3D printing femoral intramedullary and extramedullary biological matching composite fixing prosthesis and mounting method

Abstract

The invention relates to a 3D printing femoral intramedullary and extramedullary biological matching composite fixing prosthesis and an installation method, the 3D printing femoral intramedullary and extramedullary biological matching composite fixing prosthesis comprises a fixing prosthesis body and a far-end prosthesis body, the fixing prosthesis body is formed by an intramedullary fixing component, an extramedullary fixing component and a connecting component in an integrated 3D printing mode, and the intramedullary fixing component is used for being inserted into a femoral medullary cavity of a patient; the extramedullary fixing component is provided with two supporting wing plates which are symmetrically distributed and attached to the surfaces of cortical bones on the two sides of a femur and used for forming biological fixation with the femur, and the connecting component is arranged between the intramedullary fixing component and the extramedullary fixing component and mechanically connects the intramedullary fixing component and the extramedullary fixing component into a whole to form a composite bearing structure crossing the inside and the outside of a medullary cavity. Technical innovations such as arc-shaped medullary rod anatomy adaptation, a double-side clamping wing plate structure, integrated 3D printing connection, a composite fixing mechanism and a simplified mounting mode are fused, and a prosthesis system with stability, long-term firmness, rebuilding feasibility and operation convenience is constructed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of artificial prostheses, in particular to a 3D-printed intramedullary and extramedullary biocompatible composite femoral prosthesis and a mounting method. BACKGROUND

[0002] Currently, the widely used femoral prosthesis in clinical practice is a smooth-surfaced metal intramedullary stem that relies on bone cement for short-term mechanical fixation. However, the existing bone cement intramedullary stem system only has initial stability, and the long-term failure rate is high. The bone marrow cavity is hollow like a bamboo, and bone cement is first injected into it, then a straight metal light rod is inserted into the bone marrow cavity, and the bone cement is dried to fix and connect them. However, the femur not only has a supporting function, but also has a rotating function, especially in the thigh. This cement-fixed intramedullary stem is very stable immediately and in the short term (3-5 years), but over time, due to the influence of rotational force, it will soon become loose, leading to fixation failure, which requires revision surgery.

[0003] Among them, the existing 3D-printed biological intramedullary stem of the bone prosthesis is difficult to apply to primary surgery patients, (most of whom are primary surgery patients), because the femoral bone marrow cavity of the primary surgery patients is narrow, with a maximum diameter of about 13 mm. If the diameter of the 3D-printed biological intramedullary stem is 13 mm, its strength will be greatly limited, and the risk of intramedullary stem breakage will be extremely high. Moreover, since the 3D-printed prosthesis quickly heals and grows well in the intramedullary cavity, it is more serious that once such a 3D-printed prosthesis breaks, it is extremely difficult to remove due to the deep penetration of bone tissue into the porous structure, greatly increasing the risk and complexity of revision surgery.

[0004] To address the above problems, the prior art proposes a "extramedullary fixation" scheme that completely avoids the intramedullary cavity, such as CN113456314A, a distal femur revision type tumor prosthesis, which includes a combined distal femur assembly and a femoral stump fixation assembly. The lower end of the combined distal femur assembly is used to form a hinged joint with the tibia, and the upper end forms a tapered end. The femoral stump fixation sleeve is integrally formed on the central platform of the combined extension segment, and the femoral stump fixation sleeve is configured to be sleeved on the outside of the femoral stump and tightly connected therewith. Although this design avoids the problem of difficulty in removing the intramedullary fixation, it also has the problem that the existing prosthesis fixation method uses a sleeve, which is only suitable for revision cases and has poor early stability, and needs to rely on late bone growth to bear the load. At the same time, if the extramedullary part completely wraps the bone cortex, it will cause local bone loss of nutrition, leading to progressive bone resorption and ultimately resulting in prosthesis failure.

[0005] Second part design in the prosthesis and bone contact surface plus 3D coating, if the insertion femoral intramedullary rod is bone cement fixation, this 3D printing interface is easy to embed in bone cement, cannot contact with bone, cannot achieve 3D interface effect, at the same time, the surgical skill requirement is extremely high, and the installation difficulty often occurs during operation, (either thick and insert, or thin and insert, it is difficult to match completely), early loosening, unable to install and other risks.

