When was the last time you looked at your foot? I mean really looked at it — examined the complex structure of bones that supports you as you walk... watched your ankle as it turns and twists and flexes... felt the power and strength in your toes as they help propel you from one step to another...
Now imagine what your life would be like without that foot. Would you be able to walk to your next business meeting? Climb stairs? Play sports? Keep up with your kids or grandkids? Move around your kitchen as you prepare a meal? Drive a car?
Every day, at least 500 people in the United States undergo an operation to amputate one or more of their limbs. More than 80 percent of those surgeries are vascular-related, caused by conditions such as diabetes or heart disease. Other people lose their limbs to cancer, various illnesses or trauma. Today, two million American have experienced and live with the loss of a limb. According to The Amputee Coalition, that number is expected to double by 2050 as our society gets older, more obese and generally less healthy.
So where can people who have lost a limb turn to as they hope to regain their mobility and improve the quality of their lives? The growing field of prosthetics holds many of the answers.
A Feel-Good Profession
The people working in prosthetics are passionate about what they do and they swear there's no other way to make a living. "I still can't believe we get paid for doing this," says Brian Glaister, President and CEO of Cadence Biomedical, a start-up he co-founded to develop technologies for people with disabilities, including prosthetic legs for lower-limb amputees. "We're getting up every morning, working hard, and immediately seeing the difference we're making. We can put one of our devices on somebody and immediately see the smile on their face."
Andrew Bache, a mechatronic engineer with orthopedics manufacturer Össur in Iceland, calls prosthetics "a feel-good profession." He says he wanted a job that would be more than just a job, and he got it. "It's not uncommon for you to see someone shed a tear of joy," he says. "You can see someone who was told they would never be able to walk again and get them to take their first steps. It really is that dramatic. It's a hell of a thing to see."
A Growing Field — But Still a Small One
The field of prosthetics has practically "exploded" over the past ten years, says Bache. "It wasn't that many years ago you could count the number of engineers working in this field on two hands."
Today the field is still small compared to the automotive or aerospace industry, but it is growing rapidly. "As the Baby Boomers retire and their health starts to deteriorate, they're going to demand therapies and technologies to support the lifestyles they want to keep," says Glaister. While only a few large companies exist in the prosthetics market, hundreds of smaller startups have sprung up to fill both the need for service and innovation.
"This is the era of device-oriented research," says Glenn Klute, Research Health Scientist with the Department of Veterans Affairs Center for Limb Loss and Prevention and Prosthetic Engineering and an assistant professor of electrical and mechanical engineering at the University of Washington. Many modern prosthetics now contain microprocessors, sensors and actuators to improve their functionality. He says future devices might even be able to interpret what an amputee wants to do, whether that means implants in the cortex or electrodes on the skin to detect what a user's muscles are doing.
Some of this new research is being funded by the Department of Veterans Affairs (VA), the National Institute of Health and other organizations following more than a decade of military conflicts in Afghanistan and Iraq. The number of veterans needing prostheses is relatively small compared to the number of vascular-oriented cases; according to the VA, 1,600 soldiers have sought VA treatment for limbs lost in the two wars. Klute says veterans — who tend to be both younger and healthier despite their injuries — benefit from limb systems that allow a high level of performance, so this research further drives innovation in the field.
One Field, Multiple Career Opportunities
Interestingly, there's no one specific way to enter the field of prosthetics. Many engineers got their start volunteering with the disabled and quickly saw that they wanted to continue in that path professionally. Others studied mechanical or biomedical engineering and gravitated toward prosthetics. Still others find that the work they are doing in different fields has applications in prosthetic limbs. For example, computer scientists might get involved in developing the software that helps prosthetics operate.
Some engineers in this field work in either corporate R&D or academic research. Klute says he might set out to solve a particular problem related to walking on a prosthetic leg and build preliminary prototypes, which can then be used to support grant applications to make more robust prototype, which can then be patented and licensed to manufacturers.
