CN111728741B

CN111728741B - Human body personalized hip joint femoral stem prosthesis adopting light weight design and manufacturing method thereof

Info

Publication number: CN111728741B
Application number: CN202010638367.1A
Authority: CN
Inventors: 张志辉; 张晓龙; 于征磊; 谢鑫宇; 孔德印; 王金成; 任露泉
Original assignee: Jilin University
Current assignee: Jilin University
Priority date: 2020-07-06
Filing date: 2020-07-06
Publication date: 2022-05-13
Anticipated expiration: 2040-07-06
Also published as: CN111728741A

Abstract

The invention relates to a human body personalized hip joint femoral stem prosthesis adopting a lightweight design and a manufacturing method thereof, belonging to the field of medical instruments. Comprises a handle neck, a handle body, a vertebral body and a vertebral tip, wherein the upper part of the prosthesis is triangular, and the inner side angle is 90-120 degrees; the handle body is designed in a light weight mode by adopting a hexagonal honeycomb structure unit; the handle body and the cone body can be designed in a light weight mode at the same time, the light weight design can adopt an irregular open pore or closed pore structure design, and can also adopt a 3D lattice structure design, and the structural units are preferably diamond units, rhombic dodecahedron units or truncated cube units; the vertebral tip is designed by a solid structure. According to the invention, through extraction of personalized features of the solid model and forward design with light weight as a guide, the light weight design is realized while personalized customization is carried out, the weight of the hip joint femoral stem prosthesis can be reduced on the premise of meeting mechanical properties, the maximization of the material utilization rate is realized, a large amount of space is provided for bone regeneration and bone growth, and the stability is improved.

Description

Human body personalized hip joint femoral stem prosthesis adopting light weight design and manufacturing method thereof

Technical Field

The invention relates to the field of medical instruments, in particular to a human body personalized hip joint femoral stem prosthesis adopting a lightweight design and a manufacturing method thereof.

Background

The hip joint is one of important bearing joints of a human body and plays an important role in maintaining the upright posture of the human body and walking in movement. However, with the age, the normal physiological functions of the hip joint are seriously affected by the occurrence of arthritis and other problems, and at present, 50 ten thousand cases of hip joint patients are broken through all over the world. Based on the needs of patients, through the development process of nearly 40, the replacement of the artificial hip joint becomes an important means for relieving the pain of patients and recovering the normal physiological function of human bodies.

However, most of the hip-joint femoral stem prostheses clinically used at present are standard in size, are produced in batches, and cannot meet the individual customization requirements of patients; in addition, most of the clinically practical hip joint femoral stem prostheses are solid structures, the mass is heavy, the stability is poor, and the prosthesis installation patients cannot adapt to the prosthesis installation patients after the operation completely. For this reason, with the development, exploration and improvement of additive manufacturing technology, it is more significant to make a special design and manufacturing that is highly matched with the hip stem size and space information of each patient, especially for the following two groups: for patients with abnormal femur size or deformity, the conventional artificial prosthesis cannot be matched and special personalized design is required. Secondly, aiming at a bone defect patient, the defect part needs to be completely repaired, and a connection technology with high adaptability needs to be individually designed.

Disclosure of Invention

The invention aims to provide a human body personalized hip joint femoral stem prosthesis adopting a lightweight design and a manufacturing method thereof, and solves the problems in the prior art. The hip joint femoral stem prosthesis handle body adopts a lightweight design, reduces the weight of the hip joint femoral stem prosthesis on the premise of meeting the mechanical property, promotes bone regeneration and bone ingrowth, and improves the stability of the implanted hip joint femoral stem prosthesis. The individual customization requirements of the patients are met.

The above object of the present invention is achieved by the following technical solutions:

a human body personalized hip joint femoral stem prosthesis adopting a lightweight design comprises a stem neck 1, a stem body 2, a vertebral body 3 and a vertebral tip 4, wherein the stem body 2 adopts a hexagonal honeycomb structure unit for the lightweight design; the handle body 2 and the cone body 3 can be designed in a light weight mode at the same time, the light weight design adopts an irregular open pore or closed pore structure design or a 3D lattice structure design, and the structural units are preferably diamond units, rhombic dodecahedron units or truncated cube units; the tip 4 is designed to adopt a solid structure.

