Dolph Houben

87 Outcomes of vascularized bone allotransplantation 4 Quantitative histomorphometry With the use of quantitative histomorphometry, we were able to quantify bone remodeling and bone formation. By quantifying the label uptake and the distance between the two labels, we were able to calculate bone formation and static and dynamic bone remodeling parameters (Table 4). Bone remodeling parameters measured on the endosteal surface with close proximity to the implanted AV-bundle showed an increase of the labeled surface (LS), single labeled surface (sLS), double-labeled surface (dLS), and mineralizing bone surface (MS/BS). Implantation of a recipient-derived AV-bundle significantly increased the bone formation ratio (BFR/BS) on endosteal surfaces in group1 compared to group 2 (Fig. 6). No significant differences in static and dynamic bone remodeling parameters were found on the periosteal surface of the allotransplants between groups. Table 4: Quantitative histomorphometry analyses of the allotransplant in respect to the AV-bundle patency measured on the endosteal surface of the bone Contra-lateral (cl) (n=12) Group I (AV+) (n=6) Group II (AV-) (n=6) p-value cl-I p-value cl-II p-value I-II BFR/BS (mcm 3 / mcm 2/ d) 340.57 (317.75-402.74) 512.55 (476.76-643.71) 379.29 (226.49-491.17) 0.06 0.69 0.03* BFR= bone formation rate, BS= bone surface, values are median and interquartile range, *= Significant Figure 6: Representative images of fluorescent microscopy at 10X magnification on the endosteal surface of the allotransplants. Calcein and tetracycline label uptake in normal bone (A), Allotransplants with surgical induced neo- angiogenesis (B) compared to allotransplants without (C). A significant (p=0.03) increase in BFR/BS (mcm 3 /mcm 2/ d) was seen in the patent AV-bundle (B) group compared to the group with the ligated AV-bundle (C).