Apparent trabecular bone volume fraction (BV/TV), mean trabecular area, mean trabecular perimeter and mean skeleton length negatively correlated with Euler number in OA group.
Mean trabecular area, mean trabecular perimeter and mean skeleton length were calculated by total trabecular area, perimeter and skeleton length in ROI relative to trabecular number, respectively.
There was no significant difference between the two groups in apparent trabecular number, mean trabecular area, mean trabecular perimeter, mean skeleton length, total skeleton length, energy, absolute value, inverse difference, angular second moment and other parameters (p > 0.05).
Structural parameters included the apparent trabecular bone volume fraction (BV/TV), apparent trabecular number (Tb.N), apparent trabecular separation (Tb.Sp), apparent trabecular thickness (Tb.Th), mean trabecular area, mean trabecular perimeter, mean trabecular roundness and mean skeleton length [ 41].
In OP group, apparent trabecular separation (Tb.Sp), inertia, absolute value and contrast were positively correlated with Euler number, whereas apparent trabecular number (Tb.N), mean trabecular area, inverse difference and inverse different moment were negatively correlated.
In OA group, bivariate correlation analysis showed App BV/TV (r=−0.559), mean trabecular area (r=−0.940), mean trabecular perimeter (r=−0.574), mean skeleton length (r=−0.529) were associated with Euler number.
In our study, this index was related to mean trabecular bone area in the OP group, but there was no relation with structural parameters in OA group.
The following parameters were determined from the trabecular bone using a direct three-dimensional approach [40]: total bone marrow volume including the trabeculae (TV; mm3), trabecular bone volume (BV; mm3), trabecular bone volume fraction (BV/TV), mean trabecular number (Tb.N; 1/mm), mean trabecular thickness (Tb.Th; mm), and mean trabecular separation (Tb.Sp; mm).
Trabecular bone volume per total volume (BV/TV), mean trabecular thickness (Tb. Th), mean trabecular number (Tb. N, and mean trabecular separation (Tb. Sp) were calculated using Scanco μCT V6.1 software.
Trabecular morphometric traits were computed from binarized images using direct 3D techniques that do not rely on prior assumptions on underlying structures: trabecular bone volume per total volume (BV/TV), mean trabecular thickness (Tb.Th)., mean trabecular number (Tb.N ., and mean trabecular separation (Tb.Sp).
Afterwards, a three-dimensional (3D) analysis for the indices including bone volume density (bone volume/tissue volume, BV/TV, %), bone surface density (bone surface/tissue volume, BS/TV, mm−1), mean trabecular thickness (Tb.Th, mm), mean trabecular number (Tb.N, mm−1), and mean trabecular separation (Tb.Sp, mm) was done for the spongy bone [ 14].
