NJR research finds metal-on-metal hip replacement patients are at no more risk of developing cancer in seven years following surgery
4 April 2012
A study commissioned by the National Joint Registry, published online at bmj.com today (British Medical Journal, Wednesday 4 April), confirms that patients who have had a metal-on-metal hip replacement are at no more risk of developing cancer in the first seven years after surgery than the general population. The authors of the research add that a longer study is required, to monitor incidences for cancers that take many years to develop.
The study was carried out by the NJR statistical support, analysis and research team led by Professor of Orthopaedic Surgery Ashley Blom at the University of Bristol, who said:
"The results, using a large representative sample, show that there is no association between metal-on-metal hip replacements and increased incidence of cancer in the first seven years after hip replacement."
"The data also shows that the incidence of cancer diagnosis is low after hip replacement in general and lower than that predicted for the age and sex matched general population. However comparisons with the general population are not straightforward as hip replacement patients tend to be healthier than others of the same gender and age group."
The study looked at incidence of new diagnoses of cancer for more than 40,000 patients with a metal-on-metal implant and compared them to those with different bearing surfaces (over 245,000 patients) and the general population.
The chance of a 60 year-old man with a metal-on-metal hip being diagnosed with cancer in the five years following surgery is 6.2%, compared to 6.7% chance with hip replacement using other bearing surfaces. For women, these figures were 4.0% for metal-on-metal and 4.4% for other bearing surfaces.
Recent coverage on metal-on-metal hip replacements has highlighted concerns about the effect metal ions, from the wear of metal-on-metal implants, have on the body. As yet, there is no proven link between DNA changes and an increased incidence of cancer.
National Joint Registry Lead Elaine Young said:
"Each year we commission special topic studies, to accompany the annual reporting process. This time the studies are looking at the metal-on-metal hip replacements and we are pleased to have this second paper published at BMJ online, following the recent stemmed metal-on-metal paper in The Lancet."
"The National Joint Registry is an extremely valuable source of information based on a mature data set (7 years). We are committed to supporting and enabling further research so that clinicians can use this information to make the best choices for their joint replacement patient. Importantly too, we are sharing more data with patients, to enable them to seek out up-to-date information and advice."