Machine to mend bones in half the time...
June 27, 2000
AFEW months ago, amputation seemed the only option left for Paul Allum, 32, whose right leg failed to heal after he was crushed between two lorries four years ago. Now he is walking on the leg and hopes to return to work for the first time since his accident.
Paul’s unexpected recovery has come thanks to a revolutionary new device — the Exogen Sonic Accelerated Fracture Healing System. It has just been launched in Britain and promises not only to promote healing in difficult fractures, but also to cut in half the time it takes for any broken bone to heal.
‘In the future, the Exogen system will be routinely prescribed for every fracture,’ says Alan Rorke, whose company Orthos Ltd has introduced the ultrasound device from the U.S.
‘It is real Star Trek stuff — we are forging new frontiers with this equipment.’
Paul, from Sheerness, Kent, is certainly convinced. Since his accident in 1993, he has had many operations to pin the shattered bones together. He was confined to a wheelchair for two years.
Much of the surgery was successful, but 15 months ago he stepped off a kerb and his leg snapped again just above the knee. The bone had been weakened by three holes drilled for pins and further surgery was not possible.
His orthopaedic surgeon had already suggested that amputation might be the only solution, so Paul feared the worst.
He was put on traction, with limited success, and was unable to bear weight on the leg. But 12 weeks ago, he was introduced to the Exogen system.
He was given the hand-held gadget to take home and told that its job was to encourage bone growth.
All he had to do was place the head of the battery-powered device on the skin above the fracture for 20 minutes each day. There was no discomfort.
When his leg was X-rayed ten weeks later, he was ‘stunned’. He says: ‘The bone had knitted together completely top and bottom and there was just a small hole left in the middle. The doctor seemed pretty surprised, too. ‘Now it will just be a case of physiotherapy. I could have lost a leg — but now I expect to get more or less back to normal and I intend to go back to my job as a docker as soon as possible. ‘My leg feels strong and I’m putting 75 per cent weight on it. Without the gadget, I’d probably still be in bed.’ So what exactly is this device and how does it work? The Exogen is nothing like the ultrasound equipment currently in use, for instance, to examine babies in the womb. Using a frequency many times lower, it exerts a force on the bone that helps fractures heal, just as weight-bearing exercises build and strengthen bone in healthy people.
It was pioneered by Brazilian scientist Dr Luiz Duarte. He based his work on Wolff’s Law, a theory dating back a hundred years which states that the more pressure is placed on bone, the more tissue is laid down.
This can be demonstrated by the fact that human fractures take longer to heal than those of wild animals.
In the wild, necessity compels an animal with a fractured leg to walk on it as soon as it has first knitted. It is painful, but the pressure exerted on the bone stimulates faster growth and repair.
The Exogen system places pressure on the fracture — at around 10mg, the equivalent of the weight of a postage stamp — but without the associated pain.
The system was first used in the U.S. in 1995. It has proved particularly useful in the treatment of stress fractures, caused by a breakdown of the layers of bone, which are notoriously painful and difficult to heal.
Following trials, the device was launched nationwide last month. As yet it has only been used on difficult fractures, because it costs £2,000 per treatment.
MIcHAEL SALEH, a professor of orthopaedic Surgery at the University of Sheffield, gave the system a cautious welcome.
‘It’s too early for me to say whether it can live up to the claims, as I’ve only used it on one patient,’ he says.
‘All I can say is that I wouldn’t have expected the X-ray results I saw with this patient. The response was quicker than expected. I would certainly be prepared to try it again.
‘In the case of my patient, we were running out of treatment options. But I can also see it having value in the treatment of simple fractures, if the results were impressive enough to justify the expense.
‘If the claims that it reduces healing time by 48 per cent are right, then it would certainly be worth it in terms of adults returning more quickly to work.’
The system is being tested for use on other conditions. Low intensity ultrasound may help speed up the growth of cartilage and the healing of skin ulcers. There are plans to develop the technology to help reduce bone loss in older women. TODAY’S ADVICE: Under NIcE guidelines, Exogen is now available on the NHS to treat fractures that have failed to heal after nine months.