A 2,200-year-old prosthetic leg was discovered in a tomb in China and would've been worn by a man with a deformed knee.
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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.
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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.
The 2,200-year-old remains of a man with a deformed knee attached to a prosthetic leg tipped with a horse hoof have been discovered in a tomb in an ancient cemetery near Turpan, China.
The tomb holds the man and a younger woman, who may or may not have known the male occupant, scientists say.
“The excavators soon came to find that the left leg of the male occupant is deformed, with the patella, femur and tibia together and fixed at 80 ,” archaeologists wrote in a paper published recently in the journal Chinese Archaeology. [In Photos: Ancient King's Mausoleum Discovered in China]
The fused knee would have made it hard for the man to walk or ride horses without the prosthetic leg, the researchers found. The man couldn’t straighten his left leg out so the prosthetic leg, when attached, allowed the left leg to touch the floor when walking. The horse hoof at the bottom of the prosthetic leg acted like a foot.
The prosthetic leg was “made of poplar wood; it has seven holes along the two sides with leather tapes for attaching it to the deformed leg,” the archaeologists wrote. “The lower part of the prosthetic leg is rendered into a cylindrical shape, wrapped with a scrapped ox horn and tipped with a horsehoof, which is meant to augment its adhesion and abrasion.”
“The severe wear of the top implies that it has been in use for a long time,” they added.
Radiocarbon dating indicates that the tomb in Turpan (also spelled Turfan) dates back around 2,200 years. The only other known prosthetic leg in the world that dates to that time is part of a bronze leg found in Capua, Italy. That leg was destroyed in a bombing raid during World War II. Prosthetic toes, dating to earlier times, have been found in Egypt.
Who used it?
Two other studies, published in the journals Bridging Eurasia and Quaternary International, provide more details about the man who used the hoofed leg. Researchers estimate that the man was about 5 feet 7 inches (1.7 meters) tall, and between 50 and 65 years old when he died.
What caused the odd fusion of his left knee joint? “Different causes, like inflammation in or around the joint, rheumatism or trauma, might have resulted in this pathological change,” archaeologists wrote in the journal Bridging Eurasia.
Researchers found evidence that the man was infected with tuberculosis at some point in his life. They think that inflammation from the infection may have resulted in a bony growth that allowed his knee to fuse together. “The smooth surface of the bones affected by the ankyloses [joint fusion] suggests the active inflammatory process stopped years before death,” the researchers wrote in Bridging Eurasia.
The man appears to have been a person of modest means, as he was buried with nonluxurious items: ceramic cups and a jar, a wooden plate and wooden bows, the archaeologists found. Sometime after he died, his tomb was reopened, and the body of a 20-year-old woman was put in, disturbing the man’s bones. What relationship the man and woman had (if any) is unknown. The tomb was one of 30 that archaeologists excavated in the cemetery.
Based on the results of the radiocarbon dating, “the occupants of the cemetery might have belonged to the Gushi [also spelled Jushi] population,” archaeologists wrote in the Chinese Archaeology article.
Little is known about these people. Ancient Chinese texts suggest that the Gushi had a small state. “As recorded in the Xiyu zhuan (the Account of the Western Regions) of the Hanshu (Book of Han, by Ban Gu), during the middle of the Western Han, there lived in the Turfan Basin the Gushi population, who constitutes one of the ‘Thirty-six States of the Western Regions’ of the Qin and Han Dynasties,” the archaeologists wrote.
The Gushi state was conquered by China’s Han Dynasty during a military campaign in the first century B.C., according to ancient records. “Given that the study of the Gushi culture is yet at its nascent stage, the provides valuable new materials,” the archaeologists wrote.
Excavations at the cemetery were conducted between 2007 and 2008 by scientists at the Academia Turfanica, a research institute. A paper reporting their findings was published in 2013, in Chinese, in the journal Kaogu. That paper was recently translated and published in the journal Chinese Archaeology.
The papers reporting the study of the man’s skeleton were published in 2014 in the journal Bridging Eurasia and in 2013 in the journal Quaternary International.
Original article on Live Science.
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