Tiny plastic pellets injected into your knee — and they could end the pain of knee arthritis

NHS research suggests injecting tiny plastic pellets into the knee joint could offer hope to patients suffering from arthritis pain.

This groundbreaking technique requires only local anesthesia, a few hours’ hospital stay and leaves little to no scarring.

About 40 patients with knee arthritis have undergone the treatment, called genicular arterial embolisation, as part of a study by the Royal Berkshire NHS Foundation Trust and the University of Reading.

Two-thirds reported significant reduction in swelling and more than half experienced less pain.

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

This groundbreaking technique requires only a local anesthetic, a few hours of hospital stay and leaves little to no scarring. (Stock photo)

10 million people in the UK suffer from osteoarthritis, which causes chronic joint pain. (Stock photo)

This causes the knee to no longer function properly, causing the cartilage that protects the ends of the bones in a joint to wear away.

The surgery targets new ‘defective’ blood vessels that grow in the synovium, releasing chemicals that start the cycle of pain and inflammation.

Patient Tim Cooper, 67, entered the trial after pain in his left knee kept him awake, he struggled to climb stairs and he was unable to garden or walk. But the retired Ministry of Defence manager says the procedure has changed his life in 2021, with him now symptom-free.

The Navy veteran, from Gosport in Hampshire, is now a beekeeper, tends several vegetable gardens and walks five miles every day with foster dogs.

Mr Cooper said: ‘It has made such a difference to my life. I was in constant pain and it limited what I could do. Now it is just like the other knee.

“I’ve always loved being outdoors, and I couldn’t go for walks or gardening, do the things that make life fun. This has given me my life back.”

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

In the new knee version of the surgery, the patient is given a local anesthetic, after which a needle is used to reach an artery in the groin.

The surgery targets new ‘defective’ blood vessels that grow in the synovium, releasing chemicals that start the cycle of pain and inflammation. (Stock photo)

Injecting tiny plastic pellets into the knee joint could offer hope to patients suffering from arthritis pain. (Stock photo)

Under the guidance of an X-ray machine, a narrow hollow tube is guided through the main blood vessel to the knee.

Small amounts of fluid containing the plastic beads, which are the size of grains of sand, are then injected through the catheter. These enter the defective blood vessels in the synovium, blocking blood flow.

This stops the production of chemicals that cause inflammation, thereby relieving pain and swelling. Professor Little said: ‘If we can stop these chemical messengers where they are being made, then our theory is that we can stop the inflammation and perhaps pause the disease.

“This could dramatically reduce the level of pain and potentially prevent so many people from needing a knee replacement. While it won’t work for everyone, it offers a hopeful and exciting new option.”

The procedure is best suited for patients with mild to moderate disease who do not respond to standard treatment, such as painkillers and physical therapy, but whose condition is not bad enough for knee replacement.

‘A lot of the people I see are in their 50s and 60s and they live with the nightmare of chronic pain. It has a huge impact on their daily lives.’

Nine of the original 40 patients underwent knee replacement surgery. Six others who were initially enrolled 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 during recovery, but otherwise there were few complications. The approach was rejected by the National Institute for Health and Care Excellence (NICE) in 2021, after health leaders said there was insufficient evidence of its long-term impact.

The Reading team is now running a larger trial involving 110 patients, half of whom will undergo a sham procedure. It hopes that this new study, along with similar trials in Japan and the US, will persuade NICE to approve it.

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