A new type of 3D printed bone plate

Abstract

The present invention provides a novel 3D-printed bone plate, belonging to the field of medical device technology. The novel 3D-printed bone plate comprises: a bone plate, which is made by an additive manufacturing process and has a local reinforcement structure design for the reinforcement area. Through a 3D printing strategy with layer-by-layer energy density gradient changes, the density and mechanical properties of key parts are significantly improved, which not only greatly enhances the compression and shear resistance of the bone plate in the local area, but also ensures precise matching with the patient's bones, which is conducive to promoting stability in the fracture healing process. In addition, the design process based on the patient's CT / MRI data ensures that the bone plate can be customized for individual differences, thereby improving the success rate of the operation and the patient's recovery speed.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices, and in particular relates to a novel 3D printed bone plate. Background Art

[0002] The development of additive manufacturing, also known as 3D printing, has provided new solutions for the medical device sector, particularly for personalized medical products. 3D printing technology can produce customized bone plates based on a patient's CT or MRI imaging data, achieving a close fit with the patient's anatomy and enhancing treatment effectiveness. Furthermore, by adjusting printing parameters, localized reinforcement can be achieved in specific areas to improve the plate's mechanical properties, such as compressive and shear resistance, while also optimizing overall weight and rigidity, mitigating the negative effects of a mismatch in elastic modulus with human bone.

[0003] For patients who undergo distraction osteotomy surgery, after the plate is installed, there are often large blank areas in the distraction zone, forming high-stress areas of the plate. In order to fill these gaps, some doctors choose to take bones from the patient's ilium for filling, while others choose not to do any filling. Not filling may increase the risk of plate fracture, while taking bones from the ilium may cause damage to the bones in the patient's healthy area. Summary of the Invention

[0004] The purpose of the present invention is to provide a new type of 3D printed bone plate, which aims to solve the problem in the prior art that for patients undergoing distraction osteotomy surgery, after the bone plate is installed, there are often large blank areas in the distraction area, forming high-stress areas of the bone plate. In order to fill these gaps, some doctors will choose to take bones from the patient's ilium for filling, while others choose not to perform any filling. Not filling may increase the risk of plate fracture, while taking bones from the ilium may cause damage to the bones in the patient's healthy area.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A new type of 3D printed bone plate, comprising:

[0007] The bone plate is made using an additive manufacturing process and has a local reinforcement structure designed for the reinforced area. Through a 3D printing strategy with a layer-by-layer energy density gradient change, the density is increased in key areas, forming a gradient material structure, which significantly enhances the local compression and shear resistance.

[0008] Screw holes are provided on the surface of the bone plate;

[0009] The design of the local enhancement structure includes the energy input strategy in the enhancement area. By adjusting the laser power, scanning speed and layer thickness, the energy density is increased layer by layer in the enhancement area to form a density gradient.

[0010] The enhanced area was laser-melted using TC4 titanium alloy powder with a laser power of 300-400W, a scanning speed of 800-1000mm / s, and a layer thickness of 20-30μm. TC4-high material was then 3D printed.

[0011] The non-reinforced area was laser-melted using TC4 titanium alloy powder with a laser power of 200-300W, a scanning speed of 1100-1200mm / s, and a layer thickness of 40-50μm. TC4-1ow material was produced by 3D printing.

[0012] As a preferred solution of the present invention, the local enhancement structure design includes an energy input strategy in the enhancement area, and by adjusting the laser power, scanning speed and layer thickness, the energy density in the enhancement area is increased layer by layer to form a density gradient.

[0013] As a preferred solution of the present invention, in the additive manufacturing, the printing parameters used in the enhanced area are controlled as follows: laser power 300-400W, scanning speed 800-1000mm / s, and layer thickness 20-30μm; the printing parameters used in the non-enhanced area are controlled as follows: laser power 200-300W, scanning speed 1100-1200mm / s, and layer thickness 40-50μm.

[0014] As a preferred solution of the present invention, the design of the bone plate is based on the DICOM file generated by the patient's CT / MRI data. The morphology of the bone after correction is simulated by three-dimensional modeling software, and the position and angle of the enhanced area are planned to ensure accurate matching with the patient's bones.

