The hearing at the Royal Courts of Justice is believed to be one of the largest product liability group actions in the UK and is one of the first group claims against a manufacturer that has been taken to court in this country over allegations relating to the failure of metal-on-metal hip implants.

Hundreds more metal-on-metal claims against a number of other manufacturers are stayed awaiting the outcome of this trial.

Law firm Leigh Day are the lead solicitors in the case, which is being brought on behalf of over 300 individuals who claim to have been injured as a result of the early failure and consequent revision surgery of their metal-on-metal prosthetic hips.

Lawyers will claim that their clients have been affected by the release of metal particles from the implants, which can lead to severe soft tissue reactions and muscle necrosis.

Those affected allege that their symptoms included pain, difficulty walking, swelling and numbness or loss of sensation in the leg. All those taking legal action have had early revision surgery to have the components replaced.

Since the first attempt at total hip replacement surgery in the early 20th century, the procedure has become one of the most common and effective types of surgery.

Although early hip replacement systems involved metal-on-metal articulations, by the 1970s these models had been rejected in favour of hip systems using other materials such as polyethylene.

In the 1990s metal-on-metal bearings began to be reintroduced as these systems were thought to be more durable and their larger head sizes were thought to present a lower risk of dislocation.

The DePuy Pinnacle Ultamet was marketed as a device that was able to achieve “exceptionally low wear rates” and as having excellent survivorship, a factor which led surgeons to believe that the Pinnacle would last longer than conventional hip replacements.

However, the UK National Joint Registry 2017 has identified that the Pinnacle metal-on-metal total hip replacement has a failure rate at 10 years that is six times higher than the failure rate of the mostly common used standard conventional components.

Depuy discontinued sales of the Pinnacle Ultamet device in August 2013.

Bozena Michalowska-Howells from the consumer law and product safety team at Leigh Day, the lead solicitor for the Pinnacle metal-on-metal group litigation, said:

“After five years working on these cases I look forward to our clients finally having their day in court. They believe that the Pinnacle device has failed to deliver on the level of safety they were entitled to expect.

“As a result of this failure, they have suffered pain and early revision surgery which we believe would have been avoided had they been implanted with a conventional hip product.”