Prolotherapy: Sugar dose can ease the pain of creaky knees by releasing cells that heal damaged ligaments Prolotherapy involves injecting a sugar solution into the knee This stimulates the release of cells that can help the healing process New solution: A sugar solution injected into the knee may be a new method of treating osteo-arthritis A sugar solution injected into the knee could be a new way to treat osteo-arthritis. Research suggests the sugar and water mixture reduces pain and stiffness by stimulating the body's natural repair mechanisms. The sweet solution works by acting as a mild irritant inside the joint, triggering low-level inflammation. This inflammation is not enough to cause any severe harm, but is sufficient to stimulate the release of cells that can help to heal some of the damage caused by the disease. Doctors use a solution containing water and between 10 and 25 per cent dextrose, a type of sugar. They use dextrose because it is cheap, readily available and safe - causing only mild irritation inside the knee joint. The treatment, known as prolotherapy, is thought to work by triggering the release of fibroblasts, cells that build and maintain connective tissue such as ligaments. The fibroblasts repair damaged ligaments in the knee, making it more stable and relieving discomfort. In a recent study at the University of Wisconsin in the U.S., researchers recruited 90 men and women with painful knee osteoarthritis and split them into three groups. One group received three separate sugar jabs, each one four weeks apart, and another had injections of a salt water solution. The last group did not have any injections but instead followed an at-home exercise regimen designed to alleviate some of the pain and discomfort. Each volunteer was monitored using a scoring system, called the Western Ontario McMaster University Osteo-arthritis Index, to measure the severity of the condition. The 12-minute test uses a 100-point scale and includes questions on how easy it is to use the stairs, get in and out of a car or put on a pair of socks. The results, published in the Annals of Family Medicine, showed that one year after the treatment began, the sugar jab group had the biggest improvement in symptoms and were better able to carry out everyday activities. On average, the sugar group improved by a total of 16 points, compared with five points for salt water jabs and seven for the exercise group. The team are unsure why salt water was not as effective as sugar. Sweet release: The treatment, known as prolotherapy, is thought to work by triggering the release of cells that repair damaged ligaments in the knee This technique is also being tried in other conditions such as chronic back pain and tennis elbow. Commenting on the approach, Professor Alan Silman, medical director of Arthritis Research UK, said: 'Though some "irritant" treatments can be effective, much more work is needed before a treatment based on sugar solution could be recommended to patients.' Meanwhile, scientists have designed a special glove that may ease the pain of hand arthritis. Around 130 people who suffer from rheumatoid and osteoarthritis are being treated with the compression glove in a new clinical trial. The gloves are made from a special fabric that when stretched (when it is worn) puts pressure on the hand and joints. It's thought that the pressure might trigger mild inflammation, which, unlike severe inflammation, eases pain although it is not clear why. In the year-long trial, due to start in September and being co-ordinated by the University of Salford, patients will be given the compression gloves as part of their usual care. They will be assessed before and after for pain and stiffness.