Titanium and its alloys have many advantages as surgical implants, such as low density, high strength, good toughness, good biocompatibility, non-toxic, low modulus of elasticity, good corrosion resistance, low X-ray absorption, etc., so they play an increasingly important role in medical metal materials
 
Titanium and its alloys can be used in the repair and replacement of human hard tissues, or in the repair of cardiovascular and soft tissues, as well as in the manufacture of artificial organs. It is a special functional material closely related to human life and health
 
At present, it has become the first choice of metal materials for replacement or repair products such as artificial joints, artificial bones, bone fracture fixators, spine correction rods, intramedullary nails, artificial heart valves, dental implants, skull, etc
 
The world population is nearly 6.5 billion, and the global aging problem is very serious
 
According to the data of F & S company, the global orthopedic implant market has a compound growth rate of about 10.4% in the past five years, which is expected to reach 27.7 billion US dollars by 2015, while the Chinese orthopedic implant market will grow to 16.6 billion yuan, with an annual compound growth rate of 18.1%
 
Therefore, as the first choice of medical metal materials, titanium and its alloys have a strong market demand in the future. So, it is of great significance to increase the research, development and application of medical titanium and its alloys in China
 
Research and development of titanium materials for surgical implants
 
Vanadium free medical titanium alloy
 
Ti-6Al-7Nb alloy is a kind of medical alloy developed by Sulzer medical technology company in Switzerland
 
Compared with Ti-6Al-4V alloy, Ti-6Al-7Nb alloy uses the non-toxic β stable element Nb with the same atomic concentration as V to replace V. in terms of performance, it is equivalent to the recognized Ti-6Al-4V alloy. It is a safe and potential material for human implantation
 
The Ti-6Al-7Nb alloy implants have been put into clinical application with good results.
另一种医用钛合金Ti-5Al-2.5Fe是由德国研发的Another medical titanium alloy Ti-5Al-2.5Fe was developed in Germany
 
Ti-5Al-2.5Fe is a medium strength material, which is equivalent to Ti-6Al-4V in mechanical properties, toughness and fatigue strength
 
These two kinds of alloys have also been developed in China
 
Ti-6Al-7Nb and Ti-5Al-2.5Fe alloys, which are jointly developed by BaoTi Group Co., Ltd., Beijing General Research Institute of non ferrous metals, Hebei Medical University, Shandong Wendeng osteosynthesis hospital and the second orthopedic medical device factory of Tianjin medical device industry company, have good biocompatibility and good osseointegration with bone tissue.
 
A new type of β - titanium alloy
 
Since the 1990s, there have been continuous reports on the potential harm of V and Al elements to human body in titanium alloy implant materials
 
Therefore, the development of advanced medical metal materials with excellent comprehensive mechanical properties and more compatible with human soft and hard tissue biology and mechanics - New β - titanium alloy has become the research focus of Biomedical Metal materials.
 
A series of new β - titanium alloys were developed by adding non-toxic elements such as Nb, Ta, Zr, Mo and Sn.
 
Ti-Ni alloy
 
Ti-Ni shape memory alloy is a new type of functional material, which has unique shape memory effect, hyperelasticity, fatigue resistance, wear resistance, corrosion resistance and good biocompatibility. Therefore, the alloy has been widely used in the medical field.
 
Ti-Ni shape memory alloy has been successfully used in orthopedic clinical, which has attracted the attention of orthopedic experts and clinicians, and is called "magic metal"
 
Ntsma used in orthopedic clinic has a deformation temperature of 0 ℃ ~ 5 ℃ and a recovery temperature of 37 ℃
 
After the fracture was fixed with ntsma material, the temperature or hot brine wet compress increased to produce shape recovery, but the bone restricted the material recovery, so that a dynamic and continuous pressure or clamp force was produced at the fracture end to achieve the function of fracture fixation
 
Porous titanium alloy
 
The surface structure of surgical implants is closely related to the biological behavior after implantation
 
Compared with the dense materials, the introduction of pores can significantly reduce the elastic modulus of titanium and its alloys, and the strength and modulus of porous titanium can be adjusted by changing the porosity, pore diameter and other parameters, so as to make full use of its open through-hole structure to promote the adhesion, growth, regeneration and reconstruction of bone tissue and accelerate the healing process,it can make titanium and its alloy match the elastic modulus of bone and material under the condition of maintaining certain strength
 
At the same time, the rough surface geometry of porous titanium alloy can promote the new bone tissue to grow into the pores, not only strengthen the biological fixation between the implant and the bone, but also make the stress transfer to the surrounding bone along the implant.
 
Surface activation technology of titanium alloy
 
Titanium alloy surface activation technology is one of the key areas of orthopedic implant material research and development.
 
The surface of the implant is in direct contact with the human body. Through surface modification, the biocompatibility can be improved and wear can be reduced, so as to reduce the possibility of implant loosening and ensure the long-term performance of the implant.
 
