Years after all-metal hip implants are removed, they can continue to cause problems for patients, according to new research presented this week at the annual meeting of the American Academy of Orthopaedic Surgeons (AAOS).
The news was hardly a revelation. Last year, Johnson & Johnson subsidiary DePuy Orthopaedics issued a recall on its metal-on-metal ASR XL hip replacement and resurfacing implants after a higher than expected number of failures. Hip implant failures occur when the device loosens, fractures or dislocates causing patients pain and difficulty walking.
What surgeons realized is that the problems with DePuy devices were caused by inflammation in the joint space. They suspected this inflammation was the result of tiny bits of metal debris from the metal parts of the device rubbing together. To make matters worse, they discovered the debris was leeching into the blood stream, potentially causing a type of blood poisoning known as metallosis. And that is just the tip of the iceberg.
Data from the new research presented at the AAOS meeting shows just how dangerous the metal hips can be. A third of patients in a Netherlands study on metal hips experienced adverse reactions in soft tissue; a quarter of patients in an English study had revision surgery after experiencing worsening symptoms, and a third of those patients required additional surgery because their disease progressed; and 98 percent of cups and 93 percent of balls from metal implants showed moderate to severe scratching in 46 retrieved metal-on-metal implants.
DePuy is one of about 20 companies that manufacture all-metal hip implants and market them in the United States. While DePuy’s device was the only one of that kind recalled last year, other brands of metal hips have been reportedly causing similar problems.
This prompted the Food and Drug Administration (FDA) to take an unprecedented step and order metal hip manufacturers to gather data on problems associated with their devices, in particular, conditions in which metal debris was found in the joint space.
Source: USA Today