[0006] Therefore, there is no simple and practical prosthesis on the market at present, which is aimed at realizing initial stability and long-term stability, and the prosthesis design also needs to consider incision, various blood vessels, nerves, muscle tension, body position blocking and other factors during operation, so that the current conventional prosthesis structure cannot meet the prosthesis which is convenient to install during operation, can realize long-term stability, and takes into account mechanical transmission. SUMMARY

[0007] In view of the deficiencies of the prior art, the present application provides a 3D printed intramedullary and extramedullary biological matching composite fixed prosthesis and installation method, which is suitable for patients with narrow intramedullary cavity during initial operation, can realize high strength, good bone integration and convenient future revision of femoral prosthesis, and solves the problem that there is no simple and practical prosthesis on the market at present, which is aimed at realizing initial stability and long-term stability, and the prosthesis design also needs to consider incision, various blood vessels, nerves, muscle tension, body position blocking and other factors during operation, so that the current conventional prosthesis structure cannot meet the prosthesis which is convenient to install during operation, can realize long-term stability, and takes into account mechanical transmission.

[0008] To achieve the above purpose, the present application provides the following technical scheme: a 3D printed intramedullary and extramedullary biological matching composite fixed prosthesis, comprising a fixed prosthesis body and a distal prosthesis body which are integrally 3D printed by an intramedullary fixation member, an extramedullary fixation member and a connecting member, the intramedullary fixation member is used for inserting into the inside of the intramedullary cavity of the patient's femur, the extramedullary fixation member is provided with two symmetrical support wings which are distributed on the surface of the cortical bone on both sides of the femur and are attached to the surface, and is used for forming biological fixation with the femur, the connecting member is arranged between the intramedullary fixation member and the extramedullary fixation member, and mechanically connects the two into one, forming a composite load-bearing structure across the intramedullary cavity inside and outside;

[0009] The surface of the intramedullary fixation member and the extramedullary fixation member is provided with a three-dimensional porous structure layer, and the upper end surface of the connecting member is used as a bone contact surface, and the surface thereof is also provided with a three-dimensional porous structure layer with the same structure, the porosity of the three-dimensional porous structure layer is 50% to 85%, and the pore size is 200 to 800 μm;

[0010] The lower end of the connecting member is provided with a tapered connecting part which is matched with a standardized clamping groove at the top of the distal end prosthesis body for forming a stable connection, and the bottom of the extramedullary fixation member and the outer wall of the connecting member are formed with a circular arc transition thickening structure by using a 3D printing integrated hierarchical manufacturing process.

[0011] It should be noted that the three-dimensional porous structure layer is covered on the surface of the intramedullary fixation member and the extramedullary support wing plate, and the global porous design enables the host bone tissue to grow into the prosthesis from multiple directions, significantly improving the interface bonding strength. The porous structure adopts TPMS (Triply Periodic Minimal Surface) or Gyroid bionic topological structure, which has high connectivity rate (>95%), low elastic modulus (close to cortical bone) and good fluid permeability, further optimizing the bone induction environment.

[0012] Secondly, 3D printing integrated hierarchical manufacturing not only refers to physical integral forming, but also includes the design concept of material gradient and structure gradient. In the connection area of the extramedullary fixation member and the connecting member, local thickening, grain orientation control and pore density gradient change are used to realize smooth transition from the dense bearing area to the porous bone integration area, for example: a lower porosity (50% to 60%) is used near the connecting root to improve fatigue strength; and the porosity of the distal wing plate end is increased to more than 75% to facilitate bone growth. This hierarchical design is a unique advantage that cannot be achieved by traditional casting or machining.

[0013] Further, the intramedullary fixation member is a rod-shaped structure arranged along the femoral shaft axis, and the top thereof is a tapered insertion end. The shape of the intramedullary fixation member is designed according to the physiological bending angle α=5.1-7.4° and the bending radius r=900-1300mm of the central axis of the femoral shaft of an adult.

[0014] It should be noted that the conventional central axis of the femoral shaft of an adult has a physiological bending angle α=5.1-7.4° and a bending radius r=900-1300mm. In actual application, the curvature, length and taper of the intramedullary fixation member can be measured through preoperative CT / MRI three-dimensional reconstruction data of the patient to ensure that it completely fits the individual medullary cavity direction. The standard plus customized dual design mode not only ensures the feasibility of universal production of the prosthesis, but also meets the precise fitting requirements under complex anatomical structures, avoiding stress concentration or implantation difficulty caused by shape mismatch.

[0015] Further, each support wing plate of the extramedullary fixation member has a width of 8-15 mm, a thickness of 3-6 mm, and a length of 60-150 mm covering the proximal end to the middle or the reverse middle to the distal end of the femur, and the two support wing plates have a top spacing of L1 and a bottom spacing of L2, and satisfy L1 < L2, so that the bilateral wing plates generate a pre-tightening clamping force on the cortical bone of the femur caused by metal elastic deformation after installation.

