More than 4000 kiwis owe some part of their mobility to artificial limbs. Reporter Emma Whittaker finds out what's involved in creating the life-enhancing devices.

The amazing feeling that comes from seeing someone arrive at an appointment in a wheelchair and walk out at the end makes the working day worthwhile for Kent Perkins.

The prosthetist designs and fits artificial limbs, called prostheses, for patients at the New Zealand Artificial Limb Service's Auckland centre in Mt Eden.

Around 1400 babies, children and adults who have either been born without a limb, or lost one through illness or injury, rely on the centre.

"A lot of people are really gobsmacked when they lose a limb and don't know where to go for help. Many don't know if they'll ever have the same level of mobility again.

"Not everyone is suitable for an artificial limb though," he says.

"They might have other problems as well as missing an arm or a foot. They might be overweight, or have no upper body strength, and it takes a certain amount of fitness to walk on an artificial leg.

"We never say no completely to someone who might not be suitable," he says.

"They can do physiotherapy to get themselves fit enough."

Once a patient has been given the go-ahead, a cast is taken of what's left of their limb and used to make the socket for their prosthesis.

It's either done with plasticine or on a computer CAD system which takes a scan of the stump and generates a model for the socket.

Technicians are responsible for making the limb.

Mr Perkins was a technician before being a prosthetist.

There's no dedicated university training for the job so most technicians come from trade and technology backgrounds.

Mr Perkins went on a training course offered by the limb centre after doing a high school project on artificial limbs more than 20 years ago.

"It takes some artistic skill as well, for shaping knees and ankles, and possibly a bit of engineering," he says.

"It's not just a matter of us going out and making an artificial limb, you've got to take a lot of things into account."

Limbs can be made and modified to suit all kinds of lifestyles and sports including swimming and skiing.

The days of wooden or metal protheses are gone and most are now made from composites like fibre glass.

Some artificial hands can be controlled electronically by placing sensors on certain points on the stump which pick up the electrical signals sent from the brain to the muscle telling the hand to move.

A small motor then opens or closes the hand.

But all the technology in the world doesn't change the fact that learning to use something that is not a natural part of your body is a tough process.

"Everyone has different expectations.

"Some people think they'll get out there right away and be able to run in the Olympics," he says. "Others are expecting it to be difficult and deal with it better than you expect.

"It's not an instant process, your body needs to learn to take its weight differently to be able to walk on an artificial leg."

"For us it's about explaining the process, talking to a person and dealing with their expectations."

- © Fairfax NZ News