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U.K. to Ban Metal-on-Metal Hip Implants at Publicly-Funded Hospitals

Decision prompted by recent study.

By: Michael Barbella

Managing Editor, Rodman Media

High failure rates and toxicity concerns has prompted the United Kingdom to ban metal-on-metal (MoM) hip implants in hip replacement surgeries performed at publicly-funded National Health Service (NHS) hospitals.

The decision was prompted by a National Institute for Health and Care Excellence (NICE) study that found failure rates as high as 43 percent among 17,000 MoM hip implant patients. NICE issued a guidance to NHS hospitals after publishing the study, according to the United Kingdom-based Daily Express.

Consequently, U.K. regulators are advising the NHS to prohibit any future implants with a failure rate above 5 percent at five years. Experts, however, contend such a practice would preclude doctors from using nearly every metal-on-metal device, including the implants still on the market. Two common models already have been removed the market as safety concerns have grown more prevalent.

MoM implants have become the pariahs of joint replacement surgeries in recent years due to their high failure rates and potentially toxic wear particles, which can damage bone and/or the tissue around the implant and joint. Soft tissue damage can lead to pain, implant loosening, device failure, or the need for revision surgery, regulators warn.

Three years ago, the United Kingdom’s Medicines and Healthcare products Regulatory Agency (MHRA) issued a medical device alert that included specific follow-up recommendations for patients with MoM hip replacements. The recommendations included blood tests and imaging for patients with painful MoM hip implants. In February 2012, MHRA published a medical device alert and updated it four months later with advice on the management and monitoring of patients with MoM hip systems.

Orthopaedic surgeon Martyn Porter told the Express that seeing the NICE study failure rates was like “watching a car crash in slow motion – at first, you just don’t know how bad it is going to be.”

Research of all hip surgery in England, Wales and Northern Ireland found most metal-on-metal implants had unacceptable failure levels, falling below standards set by NICE.

One implant, DePuy Orthopaedics’ ASR, required secondary surgery in almost a quarter of cases during the first five years. Manufacturers admitted to failure rates of 13% in that time, and the device was withdrawn.

Six metal-on-metal models and a ceramic-on-metal model implanted in more than 11,00 patients having hip resurfacing procedures had five-year failure rates of 5 percent or worse. Some rose to 16 percent within nine years, figures show.

Just two types of metal-on-metal implant fall within the proposed national standard, the study found.

Stephen Cannon, an honorary consultant surgeon for the Royal National Orthopaedic Hospital, welcomed the report.

“I think there is a question about whether it goes far enough, but this is definitely a step in the right direction – it amounts to a ban on most of them,” he said. “The figures speak for themselves – even the best metal-on-metals have four times the failure rate of the rest. This is a really significant problem because these were given to an awful lot of people.”

Porter, the past president of the British Hip Society, said the full scale of the failings only now was becoming clear. “These devices, which were supposed to be innovative, had such poor results,” he said.

Some senior surgeons have called for all types of the implant to be removed from the market.

DePuy has discontinued the metal-on-metal variant of its Corail/Pinnacle implants because of low use.

Traditional implants use a metal ball in a plastic socket.


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