Magnesium alloy bone plate with keel structure

Abstract

This invention relates to the field of medical devices and discloses a magnesium alloy bone plate with a keel structure. The bone plate adopts a frame structure, including an outer frame and cross-shaped reinforcing ribs disposed inside the outer frame. The frame structure forms a hollow section in the middle region, and a hydrogen diffusion channel is formed between the hollow section and the cross-shaped reinforcing ribs. The cross-shaped reinforcing ribs connect at least two regions of the plate, providing local structural reinforcement at key stress points and enhancing the structural strength around screw holes and fracture crossing areas. This application effectively solves the technical problem that magnesium alloy bone plates cannot simultaneously meet the requirements for hydrogen dissipation and mechanical strength, enabling smooth hydrogen dissipation, avoiding subcutaneous emphysema, while simultaneously enhancing structural strength and reducing the types of standard parts, which can be achieved through traditional processing methods.

Description

Technical Field

[0001] This invention relates to the field of medical devices, and more particularly to a magnesium alloy bone plate with a keel structure. Background Technology

[0002] Internal fixation of fractures is a common procedure in orthopedic clinical treatment. As a fixation device used to support and stabilize fracture ends, the material selection and structural design of bone plates have always been a key research focus in this field. Magnesium alloys have received increasing attention in the field of internal fixation due to their good biocompatibility, biodegradability, and elastic modulus close to that of human bone tissue, and are considered one of the representatives of next-generation orthopedic implant materials. However, magnesium alloys continuously produce hydrogen gas during degradation in the physiological environment. When the design thickness of the bone plate is too large, the hydrogen gas produced by degradation cannot diffuse from the implant-tissue interface in a timely manner, easily accumulating locally and forming subcutaneous emphysema, interfering with bone healing and even leading to surgical failure. Therefore, to ensure the smooth dissipation of hydrogen gas, the overall thickness of magnesium alloy bone plates is strictly limited, and excessively thick plate structures are not advisable.

[0003] During fracture fixation, bone plates must withstand cyclic loads from muscle traction and daily activities, thus requiring sufficient mechanical strength. When the plate is thin, stress concentration areas such as around screw holes and along fracture lines often become weak points, prone to fracture or fatigue failure. Conventional reinforcement methods involve locally increasing thickness or adding reinforcing ribs, but this directly conflicts with the requirement to reduce the thickness of magnesium alloy bone plates.

[0004] How to reliably reinforce key areas without increasing the overall thickness, while ensuring unobstructed hydrogen escape channels, has long been a core technical challenge in the design of magnesium alloy frame plate structures. Summary of the Invention

[0005] This invention addresses the technical deficiency in existing magnesium alloy rib plates that make it difficult to simultaneously meet the requirements for hydrogen dissipation and mechanical strength. It provides a magnesium alloy rib plate with a keel structure and its modular system.

[0006] The magnesium alloy frame plate provided by the present invention includes a plate body with a plurality of screw holes for fixing. The plate body adopts a frame structure, which includes an outer frame and cross reinforcing ribs disposed inside the outer frame. The frame structure forms a hollow part in the middle region, and a hydrogen diffusion channel is formed between the hollow part and the cross reinforcing ribs. The cross reinforcing ribs connect at least two regions of the plate body, providing local structural reinforcement at key stress points.

[0007] Furthermore, the cross-shaped reinforcing ribs are cross-shaped reinforcing ribs, connecting the four corner areas of the plate to the central area. The outer frame forms the peripheral outline of the plate, and the cross-shaped reinforcing ribs are arranged in a cross pattern inside the outer frame, connecting the four corner areas of the plate to the central area to form a stable mechanical transmission network. A large permeable space is formed between the central area of ​​the plate and the cross-shaped reinforcing ribs, allowing the hydrogen gas generated during degradation to diffuse into the surrounding tissues along this permeable space, preventing local accumulation and the formation of subcutaneous emphysema.

[0008] The screw holes include four main fixation holes at the corners and inner auxiliary holes. The four main fixation holes are located at both ends of the plate, with at least one circular countersunk screw hole at each end, used to achieve the main fracture fixation function and provide reliable holding force. The inner auxiliary holes are located inside the four main fixation holes, each with a smaller circular countersunk screw hole for auxiliary fixation. The screw holes are countersunk screw holes with a tapered countersunk hole at the opening. The screw head is tapered and fits into the tapered countersunk hole. After the screw is tightened, the top surface of the screw head is flush with or slightly lower than the upper surface of the plate, ensuring a smooth implant surface and reducing friction and irritation to surrounding soft tissues.

