Prosthetic limbs, carbon fiber, and trade-offs

The Quartz newsletter had a fascinating article on prosthetic limbs and Carbon fiber. Here’s the excerpt.


In 1976, a young undergraduate named Van Philips got into a terrible water-skiing accident, losing his leg below his left knee. The prosthetic limbs available at the time were blocky replicas of real legs, so Philips set about designing a new one: the Flex-Foot, inspired by the springy hind leg of a cheetah. It was the first model of the Össur running blades we see today.

When Philips was searching for the right material for his invention—something strong, light, cheap, and heat-resistant—he lit upon carbon fiber. The first filaments of carbon were created more than a century ago, for use in light bulbs, but its properties were refined only in the 1960s. By itself, a single strand of carbon isn’t very strong, but when thousands of fibers (each thinner than a human hair) are woven and compressed together, the material gets up to 18 times stronger than steel.

Among the first companies to use this space-age material was Rolls-Royce, which made jet engines out of carbon composites in the late 1960s. Since then, carbon fiber has made its way into practically everything except the food we eat. It’s in airplane and car components, motorcycle racing gloves, wind turbine blades, power lines, microchips, spectacle frames, clothing, and skis.

It’s a marvel—except that it comes with a cost. Carbon fiber, despite its organic-sounding name, isn’t biodegradable, so landfills are brimming with the stuff. Recycling it is difficult, because that helpful imperviousness to heat makes it difficult to melt down and reuse. The development of carbon fiber was a true revolution, but as with so many other wondrous technologies, it now requires a second revolution, one that determines how we can use it without letting it ruin the planet.


An idea that has stuck with me after reading “The Wizard and the Prophet” is that there is no perfect strategy – there are only trade-offs.

The story of Carbon fiber is the story of most innovative solutions we’ve created. It has resulted in both awe-inspiring positive effects in our lives while causing challenges for future generations thanks to how difficult it is recycle.

There are no simple answers to problems like this. For example, natural gas supply is tenuous in these times – but we can’t simple wean ourselves off natural gas in a few months.

We need a long-term strategy that emphasizes both innovation and considered use. These are AND problems, not OR problems.

As are most of the challenging problems we face as humans.