The handle body adopting the light weight design is formed by accumulating honeycomb structural units 5; the honeycomb structure unit 5 is a hexagonal honeycomb structure unit, the pore diameter is 150-300 mu m, and each internal angle is 60 degrees; the thickness of the single strut is 100-300 μm; the porosity is 68-80%.

The prosthesis is made of stainless steel, titanium alloy and NiTi alloy, preferably NiTi alloy; the Young's modulus is 21 to 69GPa, preferably 21 to 30 GPa.

Another object of the present invention is to provide a method for manufacturing a human personalized hip femoral stem prosthesis with a lightweight design, comprising the steps of:

step one, scanning the femoral stem part of the hip joint of a patient by adopting CT or MRI to obtain the tomographic image data of the target femoral bone of the hip joint, preferably scanning by adopting CT, and controlling the scanning parameters: the thickness of the scanning layer is 1-5mm, the interval between layers is 1-3mm, the total amount of contrast agent is 60-100ml, and the flow rate is 2-3 ml/s;

step two, importing the obtained tomographic image data into a medical image control system mimics, setting a threshold value, performing smooth denoising, reconstructing a three-dimensional model, and extracting a point cloud model of a hip joint femoral stem part to be repaired;

step three, importing the processed point cloud model data into cata for reverse modeling, and repairing and perfecting the target hip joint femoral stem prosthesis model;

printing the plastic femoral stem prosthesis by using an injection molding machine according to the reverse design model, and using the plastic femoral stem prosthesis for patient analysis and personalized hip joint femoral stem prosthesis model design;

step five, importing the reverse design model into hypemesh for topology optimization according to the design scheme, wherein the topology optimization conditions are as follows: bound volume 50%, target minimum strain energy; forward design is carried out in cata according to the topological optimization result, so that the high matching performance of the prosthesis and the native hip joint femoral stem of the patient is ensured, the high reduction of the motion rule of the hip joint is realized, and the design of the personalized hip joint femoral stem prosthesis of the human body is completed;

step six, importing the designed hip joint femoral stem prosthesis model into magics software for diagnosis, repair and slicing, processing errors caused by file format conversion, eliminating the defects of three-dimensional software on a triangular mesh algorithm, and outputting the format in stl format;

step seven, guiding the processed hip joint femoral stem prosthesis model into a metal 3D printer (ProX DMP 320) for three-dimensional forming, wherein the control parameters are as follows: the laser power is 120W, the laser scanning speed is 600mm/s, the laser vector spacing is 80 μm, and the layer thickness is 30 μm.

Repairing and perfecting the target hip joint femoral stem prosthesis model specifically comprises the following steps: constructing a curved surface sheet and performing curved surface fitting operation on the irregular position; carrying out contour line editing and multi-section surface fitting operation on the regular position; after the whole curved surface is fitted, carrying out smoothing treatment; reverse modeling can also be done by geogenic Studio.

The invention has the beneficial effects that:

1. according to the invention, the reverse modeling is carried out through the tomographic image data of the patient, so that the high matching property of the prosthesis and the native hip joint femoral stem of the patient is ensured.

2. The invention carries out topology optimization and lightweight design on the hip joint femoral stem prosthesis model, wherein the prosthesis stem body adopts a honeycomb structure design, the weight of the hip joint is reduced under the condition of meeting the requirement of mechanical property, and meanwhile, the pores of the optimized hip joint femoral stem prosthesis are beneficial to bone ingrowth and the stability of the hip joint femoral stem prosthesis in the body is improved.

3. The invention adopts the selective laser cladding technology to carry out integrated molding, provides possibility for customizing the complex hip joint femoral stem prosthesis, and has higher precision and more flexibility.

4. The hip joint femoral stem prosthesis prepared by the method preferably adopts niti alloy materials, has good biocompatibility, has the Young modulus approximately similar to that of bones, avoids stress shielding and prolongs the service life of the hip joint femoral stem prosthesis.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention.

