This Life-Changing, Low-Cost Artificial Knee Is On The Market After Years Of Design

The ReMotion Knee lets people in the developing world share some of our advanced prosthetic technology, but at a price you can afford if you make $4 a day.

After he lost his leg in a traffic accident, Sonu Kumar, a 20-year-old electrician in Jaipur, India, was one of the first people to test an early prototype for a low-cost prosthetic that helped him comfortably walk again–and become so mobile he was eventually able to almost double his income.


Now known as the ReMotion Knee, the prosthetic has officially launched for sale around the world.

In low-income countries where injuries from accidents or war often lead to amputation, most people haven’t been able to afford a quality prosthetic in the past. “You really had to make a choice between a knee that was priced appropriately or one that functioned appropriately,” says Vinesh Narayan, the ReMotion business manager at D-Rev, the design firm making the knee.

In the U.S., someone with enough cash or the right insurance can get an $80,000 robotic knee. In the developing world, a prosthetic might cost “only” $1,875–which might sound cheap in comparison, but can be six times the average monthly income of a rural family. The cheapest fake knees cost much less, but don’t work well.

“They’re cheap, but they operate similar to a door hinge,” says Narayan. “They flex very easily, they aren’t steady, and that’s just not adequate, especially for someone who’s walking on uneven ground or negotiating a crowded sidewalk or street.”

Around 80% of amputees in the developing world don’t have access to a modern prosthetic, meaning they can’t work, or can’t work as much as they used to.

The ReMotion knee first began in a class at Stanford University in 2008, when an Indian clinic called the Jaipur Foot Organization came to students asking for help designing a better knee. The solution: designing a knee that could be mass-produced from plastic instead of the metal that’s commonly used in the cheaper prosthetics.


Over the last several years, the designers have continuously worked with patients to add and refine features while keeping the price low. “We learned about things that were important to patients around the world–in particular, not appearing as if they were disabled,” says Narayan. “There’s a lot of stigma about disability.” The latest version of the knee is curved in the front, so it looks natural under clothing, and pads keep it silent. It’s also able to handle heavy loads–something the designers realized was necessary after someone tested a prototype while hauling around giant bags of cement at work.

The final product has features that would normally be found in expensive prosthetics, like friction control and “extension assist,” which helps the knee move. It’s the equivalent of something that might normally sell for $400 to $500, but it only costs $80. Some clinics will provide it for free.

The designers have already seen the prosthetic change lives. Narayan tells the story of Prakash, an amputee who has a ReMotion knee. “He went in to apply for a stocking job unloading trucks and stocking a retail store,” he says. “The store owner basically said, ‘Why should I hire you? You clearly won’t be able to work as much as anyone else. Prakash said, let me work for two hours, let me show you what I can do, and after that you can decide if you want to hire me or not.” He got the job.

“That kind of motivation really inspires us to do this work, and also reiterate that these are not patients that deserve our pity, they deserve our respect,” Narayan says. “They deserve the best possible tools.”

About the author

Adele Peters is a staff writer at Fast Company who focuses on solutions to some of the world's largest problems, from climate change to homelessness. Previously, she worked with GOOD, BioLite, and the Sustainable Products and Solutions program at UC Berkeley.