Background: Bone Mineral Density (BMD) does not fully capture fracture risk, as the majority of fractures occur in patients with osteopenia. This suggests that altered bone material properties may contribute to fracture risk, independently of BMD. Recently, the microindentation in vivo technique has been made available to assess these properties. Our aim was to evaluate the relationship between Bone Material Strength (BMS), measured by microindentation in vivo, and fragility fractures in patients aged ≧40 years with low bone mass.
Methods: BMS was measured by the microindentation in vivo technique. The 10-year fracture probability was calculated using the FRAX algorithm.
Results: Ninety patients (53 female), mean age 61.0 years (range 40.4-85.5 years) were studied. 55 patients had osteopenia, 35 had osteoporosis and 63 had sustained one or more fragility fractures. There was a negative relationship between BMS and age (r=−0.539, p<0.001) and with the FRAX 10-year fracture probability with and without inclusion of femoral neck BMD (r=−0.383, p<0.001 and r=−0.426, p<0.001, respectively). In the whole group, BMS was lower in patients with a fragility fracture than in non-fracture patients (79.9±0.6 vs. 82.4±1.0, p=0.032) despite similar BMD. This was also the case in patients with osteopenia (80.3±0.7 vs. 83.9±1.2; p=0.015). There was no significant difference in BMS values in patients with a fragility fracture whether they had osteopenia or osteoporosis (79.8±0.8 vs. 78.7±1.1, p=0.456).
Conclusion: Our data suggest that patients with fragility fractures have altered material properties, as reflected by lower BMS, which are not captured by BMD. Further studies are required to establish whether BMS is of value in predicting fracture risk, particularly in patients with osteopenia.
Disclosure: The authors declared no competing interests.