Hi-tech healing breakthrough cuts to the bone
TECHNOLOGY used in electric toothbrushes will dramatically cut the
recovery time for patients with broken bones, returning them to a fully
active life in half the time it takes at the moment.
Engineers at Edinburgh University have developed an implant, smaller
than a battery watch, that can be placed against a fractured bone to
deliver a minute electrical current which encourages bone growth.
The revolutionary device can be regularly recharged using a magnetic
field to transfer energy to the battery without wires, in the same way
modern electric toothbrushes are charged.
"It is a well known fact that if you apply an electrical current to bone
it helps it heal faster," said Professor Joe McGeough, who is leading
the team at the universityís bio-engineering department.
"The problem that has been faced before is the battery wears out and any
stimulation it gave is then terminated.
"The only way around this was to have wires coming from the implant,
sticking out of the patientís body, to allow it to be recharged.
"Obviously this made them very unpopular and most doctors did not like
"Our approach was to take technology that is already available through
rechargeable batteries and wireless technology to produce a small device
that could be put inside the body. This way the battery can be recharged
from outside the body using this wireless technology."
The device uses magnetic inductive power transfer to recharge its
battery - a method presently used to charge batteries sealed inside
electric toothbrushes and shavers.
An electromagnetic field forms around the charger, which produces an
electrical current in the device when it is brought into range.
McGeough added: "It saves the need to have physical contact between the
charger and the device itself, and so can be done through layers of
It usually takes a healthy adult around six weeks to recover from a
broken arm and around 12 weeks to heal a broken leg.
Some studies have shown electrical signals supplied to broken bones can
reduce the length of time by up to three weeks. By surgically implanting
the device doctors can pinpoint the signal from the device on to the
The signal mimics the bodyís own natural electric field produced when it
wants bones to grow. The device needs to be surgically implanted to
ensure there is contact between the two ends of broken bone.
Doctors will be able to monitor the rate of growth between the two ends
and recharge the battery when necessary.
Electrically stimulated bone healing is usually used only in severe
breaks and spinal injuries, where the body has difficulty healing
itself. Each stimulator needs an attached wire to come out of the
But McGeough claims his device could be used in less serious fractures
to help reduce the amount of time patients spend in plaster.
He said: "Bone is a material that is piezoelectric, which means it
produces an electrical current when under load, for example when you
jump up and down. This current stimulates cells in the bone which help
it to grow and increase its density.
"Using this implant accelerates the amount of these bone cells at an
area that is fractured by making the bone think it is getting exercise."
The Edinburgh University team are currently waiting for their device to
be patented and are in talks to develop it for clinical trials.
Michael Sommers, the chairman of the Patients Association, hailed the
breakthrough. He said: "We really welcome this development and the
breakthrough in the technology. The scientists at Edinburgh have made a
remarkable breakthrough which should be of great help to patients.
"This is extremely beneficial and we hope the publication of their
research will lead to these devices being made available for patients
both north and south of the Border."
But some orthopaedic experts are sceptical about the effect electric
fields have on the rate of bone healing.
Professor David Rowley, an orthopaedic surgeon at Dundee University,
warned it might only help those who have poor rates of bone healing.
He said: "Large groups of people strongly believe this can work, but it
is by no means fully accepted. Bone uses a series of complicated
chemical and electrical signals to promote its growth, and it is all
about the timing of these.
"If you are looking at speeding up normal bone healing then it will
probably have little effect. Those who have slow bone healing, like
smokers, could benefit as it will speed up their bone growth."
He added: "One thing this device could do is answer the question about
the impact electrical stimulation has on bone healing by allowing
clinical trials to take place."