Thousands of hip replacement patients were given incorrectly-sized implants, it has emerged.
DePuy, one of the world’s largest hip replacement firms, admitted “an error in the measuring techniques” during production of their controversial metal-on-metal implants at a factory in Leeds, according to the Daily Telegraph.
Documents seen by the paper show that manufacturing problems have been discussed by DePuy over several years.
The DePuy ASR all-metal implant was launched in the UK in 2004 and marketed towards younger hip replacement patients with active lifestyles.
The ball and socket components were designed to last a lifetime and were said to provide more flexibility and range of motion than other hip replacement devices available at the time, thereby eliminating the risk of premature failure due to overuse.
But as early as 2006, British surgeons were reporting problems with the joint coming loose and concerns that patients were complaining of pain and swelling, and nerve, muscle and bone damage.
Previously, the main concerns focussed around the metal implant components rubbing against each other and wearing down, causing toxic metal ions to seep into the surrounding tissue, muscles and bloodstream. But now, documents seen by the Daily Telegraph suggest that a manufacturing problem may have compounded the problem.
Around 20,000 patients in the UK were fitted with the implants before DePuy issued a worldwide recall notice for all ASR products in August 2010, amid concerns about the number of patients needing revision surgery due to tissue damage caused by the implants.
The Medicines and Healthcare products Regulatory Agency (MHRA) ordered two types of DePuy hip implant to be taken off the market, the ASR, used in hip resurfacing surgery, and the ASR XL, used for full hip replacements.
In 2012, the MHRA advised that patients who had large head metal-on-metal hip replacements should be monitored annually for life to check for metal ions in their blood. Doctors say the fragments could be poisonous to the kidneys and destroy muscle by inflaming tissue around the bone.
Lawyers are representing hundreds of claimants who were given the defective hips and subsequently underwent revision procedures after suffering pain, swelling and difficulty walking. Blood tests have revealed many of them have high levels of metal particles in their blood, putting them at potential risk of cancer.
DuPuy are now under intense pressure from victims of the scandal to admit how long they were aware of the problem, amid concerns that faulty components were sold for years.