Forty-one New Zealanders are affected by a new international recall of a hip replacement device.

Medsafe said this week's recall, of Mitch THR hip implants, came amid an increasing scrutiny of similar devices.

A recall of ASR hip implants in 2010 affected more than 500 New Zealanders and led to class action lawsuits overseas.

"Companies are looking more closely at metal on metal replacements to see, in effect, if they behave the same way as ASR hips," said Dr Stewart Jessamine, Group Manager for Medsafe.


The Mitch hip implants have been found to have unacceptably high failure rates after three years, of 11 per cent in Britain.

The recall means the device will not be used in any new surgeries, and patients who already have the implants will need to be checked every year.

Dr Jessamine said the hip joint replacement was prone to loosening.

He said any recall of implanted devices was complicated by difficulties tracking down patients.

Only surgeons knew what kinds of replacements patients had received, for privacy reasons, and some patients would have shifted with no contact details available.

This was a big lesson from the ASR recall, Dr Jessamine said.

"We subsequently found out not all patients were contacted, so we're putting more resource and effort into trying to reach out to patients," he said.

"Globally, health regulators had possibly been a bit too dependent on the company getting all the advice out and the message out."

Medsafe would push the message through surgeons, GPs and other health sector channels as well as through websites and the media.

"We do have to accept at the end of the day, however, we're not always going to be able to get to every patient," Dr Jessamine said.

"Some would have moved to Australia, retired, passed away, changed their names ..."

The previous recall of the ASR device raised a controversy about how new medical devices were tested, verified and marketed.

There were lawsuits overseas, but New Zealand's no-fault ACC system has held back legal action here.

Hip recalls
ASR (2010): 507 New Zealanders affected
MITCH TRH (this week): 41 New Zealanders affected.