Crutch designers throw in a curve

Crutch design throws a curve to ease strain

By Loretta Green
Mercury News Staff Columnist

In the early days when someone needed a crutch, he simply found a suitable tree limb. In a way, today's crutch is still a kind of stick.

So says Maurice LeBlanc, longtime rehabilitation expert, who explained how Stanford University graduate students helped him invent a higher-tech crutch.

LeBlanc, a 1960 Stanford mechanical engineering graduate, was director of research for 21 years at the Rehabilitation Engineering Center at the Lucile Salter Packard Children's Hospital.

He is about to retire as head of design and fabrication at the Rehabilitation Research and Development Center at the Department of Veterans Affairs in Palo Alto.

One of his jobs was to encourage Stanford engineering and medical students to take on VA rehabilitation projects. Out of this has come a modern design for an S-shaped forearm crutch -- a single pole -- as contrasted to the common V-shape. Designers describe the modern crutch as a "compliant composite crutch.''

LeBlanc says early man's solution 5,000 years ago for an injured foot or leg was to obtain a tree branch and curl the affected limb around it.

Often a handle was produced by cutting off part of an offshoot. In the late 1800s a saw was invented that could cut a stick into the still used V-shaped design.

Before working on the modern crutch, the Stanford group polled permanent users to find out what they wanted.

Bruce Vanhousen of Redwood City was among those who said primary concerns were better shock absorption and "energy return.''

"We spend about twice as much energy ambulating as other people,'' said Vanhousen, a fitness buff who walks 4 1/2 miles every other day despite being paraplegic and has a shock-absorbing gel inside the tip of his crutch.

"On a straight crutch, you take all of the weight on your hand,'' explained LeBlanc, who has worked with Vanhousen over the years as they tested new designs. "No matter how good the hand grip on the crutch, you get trauma to the hand.''

As for energy return, LeBlanc said the material in the student-designed crutch "stores energy so that when you take off, it gives a little.''

Some paraplegics must hike themselves up to clear their feet -- the equivalent of doing a push-up, LeBlanc said.

As a result, crutch design is critical not only in conserving energy but also protecting the body from impact and repetitive strain injuries.

In a report published by LeBlanc and others connected with the project, they said crutch users listed these requirements: support of their weight, shock absorption and energy return, durability, light weight, maximum mobility, ease of object reach, comfort, silent operation and finally, that it be stylish as a personal accessory and support their self-esteem.

The crutch was funded by the U.S. Department of Defense, which expressed an interest in finding medical uses for space-age technology, LeBlanc said. It is made of a carbon fiber composite, which is desirable because of its strength and flexibility.

Now, LeBlanc is trying to find a manufacturer for the students' innovative crutch.

Vanhousen has plenty of ideas about what would make crutches fit even better into his lifestyle. For one, he wishes crutches folded. Just try taking crutches on an airplane or in a restaurant, he said.

And because he leads an athletic life, he'd love to see crutches with reflectors.

Those of us who don't use crutches rarely think about them. But for people whose mobility and self-esteem depend on being able to walk, they are a vital support for the quality of life.

Contact Loretta Green at 650/688-7565, or 650/688-7555 (fax).

Article on SJ Mercury News website