[0016] It should be noted that the overall prosthetic structure is 3D printed, and the material is an alloy (Ti6Al4V titanium alloy, and tantalum alloy, pure titanium, or cobalt-chromium-molybdenum alloy can also be selected), so that the self-adaptive pressurization mechanism is realized through the geometric characteristics of the structure itself. The clamping force can effectively inhibit micromotion in the early postoperative period, promote the stability of the bone-prosthesis interface, and at the same time will not cause cortical bone compression necrosis, because the action area is large and the unit pressure is low, which meets the physiological tolerance range;

[0017] Secondly, the two support wing plates form a V-shaped distribution, thereby having better anti-rotation function.

[0018] Further, the lower end of the connecting member is an outer conical structure, the top of the distal end prosthesis body is provided with a matching inner conical hole and a ring-shaped clamping groove, and the conical surface is press-fitted and clamped by the ring to achieve stable connection.

[0019] Further, it further includes an extension handle, which is a combined hollow tubular structure, the upper end of which is provided with a matching inner conical hole and a clamping groove at the lower end of the connecting member, and the lower end is provided with an outer conical connecting part matched with the distal end prosthesis body, which is used to realize segmented extension when the femoral defect is long, and ensure the overall mechanical continuity.

[0020] A mounting method of a 3D printed femoral intramedullary and extramedullary biocompatible composite fixation prosthesis, comprising the following steps:

[0021] S1. Use a soft drill to expand the marrow cavity of the femur, and perform subperiosteal dissection on both sides of the femur, and retain the continuity of the anterior and posterior periosteum to maintain bone blood supply;

[0022] S2. Use a test mold tool with the same size as the fixation prosthesis body to test the size of the marrow cavity and the prosthesis fitting condition;

[0023] S3. Select the appropriate model of the fixation prosthesis body according to the test mold result, and determine whether the extension handle 4 needs to be installed to adapt to the length of the femoral defect;

[0024] S4. Install a bone cement plug in the distal end marrow cavity of the femur to prevent bone cement leakage;

[0025] S5. Pour bone cement into the marrow cavity of the femur;

[0026] S6. Slowly insert the intramedullary fixation member of the fixed prosthesis body into the medullary cavity, and remove the overflowed bone cement while inserting to avoid blocking the three-dimensional porous structure layer on the surface of the support wing plate and the bone contact surface on the upper end of the connecting member;

[0027] S7. Insert to the complete position, so that the upper end surface of the connecting member closely fits the load-bearing surface of the proximal femur, realizing the airtight sealing of the medullary cavity, and the two support wing plates respectively fit the lateral cortical bone of the femur, and finally the lower end of the connecting member 3 is connected with the distal prosthesis body or the extension handle through the tapered-slot structure;

[0028] S8. Fill autologous bone, allogeneic bone or bone healing promoting material between the bone contact interfaces to assist in achieving early bone integration and long-term biological fixation.

[0029] Further, the bending angle and arc of the intramedullary fixation member of the fixed prosthesis body selected in step S3 should match the CT reconstruction data of the actual central axis of the femur of the patient.

[0030] Further, after step S7 is completed, the support wing plate can be further pressed against the surface of the femur through a temporary clamp or suture to maintain the pressurized state until the bone cement is preliminarily solidified.

[0031] Further, in step S8, the bone healing promoting material includes autologous bone, BMP-2, platelet-rich plasma PRP, demineralized bone matrix DBM or nano-hydroxyapatite particles, and is directly filled into the three-dimensional porous structure layer and the bone-prosthesis gap.

[0032] Compared with the prior art, the technical scheme of the present application has the following beneficial effects:

[0033] 1. The 3D printed femoral intramedullary and extramedullary biological matching composite fixed prosthesis and installation method, the intramedullary fixation member is an arc-shaped intramedullary rod structure, which is standardized designed according to the physiological bending angle α = 6° and the bending radius r = 1100mm of the femoral shaft center axis of an adult, can perfectly match the physiological mechanical transmission of the femur, so that the prosthesis can uniformly transmit load along the physiological force line of the femur after implantation, significantly reduces the local shear force and torsional stress, effectively avoids micro-motion, loosening or bone cement fragmentation caused by unbalanced mechanical transmission during walking, rotating and other dynamic activities, improves the immediate stability and long-term service reliability, and in addition, the arc-shaped structure is more conducive to smooth insertion during operation, reduces the range of reaming, protects bone mass, and is particularly suitable for the clinical needs of patients with narrow medullary cavity for primary surgery;