[0009] Furthermore, the plate has a central elongated hole in its middle section. This central elongated hole has a racetrack-shaped structure, including two parallel straight line segments and two semi-circular ends. The central elongated hole is connected to the hollowed-out portion, further expanding the volume of the hydrogen diffusion channel and forming a large hollowed-out area, which is conducive to hydrogen dissipation and callus growth.

[0010] The inner auxiliary hole also functions as a modular splicing interface. When multiple bone plates need to be spliced ​​to address complex fractures or large bone defects, adjacent bone plates can be connected and fixed through the inner auxiliary hole, eliminating the need for numerous auxiliary components such as connecting rods and small steel plates, thus reducing the types of standard components used during surgery. The central elongated hole and its surrounding reinforcing rib structure can serve as a splicing area, allowing connecting rods, reinforcing plates, or other reinforcing elements to be fitted or fixed here, enabling flexible configurations with various combinations.

[0011] Furthermore, the screw is a locking screw, which, when engaged with the countersunk screw hole, forms a angularly stable fixing structure to prevent the screw from loosening and coming out. The cross-shaped reinforcing rib has a rectangular, trapezoidal, or circular cross-section, and its thickness is the same as or slightly larger than the wall thickness of the outer frame, so as to provide local reinforcement at stress concentration areas such as around the screw hole and the fracture crossing area.

[0012] The present invention also provides a modular magnesium alloy support plate system, comprising at least two magnesium alloy support plates with the above-described structure, wherein adjacent magnesium alloy support plates are spliced ​​and fixed through the inner auxiliary holes. The modular system further includes at least one reinforcing element, which is fixedly connected to the magnesium alloy support plate through the central elongated hole and the inner auxiliary holes to achieve cross-regional support reinforcement.

[0013] The beneficial effects of this invention are as follows: By designing the plate as a hollow keel frame structure, a large number of permeable spaces are formed in the middle area, and the hydrogen gas generated by degradation can quickly diffuse to the surrounding tissue through these channels, effectively preventing the formation of subcutaneous emphysema. By setting cross-shaped reinforcing ribs inside the frame, the concentrated stress at the screw locking point is distributed to the entire bone plate frame, effectively enhancing the structural strength around the screw hole and the fracture crossing area, and avoiding the problem of thin plates being easily broken; while maintaining a relatively thin overall thickness, the keel frame structure achieves a stiffness amplification effect through the geometric arrangement of the ribs, achieving higher structural efficiency with less material. The keel frame structure can be achieved through traditional CNC machining or precision casting, eliminating the need for the 3D printing process of magnesium alloys, which poses safety risks. This facilitates stable quality control and large-scale production. The magnesium alloy material, with an elastic modulus close to that of natural bone, combined with the keel frame structure, can achieve a mechanical transmission path that is closer to that of natural bone, reducing stress shielding and promoting stress stimulation and bone remodeling at the fracture ends. Attached Figure Description

[0014] Figure 1 This is a top view schematic diagram of the magnesium alloy skeleton plate according to an embodiment of the present invention.

[0015] Figure 2 This is a three-dimensional structural diagram of the magnesium alloy skeleton plate according to an embodiment of the present invention.

[0016] Figure 3 This is a cross-sectional structural diagram of the mating point between the magnesium alloy bone plate and the locking screw in an embodiment of the present invention.

[0017] Figure label: 10. Plate body; 101. Four corner main fixing holes; 102. Inner auxiliary holes; 103. Central oblong hole; 104. Cross reinforcing ribs; 105. Outer frame; 107. Locking screws, hollowed-out part 106, round countersunk screw hole 102a. Detailed Implementation

[0018] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings.

[0019] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0020] like Figure 1 and Figure 2 As shown, the magnesium alloy bone plate with a keel structure according to an embodiment of the present invention includes a plate body 10, on which a plurality of screw holes are provided for fixing the bone plate to the bone surface. The plate body 10 adopts a frame structure, which includes an outer frame 105 and cross reinforcing ribs 104 disposed inside the outer frame 105. The frame structure forms a hollow portion 106 in the middle region of the plate body 10, and a hydrogen diffusion channel is formed between the hollow portion 106 and the cross reinforcing ribs 104. The cross reinforcing ribs 104 connect at least two regions of the plate body 10, providing local structural reinforcement at key stress points such as around the screw holes and fracture crossing areas.

