In the future, the FingerKit project, developed by the Fraunhofer Research Institution for Additive Manufacturing Technologies (IAPT), the Fraunhofer Institute for Ceramic Technologies and Systems (IKTS), the Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), the Fraunhofer Institute for Mechanics of Materials IWM, and the Fraunhofer Institute for Digital Medicine (MEVIS), could help restore the mobility of fingers with damaged or ruined joints – often causes by a sports accident or as a result of rheumatoid arthritis, for example.
At the moment, if a finger joint loses its function due to accident or injury, the treatment methods are limited. In most cases, the joint is fused, but this results in severe restrictions in the patient’s day-to-day life. If an implant is to be used, there are currently two options on the market: silicone implants, which often come loose quickly and need to be reattached in another procedure, or basic standard implants, which are only available in certain sizes and do not allow full movement. To ensure the best possible patient care, a personalized implant is needed.
Thanks to the five Fraunhofer institutes within the FingerKIt project, this may now be possible, with the development of an automated process chain that will allow personalized finger joint implants to be produced from metallic or ceramic materials in a rapid, safe, and certified manner. The scientists at Fraunhofer MEVIS started by developing a piece of AI-based software that can turn two-dimensional X-ray images into three-dimensional models of the finger bones and correct any malposition of the fingers. The researchers from Fraunhofer IAPT then use AI to derive the individual implant design from the finger model and send it to be 3D printed, using metal binder jetting technology, after which the implants are sintered.
Thanks to the expertise of Fraunhofer IKTS, it is also possible to use ceramic materials, which are processed using slip casting – a plaster mold casting process. Fraunhofer ITEM is taking care of questions regarding the biological compatibility and certification of the implants, while Fraunhofer IWM is responsible for the simulation of the mechanical loads.
“The AI-based calculation of a three-dimensional implant design from 2D templates such as X-ray images is completely new and is now patent-pending,” said Dr. Arthur Seibel, head of the Part Design group at Fraunhofer IAPT.
“Process engineering is special too. As the structure of the implant shaft is very delicate, we have chosen to use the metal binder jetting 3D printing method for titanium. This method allows for an extremely precise production of the small, complex implants and also enables us to structure the surface of the shaft in such a way that it grows into the bone more effectively. Furthermore, this minimizes the finishing work required for the joint surfaces, which need to be as smooth and frictionless as possible,” added Dr. Philipp Imgrund, head of the AM Process Qualification department at Fraunhofer IAPT.
The results of Fraunhofer’s FingerKIt project are promising for any patients who in the past have been unable to find the help they need. The Fraunhofer innovations mean that, in the future, it will be possible to provide effective treatment even for complicated cases such as severely bent fingers, missing bone parts, or very small joints. Furthermore, thanks to the automated model creation and 3D printing, the personalized production process also saves time – up to 60% of the normally-required time to identify and fit. As the implant design is modeled on the original joint, the level of mobility achieved is much greater than with currently available solutions.
“FingerKIt could completely change the treatment of rheumatoid arthritis, for example. Personalized implants could become the gold standard,” said Dr. Philipp Imgrund.
According to the German Society for Rheumatology, around two percent of the adult population in Germany is suffering from inflammatory rheumatic diseases. The newly developed implants will also be able to help patients who have sustained injuries. In comparison with foot or ankle implants, for example, the market for the remobilization of finger joints is still significantly underdeveloped. According to Fraunhofer, experts predict that the total potential will stretch to €5.8 million by 2026.
The technological development within the FingerKIt project has now reached a stage where the product could be made ready for the market in collaboration with a partner from the medical engineering sector: The AI-based design creation and the manufacturing process work, and exhibitable implants have already been produced. The next step is to obtain the necessary approval. “We are currently looking for corporate partners who have the required expertise to help us bring our AI-created medical devices to market,” said Dr. Philipp Imgrund.