[0034] 2. The extramedullary fixation component covers the proximal to middle femoral cortical bone area, the inner surface of which is accurately shaped according to the lateral contour of the femur, and the three-dimensional porous structure layer provides an ideal interface for host bone tissue ingrowth, achieving true biological integration, and in the assembly process, the inward resilience force is generated by the elastic deformation of the metal material, forming a continuous pre-tightening clamping effect on the femoral cortical bone. This structure not only enhances the immediate mechanical stability after surgery, preventing early displacement, but also promotes the close fit between the wing plate and the bone surface, accelerating the healing process of the bone-prosthesis interface. Compared with the bone nutrient loss caused by traditional full-wrapped sleeve prostheses, this structure only partially contacts and preserves the blood supply of the periosteum, combining the advantages of high strength fixation and good biocompatibility;

[0035] 3. The fixation prosthesis structure is integrally 3D printed, suitable for different biometal materials, and the integrated hierarchical manufacturing method completely eliminates the interface defects, stress concentration and fatigue fracture risks that may be caused by traditional welding or screw connection, greatly improving the structural integrity and durability, and designing a circular arc transition thickening structure in the connection area, so that the stiffness and stress gradually transfer between the intramedullary rod and the extramedullary wing plate, avoiding the stress shielding effect caused by sudden section changes, which is beneficial to maintaining the stability of the surrounding bone density. This structure also enhances the bending and torsional resistance, ensuring stable load bearing under complex multi-directional loads, and realizing an internal and external composite load bearing structure;

[0036] 4. Through the internal and external cooperation of the component, immediate high-rigidity stability is provided by internal anchoring to meet the early postoperative weight-bearing requirements, while external gradual bone ingrowth biological fixation is provided to form an irreversible bone-prosthesis integrated structure over time, providing long-term stability. This not only overcomes the defect of easy loosening of pure bone cement prosthesis, but also makes up for the deficiency of poor initial stability of full biological prosthesis, realizes a smooth transition from short-term dependence on adhesion to long-term dependence on integration, and significantly prolongs the service life of the prosthesis and reduces the revision rate for osteoporotic patients or large bone defect reconstruction cases;

[0037] 5. In the intraoperative installation, the intramedullary rod is inserted, the wing plate is attached, and the taper slot is connected in place to form a quick operation, fully considering anatomical variations, soft tissue tension, blood vessel and nerve avoidance, and other clinical factors. The operation process is simple and controllable, compatible with conventional hip replacement surgery path, and can be completed without special instruments, and also has the function of femoral prosthesis revision surgery, and the overall intraoperative installation is relatively fast, and the adaptability to the existing femur is good. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The overall structure of the present application is shown;

[0039] Figure 2 The structure of the extended handle of the present application is shown;

[0040] Figure 3 A top view of the present application is shown;

[0041] Figure 4 A front view of the present application is shown;

[0042] Figure 5 A side view of the present application is shown;

[0043] Figure 6 A proximal femur structure of the present application is shown;

[0044] Figure 7 A distal prosthetic body structure of the present application is shown;

[0045] Figure 8 A fixed prosthetic body structure of the present application is shown.

[0046] BRIEF DESCRIPTION OF DRAWINGS 1, intramedullary fixation member; 2, extramedullary fixation member; 3, connecting member; 4, extension handle. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0048] Total hip arthroplasty is an effective means for treating advanced osteonecrosis of the femoral head, severe osteoarthritis, femoral neck fracture and some tumor lesions. More than one million cases are performed globally each year. The long-term stability of the femoral side prosthesis directly determines the success of the surgery and the quality of life of the patient. Traditional femoral prostheses mostly use the "smooth rod + bone cement" fixation method: a smooth metal straight rod is inserted into the femoral medullary cavity, and mechanical anchoring is achieved through solidified bone cement. This mode can provide good stability in the early postoperative period, but with the increase of postoperative activity, especially the long-term effect of rotational shear force, the bone cement-bone interface is prone to micro-motion and fatigue cracking, leading to prosthesis loosening, sinking and even revision. To solve this problem, the 3D-printed biological prosthesis has emerged in recent years, which constructs a three-dimensional porous structure on the surface to promote the growth of host bone tissue and achieve true "bone-prosthesis integration" integration. In theory, it can achieve permanent fixation effect. However, this type of prosthesis still faces many challenges in actual application, especially in patients with primary surgery;

[0049] 3D printing technology makes it possible to customize, bionic structure design and gradient porosity manufacturing. The current mainstream 3D printed femoral prosthesis mainly relies on full intramedullary biological fixation, that is, the entire prosthesis relies on the porous structure to realize bone ingrowth fusion with the inner wall of the medullary cavity. Although this technology has achieved certain results in revision cases, its application in primary replacement patients is severely restricted, mainly due to the following reasons:

[0050] 1. The femoral medullary cavity of Asian population and elderly female patients is generally thin, with a diameter of only about 10-13 mm at the narrowest point. If a 3D printed prosthesis with a three-dimensional porous layer of sufficient thickness is manufactured in this space, the effective metal cross-sectional area is greatly reduced, and the bending and torsional resistance is significantly decreased. Finite element analysis shows that when the prosthesis outer diameter is ≤13 mm, the maximum stress of the conventional 3D printed titanium alloy intramedullary rod can exceed the material yield limit, and fatigue fracture is likely to occur under simulated gait load;

[0051] 2. The excellent bone ingrowth ability of 3D printed prosthesis becomes a double-edged sword. Once fracture occurs, bone tissue has penetrated into the interior of the porous structure, resulting in "welded" combination of the prosthesis and the bone, and forcibly removing the prosthesis often causes large bone defects, greatly increasing the risk and complexity of secondary surgery. There have been many cases reported in the clinic that the broken prosthesis cannot be completely removed and is forced to remain, which seriously affects the subsequent reconstruction;

[0052] 3. Due to large individual anatomical differences, standardized 3D printed prostheses often have the problem of "not fitting in" or "not fitting tightly". If used with bone cement, it is easy to block the porous structure, making it lose its biological function. In addition, pure biological fixation lacks immediate mechanical support, and the patient is limited in weight bearing before bone integration is completed (usually 3-6 months), prolonging the rehabilitation period;

[0053] In view of the above clinical problems, the present application proposes a 3D printed femoral intramedullary and extramedullary biological matching composite fixation prosthesis and installation method, which breaks through the limitations of traditional single path fixation and constructs a prosthesis system with stability, long-term firmness, revision feasibility and surgical convenience.

[0054] Example one

[0055] Please refer to Figures 1-8The 3D-printed intramedullary and extramedullary biocompatible composite femoral prosthetic device in the embodiment comprises an intramedullary fixation component 1, an extramedullary fixation component 2, and a connecting component 3, which are integrally 3D-printed to form a fixation prosthetic body and a distal prosthetic body, the intramedullary fixation component 1 is used for insertion into the intramedullary cavity of the femur, the extramedullary fixation component 2 is provided with two symmetrical support wings that are attached to the cortical bone surfaces on both sides of the femur and are used for biological fixation with the femur, the connecting component 3 is arranged between the intramedullary fixation component 1 and the extramedullary fixation component 2 and mechanically connects the two components into one to form a composite load-bearing structure that spans the intramedullary cavity, the surfaces of the intramedullary fixation component 1 and the extramedullary fixation component 2 are provided with three-dimensional porous structure layers, the upper end surface of the connecting component 3 is used as a bone contact surface and is also provided with a three-dimensional porous structure layer of the same structure, the porosity of the three-dimensional porous structure layer is 50% to 85%, and the pore size is 200 to 800 microns, the lower end of the connecting component 3 is provided with a tapered connecting portion that is matched with a standardized clamping groove at the top of the distal prosthetic body to form a stable connection, and the bottom of the extramedullary fixation component 2 and the outer wall of the connecting component 3 are integrally manufactured by using a 3D printing process to form a circular arc transition thickening structure.

[0056] It should be noted that the three-dimensional porous structure layer is designed in a Gyroid topology and is optimized by finite element simulation to achieve the best bone ingrowth efficiency under the premise of ensuring the compressive strength, the actual manufacturing sample is detected by micro-CT, the average porosity is 70.3%, the average pore size is 512 microns, and the connectivity is greater than or equal to 96%, in the sheep tibia implantation model, the histological section after 12 weeks of operation shows that the bone ingrowth depth is 1.68±0.23mm, and the bone-prosthesis contact rate (BIC) reaches 78.5%, which is significantly higher than that of the traditional titanium mesh coating control group (BIC=52.1%), at the same time, the three-point bending test shows that the porous structure can withstand a compression stress of greater than or equal to 80MPa under a thickness of 0.5mm, which meets the physiological load requirements of the proximal femur, so that the invention realizes the synergistic breakthrough of high strength and high bone integration ability under the condition of small thickness, and solves the technical problem that the thin prosthetic device cannot balance structural safety and biological activity;

[0057] Secondly, the installation direction of the intramedullary fixation component 1 can be from bottom to top or from top to bottom, which is suitable for different prosthetic replacement requirements and improves the application prospect.

[0058] In the embodiment, the intramedullary fixation component 1 is a rod-shaped structure arranged along the axial direction of the femoral shaft, the top of which is a tapered insertion end, and the shape of the intramedullary fixation component 1 is designed according to the physiological bending angle of the central axis of the femoral shaft of an adult, which is 6° and the bending radius r is 1100mm.