[0021] The magnesium alloy bone plate of this invention adopts a hollowed-out keel frame design. Traditional magnesium alloy bone plates, to prevent the accumulation of hydrogen gas generated during degradation at the implant-tissue interface, which can lead to subcutaneous emphysema, typically require strict limits on overall thickness. However, this can cause the plate to easily fracture or fail due to fatigue in stress concentration areas. This invention designs the plate as a hollowed-out frame structure composed of an outer frame 105 and internal cross-reinforcing ribs 104, creating a large area of ​​open space in the middle of the plate. Hydrogen gas generated during degradation can rapidly diffuse to surrounding tissues along hydrogen diffusion channels, preventing localized accumulation. Simultaneously, the cross-reinforcing ribs 104 form a stable mechanical transmission network within the plate, dispersing the concentrated stress at the screw locking point to the entire bone plate frame, effectively enhancing the structural strength around the screw holes and the fracture crossing area. This keel frame structure, while maintaining a relatively thin overall thickness, achieves a stiffness amplification effect through the geometric arrangement of the ribs, obtaining higher structural efficiency with less material and solving the problem of thin plates being prone to fracture.

[0022] Combination Figure 1 and Figure 2In a preferred embodiment of the present invention, the cross-shaped reinforcing ribs 104 are cross-shaped reinforcing ribs. The cross-shaped reinforcing ribs 104 connect the four corner areas of the plate 10 to the central area. The outer frame 105 forms the peripheral outline of the plate 10, and the cross-shaped reinforcing ribs 104 are arranged in a cross shape inside the outer frame 105, connecting the four corner areas of the plate 10 to the central area, forming a stable mechanical transmission network inside the plate 10. A large permeable space is formed between the central area of ​​the plate 10 and the cross-shaped reinforcing ribs 104, allowing hydrogen gas generated during degradation to diffuse into surrounding tissues along this permeable space, preventing local accumulation and subcutaneous emphysema. The arrangement of the cross-shaped reinforcing ribs 104 significantly improves the mechanical properties of the plate 10 when subjected to external forces, and the four corner areas form an integrated mechanical system with the central area through the cross-shaped reinforcing ribs 104.

[0023] In one specific embodiment of the present invention, the cross-shaped reinforcing rib 104 has a rectangular, trapezoidal, or circular cross-sectional shape, and its thickness is the same as or slightly larger than the wall thickness of the outer frame 105. At stress concentration areas such as around screw holes and fracture crossing areas, increasing the thickness of the reinforcing rib or selecting a larger cross-sectional area can provide local reinforcement. The connection between the reinforcing rib 104 and the outer frame 105 uses a rounded transition to reduce stress concentration.

[0024] Combination Figures 1 to 3 In a specific embodiment of the present invention, the screw holes include four main fixation holes 101 at the corners and an inner auxiliary hole 102. The four main fixation holes 101 are disposed at both ends of the plate 10, with at least one circular countersunk screw hole distributed at each end, for realizing the main fracture fixation function and providing reliable holding force. Specifically, in this embodiment, two main fixation holes 101 are distributed at each end of the plate 10, and the two main fixation holes 101 are arranged along the length direction of the plate 10. The diameter of the four main fixation holes 101 is designed to accommodate the tapered head of the locking screw 107, and to ensure that after the screw is tightened, the top surface of the screw head is flush with or slightly lower than the upper surface of the plate 10, thereby ensuring a smooth implant surface and reducing friction and irritation to the surrounding soft tissues.

[0025] The inner auxiliary holes 102 are located inside the four corner main fixation holes 101, each with a small circular countersunk screw hole 102a for auxiliary fixation. In this embodiment, the four inner auxiliary holes 102 are respectively located on the inner sides of both ends of the plate 10, between the four corner main fixation holes 101 and the central elongated hole 103. The diameter of the inner auxiliary holes 102 is smaller than that of the four corner main fixation holes 101 to accommodate different fixation needs. The design of the inner auxiliary holes 102 allows the surgeon to choose to use all or part of the inner auxiliary holes 102 for fixation according to the specific fracture situation, increasing the flexibility of the surgical operation.

[0026] In embodiments of the present invention, all screw holes are designed as countersunk screw holes with a tapered countersunk opening. The head of the screw 107 is tapered, precisely fitting into the tapered countersunk opening. When the locking screw 107 is screwed into the countersunk screw hole and tightened, the tapered head of the screw 107 is embedded in the tapered countersunk opening, and the top surface of the screw 107 is flush with or slightly lower than the upper surface of the plate 10, ensuring a smooth and flat surface after the bone plate is implanted into the human body. This design not only reduces friction and irritation of the bone plate to the surrounding soft tissues, but also maintains good adhesion between the bone plate and the bone surface, which is beneficial to fracture healing. The angle of the tapered countersunk opening of the countersunk screw hole is precisely designed according to the angle of the tapered head of the locking screw 107 to ensure locking effect and fitting accuracy.

