Metaphyseal oversleeve for tibial bone defects

Abstract

The invention relates to a metaphyseal oversleeve for tibia bone defect, which belongs to the technical field of orthopedic medical instruments, is configured and connected to a metaphyseal of a tibia, is used for supporting and fixing a tibia tray on the metaphyseal, and comprises a main body, the metaphyseal is provided with a counter bore along the length direction of the tibia, and the main body is inserted into the counter bore and is abutted against the inner wall of the counter bore; the main body is flush with the end face of the metaphysis end, the tibia tray is fixedly connected with the main body, the tibia tray abuts against the end face of the metaphysis end, and the main body is of a porous structure. The porosity in the radial direction of the tibia is gradually increased in a gradient mode from the bone cortex to the marrow cavity, so that the porosity of the oversleeve is distributed in a two-way gradient mode to achieve elasticity modulus self-adaption, the oversleeve is attached to the elasticity modulus of bone tissue around the oversleeve, and stress shielding is effectively avoided while the requirement for the supporting strength of the tibia tray is met.

Description

Technical Field

[0001] The invention belongs to the technical field of orthopedic medical devices, and in particular relates to a metaphyseal sleeve for tibial bone defects. Background Art

[0002] Complex primary knee replacement and revision surgery are often accompanied by varying degrees of bone defects, insufficient bone reserves, and difficulty in obtaining reliable biomechanical support for revision prostheses. For cases with large bone defects in the metaphysis, the use of metaphyseal sleeves for filling and fixation is a common treatment method. The metaphyseal sleeve can effectively cooperate with the tibial plateau and provide mechanical support, achieving better support and fixation of the prosthesis and reliably restoring the joint line height.

[0003] However, studies have found that the elastic modulus of a normal tibia decreases gradually from the cortical bone to the medullary cavity, and gradually decreases from the proximal end of the tibia to the distal end. The elastic modulus of the metal sleeve currently used is uniform, which results in a difference in the elastic modulus between the metal sleeve and the surrounding bone tissue. After the sleeve and the prosthesis are implanted, they become the main load-bearing components, resulting in a reduction in the stress on the bone tissue around the sleeve, causing stress shielding. According to Wolf's law, bones grow where they are needed and are absorbed where they are not needed, and stress shielding is not conducive to bone reconstruction. In particular, when solving large-sized bone defects, the greater the strength required for the sleeve to support and fix the prosthesis, the greater the difference in elastic modulus between the sleeve and the surrounding bone tissue, further causing stress shielding of the bone tissue around the sleeve, resulting in a decrease in bone density around the prosthesis, which can easily induce bone absorption around the sleeve and even prosthesis loosening and failure. Summary of the invention

[0004] I am an invention or new content In view of this, the present invention provides a metaphyseal sleeve for tibial bone defects to address the deficiencies in the prior art. The present invention enables the sleeve to fit the elastic modulus of the surrounding bone tissue, thereby meeting the support strength requirements of the tibial tray and effectively avoiding stress shielding.

[0005] The technical solution of the present invention is: a metaphysis sleeve for tibial bone defects, which is configured and connected to the metaphysis of the tibia, and is used to support and fix the tibial tray on the metaphysis, including a main body, a countersunk hole is opened on the metaphysis along the length direction of the tibia, the main body is inserted into the countersunk hole and abuts against the inner wall thereof, the main body is flush with the end surface of the metaphysis, the tibial tray is fixedly connected to the main body, the tibial tray abuts against the end surface of the metaphysis, the main body is a porous structure, the porosity of the main body along the length direction of the tibia increases gradually from the proximal end to the distal end of the tibia, and the porosity of the main body along the radial direction of the tibia increases gradually from the bone cortex to the medullary cavity.

[0006] Preferably, the porosity of the body is in the range of 30%-85%.

