Metal-on-Metal hip implants received an extensive set of cautionary guidelines for use from the FDA based on an FDA Orthopedic and Rehabilitation Advisory Panel Meeting in June 2012. The source of the problem with Metal-on-Metal (MoM) implants is metal release that causes bone and soft tissue damage, known as "adverse local tissue reaction" (ALTR). When bone and soft tissue damage from metal particles occurs, it leads to pain, implant loosening and the need for revision surgery. However, the metal ions can also enter the bloodstream, travel to other organs and trigger systemic illness such as rash, cardiomyopathy and renal dysfunction. The FDA is unable to define level of metal concentrations in blood or body that produce adverse effects, because different patients have different levels of reactivity to them.