She’s got company.
As the number of Americans undergoing hip and knee replacements steadily increases, a growing number of researchers are searching for ways to head off damage to these pivotal joints.
Surgeons are replacing 320,000 hips and more than 670,000 knees each year, according to the federal government’s latest count, and the numbers are expected to mushroom over the next two decades.
Many of these patients are hobbled by osteoarthritis, a disease that typically worsens with age and wears down the cartilage that cushions the bones in joints.
At least 67 million adults - a quarter of the adult population - will have arthritis by the year 2030, according to government projections, and most will have osteoarthritis.
The legions in pain could be even higher, disease trackers warn, because of the growing number of younger overweight Americans. Excessive weight is a major risk factor for osteoarthritis in weight-bearing joints.
In her lab at Boston University, Lewis has designed a device, called a robotic hip exoskeleton, that she hopes will help shrink the suffering by teaching people how to correct their walking styles.
There’s a lot that can go wrong in a single step.
“They may not be pushing with their foot as much as they should be,’’ Lewis said, “or they may be taking too long of a step, so their leg ends up far behind them.’’
Another walking no-no is excessive swinging of the pelvis from side to side.
“While that may be sexy, it may not be the best for their hip joints,’’ Lewis said.
The plastic and metal robotic device she designed, which is strapped around the pelvis and thighs, weighs about 11 pounds and is powered by an air compressor attached to each thigh - think bicycle pump - that is turned on by the researcher at the precise point when a person walking on a treadmill needs some correction. For instance, the compressor can exert pressure on the front of the thigh to shorten a stride.