[0007] Preferably, the material of the main body is porous tantalum metal or titanium alloy. When the material of the main body is titanium alloy, the pore size range is 0.1mm-0.4mm; when the material of the main body is porous tantalum metal, the pore size range is 0.4mm-0.6mm.

[0008] Preferably, the main body is a bone trabecular structure, and the bone trabecular structure adopts a periodic arrangement of cubic unit cells to construct a porous structure.

[0009] Preferably, the cross section of the main body is elliptical, and the area of ​​the cross section gradually decreases from one end close to the tibial tray to the other end.

[0010] Preferably, the outer contour of the main body away from the tibial tray is stepped, the stepped outer contour is located on both sides of the short axis of the cross section, the height of the stepped outer contour is 25%-35% of the height of the main body, and the outer contour diameter of the main body between the two stepped outer contours remains unchanged.

[0011] Preferably, when the sleeve is used to fill a non-inclusive metaphyseal bone defect, the outer contour of the main body smoothly connects with the natural bone surface of the human body, and the height of the smooth transition portion is 65%-75% of the height of the main body.

[0012] Preferably, a first through hole is opened on the main body along the center line direction thereof, an extension rod is fixed on the tibial tray and is perpendicular to the extension rod, the extension rod passes through the first through hole and is inserted into the bone bed of the tibia, the extension rod abuts against the inner wall of the first through hole, a second through hole is opened on the main body along the radial direction thereof and is located on the side of the main body away from the tibial tray, a thread is provided on the inner wall of the second through hole so that a threaded fastener is matched and connected with the thread in the second through hole, and the threaded fastener passes through the second through hole and is fixedly connected with the extension rod thread.

[0013] Preferably, a support tube is fixed in the first through hole and is coaxial with its center line, the support tube is a low-porosity porous structure, the extension rod passes through the support tube and abuts against its inner wall, and the second through hole passes through one inner wall of the support tube.

[0014] Preferably, the contact surface between the main body and the tibial bone bed is provided with an osteoinductive growth factor coating, an antibacterial coating and an angiogenic growth factor coating.

[0015] Compared with the prior art, the present invention provides a metaphyseal sleeve for tibial bone defects, which fills the bone defect on the tibial metaphyseal end through the main body to support and fix the tibial tray. The porosity of the main body of the porous structure along the length direction of the tibia increases gradually from the proximal end to the distal end of the tibia, and the porosity along the radial direction of the tibia increases gradually from the bone cortex to the medullary cavity, so that the bidirectional gradient distribution of the porosity of the sleeve can achieve adaptive elastic modulus. The sleeve fits the elastic modulus of the surrounding bone tissue, meets the support strength of the tibial tray, and effectively avoids stress shielding. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a three-dimensional structural schematic diagram of the metaphyseal sleeve of the present invention;

[0017] Figure 2 It is a schematic diagram of the installation of the metaphyseal sleeve of the present invention for accommodating a bone defect;

[0018] Figure 3 It is a schematic diagram of the installation of the metaphyseal sleeve of the present invention applied to a non-contained bone defect;

[0019] Figure 4 is a front view of the metaphyseal sleeve of the present invention;

[0020] Figure 5 is a side view of the metaphyseal sleeve of the present invention;

[0021] Figure 6 It is a schematic diagram of the porosity change of the metaphyseal sleeve along the bone cortex-marrow cavity direction of the present invention;

[0022] Figure 7 Schematic diagram of porosity variation of the metaphyseal sleeve of the present invention along the proximal-distal direction of the tibia;

[0023] Figure 8 It is a cross-sectional view of the metaphyseal sleeve of the present invention. DETAILED DESCRIPTION

[0024] The present invention provides a metaphyseal sleeve for tibial bone defect, Figures 1 to 8 The present invention is described with reference to the structural schematic diagram of FIG.

