New revelations published by the Daily Telegraph on Tuesday 26 January 2016, prompt further concerns regarding the quality of manufacturing controls at Depuy’s Leeds production facility.

On Monday 25th January the Telegraph revealed that DePuy, subsidiary of household name Johnson and Johnson, had admitted to “an error in the measuring techniques” used to make the metal liner which forms part of the company’s flagship metal-on-metal total hip prosthesis, the Pinnacle Ultamet system.

Information published yesterday by the Telegraph indicates that “the number of hours spent by Depuy on spot checking implants was halved between 2005 and 2006”.

Depuy have reportedly declined to say why this quality control procedure was apparently downgraded. However, according to the Telegraph, DePuy scaled back on spot checking three years before it became aware of the machining issues which, by the company’s own admission, had caused an error in the company’s measurement of Pinnacle Ultamet liners.

Boz Michalowska, lawyer for over 300 patients implanted with the Pinnacle Ultamet, commented: “The revelations published by the Telegraph are highly concerning. It is incumbent upon any manufacturer of medical devices, particularly those that will be implanted inside patients, that the very highest levels of production and manufacturing control are in place to safeguard all patients. The evidence that is now emerging may indicate that such safeguards were not in place at DePuy, leaving patients exposed to unnecessary and foreseeable risks that could have been discovered much sooner.”  

The Telegraph has reported that an internal audit commissioned by the Leeds branch of Depuy in 2009, a year after the company discovered the error in measuring techniques, said: “Actions have not been identified in all cases to correct or prevent recurrence of quality problems.” This may raise questions about the remedial measures taken by DePuy after discovering the error now admitted by the company, particularly in light of a report by the US Food and Drug Administration, as late as 2011, which stated: “Complaints involving the possible failure of a device to meet any of its specifications were not investigated where necessary.”

Speaking to the Telegraph, Prof Tim Briggs, former president of the British Orthopaedic Association, explained that an error in the measuring and sizing of components used with a metal-on-metal hip system could be very significant: “If there is a difference in the size – it doesn’t have to be very much at all – you will change the wear characteristics and you may well generate more metal ions”. Excessive production of metal debris and metal ions have been linked to early failure and adverse clinical reactions in patients implanted with metal-on-metal hip systems.

A spokesman for DePuy has said that it became aware of the issue with measuring equipment in 2008 and that the problem was thoroughly investigated. The firm concluded there were no safety issues and the “equipment causing the issue was removed from the manufacturing line” the same year. The spokesman added: "We have robust quality control processes at our manufacturing facilities."