A method for designing, manufacturing and testing a custom external fixation brace

Abstract

The application discloses a design, manufacturing and testing method of a customized external fixation support, and belongs to the field of medical devices. The method comprises the following steps: data collection, original scheme generation, finite element analysis and topology optimization, secondary design and finite element secondary analysis, and support manufacturing and testing. The support is subjected to mechanical testing and trial wearing testing, can provide a suitable mechanical environment for the healing of a fracture site of a limb, and is ensured in safety and effectiveness; the support is designed based on three-dimensional shape data of a patient, and has good matching degree with the affected part; the support structure is subjected to finite element analysis and topology optimization, is light in weight, is high in structural efficiency, is large in area of hollowing to ensure good air permeability, is waterproof and easy to clean, and is high in wearing comfort. The application can be widely used in the fields of design and manufacturing of customized external fixation supports.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of medical devices, and particularly relates to an orthopedic appliance for non-surgical treatment of bones or joints. BACKGROUND

[0002] "External fixation" is to maintain the affected limb in a position required for treatment, such as after reduction of fracture, dislocation or after certain limb orthopedic surgery, to maintain a certain position to facilitate the repair of fracture and other soft tissues.

[0003] External fixation brace refers to an external fixation device or product used for assisting the effect of surgical treatment by limiting certain movements of the body, or directly used for non-surgical treatment, for preventing disability, improving, compensating, replacing human functions and auxiliary treatment. The traditional external fixation made of plaster, low-temperature thermoplastic plate and high-temperature thermoplastic plate after reduction is a conventional conservative treatment for limb fracture.

[0004] For example, the utility model patent with the authorization announcement date of December 3, 2021 and the authorization announcement number of CN 214967320 U discloses a "medical external fixation brace", which comprises a fixing ring, a sliding slot is formed on one side of the fixing ring, a leg brace is slidably connected in the sliding slot, a fixing plate is fixedly installed on one side of the leg brace, a screw block is fixedly installed on one side of the fixing plate, a screw rod is threadedly connected in the middle of the screw block, a fixing block is fixedly installed on the top of the fixing plate, and a screw bolt is threadedly connected in the middle of the fixing block. The medical external fixation brace has the effect of being suitable for patients with different body shapes due to the arrangement of the elastic band. The fixing ring and the leg brace can change the distance between them during use through the cooperation of the fixing ring, the sliding slot, the leg brace, the fixing plate, the screw block, the screw rod, the fixing block and the screw bolt, thereby achieving the purpose of making the patient use comfortably.

[0005] However, these traditional external fixation braces are highly dependent on inefficient manual operation and have inherent defects in matching degree and comfort.

[0006] From the perspective of patients, the traditional brace is difficult to keep the affected area clean and dry when worn; the air permeability of the brace is poor, and problems such as itching, sweating, odor and skin rash often occur; the traditional brace (especially the plaster brace) is very heavy, which seriously affects the daily life of the patient; the matching degree is poor, there are pressure points and friction places, which are easy to cause redness and numbness; and it is difficult to put on and take off.

[0007] From the perspective of medical staff, the traditional brace requires a large amount of manual operation during production, and there is a risk of labor injury such as scald, chemical burn and dust inhalation; the manufacturer needs certain experience, especially the deformation amount and time of the thermoplastic brace are short, which often requires rework and repeated fine adjustment.

[0008] Computer aided engineering (CAE) combined with additive manufacturing (AM) to form a rehabilitation brace represents the future development direction of trauma medicine and rehabilitation medicine, and has been gradually popularized.

[0009] However, these technologies expose some problems in practical application, which hinder the large-scale clinical application of customized external fixation brace. The design process of such brace needs a large number of experienced designers to participate, and the design is difficult, low in efficiency, time-consuming, and it is difficult to make individualized design for the patient's own situation while taking into account the production efficiency. Patients often have to wait for several days or even weeks to receive the customized additive manufacturing external fixation brace, and the patient will be in the "lack" state of early stability of the affected area due to the external fixation brace still in the customization process, which will directly affect the success rate of treatment of limb fractures and cause a large number of unnecessary complications.

[0010] Therefore, in order to solve the inherent defects of traditional braces and the problems exposed in the design and use process of existing customized external fixation braces, further improvement is needed for the existing technology. SUMMARY

[0011] The technical problem to be solved by the present application is to provide a design, production and inspection method of a customized external fixation brace. The brace produced by using the method is subjected to mechanical test and trial wearing inspection, can provide a suitable mechanical environment for the healing of the limb fracture site, and has guarantee in safety and effectiveness; the brace is designed based on the three-dimensional shape data of the patient, and has good matching degree with the affected area; the structure of the brace is subjected to finite element analysis and topological optimization, is light in weight, high in structural efficiency, has good air permeability due to large area hollowing, is waterproof and easy to clean, and is high in wearing comfort.

[0012] The technical solution of the present application is to provide a design, production and inspection method of a customized external fixation brace, comprising collecting data of the affected area of a patient, designing and producing a corresponding external fixation brace according to the data of the affected area, characterized by comprising the following steps:

[0013] S1, data collection;

[0014] S2, original scheme generation;

[0015] S3, finite element analysis and topological optimization;

[0016] S4, secondary design and finite element secondary analysis;

[0017] S5, brace production and inspection.

[0018] Specifically, the S1 data collection includes processing the patient data from the CT data and the point cloud data of the affected area as follows:

[0019] S11, three-dimensional reconstruction:

[0020] Read the patient CT data using open source software or commercial software; establish a VOI for the affected area of the limb fracture and hide the rest; create a skin mask in the VOI by adjusting the threshold; fine-tune the mask to ensure that all the skin is correctly selected using tools including a brush and an eraser; perform three-dimensional reconstruction calculation; modify the reconstruction errors; export the reconstruction results;

[0021] In the sub-step S11 of three-dimensional reconstruction, the VOI established needs to be extended to one or two large joints towards the proximal and distal ends, respectively, with the joints closest to the fracture line as the reference;

[0022] S12, three-dimensional modeling:

[0023] Read the point cloud data of the affected area using the commercial software that comes with the three-dimensional scanner; establish a VOI for the affected area of the limb fracture and delete the rest of the point cloud data; use the software's built-in tools to cut off the background and clothing in the point cloud data; use the software's built-in tools to delete scattered points, burrs, and broken surfaces to ensure that there is only one piece of connected point cloud data and that the entire details of the VOI of interest are preserved; encapsulate the point cloud data and perform mesh optimization to generate a three-dimensional model;

[0024] In the sub-step S12, the criteria for establishing the VOI of interest are the same as in the sub-step S11;

[0025] S13, three-dimensional skin model:

[0026] Check if the reconstructed three-dimensional skin model of the affected area has any occlusions or defects. If so, it should be returned to the sub-step S11 or S12. The three-dimensional skin model of the affected area should also retain most of the anatomical features of the patient's fracture site along with the corresponding VOI to provide more details for the subsequent design of the brace;

[0027] The CT data of the affected area, after the steps of S12 three-dimensional modeling and S13 three-dimensional skin modeling, generates three-dimensional data of the skin of the affected area;

[0028] The point cloud data of the affected area is obtained by professional personnel using a three-dimensional scanner to scan the affected area of the patient's limbs. After the steps of S12 three-dimensional modeling and S13 three-dimensional skin modeling, three-dimensional data of the skin of the affected area is generated.

[0029] Specifically, the S2 original scheme generation includes processing the obtained three-dimensional skin model of the affected area as follows:

[0030] S21, model preprocessing: including S211 cropping, S212 repairing and S213 smoothing;

[0031] In the S211 cropping operation, the three-dimensional model of the affected skin is cropped into a curved surface piece. The contour during cropping should be a closed curve, which should completely include the projection of the patient's fracture line in the sagittal plane or coronal plane. When cropping the contour, a semi-enclosed style should be used to wrap the limb longitudinally, and space should be reserved for the patient to put on and take off;

[0032] S22, model modification: including S221 selecting potential pressure areas, S222 normal offset and S223 secondary smoothing;

[0033] In the S221 selecting potential pressure area operation, the anatomical features that are easy to cause skin pressure concentration and easy to rub with the brace are selected as the selection area. At the same time, the open fracture wound and the swelling area of the closed fracture line should also be selected as the potential pressure area;

[0034] In the S222 normal offset operation, the potential pressure area selected in the previous operation is offset outward along the normal direction by 1 to 20 mm;

[0035] In the S223 secondary smoothing operation, check whether the curved surface piece after normal offset appears damaged, and smooth the wrinkles, warping and spikes on the edge of the offset part, so that the model offset part and the original part transition naturally, avoid sharp corners and grooves to bring discomfort to the wearer, and avoid stress concentration leading to brace fracture;

[0036] S23, complete brace generation: including S231 model whole offset, S232 model whole shell and S233 repairing model error;

[0037] In the S231 model whole offset operation, the entire curved surface piece is offset outward along the normal direction by 1 to 5 mm, which is the gap between the patient's skin and the brace when the patient wears it;

[0038] In the model whole shell S232 operation, the whole offset surface piece is shell, and the wall thickness is between 2 to 5 mm;

[0039] In the repairing model error S233 operation, check whether the three-dimensional model after shell appears wrinkles, overlapping surface pieces and self-intersecting surface pieces in the edge part, and then repair these model errors to ensure that the complete brace model generated is closed and connected.

