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Greater chance of hip replacement failure in last decade, study says

Hip replacements carried out in the last decade have a greater risk of failure, a study found.

Hip replacements carried out in the last decade have a greater risk of failure, a study found.

Researchers explored the long-term performance of the most commonly implanted metal hip in the world, and say replacements fitted since 2006 are more likely to fail than earlier models.

Issues with ‘the manufacturing process’ are to blame, says lead author David Langton of the University Hospital of North Tees, Stockton.

It is estimated that 180,000 people around the world are using metal-on-metal Pinnacle hips, with the new study suggesting they are at increased risk of requiring revision surgery.

More than one third of the replacement hips since 2006 are outside the stated specifications, say researchers, who reviewed the progress of 434 patients (243 women, 191 men) fitted with 489 metal-on-metal total hip replacements at one English hospital trust, monitoring them for an average of 7.5 years after the procedure.

In all, 71 metal hips required surgical removal and replacement, adding up to a revision rate of 16.4%, which researchers call ‘unacceptably high’.

Metal-on-metal hips consist of a ball which acts as the top of the thigh bone and fits inside a metal liner, which serves as the replacement socket.

Before 2006, only five out of 43 hips (12%) failed to meet the manufacturer’s product specification. Since then, more than one third (36%, or 43 out of 118) failed to comply.

Additionally, in 40% of cases the taper surface (which anchors the implant in the thigh bone) was defective.

Reference

Langton D et al (2016) Retrospective cohort study of the performance of the Pinnacle metal-on-metal total hip replacement: a single centre investigation in combination with the findings of a national retrieval centre. BMJ.

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