FIG. 1 is a process flow diagram of the present invention for preparing a personalized hip stem prosthesis

FIG. 2 is a schematic view of a hip stem prosthesis after reverse modeling in accordance with the present invention

FIG. 3 is a schematic diagram of a topology optimized hip stem prosthesis of the present invention

FIG. 4 is a schematic view of a hip stem prosthesis of the final design of the present invention

FIG. 5 is a schematic view of a honeycomb structure unit of the stem body of the present invention

In the figure: 1. a handle neck; 2. a handle body; 3. a vertebral body; 4. a vertebral tip; 5. a honeycomb structure unit.

Detailed Description

The details of the present invention and its embodiments are further described below with reference to the accompanying drawings.

The invention relates to a human body personalized hip joint femoral stem prosthesis adopting lightweight design and a preparation method thereof, which comprises two main processes of extraction of personalized features of a solid model and forward design with lightweight as a guide, and comprises the following specific steps: scanning a femoral stem part of a hip joint of a patient by adopting CT or MRI, importing the obtained tomographic image data into mimics to obtain a point cloud model of the femoral stem of the hip joint after scanning, finishing subsequent reverse design, topological optimization and forward design work according to the point cloud data, and finishing the design of a personalized femoral stem prosthesis model of the hip joint, wherein the specific work is carried out in cata and hypemesh software; finally, printing of the target hip-joint femoral stem prosthesis is completed through an additive manufacturing method. The personalized hip joint femoral stem prosthesis solves the problems of the standard hip joint femoral stem prosthesis caused by different patients, realizes personalized customization, and simultaneously, the lightweight design related to the method can reduce the weight of the hip joint femoral stem on the premise of meeting the mechanical property, realizes the maximization of the material utilization rate, provides a large amount of space for bone regeneration and bone growth, and improves the stability.

Referring to fig. 1 to 5, the human body personalized hip joint femoral stem prosthesis adopting the light weight design comprises a stem neck 1, a stem body 2, a vertebral body 3 and a vertebral tip 4, wherein the stem body 2 adopts the light weight design and adopts a hexagonal honeycomb structure unit; the handle body 2 and the cone body 3 can be designed in a light weight mode at the same time, the light weight design can adopt an irregular open pore or closed pore structure design and can also adopt a 3D lattice structure design, and the structural units are preferably diamond units, rhombic dodecahedron units or truncated cube units; the tip 4 is designed to adopt a solid structure.

The shank body having the lightweight feature is built up of honeycomb structural units 5; the honeycomb structure unit 5 is a hexagonal honeycomb structure unit, the pore diameter is 150-300 mu m, and each internal angle is 60 degrees; the thickness of the single strut is 100-300 μm; the porosity is 68% to 80%, preferably 75%.

The prosthesis is made of stainless steel, titanium alloy and NiTi alloy, preferably NiTi alloy; the Young modulus of the material is 21-69 Gpa, and preferably 21-30 Gpa.

Referring to fig. 1 to 5, the method for manufacturing the honeycomb-structure human personalized hip-joint femoral stem prosthesis of the present invention comprises the following steps:

(1) CT or MRI is adopted to scan the femoral stem part of the hip joint of the patient to obtain the tomographic image data of the target bone of the femur, CT is preferably adopted to scan, and the scanning parameters are controlled: the thickness of the scanning layer is 1-5mm, the interval between layers is 1-3mm, the total amount of contrast agent is 60-100ml, and the flow rate is 2-3 ml/s;

(2) importing the obtained tomographic image data into a medical image control system mimics, setting a threshold, performing smooth denoising, reconstructing a three-dimensional model, and extracting a point cloud model of a hip joint femoral stem part to be repaired;

(3) importing the processed point cloud data into cata for reverse modeling, and carrying out surface sheet construction and surface fitting operation on irregular positions; performing contour line editing and multi-section surface fitting operation on the regular position; after the whole curved surface is fitted, performing smoothing treatment, and repairing and perfecting the target hip joint femoral stem prosthesis model;

(4) printing a plastic femoral stem prosthesis model by using an injection molding machine according to the reverse design model, and using the plastic femoral stem prosthesis model for patient analysis and personalized hip joint femoral stem prosthesis model design;

