Hi-tech sponge to ease painful knees

Tiny sponges inserted inside the knee joint have been developed as a new way to tackle arthritis. They are made from hyaluronic acid, the natural lubricant found in joints, and are impregnated with stem cells extracted from the patient’s own bone marrow to rebuild tissue that has worn away.

in a new trial taking place in Hungary, 200 patients with knee arthritis will have surgery to insert the high-tech sponges or a standard surgical procedure for arthritis in the knee, to see if the cells can repair or reverse damage caused by the condition.

More than a million people each year consult their GP about osteoarthritis — damage in and around a joint.

As a result of wear and tear, the cartilage that lines bones and allows joints to move easily is slowly destroyed.

Unlike other tissue, cartilage is poorly supplied by blood vessels and nerves, inhibiting its ability to heal itself, and it can gradually get worn away.

Painkillers, physiotherapy and steroids are among the treatments available to manage the symptoms, but these do not halt the progress of the disease.

Another option is microfracture surgery, where tiny holes are drilled into the bone ends to stimulate blood supply and the growth of new cartilage. However, this is only suitable for smaller defects — the success rate is thought to be between 60 and 80 per cent.

MANY patients will eventually need to have their knee replaced. each year, more than 40,000 knee replacement operations are carried out in Britain.

Healthy cartilage is kept welloiled with the help of a thin membrane, the synovium, which produces a lubricating material called synovial fluid.

Hyaluronic acid is a key component of this fluid — people with osteoarthritis have lower levels of hyaluronic acid in the joint.

The new sponge, known as Hyalofast, contains hyaluronic acid derived from fermented bacteria. it is put through a chemical reaction known as esterification, which makes it into a solid structure that’s compressible and absorbent like a sponge.

The shape and size of the sponge can be tailored to fit the damaged area using a patient’s knee scans. Several can be cut and stacked to fill deeper holes, too.

doctors use pinhole surgery — a technique where the incision is even smaller than keyhole surgery — to place the sponge in the knee.

Because of its spongy texture, it fits snugly into the damaged area and expands to fill the hole in the cartilage. At that point, surgeons extract stem cells from the patient’s bone marrow with a needle and feed them into the sponge in the knee.

The sponge dissolves over time and, as it does, it releases hyaluronic acid fluid into the cartilage. This is thought to lubricate the joint to prevent further damage and create ideal conditions to help stem cells grow and develop into new bone tissue.

As the sponge degrades, it is absorbed naturally by the body.

‘it enables patients to regenerate cartilage with the goal of allowing them to avoid or delay total joint replacement,’ say orthopaedic specialists who are carrying out the trial in four hospitals across Budapest, Hungary. A STUDY carried out with 20 patients at italy’s rizzoli Orthopaedic institute in 2010 showed the sponge therapy is highly effective, with a near-threefold improvement in symptom scores after two years, according to the Journal of Bone and Joint Surgery.

in the new trial, 200 people with knee osteoarthritis will undergo the Hyalofast therapy or microfracture surgery.

Symptoms such as pain and the amount of cartilage repair achieved will be monitored for two years after the procedure. commenting on the new approach, Stephen Simpson, the director of research at Arthritis research UK, says: ‘ We’re interested to see the progress of this study and the potential future benefits it might have for people living with arthritis.

‘However, treatments such as this are some way off and more research needs to be done to understand how the potential of stem cells might be harnessed.’