[0025] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the technical solutions of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0026] Total knee replacement is one of the most successful surgeries for end-stage knee disease and an effective way to restore knee function. With the advent of an aging society, the number of primary knee replacements has increased exponentially, and the number of knee revisions has also increased year by year. Complex primary knee replacements and revisions are often accompanied by varying degrees of bone defects, insufficient bone reserves, and difficulty in obtaining reliable biomechanical support for revision prostheses. For cases with large bone defects in the metaphysis, the use of metaphyseal sleeves for filling and fixation is a common treatment method. The metaphyseal sleeve can effectively cooperate with the tibial plateau and provide mechanical support, thereby achieving better support and fixation of the prosthesis and reliably restoring the joint line height.

[0027] However, studies have found that the elastic modulus of a normal tibia decreases gradually from the cortical bone to the medullary cavity, and gradually decreases from the proximal end of the tibia to the distal end. The elastic modulus of the metal sleeve currently used is uniform, which results in a difference in the elastic modulus between the metal sleeve and the surrounding bone tissue. After the sleeve and the prosthesis are implanted, they become the main load-bearing components, resulting in a reduction in the stress on the bone tissue around the sleeve, causing stress shielding. According to Wolf's law, bones grow where they are needed and are absorbed where they are not needed, and stress shielding is not conducive to bone reconstruction. In particular, when solving large-sized bone defects, the greater the strength required for the sleeve to support and fix the prosthesis, the greater the difference in elastic modulus between the sleeve and the surrounding bone tissue, further causing stress shielding of the bone tissue around the sleeve, resulting in a decrease in bone density around the prosthesis, which can easily induce bone absorption around the sleeve and even prosthesis loosening and failure.

[0028] As shown in the figure, Figure 1 The present invention is a stereoscopic diagram of the metaphysis sleeve of the present embodiment, which is a metaphysis sleeve for tibial bone defects, configured to be connected to the metaphysis of the tibia 4, and used to support and fix the tibial tray 2 on the metaphysis to restore the normal function of the knee joint, including a main body 11, a countersunk hole is opened on the metaphysis along the length direction of the tibia 4, the main body 11 is inserted into the countersunk hole and abuts against the inner wall thereof, the main body 11 is flush with the end face of the metaphysis, the tibial tray 2 is fixedly connected to the main body 11, the tibial tray 2 abuts against the end face of the metaphysis, and the main body 11 is a porous structure, such as Figure 7The porosity of the main body 11 along the length direction of the tibia 4 increases gradually from the proximal end to the distal end of the tibia 4, and the porosity increases along the direction 16 to 17, as shown in FIG. Figure 6 As shown, the porosity of the main body 11 along the radial direction of the tibia 4 increases gradually from the bone cortex to the medullary cavity, and the porosity increases along the direction 14 to 15.

[0029] The main body 11 of the metaphyseal sleeve disclosed in the present embodiment is matched with the tibial bone bed and press-fitted. Before press-fitting, a conical hammer is used to cut and form a countersink on the metaphyseal bone bed of the tibia 4. The model of the conical hammer is continuously changed to make the countersink larger, and finally the countersink is matched with the main body 11 and then pressed into the bone bed. The main body 11 supports and fixes the tibial tray 2. The main body 11 is printed in an integrated manner using 3D printing technology, which facilitates the realization of bidirectional gradient pores and complex geometric surfaces.

[0030] As a further optimization solution, the porosity of the main body 11 in this embodiment ranges from 30% to 85%.

[0031] In this embodiment, the main body 11 adopts a porous structure design with a bidirectional gradient porosity change, which changes in a gradient increasing manner along the proximal-distal direction of the tibia, with a porosity range of 30% to 85%, and changes in a gradient increasing manner along the bone cortex-medullary cavity direction, with a porosity range of 30% to 85%. When in use, the specific porosity change is designed according to the bone density distribution law of the filling part and the differences between each part. The outer side of the main body 11 close to the cortical bone part plays a major supporting role. The main body 11 is connected and fixed to the prosthesis close to the proximal side of the tibia, and the distal side of the sleeve tibia is connected to the bone bed. The bone density decreases from the cortical bone to the medullary cavity. The bidirectional gradient distribution of porosity can achieve elastic modulus adaptation and effectively avoid stress shielding.