[0059] It should be noted that the arc structure is verified by ABAQUS finite element analysis, compared with the traditional straight rod prosthesis, under the condition of simulating gait cycle loading (750N, rotation ±15°), the micromotion displacement in the medullary cavity is reduced to ≤42μm, which is far lower than the fatigue loosening threshold of bone cement-bone interface (150μm), while the micromotion of the traditional straight rod prosthesis is more than 210μm, the incidence of radiolucent line in the prosthesis with the arc design is as high as 94.7% (n=38) at 3 months after primary replacement, which is significantly better than 76.3% of the control group straight rod prosthesis, and the mechanical transmission path is fundamentally improved through anatomical matching arc design, which has outstanding substantial features and significant progress.

[0060] Please refer to Figures 1-5 In the embodiment, each support wing plate of the extramedullary fixing member 2 has a width of 8-15mm, a thickness of 3-6mm, and a length of 80-150mm covering the proximal end to the middle segment or the reverse middle segment to the distal end region of the femur, and the two support wing plates have a top spacing of L1 and a bottom spacing of L2, and satisfy L1 being less than L2, so that the bilateral wing plates generate a pre-tight clamping force on the cortical bone of the femur caused by metal elastic deformation after installation.

[0061] It should be noted that the elastic recovery force generated by the support wing plate during assembly is 185N-210N, and the corresponding radial compressive stress applied to the surface of the cortical bone is 9.8-11.6MPa, which is in the ideal interval (5-12MPa) of promoting bone adhesion and inhibiting micromotion. If it is lower than 5MPa, the clamping is insufficient, and if it is higher than 15MPa, it may cause bone necrosis.

[0062] Please refer to Figures 3-7 In the embodiment, the lower end of the connecting member 3 is an outer conical structure, the top of the distal end prosthesis body is provided with an inner conical hole and an annular clamping groove matched therewith, and the conical surface is stably connected by press fitting and clamping ring locking.

[0063] It should be noted that the distal end prosthesis body is a femoral condyle structure, and the standard part structure is the top and prosthesis connection, so that the bottom connecting member 3 in the application adopts a standardized connection structure matched therewith, so as to adapt to the conventional prosthesis structure, reduce the difficulty of surgical installation, and realize the adaptation to the primary femoral prosthesis replacement while having the function of femoral prosthesis revision surgery.

[0064] A mounting method of a 3D printed femoral intramedullary and extramedullary biologically matched composite fixed prosthesis, comprising the following steps:

[0065] S1. Use a soft drill to expand the medullary cavity of the femur, and perform subperiosteal stripping on both sides of the femur, while maintaining the continuity of the anterior and posterior periosteum to maintain bone blood supply;

[0066] S2. Test the size of the medullary cavity and the fitting of the prosthesis using a test tool consistent with the size of the fixed prosthesis body;

[0067] S3. Select the appropriate size of the fixed prosthesis body according to the test results, and the bending angle and arc of the intramedullary fixation member 1 should match the CT reconstruction data of the actual femoral central axis of the patient;

[0068] S4. Install a bone cement plug in the distal femoral medullary cavity to prevent bone cement leakage;

[0069] S5. Inject bone cement into the femoral medullary cavity;

[0070] S6. Slowly insert the intramedullary fixation member 1 of the fixed prosthesis body into the medullary cavity, and remove the excess bone cement to avoid blocking the three-dimensional porous structure layer on the surface of the support wing plate and the bone contact surface of the upper end of the connecting member 3;

[0071] S7. Insert to the complete position, so that the upper end surface of the connecting member 3 tightly fits the proximal load-bearing surface of the femur, realizing the airtight sealing of the medullary cavity, and the two support wing plates respectively fit the lateral cortical bone of the femur, which can be further pressed against the surface of the femur by a temporary clamp or suture, maintaining the pressurized state until the bone cement is preliminarily solidified, and finally the lower end of the connecting member 3 is connected to the distal prosthesis body through the tapered-slot structure;

[0072] S8. Fill the autologous bone, allogeneic bone or bone healing promoting material between the bone contact interfaces to assist in achieving early bone integration and long-term biological fixation, and the bone healing promoting material includes BMP-2, platelet-rich plasma PRP, demineralized bone matrix DBM or nano-hydroxyapatite particles, which are directly filled into the three-dimensional porous structure layer and the bone-prosthesis gap.

[0073] Example Two

[0074] Different from Example One, this embodiment also includes an extension handle 4, which is a combined hollow tubular structure, and the upper end is provided with an inner tapered hole and a slot matching the lower end of the connecting member 3, and the lower end is provided with an outer tapered connecting part matching the distal prosthesis body, which is used to realize segmented extension when the femoral defect is long, and ensure the overall mechanical continuity.

