Defective Hip Replacement Systems May Be Responsible For an Increase In Serum Metal Ion Levels

The adverse effects associated with metal-on-metal hip replacement systems has become a significant concern in the healthcare community. The potentially hazardous side effects of elevated systemic exposure to cobalt, chromium and molybdenum are of significant concern, especially following metal-on-metal hip resurfacing, standard total hip arthroplasty or any other joint replacement system involving metal components. High concentrations of these metals, if allowed into plasma, may be toxic to an individual and can interfere with important biological functions. However, researchers believe that metal-on-metal joint replacement systems may not be the only mode of dissemination in wear debris. Evidence shows that metal-on-polyethylene systems may generate a concentration of metal ions in plasma as well. Regardless of what the components are made of, the presence of metal ions in the bloodstream may lead to catastrophic complications.

According to the Department of Orthopaedic Surgery at the Medical University of Graz, Austria, researchers conducted a study to evaluate the levels of cobalt, chromium and molybdenum in serum (blood) after receiving rotating-hinge knee arthroplasty.

During the study, researchers sampled blood from 25 patients who had received a metal-on-polyethylene joint replacement system. Furthermore, researchers examined the blood using an electrothermal graphite furnace atomic absorption spectrometry (ET-ASS) device. To their surprise, they discovered concentrated amounts of metal ions within the blood of patients who had received rotating-hinge knee arthroplasty. More specifically, researchers found that the plasma contained trace amounts of cobalt and chromium, but not molybdenum. Metal ion release was significantly higher in patients who had received a megaprostheses, as opposed to those who had received a standard rotating-hinge knee device.

The results of their research indicated an additional metal ion release from the surface of the prosthesis where there was no metal-on-metal contact. Subsequently, the presence of metal ions in the plasma was not caused by the articulating surface of metal joints. Many rotating-hinge knee prosthesis have a metal-on-polyethylene articulation that may also contribute to the presence of metal ions in a recipients plasma.

Component wear and the dissemination of wear debris, particularly with metal-on-metal combinations, is widely considered the predominant long-term complication of defective hip replacements. However, another study was conducted to record concentrated levels of chromium and cobalt in the plasma of patients who had received a metal-on-polyethylene joint replacement system. Researchers discovered that metal-on-metal joint replacement systems are not the only friction couple that increases the serum level of metal ions in recipients.

During a 30-month period, researchers conducted a study that included 53 patients who had previously had degenerative hip disease, but recently underwent total hip arthroplasty. The conclusion of the trial witnessed 48 patients who were available for follow-up tests after 32 months. Results of the clinical and radiological examinations of those who had received arthroplasy were recorded and analyzed.

Follow-up tests were conducted at an average of 48 months after the patients underwent surgery. Data indicated that 17% of the patients recorded a fair to mediocre score in functionality, where 37% had radiological signs of femoral component loosening. Serum cobalt levels increased significantly in those who received a metal-on-polyethylene joint replacement system. However, increased levels of cobalt in plasma was significantly high in patients who showed signs of loosening or dissemination of components.

Regardless of the materials that make up joint replacement system, the wear and dissemination of metal components may significantly increase the risk of metal ions leaching into the bloodstream. Excessive amounts of cobalt or chromium ions in plasma may lead to severe and catastrophic complications. An increased presence of these ions may lead to metallic toxicity, otherwise known as metallosis. Side effects of metallosis may include cardiomyopathy, hypothyroidism, neurological damage, impaired senses, seizures, blindness, headaches and liver damage. Due to the severity of these side effects, recipients may contact a lawyer at The Senators (Ret.) Firm, LLP for a free case evaluation of their potential lawsuit.

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Again, if you or a loved one has been injured by a defective hip replacement, you should contact our lawyers immediately by clicking the link below or calling toll free 1-(949) 557-5800. You may be entitled to compensation for your injuries and we can help.