[0040] Further, in the S212 repair operation, it is checked whether the curved surface piece cut out in the previous operation has defects such as damage, holes and surface piece overlap, and then the defects are repaired; in the S213 smoothing operation, it is checked whether the repaired curved surface piece has defects such as wrinkles, warping and spikes, and then the defects are smoothed; through this operation, the skin shape of the injured area before injury is restored; in the S221 selection of potential pressure area operation, the anatomical features include at least: ulnar styloid process, radial styloid process, ulnar olecranon, fibular head, tibial tuberosity, calcaneus, lateral malleolus, medial malleolus, sustentaculum, fifth metatarsal tuberosity, navicular tuberosity or metatarsal head; in the S222 normal direction offset operation, the area prone to skin pressure concentration and friction is offset by 1 to 5 mm, so as to reduce the squeezing and friction feeling of the patient after wearing; the skin wound area is offset by 5 to 20 mm, so as to reserve enough space for dressings and bandages; in the S231 model overall offset operation, the brace for upper limb fracture is offset by 1 to 2 mm; the brace for lower limb fracture is offset by 2 to 5 mm; in the S232 model overall shell extraction operation, for the brace for upper limb, the wall thickness is selected to be 3 to 5 mm; for the brace for lower limb, the wall thickness is selected to be 2 to 3 mm.

[0041] Specifically, the S3 finite element analysis and topology optimization step comprises:

[0042] S31 finite element pre-processing:

[0043] including S311 meshing, S312 adding constraints, S313 applying loads and S314 establishing analysis steps;

[0044] S32 finite element analysis:

[0045] including S321 submitting operation operation, if an error occurs, then after performing the S322 checking setting operation, return to the S311 meshing operation; if the result converges, then perform the S323 output result;

[0046] S33 topology optimization:

[0047] including S331 establishing optimization task operation, submitting operation S332, if an error occurs, then after performing the S333 checking setting, return to the S331 establishing optimization task operation; if the result converges, then perform the next operation;

[0048] S34 topology optimization result output.

[0049] Further, in the S311 mesh division operation, the complete brace model is divided into hexahedral meshes, the mesh quality is optimized by changing the mesh size and the number of nodes to reduce the calculation power consumption and reduce the error; in the S312 constraint adding operation, additional independent nodes are added as the nodes for applying constraints and loads in the appropriate spatial coordinates for the divided meshes, and after binding with the corresponding meshes, the beams including the direction and angle are applied to these independent nodes; in the S313 load applying operation, the independent nodes added in the previous step are further added with loads including torque; in the S314 analysis step establishing operation, materials are added to the meshes, attributes are created, analysis steps containing constraints, loads, materials and attributes are created, and other parameters of the analysis steps are set, and then saved as a file format that can be read by the finite element analysis software; in the S321 operation submission operation, the file generated in the previous step is read, and whether the parts, constraints, attributes, loads and analysis steps are correctly read is checked in sequence, and the finite element analysis task set in the previous step is submitted to the server for calculation; if an error occurs, go to the S322 setting checking operation; if the result converges, go to the S323 result output operation; in the S322 setting checking operation, whether the parts, constraints, attributes, loads and analysis steps are correctly set is checked in sequence, and then the S311 mesh division is started, and whether each step is correctly set is checked in sequence; in the S323 result output operation, whether the calculation result is reasonable is checked, and the calculation result is saved as the basis for subsequent comparison and analysis with the topology optimization result; in the S331 optimization task establishing operation, a topology optimization task is created, and the response of the topology optimization to the strain energy and the model volume is set; the optimization target of the topology optimization is set, and the calculation parameters including the optimization cycle number, CPU core number and GPU acceleration are set; in the S332 operation submission operation, the topology optimization calculation task set in the previous step is submitted to the server for calculation, and if the software reports an error, go to the S333 setting checking operation; if the result converges, go to the S341 optimization result output operation; in the S333 setting checking operation, whether the topology optimization response and the optimization target are correctly set is checked in sequence, and modified as needed; in the S341 optimization result output operation, all optimization results are merged, and then the results are exported and saved, and the results are generated to enter the S41 secondary modeling substep.

[0050] Specifically, the S4 secondary design and finite element secondary analysis step comprises the following steps:

[0051] S41 secondary modeling:

[0052] The topology optimization result and the complete brace model are imported into an open source or commercial three-dimensional design software, the complete brace model is trimmed according to the optimization result, and the sharp corner parts in the optimization result that are prone to cause stress concentration are smoothed, and the result is used as a brace model after simple topology optimization;

[0053] S42 structure reinforcement:

[0054] Adding 1-5mm thickness of "L" type flanging to all edges and hollowed parts of the model after simple topology optimization, or adding 1-5mm thickness of inverted "T" type reinforcing rib to appropriate parts of the model after simple topology optimization;

[0055] S43 finite element preprocessing:

[0056] The model after simple topology optimization and the model after various structure reinforcements are preprocessed, including meshing and adding attributes, and the specific operation method is the same as that of S31 finite element preprocessing substep;

[0057] S44 finite element secondary analysis:

[0058] The model after simple topology optimization and the model after various structure reinforcements are analyzed by finite element analysis, and the specific operation method is the same as that of S32 finite element preprocessing substep;

[0059] S45 selection comparison:

[0060] The results of finite element analysis of the model after simple topology optimization and the model after various structure reinforcements are summarized, and the appropriate and personalized design scheme is selected according to the actual situation of the patient;

[0061] The S4 secondary design and finite element secondary analysis steps sequentially perform secondary modeling S41 and structure reinforcement S42 on the topology optimization results obtained in S34, then perform finite element preprocessing S43 and finite element secondary analysis S44 on the results of the two, and then perform selection comparison S45 on the results, and the generated results enter the subsequent brace manufacturing and testing S5 step.

[0062] Further, in the S45 selection comparison substep, the model after simple topology optimization has relatively complete stiffness and is more suitable for lower limb fracture; the model after hollow part reinforcement has higher stiffness than the model after simple topology optimization, but is slightly heavier, and is suitable for most parts; the model after all edge reinforcement has high stiffness and is suitable for cases of comminuted fracture.

[0063] Specifically, the S5 brace manufacturing and testing step comprises the following steps:

[0064] S51 detailed design;

[0065] S52 additive manufacturing;

[0066] S53 injection molding;

[0067] S54 post-processing and assembly;

[0068] S55 mechanical test;

[0069] S56 trial test;

[0070] The S5 brace manufacturing and inspection step, the brace model selected in the S45 selection comparison is subjected to S51 detailed design, the production mode of S52 additive manufacturing or S53 injection molding is selected according to the actual situation, and then the produced product is subjected to S54 post-processing and assembly, and the brace successively passing through S55 mechanical test and S56 trial test is taken as the final product.

[0071] Further, in the S51 detailed design substep, the brace mounting hole is added to the brace design scheme selected in the S45 selection comparison substep, so as to be used for subsequent installation of the buckle for fixing the brace; in the S52 additive manufacturing and S53 injection molding substeps, the specific molding mode is selected according to the clinical requirement; in the S54 post-processing and assembly substep, the produced brace is subjected to polishing, polishing, burr removal or further surface treatment mode including solvent vapor fumigation polishing, dyeing, sand blasting and electroplating; then the buckle including magic tape, bandage or elastic rope for fixing is assembled for the brace; in the S55 mechanical test substep, the assembled brace is subjected to mechanical test including three-point bending test and torsion test, so as to confirm that the produced product can reach the use standard; if the test cannot be passed, the design scheme is changed in the S51 detailed design stage; in the S56 trial test substep, the patient tries on the brace subjected to the mechanical test, and determines that no pain, squeezing feeling, friction feeling or other serious discomfort appears after the patient wears the brace through the ways of inquiry, visual observation and questionnaire survey; if the discomfort appears, the design scheme needs to be changed in the S51 detailed design stage.