Many engineers might also get certified to work as prosthetists, the people who design, build, tune and fit prosthetics to patients in a hospital setting. Because a prosthetic leg is not "one size fits all," this involves using a combination of existing components and parts and custom-fabricated pieces, such as the sockets that connect a prosthetic device with a person's residual limb. Prosthetists are highly in demand today and have a 100 percent employment rate according to the American Academy of Orthotists and Prosthetists, which predicts a 34 percent shortfall in available professionals by the end of the decade. (Prosthetists will be required to hold a master's degree in the field starting in 2015.)
"You need to know a lot of things to be a prosthetist," says Jon Sensinger, Director of Prosthesis Design & Control Laboratory at the Center for Bionic Medicine, a research program at the Rehabilitation Institute of Chicago. "You need to have a good understanding of medical terminology and anatomy and physiology. You have to be able to understand the biomechanical implications of how the systems work and then tune them based on the feedback your patients are giving your in real time."
Some people in prosthetics specialize in areas such as artificial intelligence or biomechanics. Others, such as Bache, find themselves working on a very broad level. "I do a little bit of electrical engineering, a little bit of mechanical, a little bit of software, and then I still work clinically with the amputees," he says. "The field is so wide that you can stretch yourself and go as far as you want to. There are almost no limits to the edges of the field."
Your ability to specialize might depend on the size of the company you choose to work for. "At a big company, your job description can be much narrower," Glaister says. "At a startup, you're going to do everything from product design to taking out the trash."
Another choice is whether you want to work in lower-limb or upper-limb prostheses. The latter is a much smaller slice of the market, since the number of upper-limb amputations is one tenth that of lower limbs. On top of that, half of the people with upper-limb amputations choose not to wear a prosthetic device. "For many tasks, one hand is good enough," says Sensinger, who specializes in the upper-limb devices. He says the marginal improvements that a prosthetic arm provides may not justify the added weight and discomfort for the patient.
No matter what you end up doing, chances are you'll be working as part of a team which can also include a physiatrist (a type of doctor who deals with rehabilitation), an orthopedic or vascular surgeon, a physical therapist, an occupational therapist, and, in traumatic cases, a psychologist. On the product side, you might need a team of mechanical, electrical and software engineers. And on the research side, you will probably also have team members who help keep your projects in compliance with regulations related to testing medical devices on human subjects.
"There are no real programs to specifically train people to be engineers working on prostheses," Klute says. But he points out that there are biomechanics or medical-device related pathways that people can take to gain the expertise to work in the field. "Usually people come from mechanical engineering, but they also come to prosthetics from electrical engineering and computer science." He recommends that anyone interested in the field learn about electromechanical systems, as well as physiology and anatomy. Taking a few life sciences classes outside of the normal engineering curriculum might be a good start.
Bache says you can learn a lot from a biomechanics book, but that might not teach you what it is actually like to be an amputee. "If you look at a biomechanics textbook what it will tell you is what it's like to walk on level ground or when you're going up or down stairs. But if you're in a kitchen shuffling around making an omelet, all of the little side steps and half turns and the shuffles that you do, that's most of what an amputee is doing and that's not in any textbook. To really give everything back to the amputee we have to learn those things as well as the physiology and the biomechanics and the software and mechanical design. It's an integral part of it."
Glaister recommends starting by volunteering with organizations that help the disabled. "It's cool to watch them and understand the effort they put in to overcome their limitations." He says working in prosthetics can be inexact, which might be a difficult adjustment for an engineer. "You learn a lot by feel and experience," he says.
All of the engineers I spoke with showed incredible passion for working with prosthetics and amputees. "It's a great field," Bache says. "I don't know anyone who has come into the field who has left it. I know I'll be doing this until I retire — and probably even after I retire."
John R. Platt is a freelance writer and entrepreneur, as well as a frequent contributor to Today's Engineer, Scientific American, Mother Nature Network and other publications.