A man who lost both legs from the hip down has walked again using braces developed by engineers at the University of Strathclyde.
The man, who was told that he would never walk again after being caught in an explosion, has since been able to cover distances up to a quarter of a mile.
It is hoped that the invention can help victims of land mines or people whose legs have been lost to diseases such as cancer.
The bio-engineering department at Strathclyde was asked to help the north African patient by Glasgow Health Care International, which had brought him to Glasgow for treatment last Christmas.
Until then scientists and engineers had failed to help anyone who had lost their entire legs to walk well. Patients who lose their legs from the hip down have no movement.
`Only a small percentage of patients have this disability,’ said Nicky Fowler, one of the two bioengineers who worked on the project. `That’s why this has never been done before.’
Fowler and fellow bio-engineer Sandy Nicol based their work on developing leg braces used by paraplegics. They worked out that if the patient shifted his weight to the left, they could make the right leg move forward using a simple hinge mechanism at the top of the artificial leg.
This is linked to the hinge of the other leg by a cable, so that once the first step has been started, the body weight only needs to move slightly from side to side to maintain the momentum – through the cable – so that the legs pace forward alternately.
Design progressed using CAD, with the department’s workshop manufacturing the components and building the artificial legs. These were attached to a socket, shaped to fit around the patient’s pelvis. Nicol and Fowler then used CAD to adapt the mechanism for the amputee and to further develop the design.
To add stability, the artificial limbs were manufactured to a shorter length than the patient’s original legs. This lowered his centre of gravity. The patient can sit down by releasing a catch on the leg hinges; as he leans forward the knees bend and he can lower himself into a seat.
It took the bio-engineers five months to develop the artificial legs, including one month spent on design and another month spent on manufacture.
The team would like to help others who are in need of the device. However, Bill Spence, the prosthetist in charge of the project, said: `The legs are expensive to make and there aren’t many of these patients in Britain.
`So anyone who approached us to enter commercial production would have to have a global reach.’