[0072] Compared with the prior art, the advantages of the present application are:

[0073] (1) The external fixation brace designed by adopting the technical scheme of the present application is based on the three-dimensional shape data of the patient himself, and has good matching degree with the affected part, so that the brace is closely attached to the skin of the affected part, which can not only prevent the brace from loosening due to too large gap, but also avoid limb numbness, poor blood supply and pain caused by too small contact area and pressure concentration;

[0074] (2) The external fixation brace designed by adopting the technical scheme of the present application has light overall weight through finite element analysis and topological optimization, so that the brace does not bring huge burden to the patient's daily life due to the weight of the brace when worn; the structure of the brace optimized by topological optimization has high structural efficiency and good rigidity, so that sufficient stability can be provided for the fracture site with relatively light structure weight;

[0075] (3) the external fixation brace designed and manufactured by the technical scheme of the application can provide a suitable mechanical environment for the fracture site to ensure the safety and effectiveness of the brace through mechanical testing and trial wearing inspection;

[0076] (4) the brace structure is treated with a circular arc and has no sharp corners and stress concentration points, and can withstand various accidental impacts when worn by a patient without breaking;

[0077] (5) the flange and the reinforcing rib structure arranged on the brace can conveniently adjust the mechanical properties of the brace to adapt to the needs of different fracture sites of the patient for the mechanical properties of the brace;

[0078] (6) the brace has a large-area hollow structure to ensure good air permeability, facilitate ventilation, and the patient will not feel hot and itchy, and has good thermal comfort;

[0079] (7) the brace is made of waterproof polymer material, is waterproof and easy to clean, and the patient can take a normal bath after wearing the brace and clean the brace with a neutral detergent;

[0080] (8) the brace can be manufactured by additive manufacturing and injection molding, and can meet the needs of both emergency custom products and batch production of prefabricated products, and can meet the requirements of response speed and production cost. BRIEF DESCRIPTION OF DRAWINGS

[0081] Figure 1 is a block flowchart diagram of the design, manufacture and inspection method of the external fixation brace of the application;

[0082] Figure 2 is a VOI diagram of a distal radius fracture;

[0083] Figure 3 is a VOI diagram of a distal humerus fracture;

[0084] Figure 4 is a VOI diagram of a tibial plateau fracture;

[0085] Figure 5 is a VOI diagram of an ankle fracture;

[0086] Figure 6 is a flowchart diagram of the original scheme generation step of the application;

[0087] Figure 7 is a flowchart diagram of the finite element analysis and topology optimization step of the application;

[0088] Figure 8 is a front view of a wrist brace embodiment;

[0089] Figures 9a to 9fProcess diagram for the design stage of the wrist brace embodiment;

[0090] Figure 10a Front view of the knee brace embodiment;

[0091] Figure 10b Side view of the knee brace embodiment;

[0092] Figures 11a to 11f Process diagram for the design stage of the knee brace embodiment;

[0093] Figure 12a Front view of the ankle brace embodiment;

[0094] Figure 12b Side view of the ankle brace embodiment;

[0095] Figures 13a to 13f Process diagram for the design stage of the ankle brace embodiment;

[0096] Figure 14a Front view structural diagram of the elbow brace embodiment;

[0097] Figure 14b Right view structural diagram of the elbow brace embodiment;

[0098] Figure 14c Top view structural diagram of the elbow brace embodiment;

[0099] Figures 15a to 15f Process diagram for the design stage of the elbow brace embodiment.

[0100] 21 is the VOI of distal radius fracture; 22 is the radius joint near the fracture line; 23 is the metacarpophalangeal joint; 14 is the elbow joint;

[0101] 31 is the VOI of distal humerus fracture; 32 is the elbow joint near the fracture line; 33 is the wrist joint; 34 is the shoulder joint;

[0102] 41 is the VOI of tibial plateau fracture; 42 is the knee joint near the fracture line; 43 is the ankle joint; 44 is the hip joint;

[0103] 51 is the VOI of ankle fracture; 52 is the ankle joint near the fracture line; 53 is the metatarsophalangeal joint; 54 is the knee joint;

[0104] 81 is the main body of the wrist brace, 82 is the forearm buckle, 83 is the first radius buckle, 84 is the second radius buckle, 85 is the palm buckle, 86 is the hollow, 87 is the flange structure, 88 is the patient's wrist affected area;

[0105] 101 is a knee brace body, 102 is a patient's knee affected part, 103 is a thigh buckle, 104 is a first knee buckle, 105 is a second knee buckle, 106 is a lower leg buckle, 107 is a rivet, 108 is a hollow, 109 is a flange structure;

[0106] 1201 is an ankle brace body, 1202 is a patient's ankle affected part, 1203 is a first lower leg buckle, 1204 is a second lower leg buckle, 1205 is a first foot buckle, 1206 is a second foot buckle, 1207 is a rivet, 1208 is a flange structure, 1209 is a hollow.

[0107] 1401 is an elbow brace body, 1402 is an upper arm buckle, 1403 is a rivet, 1404 is a forearm buckle, 1405 is a palm buckle, 1406 is a hollow structure, 1407 is a flange structure. DETAILED DESCRIPTION

[0108] The present application will be further described below in conjunction with the drawings and examples.

[0109] To solve the inherent defects of traditional braces and the problems exposed in the design and use of existing custom external fixation braces, the technical solution of the present application provides a design, production and inspection method for custom external fixation braces, as shown in Figure 1 which includes the following steps: S1, data collection; S2, original scheme generation; S3, finite element analysis and topology optimization; S4, secondary design and finite element secondary analysis; S5, brace production and inspection.

[0110] In the technical solution, the data collection in the data collection step includes three sub-steps: S11 three-dimensional reconstruction, S12 three-dimensional modeling and S13 three-dimensional skin model.

[0111] The patient data has two sources, i.e. affected part CT data and affected part point cloud data.

[0112] The affected part CT data is provided by the hospital data department after the patient's authorization, and the affected part skin three-dimensional data is generated after the S12 three-dimensional modeling and S13 three-dimensional skin model steps.

[0113] The affected part point cloud data is obtained by professional personnel using a three-dimensional scanner to scan the affected part of the patient's limbs, and the three-dimensional data of the affected part skin is generated after three-dimensional modeling and three-dimensional skin modeling. When scanning, attention should be paid to avoid clothing obstruction while removing all accessories and other coverings, and to remove the dressings and bandages on the surface of the open wound as much as possible.

[0114] The S11 three-dimensional reconstruction sub-step is: using open source software or commercial software to read patient CT data; establishing a VOI (Volum of Interest) for the fractured part of the limb and hiding the rest; in the VOI, a skin mask is established by adjusting the threshold; the mask is finely modified by using tools such as brushes and rubbers to ensure that all the skin is correctly selected; three-dimensional reconstruction calculation is performed; reconstruction errors are modified; and the reconstruction result is exported.

[0115] In the three-dimensional reconstruction sub-step, the established VOI needs to take the joint closest to the fracture line as the reference, and extend one to two large joints to the proximal end and the distal end respectively, the purpose is to make the generated brace have a large enough contact area with the affected limb to ensure the stability of the fracture part after the brace is fixed (it is known in the industry that the end closer to the heart is called the proximal end, and the end farther from the heart is called the distal end).

[0116] For the large joints, four common fractures are taken as examples for illustration:

[0117] As shown in Figure 2 : 21 is the VOI of a distal radius fracture, which should take the radius joint 22 near the fracture line as the reference, extend to the metacarpophalangeal joint 23 to the distal end, and extend to the elbow joint 24 to the proximal end, then the proximal end large joint referred to here is the metacarpophalangeal joint, and the distal end large joint is the elbow joint.

[0118] As shown in Figure 3 : 31 is the VOI of a distal humerus fracture, which should take the elbow joint 32 near the fracture line as the reference, extend to the wrist joint 33 to the distal end, and extend to the shoulder joint 34 to the proximal end; then the proximal end large joint referred to here is the shoulder joint, and the distal end large joint is the wrist joint.

[0119] As shown in Figure 4 : 41 is the VOI of a tibial plateau fracture, which should take the knee joint 41 near the fracture line as the reference, extend to the ankle joint 43 to the distal end, and extend to the hip joint 44 to the proximal end.

[0120] As shown in Figure 5 : 51 is the VOI of an ankle joint fracture, which should take the ankle joint 52 near the fracture line as the reference, extend to the metatarsophalangeal joint 53 to the distal end, and extend to the knee joint 54 to the proximal end.

[0121] The S12 three-dimensional modeling sub-step is: using the commercial software matched with the three-dimensional scanner to read the point cloud data of the affected part; establishing a VOI for the affected part of the limb and deleting the rest of the point cloud data; using the software's own tools to cut off the background and clothes in the point cloud data; using the software's own tools to delete discrete points, burrs and broken surfaces, to ensure that there is only one piece of connected point cloud data and the details of the VOI are saved; the point cloud data is encapsulated and mesh optimized to generate a three-dimensional model.

[0122] In the S12 three-dimensional modeling sub-step, the established VOI standard is the same as that in the S11 sub-step.

[0123] In the S13 skin three-dimensional model sub-step, it is necessary to check whether the reconstructed three-dimensional model of the affected skin exists shielding or defects, if so, it should be returned to the S11 sub-step or the S12 sub-step. The three-dimensional model of the affected skin should also retain the fracture site of the patient together with most of the anatomical features of the corresponding VOI, to provide more details for the subsequent design of the brace.

