Fraunhofer’s FingerKit project prints custom finger joints

Going forward, 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 The IWM and the Fraunhofer Institute for Computational Medicine (MEVIS) could help restore mobility to fingers whose joints are damaged or damaged – often caused by a sports accident or as a result of rheumatoid arthritis , for example.

Currently, if a finger joint loses function due to an accident or injury, treatment methods are limited. In most cases, the joint is fused, but this leads to serious restrictions in the daily life of the patient. If an implant is to be used, there are currently two options on the market: silicone implants, which often come off quickly and need to be reattached in another procedure, or basic standard implants, which are only available only in certain sizes and do not allow full movement. To ensure the best possible patient care, a personalized implant is necessary.

Thanks to the five Fraunhofer institutes of the FingerKIt project, this is now possible, with the development of an automated process chain that will make it possible to produce personalized finger joint implants from metallic or ceramic materials in a fast, safe and certified way. Fraunhofer MEVIS scientists started by developing AI-based software that can transform two-dimensional X-ray images into three-dimensional models of finger bones and correct any malposition of the fingers. Fraunhofer IAPT researchers then use AI to derive the individual implant design from the finger model and send it for 3D printing, 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 by slip casting – a plaster casting process. Fraunhofer ITEM deals with questions concerning the biological compatibility and certification of implants, while Fraunhofer IWM is responsible for the simulation of mechanical loads.

“The AI-based calculation of a three-dimensional implant design from 2D models such as X-ray images is completely new and is now patent pending,” said group leader Dr Arthur Seibel. Part Design at Fraunhofer IAPT.

“Process engineering is also special. As the implant stem structure is very delicate, we chose to use metal binder jetting 3D printing method for titanium. This method allows extremely precise production of the small, complex implants and also allows us to structure the surface of the stem so that it grows more effectively into the bone. In addition, it minimizes the finishing work required for the joint surfaces, which should be as smooth and frictionless as possible,” added Dr. Philipp Imgrund, Head of AM Process Qualification Department at Fraunhofer IAPT.

The results of Fraunhofer’s FingerKIt project are promising for all patients who in the past have not been able to find the help they need. 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. Additionally, with automated model creation and 3D printing, the custom production process also saves time – up to 60% of the time normally required for identification and fitting. As the design of the implant is modeled on the original joint, the level of mobility achieved is much higher 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 Rheumatology Society, approximately 2% of the adult population in Germany suffers from inflammatory rheumatic diseases. The newly developed implants may also help patients who have suffered injuries. Compared to foot or ankle implants, for example, the market for finger joint remobilization is still largely underdeveloped. According to Fraunhofer, experts predict that the total potential will amount to 5.8 million euros by 2026.

The technology development within the FingerKIt project has now reached a stage where the product could be ready for the market in collaboration with a partner from the medical engineering sector: the creation of the AI-based design and the manufacturing process work, and displayable implants have already been produced. The next step is to obtain the necessary approval. “We are currently looking for partner companies that have the required expertise to help us commercialize our AI-created medical devices,” said Dr. Philipp Imgrund.