Need a new knee? Now you can ‘grow your own’ after a one-hour op on the NHS

Thousands of NHS patients tormented by agonising knee pain are set to be offered ‘grow-your-own’ joint replacements.

The long-lasting procedure to repair damage to cartilage in the knee has been approved by the NHS spending watchdog after 20 years of research.

The technique – known as single-step scaffold insertion – involves extracting stem cells from the patient’s problematic joint and growing them within animal tissue.

The National Institute for Health and Care Excellence (NICE) concluded that many patients living with debilitating knee injuries saw their mobility ‘improved significantly’ after the surgery.

About 10,000 Britons need treatment for torn cartilage injuries every year – usually in the knee. This is where the tough-but-flexible ‘cushion’ that stops bones rubbing together in the joint ruptures, often due to heavy impacts during sporting activities, or simply twisting the knee too much while the foot is planted.

Once cartilage has been damaged, it does not heal on its own.

It leads to pain, swelling and frequent seizing-up of the joint. Many sufferers find the injured knee also gives way easily, increasing the risk of dangerous falls.

Young adults who rupture knee cartilage are also far more likely to develop agonising osteoarthritis – where the cartilage wears out so excessively that knee bones grind together in later life. Some end up requiring knee-replacement surgery in their 40s or 50s.

This is a major operation which involves cutting open the knee and replacing the joint with a metal or plastic implant. Knee replacements take about a year to recover from and sometimes the implant can become infected or wear down, leading to its removal. About a fifth of patients will require a second joint replacement.

About two decades ago researchers developed an innovative solution to fixing cartilage tears in the knee before they caused irreversible damage. The procedure, called autologous chondrocyte implantation, involves regrowing the cartilage in a laboratory.

Bone marrow – the soft, spongy material inside bones – is extracted from the hip of patients using a long needle. Stem cells, which have the capacity to grow into healthy new cartilage, are subsequently harvested from the bone marrow and cultivated in a dish. Several weeks later, the patient has a second procedure to implant the cells into the knee, where they continue to grow and become fully functioning cartilage.

While effective, autologous chondrocyte implantation is very expensive – cultivating stem cells in a laboratory can cost as much as £17,000 alone. It also requires two invasive operations.

But the new, single-step scaffold insertion procedure offers similar results with just one operation. During the hour-long surgery, surgeons drill tiny holes into the knee bone while the patient is under a general anaesthetic. This allows the stem cells to leak out of the bone marrow.

A small patch of cow or pig tissue is then placed over the torn cartilage to act as a kind of scaffold for the stem cells to populate. Over the following six to 12 months the stem cells grow into new cartilage, strengthening the knee, easing pain and restoring movement.

The method costs a fraction of autologous chondrocyte implantation – the animal tissue scaffolds cost just £1,000 to £2,000 and there is no culturing of cells in a lab.

‘This is potentially very good news,’ said Ian McDermott, a consultant knee surgeon at London Sports Orthopaedics who has carried out the one-step procedure on hundreds of private patients. ‘It has an 80 per cent success rate after five years and is a fraction of the cost of current techniques.’

Experts argue the procedure will not cure all patients, though. Studies suggest it is most effective on small cartilage tears. Patients who undergo the op may still need a knee replacement later in life, too.

However, those who have already received stem cell therapy for torn cartilage say it has changed their lives.

Rebecca Bennett, from Somerset, was one of the first people in the UK to benefit from autologous chondrocyte implantation nearly 20 years ago.

The 43-year-old was in her late teens when a freak slip caused her knee to bend backwards, leading to years of agony. ‘It was the worst pain I’ve ever felt,’ Rebecca says. ‘And I’ve had four children.’

She had damaged the cartilage in her knee. Numerous operations followed, none of which fixed the problem. ‘My knee kept suddenly dislocating. The whole joint felt like a floating bit of jelly.’

Doctors warned she could end up in a wheelchair – but in 2005 she was offered the chance to join a trial at Orpington Hospital in London, where surgeons were testing out the new technique.

‘As soon as I woke up I knew it had worked – even before I got out of bed,’ adds Rebecca. ‘It felt completely different. Twenty years later my knee is still as good as ever. It gave me back my freedom.’