(5) according to the design scheme, a reverse design model is led into hypemesh for topology optimization, and the topology optimization conditions are as follows: bound volume 50%, target minimum strain energy; according to the topological optimization result, a stem part is positively designed by adopting a honeycomb structure in cata, the pore diameter of a unit of the hexagonal honeycomb structure is generally 150-300 mu m, preferably 180 mu m, and each internal angle is 60 degrees; the thickness of the single support column is generally 100-300 μm, preferably 200 μm; the porosity is generally between 68% and 80%, preferably 75%;

(6) guiding the designed hip joint femoral stem prosthesis model into magics software for adding support, diagnosis, repair and slicing, processing errors caused by file format conversion, eliminating the defects of three-dimensional software on a triangular mesh algorithm, and outputting a stl format, wherein the support adopts a columnar support;

(7) guiding the sliced hip joint femoral stem prosthesis model into 3DXpert for printing position adjustment and parameter setting;

(8) and (3) introducing the processed hip joint femoral stem prosthesis model into a metal 3D printer ProX DMP 320 for three-dimensional forming, wherein the control parameters are as follows: the laser power is 120W, the laser scanning speed is 600mm/s, the laser vector interval is 80 mu m, and the layer thickness is 30 mu m;

(9) and taking the printed hip joint femoral stem prosthesis down from the substrate by wire cutting, and carrying out post-treatment procedures such as support removal, sand blasting, grinding and polishing, heat treatment and the like to obtain the target hip joint femoral stem prosthesis. Wherein, the heat treatment process adopts 1000-2 h of solution treatment.

The above description is only a preferred example of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like of the present invention shall be included in the protection scope of the present invention.

Claims

1. A manufacturing method of a human body personalized hip joint femoral stem prosthesis adopting lightweight design is characterized in that: the human personalized hip joint femoral stem prosthesis comprises:

the handle comprises a handle neck (1), a handle body (2), a cone body (3) and a cone tip (4), wherein the handle body (2) is designed in a light weight mode by adopting a hexagonal honeycomb structure unit; the handle body (2) and the cone body (3) can be designed in a light weight mode at the same time, the light weight design adopts an irregular open pore structure or closed pore structure design or a 3D lattice structure design, and the structural units are diamond units, rhombic dodecahedron units or truncated cube units; the vertebral tip (4) is designed by a solid structure;

the edge of the handle neck (1) and the edge of the handle body (2) form an angle of 90-120 degrees;

the prosthesis is made of NiTi alloy; young modulus is 21-30 Gpa;

the handle body (2) is formed by accumulating honeycomb structural units (5); the honeycomb structure units (5) are hexagonal honeycomb structure units, the pore diameter is 180 mu m, and each internal angle is 60 degrees; the thickness of the single strut is 200 μm; the porosity is 75%;

the manufacturing method comprises the following steps:

step one, scanning a femoral stem part of a hip joint of a patient by adopting CT (computed tomography), obtaining tomographic image data of a target femoral bone of the hip joint, and controlling scanning parameters: the thickness of the scanning layer is 1-5mm, the interval between layers is 1-3mm, the total amount of contrast agent is 60-100ml, and the flow rate is 2-3 ml/s;

the third step comprises:

constructing a curved surface sheet and performing curved surface fitting operation on the irregular position;

carrying out contour line editing and multi-section surface fitting operation on the regular position;

after the whole curved surface is fitted, carrying out smoothing treatment; reverse modeling can also be done by geogenic Studio;

step seven, guiding the processed hip joint femoral stem prosthesis model into a metal 3D printer for three-dimensional forming, wherein the control parameters are as follows: the laser power is 120W, the laser scanning speed is 600mm/s, the laser vector interval is 80 mu m, and the layer thickness is 30 mu m;

and taking the printed hip joint femoral stem prosthesis down from the substrate by wire cutting, and carrying out the procedures of support removal, sand blasting, grinding and polishing and heat treatment to obtain the target hip joint femoral stem prosthesis, wherein the heat treatment process adopts 1000-2 h of solution treatment.