FLUORESCENCE-AIDED DETECTION OF MICRODAMAGE IN COMPACT-BONE

En bloc staining with basic fuchsin is an established method for demon strating microdamage in bone. Using transmitted light microscopy, vari ations in light :intensity, depth of focus and magnification are neces sary to distinguish fully-stained microcracks generated in vivo, from partially,stained or unstained artefactual cracks due to cutting and m achining. This process is both difficult and time-consuming. In this s tudy, 2 methods were used to examine fuchsin-stained microcracks in hu man 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 da rkfield background, enablimg unstained, artefactual cracks to be scree ned out. Under UV epifluorescence, microcracks stained through the ful l 100 mu m depth of the section fluoresced purple. Partially-stained a rtefactual cracks failed to fluoresce and were screened out. Epifluore scence is a simple, rapid and accurate screening method for differenti ating fully-stained from artefactual microcracks in bone.