Over the past several years metal-on-metal hip implants have gone from an innovative and promising new prosthetic device to a colossal failure. Other countries like England and Australia have national registry systems that track medical devices and prosthetics allowing for better post operation tracking and adverse event reporting, the U.S. has no such system.
The results of a recent study that looked at total hip replacements in the UK from 2003 to 2011 shows that metal-on-metal hip replacement systems are far more likely to require revision surgery within the first five years than other options. Read the MedPage Today write up here.
The study looked at data from the National Joint Registry of England and Whales. The data included more than 402,000 total hip replacements over the eight year period including 31,171 that involved metal-on-metal implants.
The data clearly shows that patients who received metal-on-metal implants were almost twice as likely to experience issues requiring revision within five years than those who received ceramic on ceramic-on-ceramic implants (6.2% vs 3.3% respectively). Even fewer serious problems occurred when metal-on-polyethylene devices were used, with only 1.8% requiring revision surgery within five years.
The data also showed that younger women appear to be at the greatest risk for serious problems requiring subsequent revision surgery. Larger head diameters have also shown a greater propensity for problems than those with smaller diameters. It is still unclear why this is, but some believe that larger heads may increase torque on the stem which can lead to loosening.
The study provides unequivocal evidence that metal-on-metal hip implants are associated with higher failure rates than other types of prostheses. In light of the evidence researchers wrote “we therefore recommend that metal-on-metal bearing surfaces are not used in stemmed total hip replacements,” and also suggested that those who have had such devices implanted undergo annual clinical and radiographic exams.
The metal-on-metal hip implant debacle has caused significant damages to patients throughout the world, and without tracking data from the UK and Australia, many more would have suffered. It is glaringly obvious that U.S. is in dire need of creating as similar tracking system for medical devices. Hopefully this fiasco will spur regulators to start making efforts to establish our own system.