[0027] In a further embodiment of the present invention, screw 107 is a locking screw. The locking screw 107 mates with the countersunk screw hole to form an angle-stable fixation structure. The head of the locking screw 107 has external threads, and the inner wall of the screw hole has internal threads that mate with the external threads or employs a self-tapping thread design. When the locking screw 107 is screwed into the bone cortex, an angle-stable fixation structure is formed between the screw 107 and the bone plate. Even in the event of slight bone resorption, the screw 107 will not loosen or come out. This locking mechanism effectively prevents the problems of screw loosening and coming out that are prone to occur during long-term use of traditional non-locking screws, improving the reliability and long-term stability of fracture fixation.

[0028] Combination Figure 1 and Figure 2 In a preferred embodiment of the present invention, a central elongated hole 103 is provided in the middle of the plate 10. The central elongated hole 103 has a racetrack-shaped structure, including two parallel straight segments and two semi-circular ends. The central elongated hole 103 is connected to the hollowed-out portion 106, further expanding the volume of the hydrogen diffusion channel and forming a large-area hollowed-out region. The racetrack-shaped central elongated hole 103 design not only facilitates the rapid dissipation of hydrogen generated by degradation, but also provides a channel and space for callus growth. The callus can grow into the interior of the bone plate through the central elongated hole 103, forming a biological lock between the bone and the bone plate, further enhancing the stability of fracture fixation. In addition, the edge of the central elongated hole 103 can also serve as a transitional area for stress dispersion, reducing stress concentration.

[0029] In a specific embodiment of the present invention, the length direction of the central elongated hole 103 is consistent with the length direction of the plate 10. The lengths of the two parallel straight line segments are equal, and the radii of the two semicircular ends are similar to or slightly larger than the radius of the inner auxiliary hole 102. The central elongated hole 103 allows the plate 10 to minimize weight and increase the permeability area of ​​the hydrogen diffusion channel while maintaining sufficient mechanical strength.

[0030] In an important embodiment of the present invention, the inner auxiliary hole 102 also functions as a modular splicing interface. When multiple bone plates need to be spliced ​​to address complex fractures or large bone defects, adjacent bone plates are connected and fixed through the inner auxiliary hole 102, eliminating the need for numerous auxiliary components such as connecting rods and small steel plates, thus reducing the types of standard components used during surgery. The specific splicing method is as follows: After aligning the ends of two or more bone plates or arranging them at a predetermined angle, locking screws 107 are passed through the corresponding inner auxiliary holes 102 of adjacent bone plates to fix the bone plates together as a whole. The locking screws 107 at the splicing point also pass through the inner auxiliary holes 102 of two adjacent bone plates, achieving a face-to-face fixation method. After splicing and fixing, a stable connection structure is formed between adjacent bone plates, which can provide cross-regional support and reinforcement.

[0031] In a further embodiment of the invention, the central elongated hole 103 and the surrounding reinforcing rib structure can serve as a splicing area for reinforcing elements, allowing connecting rods, reinforcing plates, or other reinforcing elements to be fitted or fixed here, achieving flexible configurations with various combinations. For example, a connecting rod can be inserted into the central elongated hole 103 and fixed by locking screws 107, and a reinforcing plate can cover the central elongated hole 103 and be fixedly connected to the bone plate by several locking screws 107. This modular design allows surgeons to flexibly adjust the combination of bone plates according to the actual situation during surgery. A single bone plate can be used alone, or multiple bone plates can be spliced ​​into a fixation system of different lengths. Furthermore, reinforcing elements can be added at the splicing points as needed to enhance the mechanical strength of specific areas.

[0032] The present invention also provides a modular magnesium alloy frame plate system, comprising at least two magnesium alloy frames with the above-described structure, wherein adjacent magnesium alloy frames are spliced ​​and fixed through inner auxiliary holes 102. The modular system further includes at least one reinforcing element 200, which is fixedly connected to the magnesium alloy frame plate through a central elongated hole 103 and inner auxiliary holes 102 to achieve cross-regional support reinforcement.

[0033] Combination Figure 2 and Figure 3In a specific embodiment of the present invention, the three-dimensional form of the cross-shaped reinforcing rib 104 is shown. The cross-shaped reinforcing rib 104 is disposed inside the outer frame 105, forming a cross-shaped internal skeleton structure. The cross-shaped reinforcing rib 104 includes two mutually perpendicular reinforcing ribs, the intersection of which is located in the central region of the plate 10. One end of each reinforcing rib extends to the four corner regions of the plate 10 and is firmly connected to the inner wall surface of the outer frame 105, while the other end converges in the central region of the plate 10. The three-dimensional form of the cross-shaped reinforcing rib 104 gives the plate 10 high stiffness in the thickness direction as well. When the plate 10 is subjected to bending load, the cross-shaped reinforcing rib 104 disperses the bending stress from the loading point along two mutually perpendicular paths to the entire outer frame 105, effectively reducing the maximum stress value. When the plate 10 is subjected to torsional load, the cross-shaped reinforcing rib 104 and the outer frame 105 together form a closed mechanical system, resisting torsional deformation.

