Metal-on-metal hip replacement implants have been linked to an array of serious side effects that can lead to the need for revision surgery. Revision surgery involves removal of the defective, implanted device and replacement with a new, different device. Often, removal and replacement surgeries do not occur in the same procedure.
One of the more serious reactions is necrosis, a premature death of the body’s tissue caused by a lack of blood flow to a localized body area. Injuries from the wear and tear of defective hip replacement devices constructed of metal components are, more-and-more, leading to tissue death—necrosis. This happens because the area where the acetabular cup and femoral head meets experiences significant pressure during motion, the Mayo Clinic explained, noting that this joint bears the patient’s full body weight. In cases in which metal components wear against each other, surfaces can deteriorate, which releases metal micro-particles into the patient’s body. These metal particles can become part of the soft tissue surrounding the implant, which can lead to necrosis.
When comparing people with metal-on-metal implants to those with no implants, patients with metal-on-metal implants experienced increased serum chromium and cobalt concentrations that are significantly elevated in correlation to implant wear, the Mayo Clinic found. These serum levels increase with time after implantation, reaching a steady state at three years.
Symptoms of Tissue Necrosis
·     Warmth and redness around the area
·     Soft tissue masses
·     Local nerve palsy
·     Flu-like symptoms: Fatigue and weakness; fever with chills and sweating; nausea and vomiting
·     Increasing pain
·     Dizziness
·     Infrequent urination
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Symptoms Associated with Exposure to Metal Particles Linked to Metal-on-Metal Implant Wear The devices’ metal particles also undergo corrosion, allowing metal ions to enter and circulate in blood serum, which, in addition to tissue necrosis can also lead to soft tissue damage; elevated levels of blood cobalt and chromium; severe pain in the implant that radiates into the groin and/or back; radiographic changes, including loosening and lysis or osteolysis; and fluid collection and cystic or sold masses around the joint.
The U.S. Food & Drug Administration’s (FDA) Orthopaedic and Rehabilitation Devices Panel recently advised that metal-on-metal hip replacement recipients who were experiencing symptoms should undergo X-rays, MRIs, and CT scans to detect abnormalities and, possibly, blood testing for metal ions. The panel also recommended regular X-rays for all patients, regardless of symptoms and called for additional warnings to be placed on the labels of all-metal implants.
About one million of these devices have been implanted, globally, over the past 15 years, leaving these patients at possible risk for metal toxicity, according to research published in Human & Experimental Toxicology.
Metal-on-Metal Hip Implant Lawsuits
Metal-on-Metal hip implant devices have been the focus of mounting lawsuits and more are expected. For instance, reports of early failure of the DePuy ASR metal-on-metal hip replacement system were being received as DePuy was phasing out the system. DePuy Orthopaedics, a unit of Johnson & Johnson, acknowledged in March 2010 that the ASR was prone to early failure; the system was finally recalled in August 2010. Since, the entire class of metal-on-metal hip implants has come under scrutiny as a number of studies have found evidence that the devices can shed dangerous amounts of chromium and cobalt into patients’ bloodstreams and the FDA received hundreds of reports of the device being linked to early failure. Stryker’s recalled Rejuvenate and ABG II Modular-Neck Hip Implant Stems are prone to early failure and metal corrosion that put hip replacement patients at risk for suffering from adverse tissue reactions, including metallosis and tissue necrosis. Smith & Nephew issued a safety alert for its Birmingham Hip Modular Head implant components. Wright Medical Group, Inc., Biomet Inc., Zimmer Holdings Inc., and Encore Medical L.P. are other makers of metal-on-metal hip implant devices whose devices have been linked to adverse reactions.