[0015] As a preferred solution of the present invention, the mechanical properties of the local reinforced area and the surrounding materials transition smoothly, avoiding stress concentration caused by sudden change in rigidity, while reducing the overall weight and rigidity, and reducing the stress shielding effect caused by the mismatch with the elastic modulus of human bones.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. This new 3D-printed plate utilizes additive manufacturing technology and implements a locally enhanced structural design. Specifically, a 3D printing strategy with a layer-by-layer energy density gradient in the enhanced area significantly improves the density and mechanical properties of key areas. This enhances the plate's compressive and shear resistance in localized areas, ensuring a precise fit with the patient's bones, which promotes stability during fracture healing. The plate also features stress-buffering properties: In high-stress areas, the osteotomy distraction area utilizes TC4-high, a material with a high elastic modulus, to provide rigid support against transient impact loads and peak stresses during walking. The fitting area utilizes TC4-1ow, a material with a low elastic modulus, to allow for moderate elastic deformation to absorb cyclic load energy.

[0018] 2. A smooth transition in mechanical properties is achieved between the plate's localized reinforcement structure and the surrounding material, effectively avoiding stress concentration caused by sudden changes in rigidity and reducing the risk of complications with long-term use. This design also reduces the overall weight and rigidity of the device, helping to mitigate the stress shielding effect caused by a mismatch with the elastic modulus of natural bone, thereby promoting normal bone growth and reconstruction. By optimizing printing parameters, the plate achieves both the desired localized reinforcement and the overall lightweight structure, making it more biocompatible and providing better support for the patient's recovery.

[0019] 3. Improved biomechanical compatibility: The gradient transition of the elastic modulus between the high-stress area and the fitting area makes the overall modulus of the plate closer to the mechanical matching range of the cortical bone and cancellous bone, resulting in a more uniform stress distribution and better matching of the elastic modulus of the fitting area with the bone, effectively reducing the risk of stress shielding and accelerating the bone integration process.

[0020] 4. Optimized design of locally reinforced plates: This process uses precise gradient design and dynamic adaptability optimization strategies. The plates in high-stress areas are reinforced at the bone distraction site to significantly improve the material's load-bearing performance. The non-reinforced process is retained in the fitting area to reduce the stress shielding effect. The locally reinforced plates perform optimally in core biomechanical indicators such as stress distribution uniformity and bone surface adaptability. The elastic modulus has a gradient transition, and the low elastic modulus material allows moderate elastic deformation to absorb cyclic load energy, which can effectively meet the clinical needs of complex fracture surgery. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to provide an understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0022] Figure 1 It is a main perspective view of the present invention;

[0023] Figure 2This is a diagram showing the loading of the bone plate in the present invention;

[0024] Figure 3 This is a curve diagram for verifying the convergence of the equivalent elastic strain of the matching metal bone plate in the present invention;

[0025] Figure 4 This is a graph showing the convergence verification results of the equivalent elastic strain and its percentage change in the present invention;

[0026] Figure 5 Schematic diagram of constraints and load loading in the present invention;

[0027] Figure 6 is a material parameter diagram in the present invention;

[0028] Figure 7 This is a mechanical test design drawing of the metal bone plate in the present invention;

[0029] Figure 8 This is a comparison diagram of equivalent elastic strain in the present invention;

[0030] Figure 9 This is the equivalent elastic strain analysis result diagram in the present invention;

[0031] Figure 10 This is an equivalent stress comparison diagram in the present invention;

[0032] Figure 11 This is the equivalent stress analysis result diagram in the present invention;

[0033] Figure 12 This is a diagram showing the dynamic cantilever test results of the present invention;

[0034] Figure 13 This is a dynamic cantilever cycle test curve diagram in the present invention;

[0035] Figure 14 This is a static cantilever test result diagram in the present invention;

[0036] Figure 15 This is a static cantilever test curve diagram in the present invention;

[0037] Figure 16 This is the scanning power diagram of the 3D printing of the bone plate in the present invention;

[0038] Figure 17 This is a scanning speed diagram of the 3D printing of the bone plate in the present invention;

[0039] Figure 18 This is a 3D printed layer thickness map of the bone plate in the present invention.