[0034] In a specific embodiment of the present invention, the overall thickness of the magnesium alloy frame plate is designed to be two millimeters. In another specific embodiment, the width of the outer frame 105 of the plate body 10 is designed to be four to eight millimeters. The width of the outer frame 105 needs to be sufficient to accommodate the four corner main fixing holes 101 and the inner auxiliary holes 102, while maintaining the structural integrity of the outer frame 105 itself. The width of the cross-shaped reinforcing ribs 104 is designed to be two to five millimeters. The area of ​​the hollow portion 106 occupies 40%-70% of the total projected area of ​​the plate body 10 to ensure the permeability of the hydrogen diffusion channel.

[0035] In a specific embodiment of the present invention, the magnesium alloy bone plate is made of biodegradable magnesium alloy. Magnesium alloy has an elastic modulus close to that of human bone tissue, approximately half that of titanium alloy, and close to the elastic modulus of natural bone. By adopting the keel frame structure of the present invention, the overall elastic modulus of the bone plate can be further adjusted to more closely approximate the elastic modulus of natural bone, achieving a mechanical conduction path closer to that of natural bone. This mechanical environment, close to that of natural bone, helps reduce stress shielding effects and promotes stress stimulation and bone remodeling at the fracture ends. The degradation products of magnesium alloy in vivo are magnesium ions, which can be absorbed and utilized by the human body. The degradation products have no toxic side effects and exhibit good biocompatibility.

[0036] Combination Figure 3In a specific embodiment of the present invention, a cross-sectional structure of the mating area between the four corner main fixing holes 101 and the locking screw 107 is shown. This cross-sectional structure clearly shows the tapered countersunk hole structure of the countersunk screw hole. The opening angle of the tapered countersunk hole matches the tapered head angle of the locking screw 107. The bottom of the tapered countersunk hole is the mating surface that accommodates the tapered head of the locking screw 107. The mating surface requires high precision, ensuring that after the screw 107 is tightened, the top surface of the screw head is flush with or slightly lower than the upper surface of the plate 10. The tapered countersunk hole can be precision machined using a tapered milling cutter on a CNC machining center or a dedicated tapered reamer to ensure mating accuracy and surface quality.

[0037] In another optional embodiment of the invention, the inner walls of the four main fixing holes 101 and the inner auxiliary holes 102 are provided with internal threads or self-tapping threads. The internal thread structure is machined on the hole wall using a special tap. The self-tapping thread structure directly taps the thread in the hole wall material when the locking screw 107 is screwed in. This design allows a threaded connection between the locking screw 107 and the screw hole. During the tightening process, the screw 107 can generate axial compressive stress on the bone plate, firmly pressing the bone plate against the bone surface. At the same time, an angle lock is formed between the screw 107 and the bone plate, preventing the screw from loosening during bone resorption or vibration.

[0038] In a specific embodiment of the present invention, the splicing process of the modular magnesium alloy bone plate system is as follows. First, select an appropriate number and size of magnesium alloy bone plates according to the type and location of the fracture. For simple linear fractures, a single bone plate can be selected for fixation. For complex comminuted fractures or large bone defects, two or more bone plates can be selected for splicing. During splicing, align the ends of adjacent bone plates or arrange them at a predetermined angle. The arrangement can be a straight splicing, that is, connecting multiple bone plates end to end along the length direction to form a longer fixation system; or an angled splicing, that is, forming a certain angle between two bone plates to adapt to the geometry of different anatomical locations. After the arrangement is completed, the bone plates are fixedly connected as one unit by passing the locking screws 107 through the corresponding inner auxiliary holes 102 of the adjacent bone plates and tightening them. When the locking screws 107 pass through the inner auxiliary holes 102, it is necessary to ensure that the screws 107 simultaneously penetrate the hole walls of two adjacent bone plates and form a stable mechanical connection between the two bone plates. If it is necessary to further enhance the mechanical strength of the splice, a reinforcing element 200, such as a connecting rod or a reinforcing plate, can be installed at the central elongated hole 103 and fixed to the splice area by several locking screws 107.

