FDA warns about metal-on-metal hip replacementsBMJ 2013; 346 doi: http://dx.doi.org/10.1136/bmj.f429 (Published 21 January 2013) Cite this as: BMJ 2013;346:f429
The US Food and Drug Administration last week told healthcare professionals that it is updating safety information and recommendations on metal-on-metal hip replacements because of early failures in many cases.
The FDA also issued a proposed order that would require manufacturers of metal-on-metal hip replacements to submit premarket approval applications to prove the safety of the devices. At present the manufacturers have to show only that their devices are similar to ones on the market.
The FDA announcement said, “In metal-on-metal hip implants, the metal ball and the metal cup slide against each other during walking or running. Metal can be released from other parts of the implant where two implant components connect. Metal release will cause some tiny metal particles to wear off of the device . . . which may cause damage to bone and/or soft tissue surrounding the implant and joint.
“Soft tissue damage may lead to pain, implant loosening, device failure, and the need for revision surgery. Some of the metal ions released will enter the bloodstream . . . They may cause symptoms or illnesses elsewhere in the body . . . The reaction seems to be specific to individual patients, with different patients having different reactions.”1
The FDA asked healthcare providers and patients to report adverse events such as pain, malposition, adverse local tissue reaction, metallosis, hypersensitivity, loosening, and dislocation.
It recommended that orthopedic surgeons use a metal-on-metal hip implant only when its benefits outweighed those of an alternative type. It said that patients should be told about the risks of metal-on-metal hip implants and the possible need for replacement.
Surgeons should also “pay close attention” to the groups of patients receiving metal hip implants and the risk factors that may predispose to excess wear and early failure.
The FDA said that patients at risk of problems were those with bilateral implants, with resurfacing systems with small femoral heads (44 mm or smaller), women, people taking high doses of corticosteroids, and those with evidence of renal insufficiency, suppressed immune systems, suboptimal alignment of device components, suspected metal sensitivity, severe overweight, and high levels of physical activity.
The FDA recommended follow-up of symptomatic patients at least every six months.
Cite this as: BMJ 2013;346:f429