With respect to total hip replacements, we are in a very good position to assess the implants' performance. There are methods such as radiostereometric analysis, which allow us to measure any change of position in the implants for a period of two years. If, over the course of those two years, the implant being tested does not demonstrate abnormal migration, we can predict that implant will work well for the next 15 to 20 years.
The National Institute for Health and Care Excellence, in England, and the Dutch government, have asked that preclinical tests using radiostereometric analysis be mandatory before any new hip or knee implant can be marketed. These are national standards set up in England and Holland. It takes approximately two years to do these tests. As you know, these implants are designed to last 15, 20 or 25 years and that is a bit long to wait before being able to market a new implant. That is why we must rely on available, very precise preclinical tests to assess performance properly before marketing anything.