The DePuy hip replacements in question were fast-tracked by the Food & Drug Administration (F.D.A.) review process because they differed little from other hip replacement systems already being manufactured by the company. The F.D.A. allows manufacturers to make small improvements to existing designs without going through its entire review process.
The Problem With the DePuy Hip
Both parts of the ball-and-socket hip replacement joint design are made of metal (chromium and cobalt) in the Depuy hip system. These materials were expected to be stronger and more resilient, and thus offer patients a long time before needing subsequent replacement.
Unfortunately, many patients reported difficulties with their new hips after only a few months or years. Subsequent revision surgeries revealed that the patients had permanent tissue damage to the surrounding tendons and muscles, as well as elevated levels of chromium and cobalt in their blood. The metal-on-metal design of the DePuy hip joint was causing microscopic particles of metal to flake off, that was then absorbed into surrounding tissue.
Although DePuy says only 12 to 13 percent of patients with the hip needed revision surgery after five years, one study from Britain found that 49 percent of the hips had failed after six years.
Defective Medical Devices
Medical products can be found defective in one of two ways: design or manufacturing If the design was defective then all of the devices have the same problem. Conversely, if the manufacturing was defective some devices may be defective while others were properly made.
It isn’t yet known whether all of the metal-on-metal hips made by DePuy are defective due to design issues or whether only some have failed due to manufacturing flaws.
Often manufacturing errors result from using lower-quality materials, and ironically chromium and cobalt were chosen for their high quality. Doctors have reported similar problems in patients receiving metal-on-metal hips from other manufacturers (although the failure rate seems to be much lower), so it remains to be seen whether these problems stem from a design or manufacturing defect.
A products liability attorney who understands product design and/or manufacturing defects can help you understand your options if you received a defective hip replacement system.