Please refer to the details. Figure 2 The length of the intramedullary fixation segment of the tibial bone marrow needle 6 can be selected and configured between 60mm and 140mm according to the remaining medullary cavity length.

[0032] In this embodiment, the length of the intramedullary fixation segment of the tibial bone marrow needle 6 can be selected and matched between 60mm and 140mm according to the remaining medullary cavity length, so that the tibial bone marrow needle 6 can better adapt to the medullary cavity length of different patients and improve the fit and stability of the prosthesis.

[0033] Please refer to the details. Figure 3 The prosthesis 5 is reverse-engineered using the patient's CT data before surgery and manufactured using EBM or SLM metal 3D printing technology.

[0034] In this embodiment, the prosthesis is reverse-engineered using the patient's CT data before surgery and manufactured using EBM or SLM metal 3D printing technology, so that the prosthesis can more accurately match the patient's anatomical structure and improve the individualization and efficacy of the prosthesis.

[0035] The working principle and usage process of this invention are as follows: Individualized modeling is performed based on the defect shape, precisely dividing the solid area 501 and porous area 503, and designing the internal thread 502 and internal conical hole 504. The diameter and selectable length of the tibial medullary needle 6 are determined according to the diameter and length of the medullary cavity. The prosthesis 5 is manufactured using EBM or SLM metal 3D printing technology to create a titanium alloy prosthesis, forming the solid 501 and porous structure 503 in one step. The porous area 503 of the prosthesis 5 is treated with an HA coating of 50-100μm. The intramedullary fixation segment of the tibial medullary needle 6 is treated with a Ti+HA double coating. The conical hole 603 of the tibial medullary needle 6 is connected to the conical head 40 of the tibial plateau 4. 3. Connect the prosthesis and tighten it using a special tool. Fill an appropriate amount of bone cement into the inner conical hole 504 of the prosthesis 5. Apply bone cement evenly to the external thread of the support 402 of the tibial plateau 4 and the internal thread 502 of the prosthesis 5. Insert the prosthesis 5 and rotate it until the external thread and internal thread 502 are fully engaged. The assembled complete tibial prosthesis is inserted into the prepared tibial medullary cavity and tightened in place to ensure that the prosthesis 5 is in close contact with the osteotomy surface of the host bone. Wait for the bone cement to solidify. Lock the platform pad 3 onto the platform surface 401 of the tibial plateau 4 with a disposable buckle. Reduce the knee joint and check the range of motion, stability and alignment of the joint. Close the incision routinely to complete the surgery.

[0036] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A personalized knee joint prosthesis for repairing tibial defects, characterized in that: include: Femoral condyle (2); Femoral bone marrow needle (1), wherein the femoral bone marrow needle (1) is fixedly connected to the femoral condyle (2); Platform pad (3), which matches the articular surface of the femoral condyle (2); Tibial plateau (4), the tibial plateau (4) includes a plateau surface (401), a support body (402) and a cone head (403). The plateau surface (401) is provided with a buckle and a plateau pad (3) for locking. The support body (402) is provided with an external thread on its outer periphery. The cone head (403) is a standard taper structure. The restoration (5) includes a solid region (501) and a porous region (503). The solid region (501) is provided with an internal thread (502) that engages with the external thread of the support (402). The porous region (503) has a porous structure with a pore diameter of 300-1000 μm, a wire diameter of 300-800 μm, and a porosity of 50-80%, and is coated with an HA coating. The restoration (5) has an internal conical hole (504). Tibial bone marrow needle (6), the tibial bone marrow needle (6) includes a bone marrow needle osteotomy segment (601), a bone marrow needle body (602) and a bone marrow needle conical hole (603), the bone marrow needle conical hole (603) is connected to the conical head (403), the surface of the bone marrow needle body (602) is provided with a Ti plus HA double coating, the surface of the bone marrow needle body (602) is provided with a Ti plus HA double coating and fits with the conical hole (504), and a gap is reserved between the two for filling bone cement.

2. The individualized knee joint prosthesis for repairing tibial defects according to claim 1, characterized in that: The solid area (501) and the porous area (503) of the prosthesis (5) are integrally printed. The porous area (503) is located on the side away from the knee joint, and the solid area (501) is located on the side closer to the knee joint.

3. The individualized knee joint prosthesis for repairing tibial defects according to claim 2, characterized in that: Bone cement is applied between the external thread of the support (402) and the internal thread (502) of the repair (5).

4. The individualized knee joint prosthesis for repairing tibial defects according to claim 3, characterized in that: The anti-loosening structure of the tibial bone marrow needle (6) is a Mohs taper of 1:10-1:

20.

5. The individualized knee joint prosthesis for repairing tibial defects according to claim 4, characterized in that: The platform pad (3) and the platform surface (401) are locked together by a one-time snap fastener, and the snap fastener release force is ≥150N.

6. The individualized knee joint prosthesis for repairing tibial defects according to claim 5, characterized in that: The thickness of the HA coating in the porous region (503) of the repair (5) is 50-100 μm.

7. The individualized knee joint prosthesis for repairing tibial defects according to claim 6, characterized in that: The length of the intramedullary fixation segment of the tibial bone marrow needle (6) can be selected and configured between 60mm and 140mm according to the remaining medullary cavity length.

8. The individualized knee joint prosthesis for repairing tibial defects according to claim 7, characterized in that: The prosthesis (5) is reverse-engineered using the patient's CT data before surgery and manufactured using EBM or SLM metal 3D printing technology.

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