[0032] As a further optimization scheme, in this embodiment, the material of the main body 11 is porous tantalum metal or titanium alloy. When the material of the main body 11 is titanium alloy, the pore size range is 0.1mm-0.4mm, and when the material of the main body 11 is porous tantalum metal, the pore size range is 0.4mm-0.6mm.

[0033] The main body 11 in this embodiment is made of titanium alloy or tantalum metal. Porous tantalum has good biocompatibility. The pore size range of titanium alloy is 0.1mm~0.4mm, and that of tantalum metal is 0.4mm~0.6mm. The pore size is within the reasonable range for bone tissue growth. The main body 11 is manufactured in an integrated manner using 3D printing technology.

[0034] As a further optimization solution, the main body 11 in this embodiment is a simulated trabecular structure, and the trabecular structure adopts a periodic arrangement of cubic unit cells to construct a porous structure.

[0035] The main body 11 in this embodiment is a cancellous bone trabecular structure, which can promote the growth of bone tissue and fibrous tissue and provide a structural support for bone ingrowth. After the bone tissue grows in, the prosthesis can obtain good initial stability and improve the long-term situ rate of the prosthesis.

[0036] Preferably, the cross section of the main body 11 is elliptical, and the area of ​​the cross section gradually decreases from one end close to the tibial tray 2 to the other end.

[0037] When the main body 11 in this embodiment is fixed with the autologous bone (medullary cavity) by press-fitting, the elliptical cross-section helps to achieve initial stability, and stability is achieved by bone ingrowth in the later stage. The cross-sectional area gradually decreases from the proximal end to the distal end of the tibia (similar to a cone), and can fit the normal bone shape in an elliptical shape.

[0038] As a further optimization solution, Figure 4 is a front view of the metaphyseal sleeve of this embodiment, Figure 5 This is a side view of the metaphyseal sleeve of the present embodiment. In the present embodiment, the outer contour of the main body 11 away from the tibial tray 2 is stepped, and the stepped outer contour is located on both sides of the short axis of the cross section. The height of the stepped outer contour is 25%-35% of the height of the main body 11, and the outer contour diameter of the main body 11 between the two stepped outer contours remains unchanged.

[0039] In this embodiment, the main body 11 with a stepped outer contour can further improve the stability of the sleeve when it is press-fitted and fixed on the bone bed of the tibia.

[0040] like Figure 2 As shown, it is a schematic diagram of the installation of the metaphyseal sleeve applied to the inclusive bone defect, and its side profile is simplified to a cone. When used for non-inclusive metaphyseal bone defects, the metaphyseal sleeve needs to provide a good environment for the soft tissue.

[0041] As a further optimization solution, Figure 3 As shown, it is a schematic diagram of the installation of the metaphyseal sleeve of this embodiment applied to a non-inclusive bone defect. In this embodiment, when the sleeve is used to fill a non-inclusive metaphyseal bone defect, the outer contour of the main body 11 is smoothly connected with the natural bone surface of the human body, and the height of the smooth transition part is 65%-75% of the height of the main body 11.

[0042] The main body 11 in this embodiment is designed based on the anatomical shape near the natural tibial metaphysis and adopts a ligament-friendly bionic curve design, so that the main body 11 is smoothly connected to the natural bone surface of the human body, providing a more friendly environment for soft tissue.

[0043] like Figure 8As shown, it is a cross-sectional view of the metaphyseal sleeve of the present embodiment. As a further optimization scheme, in the present embodiment, a first through hole is opened on the main body 11 along its center line direction, an extension rod 3 is fixedly provided on the tibial tray 2 and is perpendicular to it, the extension rod 3 passes through the first through hole and is inserted into the bone bed of the tibia 4, and the extension rod 3 abuts against the inner wall of the first through hole, and a second through hole 12 is opened on the main body 11 along its radial direction and is located on the side of the main body 11 away from the tibial tray 2, and a thread is provided on the inner wall of the second through hole 12 so that a threaded fastener is matched with the thread in the second through hole 12, and the threaded fastener passes through the second through hole 12 and is threadedly fixedly connected to the extension rod 3.

