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Last updated: March 17, 2012 1:58 am
My grandmother had a tin leg. I never actually saw it because she kept it well covered. I don’t know if there’s a link but when I was leaving school, the careers adviser told me about a new subject I could study: prosthetics and orthotics. I signed up straight away.
It was the early 1980s and, at the time, there was a transition between the very basic tin legs and a new kind of limb made of tubes and joints and covered with soft foam. The course was four years at the University of Westminster. We were taught about the psychological impact of losing a limb, as well as anatomy, engineering, physiology and material science. The more I learnt about the body, the more I saw that we are just machines.
When I graduated in 1984, I worked in Manchester for the NHS. My first patient was an engineer who’d lost a limb through vascular disease. He wanted to know all about my clinical reasoning and how the leg would work mechanically. I felt a huge sense of responsibility as I fitted the leg on to him. Apart from getting the measurements correct, you also have to consider weight, alignment and balance. The slightest imbalance will cause problems such as friction against the stub of the real leg. When I saw the engineer take those first slow, unsteady steps, I knew I had the right career.
There were great innovations happening so, in 1995, I moved to a private company and began working with Paralympians. Prosthetics for athletes are much the same as for other amputees except aspects will be changed depending on the athlete’s event. For example, a blade foot for a runner is technically similar to a regular foot – both involve the same spring mechanisms – but aesthetically the two are very different.
Paralympians have many more things to worry about in a race. Oscar Pistorius – “Blade Runner” – whose limbs we design, told me that rain is a far bigger challenge when you’re running on a blade, as is wind, because when your centre of gravity is shifted, it can blow you over.
With the track cyclist Jody Cundy, I made his leg wing-shaped to be aerodynamically efficient. It only made a fraction of a second benefit but for an Olympic competitor, that’s worth it.
Legs for athletes are also made to be very light. Some people say a prosthetic leg should weigh the same as a normal leg but I disagree. A normal leg has its own dedicated muscles to power it whereas a prosthesis is dead weight.
Recently, I worked with marathon and 200m runner Richard Whitehead. He is a double above-knee amputee and he wanted his prosthesis adapted to help him balance at the starting block. A knee gives more stability, but Richard chooses not to run with bendy knees. For him, it would require more effort to bend the knee at the right time and then straighten it. I debated with Richard about putting knees into his legs. I could have designed a knee to clamp straight once he was running. We decided against it, though, because he couldn’t stand quickly enough with it.
Often, I will watch an athlete in his or her sport and be on hand with a spanner and Allen keys to tweak things. Prostheses are like shoes. Small adjustments can make them more comfortable or biomechanically efficient.
The big stuff is done early on, then I just tweak until the athlete is happy.
There’s always a debate about whether we are giving athletes an unfair advantage. But all springy legs do is give back the effort an athlete puts in. Oscar Pistorius is a great runner because of his dedication, and he achieves in spite of having a blade, not because he has a blade. However, there is a move towards power prosthetics. With powered legs, you’d theoretically get more out than you put in. I don’t envisage powered limbs at the next Paralympics but I do think that one day we might have a separate event for this kind of thing – a kind of augmented, no-limits games.
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