[0075] A method for installing a 3D printed femoral intramedullary and extramedullary biologically matched composite fixed prosthesis, comprising the following steps:

[0076] S1. Use a soft drill to expand the femoral medullary cavity, and perform subperiosteal dissection on both sides of the femur to maintain the continuity of the anterior and posterior periosteum to maintain bone blood supply;

[0077] S2. Test the size of the medullary cavity and the fitting of the prosthesis using a test tool consistent with the size of the fixed prosthesis body;

[0078] S3. Select the appropriate type of fixed prosthesis body according to the test results, and the bending angle and arc of the intramedullary fixation member 1 should match the CT reconstruction data of the actual femoral central axis of the patient, and a lengthening handle 4 should be added according to the length of the femoral defect;

[0079] S4. Install a bone cement plug in the distal femoral medullary cavity to prevent bone cement leakage;

[0080] S5. Pour bone cement into the femoral medullary cavity;

[0081] S6. Slowly insert the intramedullary fixation member 1 of the fixed prosthesis body into the medullary cavity, and remove the overflowing bone cement to avoid blocking the three-dimensional porous structure layer on the surface of the support wing plate and the bone contact surface of the upper end of the connecting member 3;

[0082] S7. Insert to the complete position, so that the upper end surface of the connecting member 3 tightly fits the proximal load-bearing surface of the femur, realizes the airtight sealing of the medullary cavity, and the two support wing plates are respectively attached to the lateral cortical bone of the femur. The support wing plate can be further pressed against the surface of the femur by a temporary clamp or suture, and the pressure state is maintained until the bone cement is preliminarily solidified. Finally, the lower end of the connecting member 3 is connected with the upper end of the lengthening handle 4 through the tapered-slot structure, and then the lengthening handle 4 and the distal prosthesis body are connected through the relative slot structure;

[0083] S8. Fill autologous bone, allogeneic bone or bone healing promoting material between the bone contact interfaces to assist in achieving early bone integration and long-term biological fixation. The bone healing promoting material includes BMP-2, platelet-rich plasma PRP, decalcified bone matrix DBM or nano-hydroxyapatite particles, which are directly filled into the three-dimensional porous structure layer and the bone-prosthesis gap.

[0084] It should be noted that the integrated 3D printing process described in the present application adopts the following parameters:

[0085] Equipment: 3D printing equipment (EOS M290 or SLM Solutions SLM280);

[0086] Powder: Ti6Al4V ELI medical grade titanium alloy powder (particle size 15-45 μm);

[0087] Laser power: 280 W, scanning speed: 1200 mm / s, layer thickness: 30 μm;

[0088] After molding, heat isostatic pressing (HIP) treatment: 920°C / 100MPa / 2h, to eliminate internal pores;

[0089] Surface treatment: sandblasting and acid washing to ensure that the porous structure is clean and free of residues.

[0090] The three-dimensional porous structure is generated by modeling software to generate a Gyroid unit array, and local density is regulated according to the mechanical simulation result, so as to realize the function gradient design.

[0091] It should be noted that in this text, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or equipment including the element.

[0092] Although the embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A 3D printed femoral intramedullary, extramedullary biometrical matching composite fixed prosthesis, characterized in that, The application relates to a fixed prosthesis body and a distal prosthesis body which are integrally 3D-printed by a medullary internal fixation component (1), a medullary external fixation component (2) and a connecting component (3), the medullary internal fixation component (1) is used for being inserted into the inside of the femoral medullary cavity of a patient, the medullary external fixation component (2) is provided with two symmetrically-distributed supporting wing plates which are attached to the surface of the cortical bone on both sides of the femur and are used for forming biological fixation with the femur, the connecting component (3) is arranged between the medullary internal fixation component (1) and the medullary external fixation component (2) and mechanically connects the two components into one, thereby forming a composite load-bearing structure which spans the inside and outside of the medullary cavity. The medullary internal fixation component (1) is a solid 3D-printed arc-shaped femoral medullary cavity matching structure, the bone-contacting side surface of the medullary external fixation component (2) is provided with a three-dimensional porous structure layer, and the upper end face of the connecting component (3) is used as a bone-contacting face, the surface of the upper end face is also provided with a three-dimensional porous structure layer with the same structure, the porosity of the three-dimensional porous structure layer is 50%-85%, and the pore diameter is 200-800 mu m. The lower end of the connecting component (3) is provided with a tapered connecting part which is matched with a standardized clamping groove at the top of the distal prosthesis body and is used for forming stable connection, and the bottom of the medullary external fixation component (2) and the outer wall of the connecting component (3) are manufactured by using a 3D-printing integrated level manufacturing process, thereby forming a circular-arc transition thickening structure.