[0124] In the technical scheme of the present application, the S2 original scheme generation step is completed by using open source or commercial three-dimensional design software, which includes model preprocessing S21, model modification S22 and complete brace generation S23, and the detailed flow chart is as shown in Figure 6 .

[0125] In the sub-step S13 skin three-dimensional model, the three-dimensional model of the affected skin is obtained, in the S21 model preprocessing sub-step, three-step operations of S211 cutting, S212 repairing and S213 smoothing are sequentially performed; then in the S22 model modification sub-step, three-step operations of S221 selecting potential pressure area, S222 offsetting along the normal and S223 secondary smoothing are sequentially performed; finally in the S23 complete brace generation sub-step, three-step operations of S231 model overall offsetting, S232 model overall shell extracting and S233 repairing model errors are sequentially performed, and the result of the above-mentioned process enters the S31 finite element preprocessing sub-step.

[0126] In the S211 cutting operation, the three-dimensional model of the affected skin is cut into a curved surface piece, and the contour during cutting should be a closed curve, which should completely include the projection of the patient's fracture line in the sagittal plane or the coronal plane, so that the brace generated according to the contour subsequently can provide sufficient protection for the fracture site. At the same time, when cutting the contour, a semi-enclosed style should be adopted to wrap the limb along the longitudinal direction, and a space for the patient to put on and take off should be reserved.

[0127] In the S212 repairing operation, it is necessary to check whether the curved surface piece cut out in the previous step operation exists damage, hole and surface piece overlap, and then repair these defects. The model after the repairing operation should be guaranteed to be complete, without holes, without overlapping and without broken surfaces.

[0128] In the smoothing operation in S213, it is necessary to check whether the repaired curved surface sheet has wrinkles, warping and nails, and then to smooth these features. The smoothing operation should pay attention to eliminating the anatomical features in the patient's skin model that are not necessary to be embodied in the subsequent brace, including: the protrusions caused by epidermal blood vessels, moles, birthmarks, palm prints, fingerprints, and hair. If there are shielding objects such as dressings and bandages in the open wound, it is necessary to restore the skin appearance of the affected area before the injury through this step operation. The processed curved surface sheet then enters the model modification sub-step S22.

[0129] In the selection of potential pressure area operation in S221, the protruding anatomical features on the patient's skin surface that are prone to cause skin pressure concentration and are prone to friction with the brace should be selected as the selection area. These anatomical features at least include: ulnar styloid process, radial styloid process, ulnar olecranon, fibular head, tibial tuberosity, calcaneus, lateral malleolus, medial malleolus, talocalcaneal process, fifth metatarsal tuberosity, navicular tuberosity, metatarsal head, etc. At the same time, the open fracture wound and the swelling area of the fracture line of the closed fracture should also be selected as the potential pressure area.

[0130] In the normal direction offset operation in S222, the potential pressure area selected in the previous operation is offset outward along the respective normal direction by 1 to 20 millimeters. Among them, the area prone to cause skin pressure concentration and friction is offset by 1 to 5 millimeters to reduce the squeezing and friction feeling of the patient after wearing; the skin wound is offset by 5 to 20 millimeters to reserve enough space for dressings and bandages and other bandages.

[0131] In the secondary smoothing operation in S223, it is necessary to check whether the curved surface sheet after the normal offset has damage, and to smooth the wrinkles, warping and nails on the edge of the offset part, so that the model offset part and the original part are naturally transitioned, avoiding the discomfort brought by sharp corners and grooves to the wearer, and avoiding stress concentration leading to the fracture of the brace. The processed curved surface sheet then enters the complete brace generation sub-step S23.

[0132] In the model overall offset operation in S231, the entire curved surface sheet is offset outward along the normal direction by 1 to 5 millimeters, which is the gap between the patient's skin and the brace when the patient wears it. The upper limb bears more torque in daily life, so the brace used for upper limb fracture should be offset by 1 to 2 millimeters to make the brace fit the affected area more closely to ensure the stability of the fracture site. The lower limb bears more axial pressure in daily life, and the diameter of the lower limb changes significantly with the posture due to the weight of the blood gravity, so the brace used for lower limb fracture should be offset by 2 to 5 millimeters.

[0133] In the model overall shell extraction operation in S232, the overall offset surface sheet is extracted, and the wall thickness is between 2 to 5 millimeters.

[0134] Since the upper limb bears more torque in daily life, the wall thickness of the brace used for the upper limb is 3 to 5 millimeters.

[0135] Because the brace used for lower limb fracture has a large area, the wall thickness of the brace used for lower limbs is selected to be 2 to 3 mm to achieve sufficient rigidity.

[0136] In the S233 repair model error operation, whether the three-dimensional model after shell extraction appears wrinkles, overlapping slices and self-intersecting slices at the edge part is checked, and then the model errors are repaired to ensure that the complete brace model generated is closed and connected for subsequent finite element pre-processing.

[0137] In the technical scheme of the application, the S3 finite element analysis and topology optimization step is completed using open source or commercial finite element pre-processing and finite element analysis software, and the step includes S31 finite element pre-processing, S32 finite element analysis, S33 topology optimization and S34 topology optimization result output, and a detailed flowchart is shown in Figure 7 .

[0138] Specifically, the complete brace model obtained in the sub-step S23 complete brace generation is subjected to the S311 mesh division, S312 constraint addition, S313 load application and S314 analysis step establishment operations in sequence in the S31 finite element pre-processing sub-step; then the S321 operation submission operation is performed in the S32 finite element analysis sub-step, if an error occurs, the S311 mesh division operation is returned after the S322 check setting operation is performed, if the result converges, the S323 result output is performed; then the S332 operation submission operation is performed after the S331 optimization task establishment operation is performed in the S33 topology optimization sub-step, if an error occurs, the S331 optimization task establishment operation is returned after the S333 check setting is performed; if the result converges, the S341 optimization result output operation is performed, and the generated result enters the S41 secondary modeling sub-step.

[0139] In the S311 mesh division operation, the complete brace model is divided into hexahedral meshes using open source or commercial finite element pre-processing software, at this time, the mesh quality is optimized by changing the mesh size and node number to reduce the calculation power consumption and reduce the error.

[0140] In the S312 constraint addition operation, additional independent nodes are added as constraint application nodes and load application nodes at appropriate spatial coordinates for the divided meshes, and after being bound with the corresponding meshes, the independent nodes are subjected to displacement, direction and angle constraints.

[0141] In the S313 load application operation, forces and torques and other loads are further added to the independent nodes added in the previous operation (referring to the S312 constraint addition operation).

[0142] In the S314 analysis step operation, materials are added to the grid, properties are created, an analysis step containing constraints, loads, materials, properties is created, and other parameters of the analysis step are set, and then saved in a file format readable by the finite element analysis software, such as an inp file.

[0143] In the S321 operation submission operation, the open source or commercial finite element analysis software is used to read the file generated in the previous operation, and it is checked in sequence whether the parts, constraints, properties, loads and analysis steps are correctly read, and after the CPU core number and GPU acceleration and other calculation parameters are set, the finite element analysis task set in the previous operation is submitted to the server for calculation; if the software reports an error, go to S322 to check the setting operation; if the result converges, go to S323 to output the result operation.

[0144] In the S322 check setting operation, it is checked in sequence whether the parts, constraints, properties, loads and analysis steps are correctly set, and then from S311 mesh division, it is checked in sequence whether each step is correctly set.

[0145] In the S323 output result operation, it is checked whether the operation result is reasonable, and the operation result is saved as a basis for subsequent comparison and analysis with the topology optimization result.

[0146] In the S331 establish optimization task operation, the file verified by the finite element analysis to be able to be normally solved is used to create a topology optimization task, set the response of the topology optimization to strain energy and model volume, and other responses can also be added according to requirements; set the optimization target of the topology optimization, such as: minimum strain energy, volume not greater than 50%, and other targets can also be added according to requirements; set the optimization cycle number, CPU core number and GPU acceleration and other calculation parameters.

[0147] In the S332 operation submission operation, the topology optimization calculation task set in the previous operation is submitted to the server for calculation, if the software reports an error, go to S333 to check the setting operation; if the result converges, go to S341 to output the optimization result operation.

[0148] In the S333 check setting operation, it is checked in sequence whether the topology optimization response and optimization target are correct, and modified according to requirements.

[0149] In the S341 optimization result output operation, all optimization results are merged, and then the results are exported and saved, and the results are generated to enter the S41 secondary modeling substep.