[0040] In the figure: 1. Bone plate; 2. Screw hole. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0042] Example 1

[0043] See also Figures 1-18 , the present invention provides the following technical solutions:

[0044] A new type of 3D printed bone plate, comprising:

[0045] Bone plate 1 is made using an additive manufacturing process and features a localized reinforcement structure designed for the enhanced area. Through a 3D printing strategy with a layer-by-layer energy density gradient, the density is increased in key areas, forming a gradient material structure that significantly enhances local compressive and shear resistance.

[0046] Screw hole 2, which is provided on the surface of the bone plate 1;

[0047] The design of the local enhancement structure includes the energy input strategy in the enhancement area. By adjusting the laser power, scanning speed and layer thickness, the energy density is increased layer by layer in the enhancement area to form a density gradient.

[0048] The enhanced area was laser-melted using TC4 titanium alloy powder with a laser power of 300-400W, a scanning speed of 800-1000mm / s, and a layer thickness of 20-30μm. TC4-high material was then 3D printed.

[0049] The non-reinforced area was laser-melted using TC4 titanium alloy powder with a laser power of 200-300W, a scanning speed of 1100-1200mm / s, and a layer thickness of 40-50μm. TC4-1ow material was produced by 3D printing.

[0050] In a specific embodiment of the present invention, the bone plate 1 has a local enhanced structural design in the enhanced area, and the density and mechanical properties of key parts are improved by the strategy of energy density gradient change. In the enhanced area: the parameters of laser power 300-400W, scanning speed 800-1000mm / s and layer thickness 20-30μm are set to form a density gradient in the enhanced area in a way of increasing energy density layer by layer, thereby significantly improving the compressive and shear resistance. In the non-enhanced area: for areas that do not require enhancement, lower laser power 200-300W, higher scanning speed 1100-1200mm / s and larger layer thickness 40-50μm are used for printing to ensure the lightweight and economy of the overall structure. A plurality of screw holes 2 are provided on the surface of the bone plate 1, and the screws are used to print the parts. Insertion is used to fix the bone plate 1 to the bone, and the energy input strategy for the enhanced area is achieved by precisely adjusting the laser power, scanning speed and layer thickness, ensuring the density and strength of the material in key areas. Due to the use of gradient material structure design, it can better simulate the natural structure of human bones and improve compatibility with human tissues. Through the 3D printing strategy of layer-by-layer energy density gradient change, a gradient material structure is achieved, so that the bone plate 1 can significantly improve the local strength while ensuring overall lightness. The size and degree of enhancement of the enhanced area can be adjusted according to the patient's specific fracture situation to achieve personalized customization and improve the treatment effect. The additive manufacturing process is used. At the same time, personalized customization can reduce the number of operations and reduce treatment costs. This experiment is based on YY / T0342-2020 According to the YY / T1503-2016 standard, ANSYS Workbench 2020 was used to establish a finite element model of the bone plate. The mechanical response under the simulated compressive load was simulated, and the strain distribution data of different material properties were extracted. Among the three types of additively manufactured bone plates, the maximum equivalent stress and strain of the locally reinforced bone plate were better than those of the unreinforced bone plate, but slightly lower than those of the overall reinforced bone plate. The overall reinforced bone plate has a high elastic modulus and a low elastic modulus of the bone, which easily forms stress shielding in the bone surface contact area, affecting postoperative bone healing.

[0051] Optimal design of locally enhanced bone plates: This process uses precise gradient design and dynamic adaptability optimization strategies;

[0052] High stress area: The bone plate is reinforced at the bone distraction area to significantly improve the material's load-bearing performance;

[0053] Lamination area: retain the non-reinforcement process to reduce stress shielding effect;

[0054] The locally reinforced bone plate performs optimally in core biomechanical indicators such as stress distribution uniformity and bone surface adaptability, effectively meeting the clinical needs of complex fracture surgery.

