CN-115188479-B - Radius distal bone plate optimization method based on optimal fracture gap strain

CN115188479BCN 115188479 BCN115188479 BCN 115188479BCN-115188479-B

Abstract

The invention discloses a radius distal end bone plate optimizing method based on optimal fracture gap strain, which specifically comprises the steps of constructing a radius distal end fracture internal fixation system finite element model, analyzing, constructing a topology optimizing model based on a weighted sum variable density method by taking the minimum displacement of a weighted bone fracture end as an objective function and taking the volume as a constraint, updating iteration till meeting convergence criteria to obtain an optimal topology configuration, evaluating whether the optimal topology configuration meets the optimal fracture gap strain, and utilizing weighted optimization to be more fit with the stress condition of a wrist joint in actual life, wherein the bone plate obtained by weighted optimization enables the displacement of the bone fracture end to meet the optimal fracture gap strain under the condition of meeting rigidity when in use, pursuing optimal healing and improving the life quality of patients.

Inventors

XING HONGYAN
WEI JINGYI
ZHANG PEIJIAN

Assignees

天津科技大学

Dates

Publication Date: 20260512
Application Date: 20220707

Claims (4)

1. A radius distal bone plate optimizing method based on optimal fracture gap strain is characterized by comprising the following specific implementation steps: S1, collecting radius CT data of a patient, obtaining a radius three-dimensional model by using data processing software, determining fracture parting, and cutting the radius model by using Solidworks software to obtain a radius distal end fracture model; S2, establishing an internal fixation system bone plate and screw model, assembling with a radius distal fracture model to obtain a radius distal fracture internal fixation system finite element model, and carrying out finite element analysis; S21, establishing a bone plate and screw model by utilizing Solidworks software, wherein the screw model is simplified to a cylinder structure because a main study object is the bone plate, and the assembled geometric model is imported into ABAQUS analysis software to obtain a finite element model of the distal radius fracture internal fixation system; s22, defining material properties and contact in ABAQUS, wherein the radius body is set to be cortical bone, the distal radius end is set to be cancellous bone, and the bone plate and the screw are made of titanium alloy materials; s23, defining boundary conditions, wherein the boundary conditions are divided into constraint boundary conditions and load boundary conditions; constraint boundary conditions, namely setting a fixed constraint on the proximal end of the radius and applying a load on the distal end; the load boundary condition is that a load applying point is established on the contact surface of the wrist joint at the distal radius to be coupled with the radius, and three loads of compression, torsion and bending are applied; S3, constructing a topological optimization model based on a weighted sum variable density method by taking the minimum displacement of the weighted bone fracture end as an objective function and taking the volume as a constraint according to the finite element analysis result, selecting an optimization area, and performing topological optimization on the bone plate to obtain a preliminary optimization result; And S4, judging whether the displacement of the broken end of the bone under the fixation of the optimized bone plate meets the optimal fracture gap strain, if so, completing the optimization, carrying out the design resetting treatment, and if not, changing the value of the optimization parameter, and continuing to execute the step S3.
2. The method for optimizing distal radius bone plates based on optimal fracture gap strain according to claim 1, wherein in step S3, the topological optimization model based on the weighted sum variable density method is: Objective function Constraint function 0<ρ i ≤1; The meaning of the objective function is that the maximum bone fracture displacement in the minimized area, U represents the function of displacement, i represents a unit, n is a design response, U t is a displacement vector, ρ (i) is the density of the ith unit, W t is a weight, V (ρ) is an optimized volume, V 0 is the volume of the design domain, and f is a set volume percentage.
3. The method for optimizing distal radius bone plates based on optimal fracture gap strain according to claim 1, wherein in step S3, the weights of axial, bending and torsion loads in the weighted optimization are sequentially 50%, 30% and 20%, and the optimization module performs parameter setting in ABAQUS.
4. The method of optimizing a distal radius bone plate based on optimal fracture gap strain of claim 1, wherein in step S4, the fractured bone end displacement is evaluated by selecting a node displacement of an outer contour path of the fracture.

Description

Radius distal bone plate optimization method based on optimal fracture gap strain Technical Field The invention relates to an optimization method, in particular to a radius distal bone plate optimization method based on optimal fracture gap strain. Background Distal radius fractures are the type of upper limb fractures commonly seen in current clinical treatment, accounting for about one sixth of the total body fractures. The non-operative treatment can play a better role on the fracture of the distal radius, but the fracture deformity healing phenomenon exists in part of patients. Therefore, the use of bone plates has become a preferred option for better healing of the wrist joint, and for reduced complications. The designs of bone plates include personalized designs and serialized designs, and the serialized bone plates with versatility are more widely used than personalized bone plates, but the serialized bone plates have different effects in use from person to person. Therefore, the study analyzes biomechanics of the distal radius fracture of the bone plate fixation, optimizes the bone plate on the basis of guaranteeing basic functions, and can meet the requirements of different individuals better and achieve the best healing effect. At present, many optimization methods are standard topological optimization under a single load, but in actual life, the load born by the radius of a human body is not single, but multiple loads act together. Secondly, many optimization methods are aimed at optimizing the rigidity of the bone plate, and the purpose is to enable the displacement of the broken end of the bone to meet the optimal healing effect. Therefore, the method is improved aiming at the existing optimization method, the load is weighted, the displacement of the broken bone end is used as an optimization target, and the optimization effect is more direct. Disclosure of Invention The invention aims to provide a radius distal bone plate optimizing method based on optimal fracture gap strain. In order to achieve the above purpose, the present invention provides the following technical solutions: a radius distal bone plate optimization method based on optimal fracture gap strain, which is characterized by comprising the following steps: S1, collecting radius CT data of a patient, obtaining a radius three-dimensional model by using data processing software, determining fracture parting, and cutting the radius model by using Solidworks software to obtain a radius distal end fracture model; S2, establishing an internal fixation system (bone plate and screw) model, assembling with the distal radius fracture model to obtain a distal radius fracture internal fixation system finite element model, and carrying out finite element analysis; S21, establishing a bone plate and screw model by utilizing Solidworks software, wherein the screw model is simplified to a cylinder structure because a main study object is the bone plate, and the assembled geometric model is imported into ABAQUS analysis software to obtain a finite element model of the distal radius fracture internal fixation system; s22, defining material properties and contact in ABAQUS, wherein the radius body is set to be cortical bone, the distal radius end is set to be cancellous bone, and the bone plate and the screw are made of titanium alloy materials; s23, defining boundary conditions, wherein the boundary conditions are divided into constraint boundary conditions and load boundary conditions; constraint boundary conditions, namely setting a fixed constraint on the proximal end of the radius and applying a load on the distal end; the load boundary condition is that a load applying point is established on the contact surface of the wrist joint at the distal radius to be coupled with the radius, and three loads of compression, torsion and bending are applied; S3, constructing a topological optimization model based on a weighted sum variable density method by taking the minimum displacement of the weighted bone fracture end as an objective function and taking the volume as a constraint according to the finite element analysis result, selecting an optimization area, and performing topological optimization on the bone plate to obtain a preliminary optimization result; And S4, judging whether the displacement of the broken end of the bone under the fixation of the optimized bone plate meets the optimal fracture gap strain, if so, completing the optimization, carrying out the design resetting treatment, and if not, changing the value of the optimization parameter, and continuing to execute the step S3. Further, in step S3, the topology optimization model based on the weighted sum variable density method is: Objective function Constraint function 0<ρi≤1; The meaning of the objective function is that the maximum bone fracture displacement in the minimized area, U represents the function of displacement, i represents a unit, n is a design response, U t is a displa