Scientists Improved a Titanium Alloy for Creating Prosthetic Limbs

08:29, June 5, 2024

This increased the biocompatibility of the substance and reduced its rigidity

Scientists from UrFU and colleagues from Moscow have managed to modernize a titanium alloy used to create bone implants. After a number of special treatments, the stiffness of the material decreased by 1.5 times compared to another titanium alloy widely used in medicine. In addition, this alloy does not contain harmful elements that could limit the biocompatibility of the substance with the body. The researchers note that the improved titanium alloy will be useful in traumatology and orthopedics, for example, in fractures of the foot, femur, etc. The scientists published detailed information about the obtained properties of the alloy and processing methods in Metals. The research was supported by the Priority-2030 program.

"The problem with existing titanium alloys for creating bone implants is that they contain a significant amount of chemical elements that reduce the biocompatibility of the substance with the human body, for example, aluminum and vanadium. This can lead to side effects: allergic, toxic, mutagenic, and other reactions. The alloy we have improved contains minimal amounts of these elements. In addition, many alloys have extremely high stiffness relative to the stiffness of bone. The point is that the material from which the implant is made should have mechanical properties as similar as possible to bone: strength, plasticity, and elasticity. If the material is too rigid, atrophy and degradation of the bone tissue may occur at the border between the bone and the implant - because of this a crack and destruction may appear in the bone. After a set of special treatments, we managed to increase the strength and reduce the rigidity (elastic modulus) of the alloy," explains Galymzhan Mukanov, a research laboratory assistant at the Department of Heat Treatment and Physics of Metal at UrFU.

Medical implants are needed to help rebuild bone tissue, such as after fractures. The fact is that a broken bone can lose too much bone tissue, which in turn makes it harder to heal. In such cases, implants are used to fill the gap between the damaged ends of the bone, helping it to recover.

"Implants can be subjected to high loads, so it is very important to improve their mechanical properties. In addition to the quality of the alloy from which the implants are made, the methods of its processing for further use are of particular importance. One such method, thanks to which the required material structure appears, is rotary forging," says Galymzhan Mukanov.

The scientists used titanium alloy Ti-39Nb-7Zr as a sample for the study. Using the rotary forging method, the specialists processed the alloy at a temperature of 450 °C. This allowed to change its structure: microparticles (grains) of the substance decreased about 5-7 times: from 2500-3500 nanometers to 500 nanometers. Thus, the substance became stronger and more elastic. The combination of these properties brought the resulting alloy closer to the Ti-6Al-4V alloy widely used in medicine; however, in addition, the new alloy is less toxic. 

"Today another titanium alloy Ti-6Al-4V is widely used, as it has quite acceptable properties for osseointegration, but it has toxic elements such as aluminum and vanadium in its base. The results of our study will allow us to obtain more effective properties on another titanium alloy, which, in addition, is also less harmful to the body," Galymzhan Mukanov explains.

Scientists from the Ural Federal University and specialists from the Baikov Institute of Metallurgy and Materials Science of the Russian Academy of Sciences took part in the study.

Reference

Due to the aging of the world's population, bone diseases are becoming more common. Osteoporosis, a chronic decrease in bone content in the body, is one of the main causes of bone fractures.

In Russia, according to Rospotrebnadzor, about 14 million people over the age of 50 have been diagnosed with osteoporosis. In addition, about 20 million people are prone to decreased bone density, i.e. the initial stage of osteoporosis.

Rospotrebnadzor also states that the most dangerous fracture is a femur fracture, in which case surgical intervention is almost always required. Femur fractures lead to disability in 50% of cases, and to death in 20% of cases.

According to the Ministry of Health, there are 9 million cases of fractures in people's limbs in Russia every year.

Sergey Lukyanchenko

The news article was translated by UrFU International Marketing Office.
info.international@urfu.ru, +7 (343) 375-45-19