Metal-on-metal (MoM) hip resurfacing was developed in the 1990s by surgeons in Birmingham, UK, as a surgical solution to the problem of osteoarthritis in younger, more active patients. Early results were promising and the procedure gained in popularity. However, adverse reports of soft-tissue reaction and failure started to appear from 2008 onwards. Surgeons may be asked to write medico-legal reports on the surgical aspects of an individual case for claimant lawyers or in defence for the NHSLA or indemnity insurers. The purpose of this article is to cover some of the aspects of the operation that may be considered in such medico-legal reports