A high-tech knitted glove has been engineered to treat hand oedema — swelling of the fingers and hands caused by a build up of fluid.
The massaging KnitDema glove is made from a yarn with thread-like springs woven through it. These wrap around a finger and, once activated by a mild electric current, expand and contract sequentially, which shunts excess fluid out of it.
In a recent US trial with five patients, the glove reduced fluid in the hands by up to 10 per cent after one 30-minute session, the journal Proceedings of the CHI Conference on Human Factors in Computing Systems reported last month.
The gloves were developed for chronic hand oedema. While the hands can often swell temporarily as a result of hot weather, for instance, or of being sedentary, for thousands of people it is a chronic problem, causing pain and restricting joint mobility.
The condition can result from a physical injury or be a complication of hand surgery. This is because the body’s natural response is to send fluid to an affected area to start the healing process, and this fluid can then build up.
Hand oedema can also be a symptom of thyroid, liver or kidney diseases, as these can disrupt the body’s natural fluid balance mechanisms.
It can also be a side-effect of certain medications, such as those used to treat high blood pressure or depression, and contraceptives (again, because they can interfere with the body’s balance of water and salts).
The main treatment is physiotherapy, during which the fingers are massaged from tip to base, to ‘push’ the liquid out of the hand. This is then absorbed by the body. Although effective, this treatment is time-consuming, expensive and patients have to have regular appointments in hospital. There may also be a waiting list.
The new glove, developed at Cornell University in the US, mimics physiotherapy.
It has thread-like alloy springs that fit around the fingers like rings, as well as a tiny built-in battery: once activated, this sends an electrical current to each spring in turn, starting at the fingertip.
The current generates mild heat — about 45C — which makes the spring change shape and contract.
When the current stops, the spring cools down and ‘remembers’ its original shape and expands back to it. Each spring is activated in turn, moving down each finger like a wave, squeezing the fluid out of the tissue.
The glove is designed for home use, and both the duration and the intensity of the compressions can be adjusted by the user to suit their needs, using a remote control.
Commenting on the technology, Mike McNicholas, a consultant orthopaedic surgeon at Liverpool University Hospitals, said: "This is a really innovative use of the material properties of a memory metal by incorporating it into smart clothing to address a problem that is very disabling.
"It is wonderful to see that this is being studied properly to ensure it is being safely introduced to patient care. There are other applications of such technology that will follow, I am sure."
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