Within the past 13 years, roughly 2000 veterans who have returned from Afghanistan and Iraq have sustained injuries that required amputations. Of these injured veterans, 14% required upper extremity amputations. An article published in the June issue of the Journal of the American Academy of Orthopaedic Surgeons reviewed recent advancements in upper extremity bionics. Also reviewed were the challenges that linger in creating a prosthesis that meets or surpasses the abilities of the human hand and arm.
During the next 50 years, “I truly believe we will be able to make artificial arms that function better than many injured arms that doctors are saving today,” said article author Dr. Douglas T. Hutchinson, Associate Professor of Orthopedics at the University of Utah Medical School and Chief of Hand Surgery at Primary Children’s Medical Center, the Veterans Affairs Medical Center, and Shriners Intermountain Hospital.
Created more than 50 years ago, the myoelectric prosthesis continues to be the most commonly used upper extremity prostheses. This prosthesis allows residual muscles to act as natural batteries to create transcutaneous signals, to control the movements of the prosthetic hand and arm. However, the muscles used most often are the triceps and biceps, which do not inherently translate to the opening and closing of the hand. Another drawback is that sometimes the socket interface used to attach the prosthesis may interfere with the function of the residual joint, such as the elbow. Myoelectric prosthetics also do not look natural and are heavy, hot, and uncomfortable, and are not waterproof.
The current federal budget for prostheses research is $2.5 billion. The US Department of Defense Advanced Research Project (DARPA) already has invested more than $150 million for their Revolutionizing Prosthetics Program. The later program, which seeks to create an upper extremity prosthesis that can function as a normal hand and arm does, but with full sensory and motor functions.
In order for these prosthetic devices to be used effectively in a broad range for patients, adjustments still need to be made. For example, many have short-life batteries, along with being weighty and uncomfortable. Particularly challenging is the problem of accurately and efficiently sending brain signals through the peripheral nerves and muscles of the hands and arm, a feat that may warrant the creation and use of a reliable wireless device or direct wiring through an osseous-integrated implant. Current infection rates (nearly 45%) with osseous-integrated devices at the prosthesis-skin interface also pose an issue.