Surgeons at the Johns Hopkins University in Baltimore, Maryland have managed to develop a system wherein a man can move his prosthetic arm by using nothing but the power of thought. The Modular Prosthetic Limb (MPL) is a resounding success, as was the unique method used to attach it.

Prosthetic arms controlled by nothing but the mind of the user aren’t actually new, but this is arguably the most advanced system to date. The patient in question, Johnny Matheny, has used the MPL before, but it’s previously required an uncomfortable harness to keep it in place.

In this novel process known as “osseointegration,” a titanium threaded component was carefully connected to the marrow space of the bone. After allowing the body to adjust to this new artificial segment for a few weeks, an extension is added to the fixture, and the entire thing is brought out through the soft tissue.

The socket of the prosthetic needs to be aligned perfectly with the implant. Any erroneous connection can cause the amputee extreme pain, and even the slightest misalignment can cause chaffing. When everything is correctly set up, the prosthetic is then attached to the fixture.

Prior to this, damaged or severed nerves that once controlled the arm and hand were “reassigned” through surgery, meaning that they can essentially work again with the prosthetic, responding dynamically to signals sent from the brain to the artificial limb. The system is so advanced that individual finger control, some wrist freedom, and grasping were all shown to be possible.



Matheny, whose arm was amputated in 2008 due to cancer, is the first in the world to be able to use a prosthetic limb in this way. “It’s all natural now,” Metheny said after his first trial run using the MPL with the new implant, as reported by Futurity. “Nothing is holding me down. Before, I had limited range; I couldn’t reach over my head and behind my back. Now –boom! – that limitation is gone.”

This pioneering project is part of a wider series of experiments and trials being conducted by the Revolutionizing Prosthetics program, an effort led by the Applied Physics Laboratory (APL) of Johns Hopkins University. It is funded by the U.S. Defense Department, and its primary aim is to provide improved functionality for injured soldiers, as well as civilian amputees.

The U.S. military and its scientific and technological wing, the Defense Advanced Research Projects Agency (DARPA), are known for either starting or funding similar projects designed to help soldiers injured in combat zones, including thought-powered artificial limbs. For example, advanced cranial implants, which are designed to restore memory recall and consolidation in those with brain injuries, were announced to be in development at the end of last year.

Michael McLoughlin, chief engineer in APL’s Research and Exploratory Development Department, said that “the challenge for us next is to really figure out how to get this technology out of the laboratory and into the hands of people that need it.”