Brown, VA team for prosthetics research, rehab

A GAIT ANALYSIS looks at markers on specific landmarks on the body, examines their motion and uses the results to refine prosthetics. /
A GAIT ANALYSIS looks at markers on specific landmarks on the body, examines their motion and uses the results to refine prosthetics. /

For as long as there has been war, there have been soldiers – and often civilians – with grievous injuries and lost limbs. But with medicine now able to save people who before would have perished, the Iraq and Afghanistan wars have left a particularly large number of amputees.
The Veterans Administration has responded by investing heavily in research on prosthetics, tissue regeneration and advanced rehabilitation. One high-profile effort is the Center for Restorative and Regenerative Medicine, a collaboration between Brown University and the Providence VA Medical Center.
Susan E. D’Andrea, director of the Gait and Motion Analysis Laboratory at the center, spoke with Providence Business News about how technology many know best from the video game world is helping advance prosthetics, orthopedics and rehabilitation efforts.

PBN: What role does the gait lab play in the center’s work?
D’ANDREA: Let me tell you about one project. Hugh Herr, an MIT professor, has an expertise in prostheses. He designed something called the powered ankle-foot prosthesis, which is motorized to help make gait transitions much easier and smoother for below-the-knee amputees. What we’re going to do is take 10 amputees who have regular prostheses and analyze them, look at their energy expenditure – how much energy is it taking them to walk with their regular prosthesis? – and then fit them with this powered ankle-foot prosthesis and see if there’s less energy expended, which is what we anticipate. … We’ll also see if they’re symmetrical: Most people, when they take a right step or a left step, how they move is about the same, but with amputees that can be very different; we think this will improve symmetry.

PBN: So how do you measure these things?
D’ANDREA: We measure the energy by analyzing the gases that we breathe in and out, basically, how much oxygen we’re consuming. The more energy you’re expending, the more oxygen you need to pull in. … With the gait, we have these little reflective markers we put on their body, and all of these cameras [D’Andrea points to cameras all around the lab] have infrared lights that reflect on the markers. We put the markers on very specific bony landmarks on the body, so we can define the calf, the thigh, the foot, the pelvis, the trunk, and then … as people walk through the space, we know the positions of all these markers.

PBN: How does that translate into gait analysis?
D’ANDREA: We look at the markers relative to each other. If you look at the calf relative to the knee, it tells us how much the knee is moving, and the same thing with the foot relative to the calf; you can see the angles, the direction. … We also ask them to step on the force plates [platforms in the middle of the room], one foot on each one, and we can tell how much force is being exerted on the ground, doing inverse dynamics – a mathematical procedure – we can calculate how much force is going through the ankle, through the knee, through the hip.

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PBN: How do scientists then use this information?
D’ANDREA: We can certainly use it to refine prosthetics. … We can also look at outcomes, for instance, people who have an ankle fracture, and there’s different types of treatments, so what kind of treatment is the best? You can take a questionnaire and say, “I feel like I walk better or worse after so many months of rehab,” but also correlate it to a more objective measure that we can do here. Is their knee bending to the amount that it should be bending?

PBN: You work with researchers, but you also work with clinicians who may not be as used to working with data like this. How well can they use the information you provide?
D’ANDREA: There are orthopedic surgeons who specialize in this, and they’re very well-versed, and so incredibly good at looking at the data and understanding what it is. The doctors here, we haven’t been around enough, so it’s different. An orthopedic surgeon will look at a patient and do a visual analysis, say, “Walk to the end of the room” and see if there’s any asymmetries or what’s going on. This makes it objective, and it’s much more technical, so usually you have to sit down with the docs and say, this is what this means, and this is what it’s telling you.

PBN: Do you have benchmarks so a doctor can look at a chart of someone’s knee movement, say, and compare it to data from a healthy, normal knee?
D’ANDREA: There are normal databases, and that’s one of the things we’re going to be doing, generating a database for our lab. … There’s definitely a standard that you can compare it to, like the knee should flex up to 60 degrees when you’re swinging it through, and the hip should flex 40 degrees, and at certain points whether you’re walking, when your foot hits the ground. &#8226

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