[0039] In a further embodiment of the invention, the reinforcing element 200 is fixedly connected to the magnesium alloy bone plate through a central elongated hole 103 and an inner auxiliary hole 102. The reinforcing element 200 can be a long strip connecting rod, the length of which is the same as or perpendicular to the length of the plate 10. After the connecting rod is inserted into the central elongated hole 103, it is pressed down from above by locking screws 107 to fix it in the central elongated hole 103. The material of the connecting rod can be the same magnesium alloy as the bone plate, or it can be a titanium alloy with better biocompatibility to provide higher connection strength. The reinforcing element 200 can also be a flat reinforcing plate, which covers the middle area of ​​the bone plate and is fixedly connected to the bone plate by several locking screws 107. The use of a flat reinforcing plate can significantly increase the local stiffness of the splicing area or the fracture crossing area, effectively preventing the bone plate from excessively bending or fatigue fracture in this area.

[0040] In specific embodiments of the present invention, the magnesium alloy bone plates of the present invention are suitable for fracture fixation in multiple locations of the human body, including but not limited to distal radius fractures, tibial plateau fractures, ankle fractures, proximal humeral fractures, and distal femoral fractures. Fractures in different anatomical locations have different geometric shapes and mechanical requirements. Physicians can select bone plates of appropriate specifications according to specific clinical conditions and flexibly combine them using a modular splicing system. For example, for bicondylar fractures of the tibial plateau, two bone plates can be used to fix the medial and lateral condyles respectively, and then the two bone plates can be connected into a single fixation system through splicing. For oblique or spiral fractures of long bones, reinforcing plates can be loaded into the fracture area to enhance local stiffness and prevent displacement of the fracture ends.

[0041] In a specific embodiment of the present invention, the manufacturing process of the magnesium alloy bone plate is as follows. First, a biodegradable magnesium alloy material with appropriate composition is selected according to the design parameters. The composition design of the magnesium alloy needs to take into account mechanical properties, corrosion resistance, and biocompatibility. Preferred magnesium alloy compositions include magnesium-zinc-calcium alloys, magnesium-zinc-manganese alloys, or magnesium-rare earth element alloys. These alloy systems ensure good mechanical properties while having a controllable degradation rate and good biocompatibility. Then, the magnesium alloy material is processed into a plate with a keel frame structure using CNC machining or precision casting. CNC machining uses a five-axis machining center to mill the magnesium alloy blank, which can obtain high-precision geometric dimensions and good surface quality. Precision casting uses a plaster mold or ceramic mold casting process to pour molten magnesium alloy into a pre-made mold for shaping. After casting, the blank needs to be heat-treated to improve the microstructure and mechanical properties. Finally, the processed bone plate undergoes surface treatment, including cleaning, polishing, and passivation. Surface passivation treatment can form a dense oxide film on the surface of the bone plate, which can delay the early and rapid degradation of magnesium alloy and improve the corrosion resistance of the bone plate.

[0042] In another optional embodiment of the invention, a functional coating may also be applied to the surface of the magnesium alloy bone plate. The functional coating may be a bioactive ceramic coating, such as a hydroxyapatite coating or a tricalcium phosphate coating. The bioactive ceramic coating can promote the adhesion and growth of bone tissue on the bone plate surface, accelerating the fracture healing process. The functional coating may also be a polymer coating, such as a polylactic acid coating or a polyglycolic acid coating. The polymer coating can provide additional corrosion protection in the early stages of degradation, delaying direct exposure of the magnesium alloy and regulating the degradation rate. The functional coating may be applied using processes such as plasma spraying, electrochemical deposition, or dip-coating.

[0043] In specific embodiments of the present invention, in addition to the cross-shaped reinforcing ribs 104, other forms of cross-shaped reinforcing ribs can be used in other optional embodiments of the keel frame structure. For example, herringbone reinforcing ribs can be used, where two reinforcing ribs are arranged in a herringbone pattern extending from one end of the plate 10 to the other end and converging in the middle of the plate 10. Star-shaped reinforcing ribs can also be used, where four diagonal reinforcing ribs are added to the cross-shaped reinforcing ribs to form a denser internal skeleton network. The star-shaped reinforcing rib structure is suitable for clinical applications requiring higher rigidity and strength, but the permeability area of ​​the hydrogen diffusion channels will be reduced accordingly. Parallel reinforcing ribs can also be used, where several parallel reinforcing ribs are provided inside the outer frame 105, with the direction of the reinforcing ribs being the same as or perpendicular to the length direction of the plate 10. The parallel reinforcing rib structure is simple and suitable for regularly shaped bone plates. Various forms of reinforcing ribs can be optimized according to specific mechanical requirements and hydrogen dissipation requirements.

