O bone cements These are materials used as adhesives for the fixation of bone prostheses (hip, knee, shoulder…) when the patient’s bone quality is insufficient. However, during the assembly and placement process of the components, high temperatures are generated, which can lead to necrosis of the tissues surrounding the patients.
Add graphene oxide Highly reduced, it helps to avoid this problem and, in addition, improves the mechanical and thermal properties of materials, according to a study carried out by researchers at the Polytechnic University of Madrid (UPM). The results, published in journals Polymers and Biomedical Journal of Scientific and Technical Research, are of interest in surgeries for insertion of prostheses fixed with bone cement, more common in the elderly.
Adding highly reduced graphene oxide to bone cements improves their mechanical and thermal properties
O implantation of prosthesis It is an increasingly common practice around the world, due to causes such as the increase and aging of the population, and due to the higher incidence of pathologies such as obesity or osteoarthritis. Bone cements are used to adhere and fix prostheses to the injured bone when the bone does not have sufficient mechanical strength and cannot grow in the prosthesis and stabilize it, in addition to distributing loads and helping to dampen stresses at the prosthesis-bone junction.
However, this material has some limitations. The maximum lifespan of this bone cement is 20 years and, statistically, it is very risky to operate on people over 85 years of age, so that after that age it would no longer be advisable to repair a prosthesis whose materials have deteriorated. Therefore, a 65-year-old patient who is implanted with a hip prosthesis fixed to the bone with bone cement will be exposed to bone cement to degrade or break, due to cracks that grow slowly over time, which would generate discomfort for the rest of their life because new surgery was not feasible.
Improve the quality of life of the elderly
“Improving the durability of these bone cements is essential to improve the quality of life of the elderly. In other words, avoid having to endure an existence with chronic pain due to the broken prosthesis”, he says. José Ygnacio Pastor, a UPM researcher who participated in the study.
In the survey carried out by members of the Structural Materials Research Center (CAP) from this university, several materials were developed with potentially interesting results, such as the reduction of the maximum curing temperature that damages adjacent tissues.
It takes just a few minutes to place the cement between the bone and the prosthesis, and during this reaction a large amount of energy is released that reaches and heats the surrounding tissues. The addition of graphene slows down and lowers the reaction temperature
Regarding mechanical properties, researchers found that adding an excess of graphene is harmful and worsens, but small amounts (between 0.01% and 0.1% by weight) They can also produce improvements in mechanical properties while maintaining the thermal benefit.
“Until now we have mainly talked about the mechanical strength and durability of bone cement; however, there are more problems associated with the use of these cements in the human body”, highlights co-author Jaime Orellana.
Common cements are made up of two components which, once they come together, begin to react and harden. During this reaction, the material quickly solidifies, with only a few minutes left to place it between the bone and the prosthesis. Furthermore, a large amount of energy is released during this reaction which reaches the surrounding tissues.
From 42⁰C onwards, the proteins are denatured, if the bone is too heated, the cells die and there is necrosis of the tissue surrounding the prosthesis. Thus, “it is essential keep the bone from getting hotA result we achieved by slowing down the reaction thanks to the addition of highly reduced graphene”, continues Orellana.
According to the researchers, the expectations of these new materials are very promising, as there is also evidence that graphene has antibacterial properties, ideal for reducing infection problems after surgery. “However, there is a lot of work ahead, because not only the amount of graphene to be introduced must be optimized, but also the chemical treatments that allow better adhesion and dispersion of graphene in the bone cement”, they conclude.
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