Sunday, July 10, 2022, 11:15 am
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The solutions monitor the healing process directly on the bone.
Accident surgeon Bergita Ganse is the Werner Siemens Foundation professor responsible for innovative implant development at Saarland University, and she coordinates the project called Intelligent Implants. The new generation of intelligent implants monitors the healing of tibial fractures directly on the bone. If necessary, it actively stimulates the healing process directly at the fracture site with targeted movement. A medical, engineering and IT research group is working on this. For the first time, the team led by Bergita Ganse and Tim Pohlemann compiled the necessary knowledge on how to best stimulate bone fractures to achieve the fastest healing results.
Every lower leg fracture is different. Whether it is a motorcycle accident or a slip in football, depending on the forces acting on the bone, the injury varies from large splinters to small bone fragments. Accordingly, each fracture heals individually. If we could observe the healing of a bone in acceleration, continuous changes would be visible at the fracture site as new bone tissue is formed. However, the usual treatment today is to screw a standard size implant to the bone pieces, current implants are purely passive. X-rays only show the progress of healing at intervals and with a delay.
“The fact that the bone does not grow together despite the implant is a relatively common complication of tibial fractures. This affects about fourteen out of a hundred patients. Nowadays, it is difficult to detect the delay in the healing of the fracture externally, at an early stage, so that we can intervene. This means lengthy treatment for those affected and very high costs for the healthcare system” – He told Bergita Ganse.
In the established interdisciplinary team, doctors, engineers and computer scientists develop an implant that is individually adapted to the bones of each patient and that provides information about how well or poorly a fracture heals right on the spot, in the body, right from the time of surgery. It can also warn in case of improper loading, and even if necessary, the implant itself must actively promote bone healing.
The prototype of the intelligent implant will be available in 2025. To this end, researchers combine state-of-the-art material technology, artificial intelligence and medical know-how. “With this new class of implants, we want to continuously monitor fracture stiffness and fracture displacement directly at the fracture site. If problems are detected, the implant itself should actively compensate by moving or stiffening without the need for further intervention,” explained the professor.
The Saarland University research group has already established in several preliminary studies that fractures heal faster if the fracture site is stimulated with micromovements. Professionals break new ground in many areas. In order to develop an implant to optimally support patient-tailored healing, many complex details and relationships must be clarified. “For example, it has not yet been determined what forces, frequencies, force directions or other stimuli should ideally be exerted by such implants for how long in order to achieve the best healing results,” the accident surgeon said.
Therefore, together with his research team, he compiled what we know so far in this field, discussed the possible mechanisms of active implants and determined where further research is needed to develop an active implant that provides the most ideal support. The research group has now published it in the journal Acta Biomaterialia results. “This is basic research, so this is the first review study that has so far been published anywhere in the world on this topic,” emphasized Bergita Ganse, who previously researched how bones and muscles atrophy in European Space Agency (ESA) and NASA projects. away in space and helped develop training methods for astronauts to prevent this.
One of the fundamental new developments is the use of memory wires in the implant. They must receive the right “physiotherapy” at the right moment. This requires a lot of data and information. Hair-thin wires with shape memory are made of nickel-titanium. At Saarland University, experts in intelligent material systems led by Professor Stefan Seelecke are researching this. The wires built into the implant are planned to use electrical signals to make the healing process visible on the one hand as a sensor, and on the other hand to stimulate healing through movement.
Shape memory wires return to their original shape when deformed or stretched, and are able to contract and relax just like muscles. They achieve high tensile strength in a small space; they have the highest energy density of all known propulsion mechanisms. They work with electric current, the exact measured value of the electric resistance can be assigned to each length of wire. When the wires are installed in the implant, even the smallest change in the fracture gap can be read from the measured values. This makes these artificial muscles sensors in the implant.
A sequence of measured values corresponds to a movement sequence. With the help of intelligent algorithms, the movement sequences can be calculated and programmed in advance and the wires can be automatically controlled accordingly. In this way, the implant can easily move directly over the fracture gap and stimulate healing by actively shortening and lengthening, emitting pulses, waves or electromagnetic fields. Currently, researchers are working on the fine-tuning and details to make these muscles suitable for use in the implant. The Werner Siemens Foundation supports the research with 8 million euros.
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