The grid radiograph, a new technique for radiographic evaluation of
total hip replacements, ensures reproducible positioning of the hip and the
x-ray beam. When this method was used, the images of stable acetabular and
femoral components on one radiograph could be superimposed perfectly on the
images of these components on subsequent radiographs. Subtle shifts in the
positions of the components, such as tilting of the femoral surface
replacement, subsidence of the femoral component, or migration of the
acetabular component, were detected. When used with high-contrast
radiographic technique and film, the implant-bone interfaces were depicted
better by this method than by others. Grid radiographs can be used for
detailed prospective evaluation of total hip replacements and are of
practical value in counseling patients about the probable durability of the
replacement.