Joint conditions such as rheumatoid arthritis, or those resulting from injuries can cause physical misery and even ruin the careers of professionals requiring fine dexterity in their jobs.
But thanks to a specialist consortium from the Fraunhofer institute, AI, and some good ol’ 3D printing, there may be some hope in sight.
The FingerKIt Consortium, which brings together five Fraunhofer institutes, uses AI to develop personalized 3D-printed joint implants so that these delicate finger parts can be replaced when necessary.
The institutes in question are, the Institution for Additive Manufacturing Technologies (IAPT), the Institute for Ceramic Technologies and Systems (IKTS), the Institute for Toxicology and Experimental Medicine (ITEM), the Institute for Mechanics of Materials (IWM) and the Institute for Digital Medicine (MEVIS).
Each group has brought expertise from their own particular domain into the project which offers a way forward for patients with various joint-related ailments.
The Problem with Implants
At the moment, if a finger joint loses its function due to accident or injury, the treatment methods are limited.
In the majority of cases, a joint fusion procedure is undertaken.
This process, also known as arthrodesis, is normally achieved through surgery. During the procedure, the damaged joint is manually straightened, the cartilage is removed, and the bones are stabilized for long enough for them to naturally fuse together.
This results in a finger that does not bend, and as you can imagine, this can reduce the quality of the patient significantly.
In the cases where traditional implants are used, the options are limited. Patients can opt for a silicone implant, which has a risk of working loose, needing further surgery to correct it. Or else patients can opt for a standard implant, which as you can tell by the name, is only available in certain standard sizes, and do not fully restore the full range of movement to the finger in question.
Optimal Custom Solution
The optimal solution, therefore, is the one that avoids both of these pitfalls associated with the traditional implant. That is to say, the best joint is the one that doesn’t come loose, and also allows the full range of motion to be restored to the finger. For this, a custom solution is best.
And this is what the FingerKIt Consortium has successfully demonstrated with their AI-assisted, 3D printed joints.
The workflow developed by the Fraunhofer engineers and scientists is largely automated, and removes a lot of the hands-on work associated with such highly customized work.
The researchers have developed software that makes use of AI to convert 2D X-ray images into 3D models of the finger bones and joints. Any correction of the ruined joints can then be corrected virtually in the 3D model.
The researchers from Fraunhofer IAPT (AM group) then use AI to derive the individual implant design from the finger model and send it for 3D printing.
A metal binder jetting process is then used to manufacture the replacement joints at high resolution. After that, the green parts are sent for sintering, where they are solidified and densified by engineers at Fraunhofer IKTS. The near net-shape part can then be sent for finishing, to reduce the friction and allow better movement when implanted into the patient.
“As the structure of the implant shaft is very delicate, we have chosen to use the metal binder jetting 3D printing method for titanium,” said Dr. Philipp Imgrund, head of the AM Process Qualification department at Fraunhofer IAPT.
“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.”
Fraunhofer IKTS (the ceramics group) has also demonstrated the use of ceramic materials for fabricating the implants, which are processed by means of slip casting.
The Fraunhofer ITEM (toxicology group) has been dealing with the biocompatibility of the materials and the certification of the implants, while Fraunhofer IWM (mechanics of materials group) has been performing the mechanical simulation of the parts.
A Hopeful Future
The new workflow from the Fraunhofer consortium can produce and implant highly custom parts in just 60% of the time it would typically take to produce with traditional means. This means that the entire process, from X-ray to implant, could be completed in just a few days. This would result in shorter hospital days, and therefore reduced inpatient costs also.
And this workflow isn’t just good for bent fingers. It can be applied to patients with missing bones, or for smaller joints also.
This is good news for many. According to the German Society for Rheumatology, around two percent of the adult population in Germany are suffering from inflammatory rheumatic diseases which could be treated with the Fraunhofer process.
“FingerKIt could completely change the treatment of rheumatoid arthritis, for example. Personalized implants could become the gold standard,” said Imgrund.
The technological development within the FingerKIt project has now reached a point of maturity to the point that the product / process is market ready.
The consortium is now working on obtaining necessary approvals, and is also seeking corporate partnerships in the medical engineering sector, who can help bring FingerKIt to market.