A Missouri orthopedic surgeon and colleagues have initiated a study that identifies the patients who underwent total joint replacement reporting a metal allergy. The study analyzes the effect of voluntary reported metal allergies on the clinical outcomes following the surgery.
Dr. Denis Nam, recipient of the Orthopaedic Research and Education/Current Concepts of Joint Replacement (CCJR) Clinical Award Paper, along with other researchers, gathered retrospective data from 589 patients who received total knee arthroplasty (TKA), and 906 patients who received total hip arthroplasty between the years of 2009 and 2011. Before January 2010, the incidence of self-reported metal allergy was 1.7 percent. After January 2010, the incidence was 4 percent.
“The clinical impact of metal sensitivity and allergic reactions have received increased attention following total hip arthroplasty,” said Nam, “and this has largely been due to the recognition of catastrophic, aseptic reactions with large-diameter metal-on-metal bearings, tapered trunnion corrosion and associated with modular neck prostheses.”
The researchers also found that patients with metal allergies who underwent total hip arthroplasty experienced decreased mental health scores after surgery.
Many patients who have received metal-on-metal hip implants have reported failure of their new device, in some cases less than five years after surgery. The metal-on-metal design has been known to shed metal particles into the body with normal use, embedding into the surrounding tissue causing damage or death of the tissue.
The device is often constructed with a cobalt-chromium alloy, which has been linked to blood poisoning. The excessive cobalt in the blood has also been linked to serious symptoms such as blindness, deafness, numbness of the hands and feet, and severe weakness.
The device failure has resulted in hundreds of lawsuits. A recent verdict of $1 billion against DePuy Orthopaedics, a subsidiary of Johnson & Johnson, confirmed the device’s bad design. Wright Medical, another medical device manufacturing giant, entered a $240 million settlement involving its failed metal-on-metal hip implants.