[0150] In the technical solution of the application, the S4 secondary design and finite element secondary analysis steps are completed using open source or commercial three-dimensional design software, finite element pre-processing and finite element analysis software, and the steps include five sub-steps of S41 secondary modeling, S42 structure reinforcement, S43 finite element pre-processing, S44 finite element secondary analysis and S45 selection comparison, and a detailed flow chart is shown in Figure 1 The topology optimization result obtained in S34 is sequentially subjected to S41 secondary modeling and S42 structure reinforcement, then the results of the two are simultaneously subjected to S43 finite element pre-processing and S44 finite element secondary analysis, and then the results are subjected to S45 selection comparison, and the generated results enter the S5 subsequent brace manufacturing and inspection step.

[0151] In the S41 secondary modeling sub-step, the topology optimization result and the complete brace model are imported into the open source or commercial three-dimensional design software, the complete brace model is trimmed with reference to the optimization result, and the sharp corner parts in the optimization result that are prone to cause stress concentration are smoothed, and the result is used as a simple topology-optimized brace model.

[0152] In the S42 structure reinforcement sub-step, the three-dimensional design software is used to add a 1-5 mm thick "L" shaped flange to the edges of the simple topology-optimized brace model and the edges of the hollowed-out parts, which can reinforce the rigidity of the brace without increasing the contact area between the brace and the skin, and provide better stability for the fracture site; or a 1-5 mm thick inverted "T" shaped reinforcing rib can be added to the appropriate parts of the simple topology-optimized brace model, which can also achieve the effect of structural reinforcement.

[0153] In the S43 finite element pre-processing sub-step, the open source or commercial three-dimensional design software and the finite element pre-processing software are used to divide the simple topology-optimized brace model and the models after various structural reinforcements into grids, add attributes and other pre-processing, and the specific operation method is the same as that of the aforementioned S31 finite element pre-processing sub-step.

[0154] In the S44 finite element secondary analysis sub-step, the open source or commercial three-dimensional design software and the finite element analysis software are used to perform finite element analysis on the simple topology-optimized brace model and the models after various structural reinforcements, and the specific operation method is the same as that of the S32 finite element pre-processing sub-step.

[0155] In the S45 type selection comparison substep, the finite element analysis results of the brace model after simple topology optimization and the models after structural reinforcement are summarized, and a suitable and personalized design scheme is selected according to the actual situation of the patient; the model after simple topology optimization has relatively lower stiffness than the complete brace, but is more portable, and is suitable for lower limb fracture; the model after reinforcement in the hollow part has higher stiffness than the model after simple topology optimization, but has slightly heavier weight, and is suitable for most parts; the model after all edge reinforcement has larger weight and extremely high stiffness, and is suitable for the case of comminuted fracture.

[0156] In the technical scheme of the application, the S5 brace manufacturing and inspection step comprises S51 detail design, S52 additive manufacturing, S53 injection molding, S54 post-processing and assembly, S55 mechanical testing and S56 trial wearing inspection substeps, and a detailed flow chart is shown in Figure 1 The brace model confirmed in the S45 type selection comparison is subjected to S51 detail design, the production mode of S52 additive manufacturing or S53 injection molding is selected according to the actual situation, then the produced product is subjected to S54 post-processing and assembly, and the brace successively passing through S55 mechanical testing and S56 trial wearing inspection is used as the final product.

[0157] In the S51 detail design substep, open source or commercial three-dimensional design software is used to add brace mounting holes to the brace design scheme selected in the S45 type selection comparison substep, so as to facilitate subsequent installation of the buckle for fixing the brace.

[0158] In the S52 additive manufacturing and S53 injection molding substeps, the specific molding mode is selected according to clinical needs; single-piece production and custom-made braces with urgent needs are produced by additive manufacturing; batch-produced prefabricated braces are produced by injection molding to reduce production and use costs.

[0159] In the S54 post-processing and assembly substep, the produced brace is subjected to polishing, polishing, deburring or further solvent vapor fumigation polishing, dyeing, sandblasting, electroplating and other surface treatment modes; then the brace is assembled with buckles such as magic tape, bandage, elastic rope and the like for fixing.

[0160] In the S55 mechanical testing substep, the assembled brace is subjected to three-point bending test, torsion test and other mechanical tests to confirm that the produced product can meet the use standard; if the test cannot be passed, the design scheme is changed in the S51 detail design stage.

[0161] In the S56 trial fitting inspection sub-step, the patient wears the brace subjected to the mechanical test, and it is determined that no pain, squeezing feeling, rubbing feeling or other serious discomfort occurs after wearing by the patient through inquiry, visual observation and questionnaire; if discomfort occurs, it needs to return to the S51 detailed design stage to change the design scheme.

[0162] Embodiment:

[0163] I. Wrist brace:

[0164] Figure 8 It is a fracture external fixation brace generated by using the design, manufacturing and testing method of the application, which is divided into a wrist brace body 81, a forearm buckle 82, a first radius buckle 83, a second radius buckle 84 and a palm buckle 85.

[0165] The wrist brace body 81 adopts a single-piece structure, and is fixed at the wrist fracture position of the patient by the forearm buckle 82, the first radius buckle 83, the second radius buckle 84 and the palm buckle 85.

[0166] Among them, the first radius buckle and the second radius buckle are close to the fracture line, and provide additional stability for the fracture site. The four buckles are made of materials such as magic tape, bandage or elastic rope, which help the patient to resist the wrist gravity and accidental pulling of the fracture site during daily activities.

[0167] There are several hollows 86 on the wrist brace body, which reduce the weight of the brace and increase the structural efficiency of the brace. When wearing, the patient will not be greatly burdened by the weight of the brace in daily life.

[0168] The position and shape of the hollows on the wrist brace body are generated according to the finite element simulation of the patient's wrist stress by the computer and the results of topological optimization. The results of topological optimization are subjected to secondary design to remove sharp corners and add excessive circular arcs to reduce stress concentration and improve the ability of the brace to resist accidental impact on the brace during the patient's daily activities.

[0169] On the edge of each hollow, a flange structure 87 is arranged, which can improve the rigidity and torsional properties of the wrist brace without increasing the contact area of the brace with the patient's skin, and enhance the stability of the patient's fracture site.

[0170] The hollow structure design is beneficial to the air circulation on the surface of the patient's skin, helps to sweat and dissipate heat, avoids the feeling of stuffiness and itching of the patient, and has good thermal comfort.

[0171] The shape of the main body of the wrist brace is generated according to the three-dimensional shape of the wrist affected area 88 of the patient, and has good adhesion with the skin of the affected area, which can effectively avoid the looseness of the brace caused by excessive gap, and also can avoid the concentration of pressure caused by too small contact area, thereby causing limb numbness, poor blood supply and pain.

[0172] The main body of the wrist brace is made of nylon material by additive manufacturing, is waterproof and easy to clean, and the patient can take a normal bath and flush with neutral detergent.

[0173] The main body of the wrist brace can also be made of ABS engineering plastic or other thermoplastic polymers by injection molding method, which can be mass produced to reduce production cost.

[0174] The main body of the wrist brace has undergone mechanical testing and trial fitting inspection after production, and can provide a suitable mechanical environment for the healing of the fracture site, ensuring the safety and effectiveness of the brace.

[0175] Figures 9a to 9f The figure shows the design process of the wrist brace in this embodiment, and the design process of this embodiment includes the following steps:

[0176] (a) Collecting CT data and affected point cloud data of the patient, establishing a three-dimensional model of the wrist skin, and generating an original design scheme of the brace according to the three-dimensional model;

[0177] (b) Finite element analysis of the original design scheme to simulate the stress distribution when the patient wears the wrist brace;

[0178] (c) Topology optimization of the original design scheme;

[0179] (d) Adding a hollow structure to the original design scheme according to the topology optimization result;

[0180] (e) Secondary finite element analysis of the topology-optimized scheme to simulate the stress distribution when the patient wears the wrist brace again;

[0181] (f) Adding a flange to the topology-optimized scheme to increase the stiffness and torsional resistance of the brace without increasing the contact area between the wrist brace and the patient's skin.

[0182] II. Knee brace:

[0183] Figure 10a And Figure 10b The front and side views of the knee brace are a fracture external fixation brace generated by using the design, manufacturing and testing method of the present application, which is divided into a knee brace main body 101, a thigh buckle 103, a first knee buckle 104, a second knee buckle 105 and a calf buckle 106.

[0184] The knee brace body 101 adopts a tile structure, and the shape of the knee brace body is generated according to the three-dimensional shape of the skin of the patient's affected part 102. The knee brace body is fixed to the knee of the patient by four buckles, i.e., a thigh buckle 103, a first knee buckle 104, a second knee buckle 105, and a calf buckle 106.

[0185] Among them, the thigh buckle 103 is located at the one-half of the patient's femur, and the calf buckle 106 is located at the one-half of the patient's tibia, which together maintains the stability of the knee brace. The first knee buckle 104 and the second knee buckle 105 are respectively close to the upper edge and the lower edge of the knee joint, providing additional stability to the knee.

