A recent study of patients that had received a metal-on-metal hip system found they had adverse reactions to their new hip, despite being asymptomatic.
Although the patients had not complained of pain and had not shown any signs of hip implant failure, 31 percent of them had cystic lesions, according to researchers. Many of the patients involved in the study returned a year later with symptoms of a failing hip, and required revision surgery.
In a multidistrict litigation (MDL) against Johnson & Johnson and its subsidiary, DePuy Orthopaedics, the number of lawsuits aimed at the medical device manufacturer has reached 8,800. Other manufacturers such as Stryker and Wright Medical have dealt with their share of lawsuits already for similar metal-on-metal total hip arthroplasty designs.
Patients who have received this type of hip, made primarily of cobalt and chromium alloy, have complained of loosening, bone erosion, damage to surrounding tissue, and metallosis, a dangerous blood condition that occurs when metal bits flake off the device and make their way into the bloodstream. The symptoms have been crippling for thousands of patients who have experienced significant pain and suffering from the failed device.
A new study suggests that the metal ions are absorbed into the bone marrow, which impairs bone-forming cells’ function. Another study found a 10- to 20-fold increase in cobalt and chromium levels in the patients, many of whom have suffered from cobalt poisoning. Those symptoms include blindness, deafness, numbness of the hands and feet, and weakness that have forced them to be wheelchair bound.