En bloc staining with basic fuchsin is an established method for
demonstrating microdamage in bone. Using
transmitted light microscopy, variations in light intensity, depth of focus
and magnification are necessary to
distinguish fully-stained microcracks generated in vivo, from partially-stained
or unstained artefactual cracks
due to cutting and machining. This process is both difficult and time-consuming.
In this study, 2 methods
were used to examine fuchsin-stained microcracks in human rib sections,
transmitted light and
epifluorescence microscopy. No differences were found in crack number,
density or length between the 2 methods indicating comparable accuracy.
Using green epifluorescence, only microcracks containing fuchsin
fluoresced orange against the darkfield background, enabling unstained,
artefactual cracks to be screened
out. Under UV epifluorescence, microcracks stained through the full
100 μm depth of the section fluoresced
purple. Partially-stained artefactual cracks failed to fluoresce and
were screened out. Epifluorescence is a
simple, rapid and accurate screening method for differentiating
fully-stained from artefactual microcracks in bone.