How it Works… the ideas behind both
the design and patent applications
C9s work because the designers, two
PhD Scientists and an Engineering Consultant who had a bad experience using
crutches after a sporting injury (ruptured Achilles Tendon… ouch!),
got their heads together to find a solution. Our objective was to relieve
the pain of crutch use sufficiently that patients would feel, in comparison,
that they were walking on ‘cloud 9’ – hence the name ‘C9’.
We wanted a product that could readily be applied to existing crutches,
rather than marketing yet another new crutch design.
We identified two separate problems:
Pressure…
Only a small part of the hand is
in contact with the crutch handle at any one point in time - typically an
area calculated to be approximately half a square inch on the ball of the
hand, near the base of the thumb. For a typical adult male, the act of walking
on crutches may exert pressures of around 170 lbs per square inch of hard
crutch handle on soft flesh and bone… apart from those moments between
steps, when one weight-bearing foot is also on the ground.
In the UK, the typical National Health
Service-dispensed crutch has a handle simply too hard and too narrow at
the point of hand contact for most adults and teenagers to use comfortably.
Abrasion…
As well as pressing your entire body
weight on two small, soft bits of skin, the crutch handle also acts as a
fulcrum as you “walk”; with the hand rocking back and forward
across the centre of the handle (normally bulbous for this reason), closer
to the wrist with crutches pointing back, and closer to thumb when reaching
forward, ready to make the next step.
The typical National Health Service-dispensed
crutch handle has a plastic or (even worse) slightly rubberised surface.
The combination of pressure, regular impact, heat, sweat, and a relatively
abrasive surface rotating across the balls of both hands is what makes repeated
crutch use so painful.
All our original tests and research
work confirmed the above analysis (with thanks to all those unsuspecting
crutch-users we hijacked in shops and at bus stops!). The C9 was therefore
developed with the fundamental principle that two components were needed
to solve the two separate constituents of the problem: an inner “something”
to absorb impact and spread weight across a wider area of the hand….
and an outer “something”, to reduce abrasion and keep the skin
drier and cooler.
