[Metal-on-metal hip implant continues to be a source of concern]

It has recently been suggested that patients with metal-on-metal (MOM) hip implants have an increased chance of mortality. These observations come from a meta-analysis including many small randomised controlled trials (RCTs) and cohort studies. Because of the high risk of bias there is no reason for great concern. In the Netherlands, the Dutch Orthopaedic Association (NOV) advised against the use of MOM implants in 2012, and that all patients with MOM implants should be followed up every year. There are good arguments to continue this policy because of the high risk of revision associated with MOM implants and the potential toxic effects of metal ions. There are also good reasons to follow up patients after a total hip procedure in which a large metal head (> 36 mm) has been used, because they also have increased metal ion release. The tragic story of MOM hip implants stresses that a minimum of 10 years of good clinical data should be required before widespread use of new hip implants is implemented.