The size of the head used in hip replacement surgery could have a correlation to its long-term success.
A new study by the Hospital for Special Surgery in New York which assessed medical records of patients who were given metal-on-metal hip joints has found that it may be the structure, as opposed to the material, which causes some problems for people.
Doctors explained that advances in materials had made it possible for bigger heads to be used to improve stability, but they could be leading to complications.
"It's not enough to say, because some metal-on-metal implants have adverse reactions, it has got to be all about the metal and let's just condemn an entire technology," said Timothy Wright, chair of orthopaedic biomechanics at the clinic.
The Daily Telegraph recently reported that around 70,000 people in the UK undergo hip replacement surgery every year and a faulty design by DePuy was taken off the market in 2010.