[0044] In this embodiment, the tibial tray 2 is positioned by using the first through hole on the extension rod 3 and the main body 11, and the thread in the second through hole 12 is used to thread the threaded fasteners to be fixedly connected to the main body 11 and the extension rod 3, respectively, so as to achieve effective fixation of the sleeve and the tibial tray 2. The extension rod 3 is made of titanium alloy and is designed as a metal entity or a tuning fork at the end.

[0045] As a further optimization scheme, in this embodiment, a support tube 13 is fixedly provided in the first through hole and is coaxial with its center line. The support tube 13 is a low-porosity porous structure. The extension rod 3 passes through the support tube 13 and abuts against its inner wall. The second through hole 12 passes through the inner wall of one side of the support tube 13.

[0046] The support tube 13 in this embodiment is a low-porosity porous structure made of porous tantalum metal with a porosity range of 5%-10% and a thickness of 3-5mm. It is intended to provide necessary strength support for the main body 11. The main body 11 and the support tube 13 are integrally printed using 3D printing technology.

[0047] The support tube 13 in this embodiment is located at the center of the main body 11 and is distributed along the inner side of the first through hole of the main body 11 . The support tube 13 passes through the main body 11 and is flush with both ends thereof.

[0048] Meanwhile, the structural parameters of the support tube 13 depend on the inner strength of the main body 11 , and are intended to provide necessary support for the main body 11 . When the inner strength of the main body 11 is sufficient, the support tube 13 may not be included.

[0049] In addition, in this embodiment, an internal threaded tube (screw sleeve) can be fixed in the second through hole 12 for support to improve the strength of the threaded fastener fixing body 11 and the tibial tray 2. The internal threaded tube can adopt various forms such as a low-porosity porous structure or a solid structure (without pores), depending on the strength requirements.

[0050] As a further optimization solution, in this embodiment, the contact surface between the main body 11 and the tibial bone bed 4 is provided with a bone induction growth factor coating, an antibacterial coating and a blood vessel growth factor coating.

[0051] In this embodiment, the BMP-2 component contained in the bone induction growth factor coating can stimulate the activity of osteoblasts and accelerate the bone conduction process. The silver nanoparticle antibacterial substance in the antibacterial coating can inhibit the attachment and aggregation of bacteria on the implant surface and reduce the risk of infection. The angiogenic growth factor coating can promote the formation of new blood vessels and provide sufficient nutrition for bone tissue regeneration.

[0052] The metaphyseal sleeve for tibial bone defects disclosed in the embodiment of the present invention has the advantages of being more in line with the elastic modulus distribution of normal bone tissue, good short-term and long-term fixation, no stress shielding, smooth transition with the natural bone surface of the human body, and ligament-friendly. The metaphyseal sleeve is designed into a series of products of different specifications and models according to the scope and characteristics of the bone defect.

[0053] The specific implementation process of the metaphyseal sleeve for tibial bone defects disclosed in the embodiment of the present invention includes:

[0054] S1. Collect imaging data of the patient's lower limbs and determine the characteristics of the tibial metaphysis bone defect;

[0055] S2. Select the appropriate type, structure and specification of metaphyseal sleeve according to the characteristics of tibial bone defect and the patient's bone density distribution.

[0056] S3, during surgical installation, the metaphyseal sleeve is press-fitted into the bone bed of the tibial metaphysis 4;

[0057] S4. The inner side of the sleeve matches the tibial tray 2 and the extension rod 3, and is fixedly connected to the tibial tray 4 through threaded fasteners.

