8 out of 10 knee replacements and 6 out of 10 hip replacements last as long as 25 years, says a large study from the University of Bristol. This is much longer than believed, the researchers said, and the findings will help patients and surgeons decide when to carry out the surgery. To date, there has been little data on the success of new hips and knees.
But this Lancet research looked at 25 years’ worth of operations, involving more than 500,000 people. Hip and knee replacements are two common procedures but doctors often struggle to answer questions from patients on how long the implants will last.
Nearly 200,000 of the operations were performed in 2017 in England and Wales, with most carried out on people between 60 and 80 years old.
Dr. Jonathan Evans, lead study author and research fellow at Bristol Medical School, said: “At best, the National Health Service (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 technology and techniques in the last 25 years, we expect that hip or knee replacements put in today may last even longer.” As the aging population grows, and life expectancy rises, this becomes even more important, Dr Evans added.
How long do they really last?
Hip replacements: 89% lasted 15 years, 70% lasted 20 years and 58% lasted 25 years;
Total knee replacements: 93% lasted 15 years, 90% lasted 20 years and 82% lasted 25 years;
Partial knee replacements: 77% lasted 15 years, 72% lasted 20 years and 70% lasted 25 years;
The researchers looked at reports from joint replacement registries in six countries which held at least 15 years of data – Australia, Finland, Denmark, New Zealand, Norway and Sweden.
They did not look at data from the UK, because its record of patients does not go back far enough, but the research team said their findings mirrored results from smaller studies of UK patients.
According to the study, when hip and knee replacements do fail it tends to be because of infection, wear and tear and, more rarely, because they have broken. This means patients require revision surgery which is more likely to fail.