Plan B for Bad Knees
About 14 million Americans have arthritis in their knees, causing pain and limited mobility. Some will have surgery to install an artificial knee, but that’s an expensive, time-consuming process that isn’t recommended for people under the age of 55. Now, a Charlottesville man is offering Plan B – a customized brace that takes pressure off the knee and allows people to walk, run and take part in sports with less pain.
Dave Johnson was trained as an engineer, but he says that’s not where he got his gift for repairing almost anything.
“I grew up on a Dairy farm, which taught me how things work, and most importantly how to fix things when they break down," he recalls. "Often times you don’t have the tool or the part, so you have to improvise.”
He loved snowboarding, but an old football injury left him with an arthritic knee that was keeping him off the slopes. Doctors like Winston Gwathmey, an orthopedic surgeon at UVA, said knee replacement was not a good option for Dave.
“Let’s say you’re in your late 20’s, early 30’s, and you have knee arthritis. A knee replacement might not be a good idea, because that knee replacement is going to have to live as long as you live," he explains. "You might be able to get 20 years out of a knee replacement, but a young person might put more mileage on that knee replacement and wear it out more quickly.”
And a second or third joint replacement may not be as effective as the first, so Johnson decided to invent Plan B -- a brace that would shift weight off his bad knee.
“Every one pound on your body is like 3-8 pounds on your knee, so you’re actually offloading weight from your body to a mechanical device. It is transferring the weight away from your knee to the back of your thigh and the back of your calf.”
He spent five years working on the design with help from doctors and engineers at UVA, and emerged with a design he calls the Icarus Ascender.
“It acts just like a normal stabilization brace, but then you can increase the amount of tension or torque in the hinge, so you can see it’s springing you back up, and you can gradually increase that torque and really get a lot of assistance,” Johnson says.
The brace weighs less than a pound, is easy to customize and relatively cheap to make.
“This is entirely 3-D printed based on an iPhone scan. We actually have this app. It takes a rapid 3-D scan. Then we can make a brace around that.”
Medicare and other insurers now cover the brace, but for those who must pay out of pocket Johnson says a customized brace is available for under $1,400 and an off-the-shelf model sells for under a thousand. Winston Gwathmey says it could be useful not only for young arthritis patients but for older people who are not strong enough to undergo surgery and rehabilitation.
“It can take 3 or 4 months to fully recover from knee replacement surgery, because you have to get the muscles strong again and learn how to walk again, and sometimes there’s realignment of the leg associated with knee replacement surgery, so it takes some time to learn how to basically walk with the new knee.”
Inventor David Johnson hopes the design could also be adapted to help people with arthritis in other joints.