[0055] To investigate the advantages of locally enhanced bone plates, 3D printed bone plates of three specifications (no enhancement, enhancement, and locally enhanced) were embedded in a fixture in a specific manner and fixed on a testing machine. The inner surface of the plate (the side that contacts the bone surface) was facing upward and parallel to the tabletop. The plate was placed so that the roller contacted the inner surface of the plate. The distance a between the embedding interface and the center of the roller was measured and recorded (set to 20 mm). Figure 14 , Strength comparison analysis: In the static cantilever test, the average bending strength of the overall reinforced plate is 31.03Nm, ​​the local reinforced plate is 26.9Nm, and the non-reinforced plate is only 18.66Nm. This shows that the overall reinforced plate significantly improves the static bending strength of the plate, and the reinforcement effect is obvious, while the effect of local reinforcement is between the overall reinforcement and non-reinforcement. Fatigue performance comparison analysis: In the dynamic cantilever test, 2 of the 3 samples of the non-reinforced plate broke within one million cycles, while the overall reinforced and locally reinforced plate samples did not break, reflecting the fatigue resistance of the overall reinforcement and local reinforcement, enabling it to withstand more cyclic loads without breaking. The overall reinforcement and local reinforcement processes have a positive effect on the mechanical properties of the 3D printed plate. In terms of static strength and dynamic fatigue performance, the overall reinforced plate performs best, followed by the locally reinforced plate. On the contrary, the non-reinforced plate is relatively weak. Judging from the test results, the overall reinforced and locally reinforced 3D Printed bone plates have greater advantages in mechanical properties. The overall enhanced elastic modulus is higher, which will cause stress shielding and affect postoperative bone recovery. Locally enhanced bone plates are more suitable for actual medical application scenarios and can better meet the needs of bone plates to resist static and dynamic loads during human use.

[0056] Dynamic cantilever test: Set the hole spacing to 17mm, the roller diameter to 10mm, align the test specimen axis so that it is perpendicular to the roller axis, set the frequency to 10Hz, the R ratio to 0.1, and perform a one million cycle test;

[0057] Static cantilever test: Set the hole spacing to 17mm, the roller diameter to 10mm, and the loading rate to 0.04mm / s. Load until the plate fails, and record the relevant load and displacement data.

[0058] The locally enhanced bone plate uses zoning performance control technology to balance mechanical strength and adaptability, providing a new solution for the customized design of orthopedic implant devices.

[0059] For details, please refer to Figure 2 The design of the bone plate 1 is based on the DICOM file generated by the patient's CT / MRI data. The 3D modeling software is used to simulate the corrected shape of the bone and plan the position and angle of the enhanced area to ensure accurate matching with the patient's bone.

[0060] In this embodiment: During the design process, it is ensured that the plate 1 can achieve precise matching with the patient's bones. By adjusting the position and angle of the local reinforcement structure to adapt to the unique anatomical structure of each patient, the treatment effect is maximized. The plate 1 designed based on the patient's specific CT / MRI data not only takes into account individual differences, but also optimizes the position and angle of the reinforcement area by accurately simulating the corrected shape of the bone. This personalized approach improves the success rate of treatment and patient satisfaction. The precisely matched plate 1 can better distribute stress, reduce the risk of postoperative complications, and promote a more natural bone healing process. By using the patient's own medical imaging data for design, it is ensured that the plate 1 can perfectly fit the patient's bones and provide the best support. The personalized plate 1 design can more accurately meet the patient's treatment needs, reduce surgical risks, and improve treatment effects. Due to the high degree of matching between the plate 1 and the patient's bones, the impact on surrounding tissues is reduced, which helps to speed up postoperative recovery.

[0061] For details, please refer to Figure 16-Figure 18 The mechanical properties of the local reinforced area and the surrounding materials transition smoothly, avoiding stress concentration caused by sudden changes in rigidity, while reducing the overall weight and rigidity, and reducing the stress shielding effect caused by the mismatch with the elastic modulus of human bones.

[0062] In this embodiment, while ensuring that the locally reinforced area has sufficient compressive and shear resistance, a smooth transition in mechanical properties with the surrounding materials is achieved. This design not only effectively prevents stress concentration problems caused by sudden changes in rigidity, but also reduces the weight and rigidity of the overall device, helping to reduce the occurrence of stress shielding effects. The smooth transition design concept also takes into account the natural elastic modulus of human bone, making the implant more closely aligned with the biomechanical properties of human tissue, promoting a more natural healing process, reducing the stress concentration problems that may be caused by sudden changes in rigidity, and improving the safety of the bone plate 1. This not only improves patient comfort, but also helps to improve the overall effectiveness of treatment.

[0063] Comparative Example 1

[0064] See also Figures 8-11 The present invention provides the following technical solution: the printing parameters of the unreinforced bone plate are controlled as follows: laser power 200-300W, scanning speed 1100-1200mm / s, and layer thickness 40-50μm.