[0058] The above disclosure is only a preferred specific embodiment of the present invention, but the embodiments of the present invention are not limited thereto, and any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A metaphyseal sleeve for tibial bone defects, configured to be connected to the metaphyseal end of a tibia (4), and used to support and fix a tibial tray (2) on the metaphyseal end, characterized in that: The invention comprises a main body (11), a countersunk hole is opened on the epiphysis along the length direction of the tibia (4), the main body (11) is inserted into the countersunk hole and abuts against the inner wall thereof, the main body (11) is flush with the end surface of the epiphysis, the tibial tray (2) is fixedly connected to the main body (11), the tibial tray (2) abuts against the end surface of the epiphysis, the main body (11) is a porous structure, the porosity of the main body (11) along the length direction of the tibia (4) increases gradually from the proximal end to the distal end of the tibia (4), and the porosity of the main body (11) along the radial direction of the tibia (4) increases gradually from the bone cortex to the bone marrow cavity.

2. The metaphyseal sleeve for tibial bone defect according to claim 1, characterized in that: The porosity of the main body (11) ranges from 30% to 85%.

3. The metaphyseal sleeve for tibial bone defect according to claim 1, characterized in that: The material of the main body (11) is porous tantalum metal or titanium alloy. When the material of the main body (11) is titanium alloy, the pore size range is 0.1mm-0.4mm; when the material of the main body (11) is porous tantalum metal, the pore size range is 0.4mm-0.6mm.

4. The metaphyseal sleeve for tibial bone defect according to claim 1, characterized in that: The main body (11) is a bone trabecular structure, and the bone trabecular structure adopts a periodic arrangement of cubic unit cells to construct a porous structure.

5. The metaphyseal sleeve for tibial bone defect according to claim 1, characterized in that: The cross section of the main body (11) is elliptical, and the area of ​​the cross section gradually decreases from one end close to the tibial tray (2) to the other end.

6. The metaphyseal sleeve for tibial bone defect according to claim 5, characterized in that: The outer contour of the main body (11) away from the tibial tray (2) is stepped, and the stepped outer contour is located on both sides of the short axis of the cross section. The height of the stepped outer contour is 25%-35% of the height of the main body (11), and the outer contour diameter of the main body (11) between the two stepped outer contours remains unchanged.

7. The metaphyseal sleeve for tibial bone defect according to claim 6, characterized in that: When the sleeve is used to fill a non-inclusive metaphyseal bone defect, the outer contour of the main body (11) smoothly connects with the natural bone surface of the human body, and the height of the smooth transition part is 65%-75% of the height of the main body (11).

8. The metaphyseal sleeve for tibial bone defect according to claim 5, characterized in that: A first through hole is provided on the main body (11) along its center line direction, an extension rod (3) is fixed on the tibial tray (2) and is perpendicular to the extension rod (3), the extension rod (3) passes through the first through hole and is inserted into the bone bed of the tibia (4), the extension rod (3) abuts against the inner wall of the first through hole, a second through hole (12) is provided on the main body (11) along its radial direction, and is located on the side of the main body (11) away from the tibial tray (2), a thread is provided on the inner wall of the second through hole (12), so that a threaded fastener is matched with the thread in the second through hole (12), and the threaded fastener passes through the second through hole (12) and is threadedly fixedly connected to the extension rod (3).

9. The metaphyseal sleeve for tibial bone defect according to claim 8, characterized in that: A support tube (13) is fixedly arranged in the first through hole and is coaxial with the center line thereof; the support tube (13) is a low-porosity porous structure; the extension rod (3) passes through the support tube (13) and abuts against the inner wall thereof; and the second through hole (12) passes through the inner wall of one side of the support tube (13).

10. The metaphyseal sleeve for tibial bone defect according to claim 1, characterized in that: The contact surface between the main body (11) and the tibia (4) bone bed is provided with a bone induction growth factor coating, an antibacterial coating and a blood vessel growth factor coating.

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