[0044] In specific embodiments of the present invention, the cross-sectional shape of the outer frame 105 can be rectangular, trapezoidal, or elliptical. In some preferred embodiments, the cross-sectional shape of the outer frame 105 is trapezoidal, with the upper base length greater than the lower base length, i.e., the outer surface of the outer frame 105 is a slightly inclined slope. This trapezoidal cross-section design helps to disperse the effect of external forces on the edge of the plate, reducing stress concentration. At the same time, the outer surface design of the trapezoidal cross-section allows the bone plate to better fit with the bone surface after implantation, reducing the gap between the bone plate and the bone surface. At the connection between the inner wall of the outer frame 105 and the cross reinforcing rib 104, a rounded transition area can be provided to reduce stress concentration.

[0045] In a specific embodiment of the present invention, the hydrogen diffusion channel is specifically configured as follows. The hollow portion 106 is located within the internal space enclosed by the outer frame 105, and is divided into several interconnected sub-channels by cross-shaped reinforcing ribs 104. The central elongated hole 103 is connected to the hollow portion 106, forming a larger hydrogen diffusion space. The gap formed between the cross-shaped reinforcing ribs 104 and the outer frame 105 constitutes a lateral hydrogen diffusion channel. When the magnesium alloy bone plate is implanted into the human body, a contact interface is formed between the surface of the plate 10 and the bone surface and soft tissue. The hydrogen produced by degradation first accumulates in the recessed area of ​​the contact interface, and then diffuses to the surrounding area along the hydrogen diffusion channel. Because the hydrogen diffusion channel has multiple pathways connecting to the outside, hydrogen can quickly diffuse into the surrounding tissues and be absorbed by capillaries or excreted through the skin, without forming local accumulation.

[0046] In a specific embodiment of the present invention, the working principle and operation process of the modular magnesium alloy bone plate system are as follows. During internal fixation surgery for fractures, the fracture site is first reduced and temporarily fixed. Then, a magnesium alloy bone plate of appropriate specifications is selected according to the location and type of fracture. The bone plate is placed in the fracture area and its position is adjusted so that it crosses the fracture line, and the four main fixation holes 101 are aligned with the normal bone areas on both sides of the fracture line. A guide is used to guide the locking screws 107 into the four main fixation holes 101 in sequence, fixing the bone plate to the bone surface. During the screw insertion process, care should be taken to control the tightening torque to avoid overtightening the screws, which could cause deformation of the bone plate or breakage of the screws. After the locking screws 107 are tightened, an angle locking structure is formed between the screw head and the bone plate, ensuring that the screws will not loosen or come out.

[0047] If the fracture type is complex or involves large bone defects, and the fixation strength of a single bone plate is insufficient to meet mechanical requirements, a modular splicing method can be used. The second bone plate is spliced ​​and aligned with the first bone plate through the inner auxiliary holes 102, and then fixed using locking screws 107 passing through the corresponding inner auxiliary holes 102 of the two bone plates. If further enhancement of the mechanical strength in a specific area is required, a reinforcing element 200, such as a connecting rod or reinforcing plate, can be installed at the central elongated hole 103. After the connecting rod is inserted into the central elongated hole 103, the locking screw 107 is used to press the connecting rod down from above, fixing it in place within the central elongated hole 103. The length of the connecting rod can span the splicing area, firmly connecting the two bone plates together to form a cross-regional support and reinforcement system.

[0048] Throughout the surgical procedure, the magnesium alloy bone plate's keel frame structure consistently plays a crucial role in providing mechanical support and hydrogen dissipation. Because the plate 10 employs a perforated keel frame structure, in the early stages of fracture fixation, the hydrogen generated during degradation can rapidly diffuse into surrounding tissues through hydrogen diffusion channels, preventing subcutaneous emphysema. Simultaneously, the cross-shaped reinforcing ribs 104 distribute the stress transmitted by the locking screws 107 throughout the outer frame 105, resulting in a more uniform stress distribution and preventing bone plate fracture due to stress concentration. As fracture healing progresses, callus gradually grows into the central elongated hole 103 and the perforated portion 106, forming a biological lock between the bone and the bone plate, further enhancing fixation stability. After fracture healing is complete, the bone plate material gradually degrades and is replaced by new bone tissue, a process consistent with the body's natural healing process.

[0049] In an optional embodiment of the present invention, the magnesium alloy bone plate can also be used in conjunction with bone graft materials. In areas of bone defect, autologous bone, allogeneic bone, or artificial bone substitutes can be filled. The bone graft material can be granular or block-shaped. Granular bone graft material can be filled in the hollow portion 106 and the central elongated hole 103, providing a bone conduction scaffold for bone regeneration. Block-shaped bone graft material can be filled in the bone defect area, with the bone plate covering its surface for fixation. The keel frame structure of the present invention provides good accommodating space and growth channels for the bone graft material, facilitating integration between the bone graft material and the bone plate.

