Tiny plastic grains that are injected into your knee - and can end agony of arthritis in the knee

Injecting tiny grains of plastic into the knee joint could offer hope to patients crippled by arthritis pain, NHS research suggests.

The ground-breaking technique requires only a local anaesthetic, a few hours in hospital and leaves little, if any, scarring.

Some 40 knee arthritis sufferers have undergone the treatment, called genicular arterial embolisation, as part of a trial by the Royal Berkshire NHS Foundation Trust and University of Reading.

Two-thirds reported swelling significantly lessened and more than half had improvements in pain.

Osteoarthritis, as it is known medically, affects 10 million people in the UK, according to charity Versus Arthritis. The disease is caused when the lining of the knee, the synovium, becomes swollen and painful.

This stops the knee working properly, causing the cartilage that cushions the ends of the bones in a joint to wear away.

The operation targets new 'faulty' blood vessels that grow in the synovium, releasing chemicals that start the cycle of pain and inflammation.

Patient Tim Cooper, 67, joined the trial after being kept awake by the aching in his left knee, struggling to climb stairs and being unable to garden or go walking. But the retired manager for the Ministry of Defence says undergoing the procedure in 2021 has transformed his life as he no longer has any symptoms.

The Navy veteran, from Gosport in Hampshire, has since taken up bee-keeping, tends several allotment plots and walks fostered rescue dogs for five miles a day.

Mr Cooper says: 'It has made such a big difference to my life. I was in constant pain and it restricted what I could do so much. Now it is just the same as the other knee.

'I have always loved being outside, and I couldn't walk or garden, doing the things that make life enjoyable. This has given me my life back.'

Professor Mark Little, a radiologist at the Royal Berkshire Hospital in Reading, started the trial after finding blocking blood vessels – a type of procedure called embolisation – was a successful treatment for other conditions. Embolisation is used to treat enlarged prostates, benign womb growths and liver tumours – and it can stop major bleeding after accidents.

During the new knee version of the op, a patient is injected with a local anaesthetic before a needle is used to access an artery in the groin.

A narrow hollow tube is fed down the main blood vessel supplying the knee, guided by an X-ray machine.

Tiny amounts of liquid carrying the plastic beads, which are the size of grains of sand, are then injected via the catheter. These travel into the faulty blood vessels in the synovium, blocking blood flow.

Doing so halts the production of chemicals that trigger inflammation, easing pain and swelling. Professor Little says: 'If we can stop these chemical messengers where they are made, our theory is we can halt the inflammation and perhaps pause the disease.

'This can drastically reduce the level of pain and possibly prevent so many people needing knee replacements. While it doesn't work for everyone, it offers a hopeful and exciting new option.'

'The procedure is best for patients with mild to moderate disease, which hasn't responded to the standard treatment such as painkillers and physiotherapy but whose condition isn't bad enough for a knee replacement.

'A lot of those who I see are in their fifties and sixties and living with the nightmare of chronic pain. It has a huge impact on their daily lives.'

Nine of the original 40 operated on did subsequently have knee replacements. Six more who were initially in the study were found to be unsuitable for the procedure.

One patient needed treatment for a blood clot in a vein after being inactive while recuperating but otherwise there were few complications. The approach was rejected in 2021 by the National Institute for Health and Care Excellence (NICE) with health chiefs feeling there was too little evidence on the long-term impact.

The Reading team is now running a larger study with 110 patients, from which half will have a sham procedure. It hopes this new research, along with similar trials in Japan and the US, will help convince NICE to approve it.