How a dash of vinegar fights infection after new knee ops

VINEGAR isn’t just for livening up fish and chips — doctors are now using its key ingredient to treat infections in knee replacements. Surgeons in Cardiff are applying acetic acid to kill bacteria when new knee joints become infected, thereby reducing the need for further surgery.

In the UK, 82,000 knee replacement operations take place every year. But bacteria can get inside the knee during surgery, causing infection — sometimes years later — leading to inflammation and swelling.

Untreated, this can cause the joint to loosen and eventually collapse. If the infection is superficial, oral antibiotics can be prescribed, but some infections don’t respond.

In such cases, surgeons’ only option is to remove the replacement joint, cut away dead tissue, wash out the knee (using saline, to sterilise, or iodine, which has antimicrobial properties) and put in a new joint.

Sometimes, they can put in the replacement knee during the same operation, but this is usually done six to eight weeks later.

In the meantime, the knee is packed with a special ‘cement’, which releases high concentrations of antibiotics to ensure the infection is killed. Each operation costs £15,000 to £20,000.

Now, surgeons at University Hospital of wales and Spire Cardiff Hospital hope that bathing the site with vinegar when they remove the infected joint means they can replace the joint in just one operation.

Tests have shown that soaking the biofilm (the sticky layer of bacteria inside the knee) in this acid solution effectively kills the bacteria better than standard saline, says Rhidian Morgan- Jones, consultant orthopaedic surgeon at both hospitals.

‘we have treated around 25 patients in a prospective trial to show it is safe. They had no increase in heart rate, breathing or blood pressure — signs of pain — and no wound complications or delayed healing, suggesting that it was effective.’

one patient who has benefited is Ron Spree, 69, a retired major in the Royal Army Physical Training Corps. After years of pain, in 2002 he had a left knee replacement on the NHS. But six weeks after the joint was put in, it began to ooze yellow gunge and he was diagnosed with an infection.

Three months later, he had surgery to remove the joint and ‘cement’ was packed into his knee. Four months later, Ron had a third operation to give him a new knee joint.

In the intervening months, he wore a splint to keep his knee straight and relied on crutches. Keeping the leg straight for so long made his skin shrink, so he needed a skin graft. For the next ten years, he was active as ever — ‘but three years ago, my knee began oozing again. Doctors said the dormant infection was back’.

He was put on antibiotics, but these didn’t help. Eventually, Ron was told doctors could remove the infected prosthesis and fuse bones together to keep the leg straight — but, if that failed, they would have to amputate above the knee.

Ron was horrified, so he sought a second opinion from Rhidian Morgan-Jones. ‘He told me he could take the infected joint out, bathe the knee in vinegar to kill the infection and replace the joint,’ says Ron.

In December 2013, Ron had the two-hour operation privately. ‘Now, the oozing has stopped, my leg has healed and I’m out of pain,’ he says. Mr Morgan- Jones hopes that, in future, acetic acid may be used in all knee replacement operations to prevent infection in the first place.

‘It could also be used in other joint replacements, including hips, shoulders and elbows, to save the NHS large sums,’ he says. Nick London, consultant knee surgeon at Yorkshire Knee Clinic and Harrogate and District NHS Foundation Trust, says infection in knee replacement surgery is ‘a huge problem, affecting around 1 per cent of patients’.

‘Revision surgery to replace an infected implant is complex, costing several times more than the initial surgery, and involves longer hospital stays and long antibiotic courses.

‘Any method of making it more effective is welcome, since revision surgery to eradicate infection can fail in up to 20 per cent of cases.

‘A simple solution with vinegar sounds interesting, but this is a small study. we need much larger ones to show it works and does no harm.’

AND vinegar’s not the only store cupboard staple finding its way into operations. New research from the University of Edinburgh shows adding sugar to the saline solution used to wash out joints in orthopaedic surgery can protect cartilage and lower the risk of osteoarthritis.

Mr Morgan- Jones is planning to use sterile medical honey, Surgihoney, in revision surgery to replace an infected knee joint. ‘There’s evidence sugar can fight bacteria,’ he says.

‘It involves coating bones to create a hostile environment for bacteria, so they don’t stick to the implant initially — though we don’t yet know how long effects will last.

‘Sugar and vinegar have been used in medicine for centuries and don’t create resistance as antibiotics do.’