[0050] In another optional embodiment of the invention, the magnesium alloy bone plate can also be used in conjunction with a temporary fixation patch made of biodegradable polymer material. The temporary fixation patch can be attached to the surface of the bone plate, covering part of the screw hole area, providing additional mechanical protection to the bone plate in the early stages of degradation. The degradation rate of the temporary fixation patch can be designed as needed, maintaining high strength in the early stages of degradation and degrading synchronously with the gradual decrease in the strength of the bone plate itself, eventually being completely absorbed by the body. This combined use can further optimize the evolution of the mechanical properties of the fracture fixation system, making it more consistent with the biological laws of fracture healing.

[0051] In this invention, unless otherwise explicitly specified and limited, the directional terms such as "upper part," "lower part," "upper surface," "lower surface," "upper end," and "lower end" are defined relative to the positional relationship of the bone plate relative to the human skeleton after it is implanted in the human body. Furthermore, the terms "inner" and "outer" are defined relative to the central region of the plate 10. The use of these terms is merely for the convenience of describing specific embodiments of the invention and is not intended to limit the scope of protection of the invention.

[0052] In this invention, the term "frame structure" includes, but is not limited to, all hollow skeleton structures consisting of an outer frame and internal reinforcing ribs. Those skilled in the art, guided by this invention, can adjust parameters such as the number, arrangement direction, and intersection angle of the reinforcing ribs as needed, without departing from the technical solution and spirit of this invention.

[0053] The embodiments of the present invention are not exhaustive. Equivalent changes, substitutions or improvements made by those skilled in the art based on the technical solutions disclosed in the present invention, such as changing the cross-shaped reinforcing rib to a herringbone shape, parallel or other forms of cross reinforcing rib, changing the central oblong hole to an elliptical or dumbbell-shaped hole, making adaptive adjustments to the number and position of the four corner main fixing holes, changing the modular splicing method to other forms of connection structure, etc., should all fall within the protection scope of the present invention.

[0054] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A magnesium alloy frame plate with a keel structure, comprising a plate body, wherein the plate body is provided with a plurality of screw holes for fixing, characterized in that, The plate adopts a frame structure, which includes an outer frame (105) and cross reinforcing ribs (104) disposed inside the outer frame (105). The frame structure forms a hollow part (106) in the middle area of ​​the plate. A hydrogen diffusion channel (106) is formed between the hollow part (106) and the cross reinforcing ribs (104). The cross reinforcing ribs (104) connect at least two areas of the plate.

2. The magnesium alloy bone plate as described in claim 1, characterized in that, The cross reinforcing rib (104) is a cross-shaped reinforcing rib. The cross-shaped reinforcing rib (104) is arranged in a cross shape inside the outer frame (105), connecting the four corner areas of the plate with the central area, and connecting the four corner areas of the plate with the central area to form a stable mechanical transmission network.

3. The magnesium alloy bone plate as described in claim 1, characterized in that, The cross reinforcing rib (104) and the outer frame (105) adopt an integrated structure.

4. The magnesium alloy bone plate as described in claim 2, characterized in that, The cross-shaped reinforcing rib (104) has a rectangular, trapezoidal or circular cross-section, and its thickness is the same as or slightly larger than the wall thickness of the outer frame (105).

5. The magnesium alloy bone plate according to any one of claims 1 to 4, characterized in that, The screw holes include four main fixing holes (101) at the corners and inner auxiliary holes (102). The four main fixing holes (101) at the corners are located at both ends of the plate, and each end has at least one round countersunk screw hole. The inner auxiliary holes (102) are located inside the four main fixing holes (101) at the corners, and each has a smaller round countersunk screw hole.

6. The magnesium alloy bone plate as described in claim 5, characterized in that, The screw hole is a countersunk screw hole with a tapered countersunk hole at the opening. The screw (107) head is tapered and fits into the tapered countersunk hole. After the screw (107) is tightened, the top surface of the screw (107) head is flush with or slightly lower than the upper surface of the plate.

7. The magnesium alloy bone plate as described in claim 5, characterized in that, The inner auxiliary hole (102) also functions as a modular splicing interface, and adjacent bone plates are connected and fixed through the inner auxiliary hole (102).

8. The magnesium alloy bone plate as described in claim 7, characterized in that, The plate has a central elongated hole (103) in the middle. The central elongated hole (103) has a racetrack-shaped structure, including two parallel straight line segments and two semi-circular ends. The central elongated hole (103) is connected to the hollow part (106).

9. The magnesium alloy bone plate as described in claim 7, characterized in that, The central elongated hole (103) and the surrounding reinforcing rib structure can serve as a splicing area, allowing reinforcing elements to be fitted or fixed here.

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