A study on the changes in the microstructure of trabecular bone and the biomechanical properties in patients with osteoporotic fractures and the correlation between them

To explore bone-quality characteristics in patients with osteoporotic femoral neck fractures by investigating trabecular-bone microstructural and biomechanical alterations of femoral-head specimens and their correlations.

Femoral-head specimens from 20 patients with osteoporotic femoral neck fractures (experimental group: 69-90 years, 80.65 ± 8.85 years) and 13 patients with early-stage hip degenerative changes (control group: 49-83 years, 64.08 ± 6.93 years) were included. Noticeable baseline age imbalance existed between groups. All specimens underwent Micro-CT scanning. Cylindrical 8-mm-diameter trabecular-bone samples were harvested along principal compressive trabeculae. Compression, bending and torsion tests were conducted to acquire microstructural and biomechanical parameters.

Compared with controls, the experimental group exhibited significantly lower bone volume fraction (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), alongside higher trabecular separation (Tb.Sp) and structural model index (SMI) (all P< 0.05). Biomechanical indicators including maximum compressive stress (MCL), maximum bending force (Fmax) and maximum torque (RST) were markedly reduced in the experimental group (P < 0.05). Trabecular microstructural indices were significantly correlated with biomechanical performance. Of note, baseline age imbalance and potential confounding from hip degenerative pathology should be considered when interpreting inter-group differences.

This ex-vivo specimen-based study demonstrates severe trabecular deterioration and impaired biomechanical properties in osteoporotic-fracture specimens, with significant correlations between microstructural damage and reduced mechanical performance. These observations only reflect bone-quality features of isolated specimens; direct extrapolation to predict individual in-vivo fracture risk should be avoided.