CHRIS UHLMANN, PRESENTER: There's an old saying: invention's born of necessity. Well imagine losing your right arm and being told the best you can do is wear a cosmetic replacement.

For engineer Mark Lesek, that wasn't good enough, so he set about making a functional arm.

Martin Cuddihy reports.

MARTIN CUDDIHY, REPORTER: Mark Lesek runs a busy engineering business, but loves nothing more than escaping for an open road cruise on his 1928 Indian Scout. Handling the 600 CC bike is not as simple as it looks, because of a car accident almost eight years ago.

MARK LESEK, ENGINEER: Completely severed my arm. It was only apparently, I've been told, a few tendons holding like rubber bands.

MARTIN CUDDIHY: A truck hit his car and he has no memory of the accident. But Mark Lesek survived. His right arm gone, but his character untouched, as his staff found out when he turned up at work just days after the crash.

TERRY DENJEN, WELDER: We were all here and thinking, well, what's gonna happen next week or next month, and we look outside and a taxi pulls up and here Mark gets out of the taxi with a drip on his arm and everything else, and, "I'm back, I'm back, I'm ready to go."

MARTIN CUDDIHY: Even though he was mentally prepared for work, Mark couldn't do many of the things he'd previously taken for granted. He needed a prosthetic arm, but because the amputation was so close to the shoulder, doctors told him all he could do was wear a cosmetic prosthesis.

MARK LESEK: I did start wearing an arm. I nicknamed it 'Dudley' because it was a dud and it didn't work.

MARTIN CUDDIHY: The only way to regain some arm movement was to undergo risky osseointegration surgery overseas. Three years ago doctors screwed a bolt through his skin and into the remaining 6.5 centimetres of bone in his upper arm. Effectively it lengthened the remaining limb.

MARK LESEK: Without the ability to point your arm, a prosthetic arm is basically useless. So it's given me my shoulder function back and in turn the ability to wear an arm and feel connected.

MARTIN CUDDIHY: Mark Lesek is now building his own prosthetics and the inspiration comes from more than a century ago. When an American lost his arm in an industrial accident in the early 1900s, he went on to build what became known as the Carnes arm. It was controlled by the body's movement and a series of wires.

TIM GALE, BIOMEDICAL ENGINEER: The Carnes arm is a brilliant bit of engineering and our challenge is to take that and turn it into the modern fully functional bionic arm.

MARK LESEK: It was way ahead of its time then and even now it has more function in some areas than modern limbs. So we've gone about reviving that limb.

MARTIN CUDDIHY: The revival is happening in Mark Lesek's engineering workshop in the northern Hobart suburb of Moona. Here, toolmakers, machinists and welders are all working on replicating and improving the Carnes arm.

TERRY DENJEN: We work on so many various things, but the arm is something unique, yeah. But that's really the different field from what I'm used to.

MARTIN CUDDIHY: For one arm they've helped modify the internal movement mechanism, so a unique set of muscles can control the prosthetic.

MARK LESEK: The biggest asset of my body, which is my tummy, the so-called six pack, and by expanding my tummy, which is a big muscle, it actually moves the arm. So, you can see the switch on my stomach going in and out and that gives me very, very good control of the arm.

TIM GALE: We're working to have the high-level understanding of what makes an arm work really well and function well on a person.

MARTIN CUDDIHY: The school of engineering at the University of Tasmania has taken an interest in Lesek's designs. It's now in the early stages of developing a prosthesis that copies the movements of the good arm, but what they really want is a design that performs at a subconscious level.

TIM GALE: The arm combines really technical parts of engineering with the human body. It's something that potentially can be very helpful for people in the community who are amputees.

MARTIN CUDDIHY: Since Mark Lesek's successful surgery, osseointegration has been recognised by the Therapeutic Goods Administration and he's now pushing for its approval in the US, particularly for returned servicemen and women.

MARK LESEK: The benefits far outweigh the risk and I'm a living example of that.

MARTIN CUDDIHY: But that's not his primary goal. Mark Lesek intends to keep building and improving his own prosthetic designs and then make them available to amputees everywhere.

CHRIS UHLMANN: Martin Cuddihy reporting.