According to an article published by BMJ, ASR metal-on-metal hip implants such as the designs made by DePuy Orthopaedics, a subsidiary of Johnson & Johnson, are shown to have a failure rate of up to 50 percent within six years.
“Metal on metal joints are designed to harness naturally occurring lubricating fluids from the native hip,” the article reads. “As wear debris is generated, hip joints become filled with high concentrations of chromium and cobalt. This leads to a chain of events culminating in extensive soft tissue necrosis and disruption of bone. The metallic ions then diffuse into the blood stream.”
But the issue isn’t necessarily the shallow cup design. An additional problem occurs when a larger diameter cup is used. According to BMJ, the larger diameter heads create too much stress in the area where they attach to the stems, which still may result in a shedding of metal debris into the body.
Makers of metal hip designs such as DePuy, Smith & Nephew and Stryker have found themselves in hot water over faulty designs linked to injury, with devices reported to be failing in as little as five years in many cases. The devices also have been linked to a type of blood poisoning called metallosis.
In a recent verdict against Johnson & Johnson and DePuy, five patients were awarded nearly $5 million for the injuries caused by their metal-on-metal hip implants that resulted in revision surgeries, bone erosion and damage to surrounding tissue. Thousands of lawsuits are in the works because of the faulty metal designs, and many injured patients are demanding compensation for their pain and suffering that they say resulted from the metal-on-metal hip implants.