Austrian Archaeological Institute (OeAI)
The skeleton of the man missing his left foot and having a foot prosthesis.
Doug Pensinger/Getty Images
When the National Academy of Sciences established the Artificial limb Program in 1945, the options for amputees were few: crude, wooden prostheses. And for those who chose none: life confined to a wheelchair. Fast-forward 65 years and the United States faces an influx of amputees from the conflict in Iraq, but the opportunities for soldiers returning home from war with an amputation are far more advanced. Listed are some of the most important advancements in robotic prosthetics in the last 20 years that give artificial limbs more function than ever before.
Duif du Toit/Gallo Images/Getty Images
1. Prosthetic Foot Materials
For years, wood was the dominant material for a prosthesis. But over the last 20 years, materials have emerged to give greater comfort and confidence for amputees. Susan Kapp, an associate professor of orthotics and prosthetics at the University of Texas Southwestern School of Health Professions, says if a prosthetic foot is cut open, most likely the material found inside is carbon fiber. Carbon fiber, according to Kapp, is a much more life-like material, giving amputees a sense of life in their foot. Thermoplastic sockets give prosthesis recipients extended comfort at the site the prosthesis is fitted, and titanium gives a prosthesis longer life and durability.
U.S. Army/ Roger J. Mommaerts Jr.
Bluetooth technology made the jump from the cell phone industry to prosthetics in 2007 when Marine Lance Cpl. Joshua Bleill received two artificial legs after seeing combat in Iraq. Each leg was fitted with a Bluetooth device. Bluetooth is more often recognized for its ability to connect pieces of technology together without the use of wires. In Bleill’s case, the Bluetooth devices communicate with each other to regulate stride, pressure and speed in the prosthetic legs. The benefit of Bluetooth technology, according to Ryan Blanck, a prosthetist at the Center for Prosthetics and Orthotics at Brooke Army Medical Center in Ft. Sam Houston, Texas, is the programmability of the software. “We can take that technology an further develop it to adjust to a patients need,” Blanck said.
3. Microprocessor Knees
With an onboard computer within the prosthesis, people with above-knee amputations have greater control over walking, stopping and moving on inclines. These “robotic” knees, termed microprocessor knees, analyze the pressure an amputee puts on the missing limb. Also contained within the knee is a fluid control unit, which the microprocessor monitors to appropriate joint resistance when walking on inclines. Available since the early 1990s, microprocessor knees have revolutionized the arenas of safety and stability for people without knees. Kapp says people that receive the prosthesis don’t have to worry about the knee buckling under them.
Touch Bionics Inc. and Touch EMAS Ltd.
4. Myoelectric Technology
When the i-LIMB hand debuted in the United Kingdom in July 2007, people caught a glimpse of the future of robotic prosthetics. The i-LIMB applies myoelectric technology, where the prefix myo- denotes a relationship to muscle. Myoelectric prostheses are controlled by placing muscle sensors against the skin at the site of amputation. The electric signals generated by the muscle at an amputee’s stump controls a processor aboard the prosthetic. This myoelectric technology allows for greater control and precision in the five fully functional digits, enabling recipients to perform everyday tasks such as picking up coins and opening tabbed aluminum cans.
5. Targeted Muscle Reinnervation
Amputees are in the infant stages of controlling prostheses directly with their minds. Through targeted muscle reinnervation, the nerves from the amputated limb are reenergized in a different part of the body, for example, the chest. When an amputee wants to use their arm in a particular fashion, he or she thinks the action, prompting the nerves in the chest to react. That reaction sends a message to a microprocessor in the robotic limb, which performs the action. Currently, there are only 35 people in the world with TMR limbs, and Blanck has fit 14 of them. He says the ever-changing prosthetic field aims to allow an amputee think about their prosthesis in a way that is normal. Jesse Sullivan (left) was the first man to receive this treatment technique from the Rehabilitation Institute of Chicago, and Claudia Mitchel (right) was the first woman to receive it.
Researchers in Austria have found Europe’s oldest functional prosthesis, according to analysis of a 1,500-year-old skeleton buried with a wooden foot.
Belonging to an adult male between the age of 35 and 50, the skeleton was unearthed in 2009 in Hemmaberg, in southern Austria. The site was an important center of early Christian pilgrimage, with several churches built there between the end of the Roman Empire and the Early Medieval period (4th–7th century AD).
The remains were unearthed in a small cemetery of 29 graves from the Frankish period, running between the defeat of Ostrogoth Empire in 536 AD and the movement of pagan Slavic groups around 600 AD.
Buried near a post-medieval church, with a brooch and a scramasax (a single-edged knife), the skeleton was found missing the left foot from above the ankle.
“In its place, an iron-ring and wooden remains were recovered and interpreted as a prosthesis replacing the lost foot,” bioarchaeologist Michaela Binder of the Austrian Archaeological Institute, and colleagues wrote in a paper which will be published in the March issue of the International Journal of Paleopathology.
Radiography and CT-scanning revealed healing of the wound after loss of the foot and ankle joint.
“Despite the severity of the injury, the person survived for at least one or two years,” Binder told Discovery News.
The prosthesis, which basically consisted of a wooden peg with an iron ring on the basis, wasn’t just a simple cosmetic device. The man was able to use the leg together with the device, perhaps through the use of a crutch.
“The prosthesis would have been fixed to the leg via a leather or textile pouch or straps. Unfortunately, none of the organic substance was preserved but dark staining on the bones of the left leg indicates their presence,” Binder said.
The researchers tried to determine what caused the injury by examining the three major causes for archaeological cases of amputation: medical treatment, mutilation and accidental or violent trauma.
They found medical amputation unlikely as such surgeries were usually done at the joint, rather than cutting through long bones, as seen in the man from Hemmaberg.
Binder and colleagues ruled out mutilation as punishment, which, until the beginning of the 7th century, was only applied to vassals and not free citizens.
The way the individual was buried — next to a church and with grave goods — indicates he had a high social status.
“It appears highly unlikely that a convicted criminal, easily identifiable through his mutilation, would have been buried in such a prominent location,” the researchers wrote.
The more likely scenario is that the injury was caused by accidental or violent trauma.
“The location of the cut on the lower leg may provide an indication towards a violent origin,” Binder and colleagues wrote.
Since osteological analysis provided evidence suggesting the man was used to riding horseback, the researchers speculate he might have been a cavalryman who was injured by a soldier on foot.
“Several bioarchaeological studies of war-related trauma in Medieval cemeteries and mass graves have found the tibia [or shankbone] to be a common site of sharp force trauma and have been interpreted as being inflicted by men on foot to mounted men,” the researchers wrote.