The FDA issued a safety communication on January 17th, stating that the metal-on-metal devices have unique risks in addition to the general risks of all hip implants. The agency also said on its website that surgeons should select a metal-on-metal hip implant for their patient only after determining that its benefits outweigh that of an alternative hip system.
Metal-on-metal hip implant risks far outweigh the benefits, particularly now that evidence clearly indicates the all-metal hip implants can cause soft-tissue damage from metallosis, along with a litany of adverse reactions already associated with the devices, including pain, swelling, numbness, and change in ability to walk.
Metallosis occurs when the metal-on-metal implants corrode and shed metal where two components connect, such as the ball and the cup that slide against each other through wear. Metal ions are released into the patient’s body or blood and can then cause damage to the bone and/or tissue surrounding the hip joint. This metallic debris that damages the bone or soft tissue surrounding the implant is known as an “adverse local tissue reaction (ALTR)” or an “adverse reaction to metal debris (ARMD)”.
Patients with all-metal hip implants are now advised by the agency to be tested for elevated metal ions. Further, the FDA has also advised patients without symptoms of hip replacement failure to follow-up after their implant with physical examination and routine radiographs every one to two years.
If a patient does experience any of the above adverse reactions, they are advised to speak with an orthopedic surgeon immediately. The FDA further advises diagnostic imaging, such as MRI with metal artifact reduction, CT scan or ultrasound for some symptomatic patients.
The agency warns the following groups of patients as being at high risk for potential adverse reactions:
Patients with bilateral implants
Patients with resurfacing systems with small femoral heads (44mm or smaller)
Female patients
Patients receiving high doses of corticosteroids
Patients with evidence of renal insufficiency
Patients with suppressed immune systems
Several medical device manufacturers have recalled their all-metal devices following safety problems. Stryker recalled its device last July and Johnson & Johnson recalled its DePuy ASR hip implant in 2010. Zimmer Holdings Inc. has also received reports of adverse events. All these hip implant makers are facing defective device and personal injury lawsuits.