2. The 3D printed femoral intramedullary, extramedullary biometrical matching composite fixed prosthesis according to claim 1, characterized in that: The medullary internal fixation component (1) is a rod-shaped structure which is arranged along the axial direction of the femoral shaft, the top of the medullary internal fixation component (1) is a tapered insertion end, and the shape of the medullary internal fixation component (1) is designed according to the physiological bending angle alpha of the central axis of the femoral shaft of an adult person, the bending radius r is 900-1300 mm.

3. The 3D printed femoral intramedullary, extramedullary biometrical matching composite fixed prosthesis according to claim 1, characterized in that: The width of each supporting wing plate of the medullary external fixation component (2) is 8-15 mm, the thickness is 3-6 mm, and the length is 60-150 mm and is attached to the proximal end to the middle segment or the reverse middle segment to the distal segment area of the femur, and the distance between the two supporting wing plates at the top is L1, the distance between the two supporting wing plates at the bottom is L2, and L1 is smaller than L2, so that the bilateral wing plates can generate a pre-tightening clamping force caused by metal elastic deformation on the cortical bone of the femur after installation.

4. The 3D printed femoral intramedullary, extramedullary biometrical matching composite fixed prosthesis according to claim 1, characterized in that: The lower end of the connecting component (3) is an outer tapered structure, the top of the distal prosthesis body is provided with an inner tapered hole and an annular clamping groove which are matched with the outer tapered structure, and the tapered surface is press-fitted and clamped and locked to realize stable connection.

5. The 3D printed femoral intramedullary, extramedullary biometrical matching composite fixed prosthesis according to claim 4, characterized in that: The application further comprises an extension handle (4), the extension handle (4) is a combined hollow tubular structure, the upper end of the extension handle (4) is provided with an inner tapered hole and a clamping groove which are matched with the lower end of the connecting component (3), and the lower end of the extension handle (4) is provided with an outer tapered connecting part which is matched with the distal prosthesis body, so that the extension handle (4) can realize segmented extension when the femoral defect is long and guarantee the overall mechanical continuity.

6. The method of installing a 3D printed femoral intramedullary, extramedullary, biologically matched composite fixed prosthesis according to claim 1, characterized in that: The application further comprises the following steps: S1. The femoral medullary cavity is expanded by using a soft drill, meanwhile, the subperiosteal stripping is implemented on both sides of the femur, the continuity of the front and rear periosteum is reserved, and the bone blood supply is maintained; S2. A test mold tool with the same size as the fixed prosthesis body is used to test the size of the medullary cavity and the prosthesis fitting condition; S3. The appropriate type of fixed prosthesis body is selected according to the test mold result, and it is judged whether the extension handle (4) needs to be installed to adapt to the length of the femoral defect; S4. A bone cement plug is installed in the distal medullary cavity of the femur to prevent bone cement leakage; S5. Bone cement is poured into the femoral medullary cavity; S6. Slowly insert the intramedullary fixation member (1) of the fixed prosthesis body into the medullary cavity, and remove the overflowed bone cement while inserting to avoid blocking the three-dimensional porous structure layer on the surface of the support wing plate and the bone contact surface of the upper end of the connecting member (3); S7. Insert to the complete position, so that the upper end surface of the connecting member (3) closely adheres to the load-bearing surface of the proximal femur, realizes the airtight sealing of the medullary cavity, and the two support wing plates respectively adhere to the lateral cortical bone of the femur. Finally, the lower end of the connecting member (3) is connected with the distal prosthesis body or the extension handle (4) through the tapered-slot structure; S8. Fill the autologous bone, allogeneic bone or bone healing promoting material between the bone contact interfaces to assist in achieving early bone integration and long-term biological fixation.

7. The method of installing a 3D printed femoral intramedullary, extramedullary, biologically matched composite fixed prosthesis according to claim 6, characterized in that: The fixed prosthesis body selected in step S3 should have the bending angle and curvature of the intramedullary fixation member (1) matched with the CT reconstruction data of the actual central axis of the femur of the patient.

8. The method of installing a 3D printed femoral intramedullary, extramedullary, biologically matched composite fixed prosthesis according to claim 6, wherein: After step S7 is completed, the support wing plate can be further pressed against the surface of the femur through a temporary clamp or suture to maintain the pressurized state until the bone cement is initially cured.

9. The method of installing a 3D printed femoral intramedullary, extramedullary, biologically matched composite fixed prosthesis of claim 6, wherein: In step S8, the bone healing promoting material includes autologous bone, BMP-2, platelet-rich plasma PRP, demineralized bone matrix DBM or nano-hydroxyapatite particles, which are directly filled into the three-dimensional porous structure layer and the bone-prosthesis gap.

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