Why most new hips and knees will now last up to 25 years

THE majority of hip and knee replacements now last for up to 25 years in patients, a major study has found.

They are among the most common forms of surgery on the NHS but people have often been told that the expected lifespan of implants is about 15 years.

But now research has revealed that eight out of ten knee replacements and six in ten hip replacements are still functioning properly years after they were expected to.

Study leader Dr Jonathan Evans, an orthopaedic registrar, said: ‘At best, the NHS has only been able to say how long replacements are designed to last, rather than referring to actual evidence from multiple patients’ experiences of joint replacement surgery.

‘Given the improvement in technolrising ogy and techniques in the last 25 years, we expect that hip or knee replacements put in today may last even longer.’

Researchers studied the outcomes of the surgery for 500,000 patients in six countries over a 25-year period.

They looked at reports from joint replacement registries based in Australia, Finland, Denmark, New Zealand, Norway and Sweden.

British data was not used because its record of patients did not go back far enough.

However, experts say their findings mirrored results from smaller studies of UK patients.

Researchers found that 82 per cent of complete knee replacements and 70 per cent of partial knee replacements lasted 25 years. Of complete hip replacements, involving the ball and socket of the joints, 58 per cent lasted 25 years.

More than two million hip and knee replacements have been performed in Britain since 2003 but the ageing population and obesity levels mean that the waiting list is growing.

Last year, the Mail revealed that three-quarters of NHS trusts were refusing to fund hip and knee operations unless patients were in severe pain.

Some patients were able to jump the queue by paying up to £15,000 for a hip replacement, rather than having to wait a year to have surgery.

Hip and knee replacements eventually fail due to infection, fractures and wear and tear, the researchers from the University of Bristol said.

Many patients have required revision surgery which is more challenging than the first operation, expensive and less likely to produce as good a result.

But experts believe that better preparation before surgery, such as weight loss and strengthening exercises, improved surgical techniques and more effective post-operative physical rehabilitation has made implants more long-last- ing. Manufacturers have also developed different plastics and metals that have been found to make the replacement joints more dependable and durable.

Doctors say that the newer devices have enhanced the remaining bone’s ability to grow into the implants, forming a secure bond that is less likely to erode over time.

Dr Evans, whose findings were reported in The Lancet, said: ‘We hope that this information will be useful to patients when deciding whether to have a hip or a knee replacement.’

He added: ‘We also hope that the information will be interesting to patients who already have a hip or a knee replacement in place.’

‘Better technique and technology’