[0186] The four buckles are made of materials such as magic tape, bandage, or elastic rope, and are combined with the brace body by rivets 107. The four buckles together help the patient to resist the gravity and accidental pulling of the knee during daily activities.

[0187] There are several hollows 108 on the knee brace body, which reduce the weight of the brace and increase the structural efficiency of the knee brace. When worn, it will not greatly burden the patient's daily life due to the weight of the brace.

[0188] The position and shape of the hollows on the knee brace body are generated according to the finite element simulation of the patient's wrist stress by the computer and the results of topological optimization. The results of topological optimization are subjected to secondary design to remove sharp corners and add excessive arcs to reduce stress concentration and improve the ability of the brace to resist accidental impact on the brace during the patient's daily activities.

[0189] On the edge of the hollows and the edge of the knee brace body, a flange structure 109 is provided, which can improve the stiffness and torsional properties of the brace without increasing the contact area of the brace with the patient's skin, and enhance the stability of the patient's fracture site.

[0190] The hollow structure is beneficial to the air circulation on the surface of the patient's skin, helps to sweat and dissipate heat, and avoids the feeling of stuffiness and itching of the patient, with good thermal comfort.

[0191] The shape of the knee brace body is generated according to the three-dimensional shape of the skin of the patient's knee affected part 102, and has good adhesion with the affected skin, which can effectively avoid the looseness of the brace caused by excessive gap, and also can avoid the pressure concentration caused by too small contact area, which can cause limb numbness, poor blood supply and pain.

[0192] The main body of the knee brace is made of nylon material or other materials that can be used for additive manufacturing, which is waterproof and easy to clean, and the patient can take a normal bath and wash with neutral detergent.

[0193] The main body of the knee brace can also be made of acrylonitrile-butadiene-styrene (ABS) engineering plastic or other thermoplastic polymers by injection molding method, which can be mass-produced to reduce production costs.

[0194] The knee brace main body is attached with a wear-resistant layer made of thermoplastic polyurethane (TPU) on the edge part and above the articular surface to reduce the pressure and friction during long-term wearing and joint movement, avoiding skin redness, itching and even ulceration.

[0195] The knee brace main body has undergone mechanical testing and trial fitting inspection after production, providing a suitable mechanical environment for the healing of the patient's ankle and ensuring the safety and effectiveness of the brace.

[0196] Figure 11 is a process diagram of the design stage of the knee brace in this embodiment. The design process of this embodiment includes the following steps:

[0197] (a) Collecting CT data and point cloud data of the affected area of the patient, establishing a three-dimensional model of the patient's knee skin, and generating an original design scheme of the knee brace according to the three-dimensional model;

[0198] (b) Finite element analysis of the original design scheme to simulate the stress distribution when the patient wears the knee brace;

[0199] (c) Topology optimization of the original design scheme;

[0200] (d) Adding hollow structures to the original design scheme according to the topology optimization results;

[0201] (e) Secondary finite element analysis of the topology-optimized scheme to simulate the stress distribution when the patient wears the knee brace again;

[0202] (f) Adding flanges to the topology-optimized scheme to increase the stiffness and torsional resistance of the knee brace without increasing the contact area between the knee brace and the patient's skin.

[0203] III. Ankle brace:

[0204] Figure 12a And Figure 12b The main and side views of the ankle brace are a fracture external fixation brace generated using the design, manufacturing and testing methods of the present application, which includes an ankle brace main body 1201, a first calf buckle 1203, a second calf buckle 1204, a first foot buckle 1205 and a second foot buckle 1206.

[0205] The main body of the ankle brace adopts an "L"-shaped tile structure, and is fixed at the ankle of the patient by four buckles, i.e., a first lower leg buckle 1203, a second lower leg buckle 1204, a first foot buckle 1205, and a second foot buckle 1206.

[0206] The first lower leg buckle is located at the tibiofibular one-half of the patient, and the second foot buckle is located at the base of the toes of the patient, which together maintain the stability of the ankle brace.

[0207] Further, the second lower leg buckle and the first foot buckle are respectively arranged close to the upper edge and the lower edge of the ankle joint to provide additional stability for the ankle joint.

[0208] The four buckles are made of materials such as magic tape, bandage, or elastic rope, and are combined with the main body of the ankle brace by rivets 1207. The four buckles together help the patient to resist gravity and accidental pulling of the ankle during daily walking.

[0209] On the main body of the ankle brace, a plurality of hollows 1209 are formed to reduce the weight of the brace and increase the structural efficiency of the brace, so that the brace does not hinder the patient's daily life due to the weight of the brace.

[0210] The position and shape of the hollows are generated according to the finite element simulation of the stress condition of the ankle of the patient and the results of topological optimization, and the results of topological optimization are subjected to secondary design to remove sharp corners and add excessive circular arcs to reduce stress concentration and improve the ability of the brace to resist accidental impact of the brace during the patient's daily activities.

[0211] On the edge of the hollows and the edge of the main body of the ankle brace, a flange structure 1208 is arranged, which can improve the rigidity and torsional resistance of the brace without increasing the contact area of the brace with the skin of the patient, thereby enhancing the stability of the fractured part of the patient.

[0212] The arrangement of the hollow structure is beneficial to the air circulation on the surface of the skin of the patient, helps to sweat and dissipate heat, and avoids the feeling of stuffiness and itching of the patient, thereby having good thermal comfort.

[0213] The shape of the main body of the ankle brace is generated according to the three-dimensional shape of the affected part 1202 of the ankle of the patient, has good adhesion with the skin of the affected part, can effectively avoid looseness of the brace caused by excessive gap, and can also avoid pressure concentration caused by too small contact area, thereby causing limb numbness, poor blood supply, and pain.

[0214] The main body of the ankle brace is made of nylon material by additive manufacturing, is waterproof and easy to clean, and the patient can take a normal bath and wash with a neutral detergent.

[0215] The main body of the ankle brace can also be made of ABS engineering plastic or other thermoplastic polymers by injection molding method, which can be mass-produced to reduce production cost.

[0216] The surface of the main body of the ankle brace in contact with the bottom of the patient's foot is rougher and has anti-slip grooves than other parts to prevent the patient's foot from slipping due to movement when walking while wearing the ankle brace.

[0217] The surface of the main body of the ankle brace in contact with the ground has a rubber-made wear-resistant anti-slip layer (not shown in the figure) adhered to the tip and heel parts, which protects the main body of the brace from wear and tear and prevents the patient from slipping due to insufficient friction when walking while wearing the ankle brace.

[0218] The main body of the ankle brace has undergone mechanical testing and trial fitting inspection after production, providing a suitable mechanical environment for the healing of the fracture site and ensuring the safety and effectiveness of the brace.

[0219] Figures 13a to 13f This is a process diagram for the design stage of the ankle brace of the present embodiment. The design process of this embodiment includes the following steps:

[0220] (a) Collect CT data and point cloud data of the affected area of the patient, establish a three-dimensional model of the skin of the ankle, and generate an original design scheme of the brace according to the three-dimensional model;

[0221] (b) Perform finite element analysis on the original design scheme to simulate the stress distribution when the patient wears the ankle brace;

[0222] (c) Topology optimization of the original design scheme;

[0223] (d) Add hollowing to the original design scheme according to the topology optimization results;

[0224] (e) Perform secondary finite element analysis on the topology-optimized scheme to simulate the stress distribution when the patient wears the ankle brace again;

[0225] (f) Add flanging to the topology-optimized scheme to increase the stiffness and torsional resistance of the ankle brace without increasing the contact area between the brace and the patient's skin.

[0226] Four, elbow brace:

[0227] Figure 14a , Figure 14b and Figure 14c The front, right and top structure schematic diagrams of the elbow brace of the present embodiment are a fracture external fixation brace generated using the design, manufacturing and testing methods of the present application, which is divided into an elbow brace main body 1401, an upper arm buckle 1402, a forearm buckle 1404 and a palm buckle 1405.

[0228] The elbow brace body 1401 adopts an "L" type tile structure, and is fixed on the elbow of the patient by three buckles, i.e., an upper arm buckle 1402, a forearm buckle 1404 and a palm buckle 1405.

[0229] Among them, the upper arm buckle 1402 is located at the one-half of the humerus of the patient, the forearm buckle 1404 is located at the one-half of the ulna and radius of the patient, and the palm buckle 1405 is located at the palm of the patient, and the three together maintain the stability of the patient when wearing the elbow brace.

[0230] The three buckles, i.e., the upper arm buckle, the forearm buckle and the palm buckle, are made of materials such as magic tape, bandage or elastic rope, and are combined with the elbow brace body 1401 by rivets 1403. The three buckles together help the patient to resist the gravity and the accidental pulling of the elbow part in daily activities.

