The ice injection that blocks pain to soothe achey knees
02:11 GMT, 4 December 2012
Crystals of ice injected into the knee could help tackle chronic pain.
Doctors have developed a new hand-held device that creates a tiny ball of ice under the skin — this blocks pain signals in patients with knee osteoarthritis.
The outpatient treatment, which takes under ten minutes, has a similar effect to local anaesthetic but provides long-term pain relief, according to a small study.
The ice treatment is a form of cryotherapy in which doctors use very cold temperatures to treat a variety of ailments
Now U.S. scientists have started a
larger clinical trial of the technique, testing it on patients who
suffer from arthritic knees.
Around eight million Britons have osteoarthritis, or wear and tear of the protective cartilage in joints.
This cushions the ends of bones; when it wears away, the bones rub against each other, causing pain.
estimated one in five adults over the age of 45 has osteoarthritic knee
Treatments range from over-the-counter painkillers and steroid
injections to surgery and joint replacement.
The manufacturers of the new gadget, called the Cryo-Touch, say that the non-surgical approach eliminates the need for medication.
The ice treatment is a form of cryotherapy in which doctors use very cold temperatures to treat a variety of ailments.
Cryotherapy is used for a range of skin conditions, for instance, to ‘freeze’ off small skin cancers as well as benign growths such as warts.
It is also used as a treatment for prostate cancer, where doctors use it to freeze off cancer cells.
More recently, they have begun using it for joint pain, particularly in ankles, knees and shoulders.
The new single-use device, which has been approved for use in the UK, consists of three stainless steel needles attached to a cylinder of liquid nitrous oxide.
These needles are designed to prevent any of this very cold liquid escaping into the tissue, where it would cause severe damage.
Instead, when the liquid is released into the needles, it’s subjected to extreme pressure which turns it into a gas.
This makes the needles even colder and triggers the formation of an ice ball around the tip (three needles are used to increase the size of the ice ball).
Doctors are using a single injection of Botox to treat the pain of knee osteoarthritis
The needles are placed a few millimetres under the skin on the side of the joint.
The device is then switched on and the tiny ball of ice forms under the skin.
This damages the small blood vessels that provide blood to the peripheral nerves around the joint.
Without a blood supply, the nerves can no longer send pain signals.
Each treatment takes around five minutes. The doctor allows the iceball to thaw for a few minutes before removing the needles.
An earlier human study by the University of Washington, which used a similar technology, showed it provided relief in 80 per cent of patients and lasted for eight to 24 months.
Pain may return when new blood vessels grow back and the nerves are re-activated. The therapy then needs to be repeated.
In the new two-month trial, at Injury Care Medical Center in Idaho, 20 patients with osteoarthritis of the knee will undergo the treatment or be given a placebo.
While experts look forward to seeing the results, they caution that evidence for the cryotherapy’s effectiveness in this field is lacking.
Professor Alan Silman, medical director at Arthritis Research UK, said: ‘There is no published evidence that localised cryotherapy offers any benefit in terms of long-tern pain relief for osteoarthritis or in reducing inflammation.
People with this painful condition can best find pain relief by keeping their weight down, remaining active and doing exercises to strengthen the quadriceps muscle that supports the knee.’
Meanwhile, doctors are using a single injection of Botox to treat the pain of knee osteoarthritis.
Around 120 people are taking part in a trial where they will receive one injection of the treatment (or a placebo jab) into the middle of the knee joint.
Patients on the trial at the University of Aalborg, Denmark, will have their pain levels monitored for 12 weeks afterwards.
Previous studies showed patients experienced a 50 per cent greater reduction in pain compared with those given a placebo.
It’s thought the botulinum toxin — which is also used to treat wrinkles — inactivates nerves around the knee, so reducing the number of pain signals sent to the brain.
Paralysing the nerves may also reduce nerve-related inflammation, say doctors.