Weigao Group Co., Ltd. and Metal Research Institute of Chinese Academy of sciences have formed composite oxide coating on the surface of titanium alloy through anodizing, hydrothermal treatment and heat treatment. The prepared gradient coating has complete crystal form, high ability to induce the formation of hydroxyapatite layer, cell adsorption and proliferation, and good biocompatibility.
 
Laser near net shape surgical implants
 
Laser near net shape technology is a 3D printing manufacturing technology. Combined with computer control, it gradually uses high-energy beam to melt titanium alloy powder in the molten pool and processes it into orthopedic implants or dental restorations with specific shapes
 
Northwest Polytechnic University and other research institutions have conducted a lot of research on laser stereo forming technology of pure titanium and other medical metals. The mechanical properties and fatigue properties of pure titanium implants prepared by this technology are higher than those of pure titanium, which can meet the requirements of dental implants on mechanical properties
 
At present, some progress has been made in the research of laser near net shaping technology for the fabrication of titanium nickel alloy and titanium alloy stent.
 
Application abroad
 
Ti-Ni alloy with unique shape memory characteristics has been used in oral cavity, neurosurgery, cardiovascular department, thoracic surgery, otorhinolaryngology, hepatobiliary department, urology and Gynecology since its successful development. Its products include dental orthodontic wires, root canal files, spinal orthodontic rods, osteosynthesis plates, intramedullary needles, patellar claws, guidewires, needles, cardiac patches, vascular scaffolds, thrombus filters, esophagus, etc.Stents, respiratory stents, biliary stents, urethral stents, rectal stents, duodenal stents, external auditory stents, birth control rings, etc.
 
STRYKER Group, one of the global orthopaedic professional group companies, uses Ti-12Mo-6Zr-2Fe alloy to manufacture hip prosthesis system, which has reached the high standard level of orthopaedic clinical requirements in terms of quality, function and clinical effect.
 
At the same time, the anterior cervical plate system made of Ti-Mo-Zr-Fe alloy has also been used in clinical practice.At present, these two products have been introduced into the Chinese market.
 
Titanium alloy precision casting prostheses were developed in Germany in 1980s and used in clinic. Its application promoted the development of modern functional prostheses. Since then, titanium alloy precision casting prostheses have been popularized and applied in various countries.
 
Craniofacial plastic surgery is widely carried out abroad, especially in Germany, the United States, Japan and other countries. Plastic surgery brings people confidence and happiness.
 
The internal fixation devices used in craniomaxillofacial plastic surgery are mainly pure titanium plates of various shapes and specifications and pure titanium screws of various specifications.
 
Overview of Domestic Application
 
Since 1970s, Baotitanium Group, a domestic titanium and titanium alloy professional manufacturer, has cooperated with other scientific research institutes to develop and develop human implant materials, such as titanium bones and titanium supports, and achieved good results
 
Since the 1970s, domestic titanium and titanium alloy artificial bones and joints have been used for clinical treatment in China.The production of artificial femur and hip joint has good clinical effect.
 
In the mid-1980s, the number of domestic titanium and titanium alloy processed materials used in the manufacture of human implants has been increasing.
 
The femoral head, hip joint, knee joint, elbow joint, shoulder joint and metacarpophalangeal joint made of titanium and titanium alloy have been transplanted into human body in China and achieved very good results.
 
Significant progress has also been made in the development of new Beta-type titanium alloys for orthopedic applications and titanium alloys for dental restorations in China.
 
A variety of medical titanium alloys independently developed by Shenyang Institute of Metals, Beijing General Institute of Nonferrous Metals Research and Northwest Institute of Nonferrous Metals have been used for surgical implants and vascular stents.
 
In the application of porous titanium alloy, Tangdu Hospital of Fourth Military Medical University, Northwest Institute of Nonferrous Metals and Shanghai Jiaotong University have designed and manufactured porous titanium alloy implants, which have been widely used in clinical practice and achieved good results.
 
The human hard tissue defect caused by the aging population has become a major problem worldwide.
 
China has a large population, and the aging problem is very serious. There are also many patients who need medical implant materials for rehabilitation surgery.
 
According to statistics, the market of surgical implants in China has developed at an alarming rate in the past 30 years.
 
The average growth rate has remained between 15% and 30% in the past 10 years, and it is expected that it will continue to grow at a rate of more than 10% in the next 10 years.Therefore, the market prospects of titanium alloy implants in China are very broad
 
Although a lot of research work has been done in the field of research, development and application of titanium alloy materials for surgical implants in China, and remarkable progress has been made, there is a big gap in design, manufacture, processing, equipment, surface treatment and technological level of titanium alloy implant products compared with developed countries such as Europe, the United States and Japan.
 
Especially in some high-end implant products, the domestic production of implants is difficult to meet the market demand, most of the high-end implants need to be imported from abroad, which brings unprecedented opportunities and challenges to medical materials research institutions, material manufacturers, medical research institutions, clinical medical experts, etc.
 
These units should strengthen cooperation, work hard together to make high-end implants localized, benefit the people, and promote the healthy and stable development of China's medical titanium alloy industry.