[0231] The elbow brace body 1401 is provided with a plurality of hollow structures 1406 for reducing the weight of the brace and increasing the structural efficiency of the brace, so that the brace does not greatly hinder the patient's daily life when worn.

[0232] The position and shape of the hollow structure are generated according to the finite element simulation of the stress condition of the wrist of the patient by the computer and the result of topological optimization. The result of topological optimization is subjected to secondary design to remove sharp corners and add excessive circular arcs, so as to reduce stress concentration and improve the ability of the brace to resist accidental impact of the brace by the patient in daily activities.

[0233] The edge of the hollow structure has a flange structure 1407, which can improve the rigidity and torsional resistance of the brace without increasing the contact area of the brace with the skin of the patient, and enhance the stability of the fractured part of the patient.

[0234] The hollow structure is beneficial to the air circulation on the surface of the skin of the patient, helps to sweat and dissipate heat, avoids the feeling of stuffiness and itching of the patient, and has good thermal comfort.

[0235] The shape of the elbow brace body 1401 is generated according to the three-dimensional shape of the upper arm of the patient, has good adhesion with the skin of the affected part, can effectively avoid the looseness of the brace caused by too large gap, and can also avoid the pressure concentration caused by too small contact area, thereby causing limb numbness, poor blood supply and pain.

[0236] The body of the elbow brace body 1401 is made of nylon material by additive manufacturing, is waterproof and easy to clean, and the patient can take a normal bath and wash with neutral detergent.

[0237] The body of the elbow brace body 1401 can also be made of ABS engineering plastic or other thermoplastic polymer by the method of injection molding, and can be mass-produced to reduce the production cost.

[0238] The elbow brace body 1401 is attached with an anti-abrasion layer (not shown in the figure) made of thermoplastic polyurethane (TPU) at the edge part and above the elbow joint surface, so as to reduce the pressure and friction feeling of the patient during long-term wearing and joint movement. The pressure on the armpit, the medial and lateral condyles of the humerus and the olecranon is avoided to prevent the skin of the patient from swelling, itching and even ulceration.

[0239] After the elbow brace body 1401 is produced, it is subjected to mechanical testing and trial wearing inspection, so as to provide a suitable mechanical environment for the healing of the fracture site and ensure the safety and effectiveness of the brace.

[0240] Figures 15a to 15f The process diagram of the design stage of the elbow brace of the embodiment is shown in the figure, and the design process of the embodiment includes the following steps:

[0241] (a) Collecting CT data and point cloud data of the affected part of the patient, establishing a three-dimensional model of the elbow skin, and generating an original design scheme of the elbow brace according to the three-dimensional model;

[0242] (b) Performing finite element analysis on the original design scheme to simulate the stress distribution when the patient wears the elbow brace;

[0243] (c) Topology optimization of the original design scheme;

[0244] (d) Adding hollowing to the original design scheme according to the topology optimization result;

[0245] (e) Performing secondary finite element analysis on the topology-optimized scheme to simulate the stress distribution when the patient wears the elbow brace again;

[0246] (f) Adding flanging to the topology-optimized scheme to increase the rigidity and torsional resistance of the brace without increasing the contact area between the elbow brace and the patient's skin.

[0247] The technical scheme of the present application provides a design, production and inspection method of a customized external fixation brace. The brace produced by using the method is subjected to mechanical testing and trial wearing inspection, and can provide a suitable mechanical environment for the healing of the fracture site of the patient's limbs, and has safety and effectiveness. The customized external fixation brace produced by using the technical scheme is designed based on the three-dimensional shape data of the patient, and has good matching degree with the shape of the affected limb. The structure of the external fixation brace is subjected to finite element analysis and topology optimization, and has light weight, high structural efficiency, good air permeability ensured by large-area hollowing, water resistance and easy cleaning, and high wearing comfort.

[0248] The present application can be widely used in the fields of design and manufacture of customized external fixation braces.

Claims

1. A method for customizing the design, fabrication and inspection of an external fixation brace, comprising collecting data of a patient's affected area, designing and fabricating a corresponding external fixation brace based on the data of the affected area, characterized in that It comprises the following steps: S1, data collection, comprising the following processing on the patient data from the CT data and the point cloud data of the affected area: S11, three-dimensional reconstruction; S12, three-dimensional modeling; S13, three-dimensional skin model; S2, original scheme generation, comprising the following processing on the obtained three-dimensional skin model of the affected area: S21, model preprocessing; S22, model modification; S23, complete brace generation; S3, finite element analysis and topology optimization, comprising the following processing: S31 finite element preprocessing; S32 finite element analysis; S33 topology optimization; S34 topology optimization result output; S4, secondary design and finite element secondary analysis, completed using open source or commercial three-dimensional design software, finite element preprocessing and finite element analysis software, comprising the following steps: S41 secondary modeling; S42 structure reinforcement; S43 finite element preprocessing; S44 finite element secondary analysis; S45 selection comparison; The S4 secondary design and finite element secondary analysis step sequentially performs secondary modeling and structure reinforcement on the topology optimization result obtained in S34, then simultaneously performs finite element preprocessing and finite element secondary analysis on the results, and then performs selection comparison on the results, and the generated results enter the subsequent brace manufacturing and inspection step; S5, brace manufacturing and inspection, comprising the following steps: S51 detail design; S52 additive manufacturing; S53 injection molding; S54 post-processing and assembly; S55 mechanical test; S56 trial fitting inspection; The brace produced using the method provides a suitable healing mechanical environment for the fracture site of a limb, is designed based on the three-dimensional shape data of the patient, and has good matching degree with the affected area; The large area of hollowing ensures good air permeability, is waterproof and easy to clean, and has high wearing comfort.

2. The method of designing, making and checking a custom orthosis according to claim 1, characterized in that The S1 data collection comprises the following processing on the patient data from the CT data and the point cloud data of the affected area: S11, three-dimensional reconstruction: Read the patient CT data using open source software or commercial software; establish a VOI for the affected area of the limb fracture, and hide the rest; in the VOI, establish a skin mask by adjusting the threshold; finely modify the mask using tools including a brush and an eraser to ensure that all the skin is correctly selected; Perform three-dimensional reconstruction calculation; modify reconstruction errors; export the reconstruction result; In the S11 three-dimensional reconstruction substep, the VOI to be established needs to extend one to two large joints towards the proximal and distal ends respectively with the joint closest to the fracture line as the reference; S12, three-dimensional modeling: Read the point cloud data of the affected area using the commercial software accompanying the three-dimensional scanner; establish a VOI for the affected area of the limb fracture, and delete the rest of the point cloud data; use the software's built-in tools to cut off the background and clothes in the point cloud data; use the software's built-in tools to delete discrete points, burrs and broken surfaces to ensure that there is only one piece of connected point cloud data and the details of the VOI are preserved; encapsulate the point cloud data and perform mesh optimization to generate a three-dimensional model; In the S12 substep, the standard for establishing the VOI is the same as in the S11 substep; S13, three-dimensional skin model: Check whether the reconstructed three-dimensional model of the affected skin exists occlusion or defect, if exists, it should be returned to S11 sub-step or S12 sub-step; the three-dimensional model of the affected skin should also retain the patient's fracture site together with most of the corresponding VOI anatomical features, to provide more details for the subsequent design of the brace; Wherein, the affected CT data, after S12 three-dimensional modeling and S13 three-dimensional skin modeling steps, generates the three-dimensional data of the affected skin; The point cloud data of the affected part is obtained by professional personnel using three-dimensional scanner to scan the affected part of the patient's limbs, and after S12 three-dimensional modeling and S13 three-dimensional skin modeling steps, the three-dimensional data of the affected skin is generated.

3. The method of designing, making and checking a custom orthosis as defined in claim 1, characterized in that The S2 original scheme generation includes the following processing on the obtained three-dimensional model of the affected skin: S21, model preprocessing: including S211 cutting, S212 repairing and S213 smoothing; In S211 cutting operation, the three-dimensional model of the affected skin is cut into a curved surface piece, and the contour in cutting should be a closed curve, which should completely include the projection of the patient's fracture line in the sagittal plane or coronal plane, and the semi-enclosed style should be adopted to wrap the limb along the longitudinal direction while reserving the space for the patient to put on and take off; S22, model modification: including S221 selecting potential pressure area, S222 offsetting along normal direction and S223 secondary smoothing; In S221 selecting potential pressure area operation, the anatomical features of the patient's skin surface which are easy to cause skin pressure concentration and easy to rub with the brace are selected as the selection area; At the same time, the open fracture wound and the swelling area of the closed fracture line should also be selected as the potential pressure area; In S222 offsetting along normal direction operation, the potential pressure area selected in the previous step is offset outward along the respective normal direction by 1 to 20 mm; In S223 secondary smoothing operation, check whether the curved surface piece after normal offset appears damaged, and smooth the wrinkles, warping and spikes on the edge of the offset part, so that the model offset part and the original part are naturally transitioned, avoiding the discomfort brought by sharp corners and grooves to the wearer, and avoiding stress concentration leading to the fracture of the brace; S23, complete brace generation: including S231 model overall offset, S232 model overall shell extraction and S233 repairing model error; In S231 model overall offset operation, the entire curved surface piece is offset outward along the normal direction by 1 to 5 mm, which is the gap between the patient's skin and the brace when the patient wears it; In model overall shell extraction S232 operation, the three-dimensional model after overall offset is shell extracted, and the wall thickness is between 2 to 5 mm; In repairing model error S233 operation, check whether the three-dimensional model after shell extraction appears wrinkles, overlapping pieces and self-intersecting pieces in the edge part, and then repair these model errors to ensure that the complete brace model generated is closed and connected.

