Life-long artificial hips in the future?
An interdisciplinary research team consisting of materials engineers, biologists and medical students from Otto von Guericke University Magdeburg is developing new materials for long-lasting implants. In future, biocompatible and antibacterial alloys with special biomechanical properties should prevent harmful interactions between the implants and surrounding human tissue and thus inhibit the resulting inflammatory reactions and infections. This will increase the durability and compatibility of artificial joints and so avoid the need to replace the implant in a surgical intervention known as implant revision. Special revision surgery represents an enormous strain for patients and is the cause of significant extra costs for the health care system.
“The increased life expectancy and prolonged activity of the target group has resulted in the strain on the joints increasing enormously, which, in turn, leads to greater wear and tear,” explains the project leader, Professor Dr. Manja Krüger from the Institute of Materials and Joining Technology at the University of Magdeburg. “The consequence is an increase in the implantation of artificial joints in patients and, as a result of this, an increasing need for especially durable and compatible materials for these implants.” The engineer goes on to explain that whilst generally the materials used for implants are currently of a very high quality, due to loosening caused by wear and corrosion, there can still be postoperative complications. To resolve these problems, patients require stressful and expensive revision surgery. “Above all, wear that arises as the implant is used in the body and the resulting infections frequently mean that the artificial joints, that is the implants, need to be removed again or replaced.”
To ensure that in future this revision surgery is only necessary in rare instances, the scientists at the University of Magdeburg are carrying out research in two areas: first, engineers from the Chair of High Temperature Materials are exploring the development of materials, that is, the design of alloys as well as the microstructural and mechanical properties of the materials and their manufacture. Second, biologists and students of medicine from Experimental Orthopedics at the University Hospital are working on understanding and optimizing the extent to which the new material can be tolerated by the body.
“What we are particularly interested in in this connection is what are known as biocompatible materials,” explains Manja Krüger, “that is, materials that can be tolerated in the broader sense by the biological system.” According to the materials scientist, examples of biocompatible materials include refractory metal-based multi-component material systems. “These so-called high- and medium-entropy materials permit a wide range of combinations, which lead to completely new materials with extraordinary properties. Recently developed materials of this kind show, for example, outstanding mechanical properties, improved abrasion resistance and resistance to corrosion and heat that exceed those of current alloys.” In comparison with the silver-coated implants that are used at present, another advantage of these alloys is that, as yet no bacteria are known to be resistant to them. “We know that over the years bacteria are able to develop a resistance mechanism against silver, so that the original antibacterial effect of the element is diluted. In turn, this means that even silver implants at some point no longer have an antibacterial effect and periprosthetic infections, i.e. infections that develop around an artificial implant in the body, may arise,” adds biologist Professor Jessica Bertrand from Experimental Orthopedics at the University Hospital.
Developing new types of implant materials
The long-term goal of the researchers is to identify and develop a suitable alloy system for use as a new implant material and to test it in the laboratory. “Specifically, this means that the underlying materials science relationships will be understood and that the mechanical properties will be known and exceed the conventional requirements placed on materials currently in use for artificial joints and/or that they can be used patient-specifically, and that evidence has been obtained regarding the biocompatibility and antibacterial effect of the system,” explains Professor Krüger.
The research team consists of Professor Dr. Manja Krüger, Maximilian Regenberg, Dr. Georg Hasemann and Dr. Janett Schmelzer from the Faculty of Mechanical Engineering plus Professor Dr. Jessica Bertrand, Caroline Grimmer and Munira Kalimov from Experimental Orthopedics. The team was recognized for its interdisciplinary research with second place in the “Most innovative basic research project” category at the 2023 Hugo Junkers Awards.