[0065] The scheme exists;

[0066] No augmentation plate defects;

[0067] Fatigue failure risk: The equivalent strain and equivalent stress are the highest, and the plate shows obvious stress concentration in the high stress area. The stress and strain of the non-reinforced plate are the highest, indicating that its strength is weak. When subjected to cyclic loads for a long time (such as the patient's gradual weight-bearing process), fatigue cracks are prone to propagate in the stress concentration area, resulting in a significantly higher risk of plate fracture than the locally reinforced plate. Bone interface micro-motion risk: Due to the highest equivalent strain, the interface between the plate and the bone is prone to small relative displacements (micro-motions) when subjected to stress, which may interfere with callus formation, prolong bone healing time, and even lead to non-union.

[0068] Comparative Example 2

[0069] See also Figures 8-11 The present invention provides the following technical solution: the printing parameters of the integrally reinforced bone plate are controlled as follows: laser power 300-400W, scanning speed 800-1000mm / s, and layer thickness 20-30μm.

[0070] The scheme exists;

[0071] Overall enhancement of bone plate defects;

[0072] Exacerbated stress shielding effect: The equivalent strain and equivalent stress are the lowest, but due to its high elastic modulus, it may lead to stress shielding effect at the bone-plate interface, inhibiting bone healing; Clinical operation limitations: The high elastic modulus makes the bone plate too rigid, and it is difficult to perform plastic micro-adjustments according to the bone anatomy during surgery, which may lead to insufficient fit between the bone plate and the bone surface, increase the risk of uneven force on the screws, and even cause micro-cracks inside the material due to forced shaping.

[0073] 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 aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A new type of 3D printed bone plate, characterized by: include: A bone plate (1) is manufactured using an additive manufacturing process and has a local enhanced structural design for the enhanced area. Through a 3D printing strategy with a layer-by-layer energy density gradient change, the density is increased at key locations to form a gradient material structure, significantly enhancing local compressive and shear resistance. A screw hole (2), wherein the screw hole (2) is provided on the surface of the bone plate (1); The local enhancement structure design includes an energy input strategy in the enhancement area, which increases the energy density layer by layer in the enhancement area by adjusting the laser power, scanning speed and layer thickness to form a density gradient; The mechanical properties of the local reinforcement area and the surrounding materials transition smoothly, avoiding stress concentration caused by sudden stiffness changes, while reducing overall weight and stiffness, and reducing the stress shielding effect caused by the mismatch with the elastic modulus of human bones; The design of the local enhancement structure includes the energy input strategy in the enhancement area. By adjusting the laser power, scanning speed and layer thickness, the energy density is increased layer by layer in the enhancement area to form a density gradient. The reinforcement area is made of TC4 titanium alloy powder through laser melting and 3D printing into TC4-high material; The non-reinforced area is made of TC4 titanium alloy powder by laser melting and 3D printing into TC4-1ow material; Adopting precise gradient design and dynamic adaptability optimization strategy: high stress area: the plate is reinforced in the bone distraction area to significantly improve the material's load-bearing performance; fitting area: the non-reinforced process is retained to reduce the stress shielding effect. The locally enhanced plate performs best in core biomechanical indicators such as stress distribution uniformity and bone surface adaptability, effectively meeting the clinical needs of complex fracture surgery and leveraging the advantages of the locally enhanced plate. In the dynamic cantilever test, two of the three unreinforced plate samples broke within one million cycles, while the overall reinforced and locally reinforced plate samples did not break, demonstrating the fatigue resistance of the overall and locally reinforced plates, enabling them to withstand more cyclic loads without breaking.

2. A novel 3D printed bone plate according to claim 1, characterized in that: In the additive manufacturing, the printing parameters used in the enhanced area are controlled as follows: laser power 300-400W, scanning speed 800-1000mm / s, layer thickness 20-30μm, and the printing parameters used in the non-enhanced area are controlled as follows: laser power 200-300W, scanning speed 1100-1200mm / s, layer thickness 40-50μm.

3. A novel 3D printed bone plate according to claim 2, characterized in that: The design of the bone plate (1) is based on a DICOM file generated from the patient's CT / MRI data. The morphology of the bone after correction is simulated by three-dimensional modeling software, and the position and angle of the enhancement area are planned to ensure accurate matching with the patient's bone.

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