My wife had a total hip replacement two months ago. The doctor advised us that there is “possible evidence of loosening.” What does this mean? Either it’s loose or it’s not, right?

Right, but our ability to tell that from outside the body is limited. X-rays may show some changes that occur when the implant starts to loosen. In the early stages, the changes aren’t always large enough or clear enough to know for sure.

For the purposes of evaluating implants, the area around the joint implant is divided into zones. The socket or cup side has three zones, whereas, the femoral side has 14. A problem can occur in any one of these zones.

Sometimes, doctors must make an educated guess. In defining the problem, the doctor may say that here is definite, probable, or possible evidence of loosening. Further testing (and sometimes waiting) is often the next step.