4. The method of designing, making and checking a custom orthosis of claim 3, characterized in that In S212 repairing operation, check whether the curved surface piece cut out in the previous step exists damage, hole and overlapping pieces, and then repair these defects; In the S213 smoothing operation, it is checked whether the repaired curved sheet has wrinkles, warping and nails, and then these features are smoothed; through this operation, the skin appearance of the injured area before injury is restored; In the S221 selecting potential pressure area operation, the anatomical features at least include: ulnar styloid process, radial styloid process, ulnar olecranon, fibular head, tibial tuberosity, calcaneus, lateral malleolus, medial malleolus, sustentaculum, fifth metatarsal tuberosity, navicular tuberosity or metatarsal head; In the S222 normal offset operation, the area prone to skin pressure concentration and friction is offset by 1-5 mm to reduce the squeezing and friction feeling of the patient after wearing; the skin wound area is offset by 5-20 mm to reserve enough space for dressings and bandages; In the S231 model overall offset operation, the brace for upper limb fracture is offset by 1-2 mm; the brace for lower limb fracture is offset by 2-5 mm; In the S232 model overall shell extraction operation, for the brace for upper limb, the wall thickness is selected as 3-5 mm; for the brace for lower limb, the wall thickness is selected as 2-3 mm.

5. The method of designing, making and checking a custom orthosis as defined in claim 1, characterized in that The S3 finite element analysis and topology optimization step includes: S31 finite element preprocessing: including S311 meshing, S312 adding constraints, S313 applying loads and S314 establishing analysis steps; S32 finite element analysis: including S321 submitting operation operation, if an error occurs, then after executing S322 checking setting operation, return to S311 meshing operation; if the result converges, execute S323 output result; S33 topology optimization: including S331 establishing optimization task operation, submitting operation S332, if an error occurs, then after executing S333 checking setting, return to S331 establishing optimization task operation; if the result converges, execute the next operation; S34 topology optimization result output.

6. The method of designing, making and checking a custom orthosis as defined in claim 5, characterized in that In the S311 meshing operation, the complete brace model is divided into hexahedral meshes, the mesh quality is optimized by changing the mesh size and node number to reduce the calculation power consumption and reduce errors during solving; In the S312 adding constraints operation, additional independent nodes are added as constraint and load applying nodes in the appropriate spatial coordinates for the divided meshes, and after binding with the corresponding meshes, the independent nodes are applied with constraints including direction and angle; In the S313 applying loads operation, the independent nodes added in the previous operation are further added with loads including torque; In the S314 establishing analysis step operation, materials are added to the meshes, properties are created, analysis steps including constraints, loads, materials and properties are created, and other parameters of the analysis steps are set, and then saved in a file format readable by finite element analysis software; In the S321 submitting operation operation, the file generated in the previous operation is read, and whether the parts, constraints, properties, loads and analysis steps are correctly read is checked in sequence, and the finite element analysis task set in the previous operation is submitted to the server for calculation; if an error occurs, enter the S322 checking setting operation; if the result converges, enter the S323 output result operation; In the S322 checking setting operation, the parts, constraints, properties, loads and analysis steps are checked in sequence to see if they are correctly set, and then starting from the S311 mesh division, each step is checked in sequence to see if it is correctly set; In the S323 output result operation, the operation result is checked to see if it is reasonable, and the operation result is saved as a basis for subsequent comparison and analysis with the topology optimization result; In the S331 establishing optimization task operation, the topology optimization task is created, the response of the topology optimization to the strain energy and the model volume is set, the optimization target of the topology optimization is set, and the calculation parameters including the optimization cycle number, CPU core number and GPU acceleration are set; In the S332 submitting operation operation, the topology optimization calculation task set in the previous operation is submitted to the server for calculation, and if the software reports an error, the S333 checking setting operation is entered; If the result converges, the S341 optimization result output operation is entered; In the S333 checking setting operation, the topology optimization response and the optimization target are checked in sequence to see if they are correct, and modifications are made as needed; In the S341 optimization result output operation, all optimization results are combined, and then the results are exported and saved, and the results are generated to enter the S41 secondary modeling substep.

7. The method of designing, making and checking a custom orthosis of claim 1, wherein The S4 secondary design and finite element secondary analysis step includes the following steps: S41 secondary modeling: The topology optimization result and the complete brace model are imported into an open-source or commercial three-dimensional design software, the complete brace model is trimmed according to the optimization result, and the sharp corner parts in the optimization result that are prone to cause stress concentration are smoothed, and the result is used as a simple topology-optimized brace model; S42 structure reinforcement: "L" shaped flanges with a thickness of 1 to 5 mm are added to all edges and hollowed-out part edges of the simple topology-optimized brace model, or inverted "T" shaped reinforcing ribs with a thickness of 1 to 5 mm are added to appropriate parts of the simple topology-optimized brace model; S43 finite element preprocessing: The simple topology-optimized brace model and the models after various structure reinforcements are preprocessed, including mesh division and attribute addition, and the specific operation method is the same as that of the S31 finite element preprocessing substep; S44 finite element secondary analysis: The simple topology-optimized brace model and the models after various structure reinforcements are subjected to finite element analysis, and the specific operation method is the same as that of the S32 finite element preprocessing substep; S45 selection comparison: The finite element analysis results of the simple topology-optimized brace model and the models after various structure reinforcements are summarized, and a suitable and personalized design scheme is selected according to the actual situation of the patient; The S4 secondary design and finite element secondary analysis step sequentially performs secondary modeling S41 and structure reinforcement S42 on the topology optimization result obtained in S34, then simultaneously performs finite element preprocessing S43 and finite element secondary analysis S44 on the results of the two, and then performs selection comparison S45 on the results, and the generated results enter the subsequent brace manufacturing and inspection S5 step.

8. The method of designing, making and checking a custom orthosis as defined in claim 7, characterized in that In the S45 selection comparison sub-step, the model after simple topology optimization has lower rigidity than the complete brace, but is more lightweight, and is suitable for use in lower limb fractures; the model with reinforcement in the hollowed-out part has higher rigidity than the model after simple topology optimization, but is slightly heavier, and is suitable for use in most parts; the model with all edges reinforced has high rigidity and is relatively heavy, and is suitable for use in cases of comminuted fractures.

9. The method of designing, making and checking a custom orthosis according to claim 1, characterized in that The S5 brace manufacturing and inspection step comprises the following steps: S51 detailed design; S52 additive manufacturing; S53 injection molding; S54 post-processing and assembly; S55 mechanical testing; S56 trial wearing inspection; The S5 brace manufacturing and inspection step, the brace model selected in the S45 selection comparison step is subjected to S51 detailed design, and the production mode of S52 additive manufacturing or S53 injection molding is selected according to the actual situation, and then the product produced is subjected to S54 post-processing and assembly, and the brace that has sequentially passed the S55 mechanical testing and the S56 trial wearing inspection is used as the final product.

10. The method of designing, making and checking a custom orthosis according to claim 1, characterized in that In the S51 detailed design sub-step, the brace mounting hole is added to the brace design scheme selected in the S45 selection comparison sub-step, so as to facilitate the subsequent installation of the buckle for fixing the brace; In the S52 additive manufacturing and S53 injection molding sub-steps, the specific molding mode is selected according to the clinical requirements; In the S54 post-processing and assembly sub-step, the produced brace is polished, polished, deburred, or subjected to further surface treatment modes including solvent vapor fumigation polishing, dyeing, sandblasting, and electroplating; and then the buckle including the magic tape, the bandage, or the elastic rope for fixing the brace is assembled; In the S55 mechanical testing sub-step, the assembled brace is subjected to mechanical testing including three-point bending test and torsion test, so as to confirm that the produced product can meet the use standard; if the test cannot be passed, the design scheme is changed in the S51 detailed design stage; In the S56 trial wearing inspection sub-step, the patient tries on the brace subjected to the mechanical test, and determines whether the patient has pain, compression, friction, or other serious discomfort after wearing the brace through inquiry, visual observation, and questionnaire survey; if discomfort occurs, the design scheme needs to be changed in the S51 detailed design stage.

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