A new minimally invasive procedure could help tackle the early stages of knee arthritis. John Legg, 65, an engineer from Hoo in Kent, underwent the treatment in July 2011.
John Legg's knee cartilage had been worn away so he underwent a keyhole surgery; the bone of his knee was drilled into to release stem cells
THE PATIENTAbout four years ago I started having tearing pains down my right knee, especially when I'd been on my feet a lot. I have always been pretty active and it hurt to climb stairs or to use an exercise bike.
I assumed it was part of getting older, so put up with it. But it was getting worse, I'd go to bed with my knee aching, and sometimes the pain would wake me up. It even hurt to drive.
So in early 2011, a couple of years after the pain started, I saw my GP. He thought I might have twisted my knee, or that I could be developing arthritis, which, he explained, is where the cushioning cartilage wears away and bone starts rubbing on bone, causing pain. At that stage, he told me to take paracetamol, which I did when the pain was bad.
But it got worse, until it was there all the time. In restaurants, I'd rise to my feet painfully after the meal and have to wait a few minutes before I could walk away, and on holiday I'd have to miss long walks. My wife, Penny, was sympathetic, but it was getting us both down.
So in June that year I saw the GP again. He sent me for an X-ray, which showed I was developing arthritis. My GP then referred me to Professor Anan Shetty at Spire Alexandra Hospital in Chatham, Kent, whom I saw on the NHS two weeks later.
More... How to get Juliette Lewis's shoulders: Secrets of an A-list body The women told they're depressed when in fact it's 'menstrual psychosis' As thousands develop tumours on their ears and even the soles of their feet... The hidden hotspots that could expose YOU to skin cancerAn MRI scan showed my cartilage was worn away - Professor Shetty said he could do a knee replacement, which would mean up to five days in hospital and a long recovery time, with the pain lasting up to four months.
The other option was a new procedure he'd devised, which meant a much quicker recovery. Using keyhole surgery he would drill into the bone of my knee to release stem cells, which can grow into new cartilage, bone or skin cells.
He would then inject a special collagen, which he said would trigger the cells to form cartilage, as well as providing a scaffold for them to grow into.
And instead of staying in hospital for up to five days, I could come home the same day. I had the 35-minute operation under general anaesthetic in July 2011, and Penny took me home that afternoon.
When I peeked under the dressing, I was amazed - there were tiny holes of under a centimetre in diameter.
It only hurt for the first week, but painkillers helped. I also used crutches for the first six weeks while the knee healed, but after that I started using the knee normally again.
For the first time in years, driving and climbing the stairs were pain-free. I was 100 per cent better.
Now I'm back in the gym and walking the dog without pain in my right knee. My left one is starting to hurt, so I might have that done too. Once I've got two good knees, I'll be back on the golf course.
THE SURGEON Knee time: When the cushioning cartilage between the bones of the joint wears away, bone grinds on boneAnan Shetty is professor of minimally invasive surgery at Canterbury Christ Church University and consultant knee surgeon at Spire Alexandra Hospital in Chatham, Kent.
The knee carries a huge amount of weight, and when the cushioning cartilage between the bones of the joint starts to wear away, bone grinds on bone. It can cause so much pain it affects people's ability to walk.
People at the greatest risk of early-stage knee arthritis (which John had) include young sports people, because of repeated injury.
Over 100,000 Britons need a knee replacement every year.
Patients can be prescribed painkillers known as non-steroidal anti-inflammatories to reduce the inflammation, but these carry long-term risks, including bleeding from the stomach.
We can also try steroid injections into the knee to reduce the inflammation in the lining membrane of the joint, but these also thin the cartilage even further.
However, knee replacements are not suitable for people under 55 because they need to be replaced in ten to 15 years.
Another option is to stimulate the growth of new cartilage using microfracture, which means drilling into the bone to release stem cells. These are part of the body's repair system and can potentially grow into any cell in the body.
But around 30 per cent of these operations fail within three years, because the cartilage it produces is soft and fibrous, rather than the smooth, hard hyaline cartilage found growing naturally in the knee.
Doctors have also tried regrowing cartilage in the lab, using stem cells and cartilage cells taken from the patient's own knee. But this is expensive and done at only a few specialist centres, and requires two separate operations.
So for patients with early-stage arthritis who were too young for a knee replacement, there was little we could do.
But a procedure I devised around four years ago could help around 9,000 UK patients every year. As well as using microfracture to stimulate new growth, we inject a special collagen gel called Cartifill, which acts as a scaffold for the new cartilage.
The collagen, which is taken from pig skin and put through a chemical process, gives the stem cells a chemical signal that encourages them to grow into hard hyaline-like cartilage.
So by stimulating bone marrow to release stem cells, and providing a stable collagen structure for them to grow into, we can grow new tough cartilage, with an 80 to 85 per cent similarity to normal cartilage.
It's about a quarter of the cost of a knee replacement, as the patient goes home that night instead of staying in hospital.
The operation takes about 35 minutes. First I make two 8-10mm incisions for the surgical instruments and arthroscope - camera on a tube - and inject saline solution to expand the joint and give me room to work.
I clean away the damaged cartilage, then drill up to 6mm into the bone to release stem cells. We drain the saline and inject compressed carbon dioxide, which is very safe, to dry the joint.
Next, I mix up to 2ml of collagen gel with a sealant, which contains natural clotting factors found in the blood. When mixed, they make collagen harden, and form a scaffold to fit the shape of the cartilage defect.
We inject the paste over the damaged area, like a thin plaster: it will form a scaffold for the stem cells to grow into, so that new, tough cartilage will grow.
The operation carries standard surgical risks of bleeding and infection, and a small risk of damage to surrounding soft tissue, but these are minimal.
We've performed it on over 60 patients so far. MRI scans done six and 12 months later show that strong cartilage has grown back in 80 to 85 per cent of patients.
In the other 15 per cent the disease has progressed too quickly and the joint has become deformed, but John had excellent results.
If his arthritis progresses, he can have a knee replacement later, but should have many pain-free years first.
The operation costs around £3,853 privately, and £3,830 to the NHS. It's available at only a few UK centres, including University Hospitals Birmingham NHS Foundation Trust, Spire Cambridge Lea Hospital and Spire Alexandra Hospital in Chatham, Kent.