New Challenges: Use and Interpretation of Radius Bone Mineral Density.

Context: It is unknown if isolated low bone mineral density (BMD) "osteoporosis" at the radius is associated with increased fracture risk, not only at the wrist but elsewhere and whether it reflects more generalized skeletal fragility.

Objective: To review the association of radius BMD and fracture risk, the epidemiology of wrist fractures, isolated osteoporosis at the radius and the concordance between radial BMD and femoral neck BMD.

Methods: We completed a narrative literature review on radius BMD and fracture risk and current recommendations for measurement of radial BMD. We updated results of radial BMD and fracture results from the Study of Osteoporotic Fractures over 20 years and examined the concordance of BMD at the distal and proximal radius with femoral neck BMD T -scores.

Results: Radius BMD is a robust predictor of all types of fractures including hip and wrist but there is insufficient evidence to suggest that radius BMD predicts wrist fractures better than fractures at other sites. Fractures of the wrist tend to occur in younger, healthier women compared with hip and spine fractures. Nevertheless, wrist fractures are associated with an increased risk of future fractures and represent a missed opportunity for intervention. On a population level, the discordance between radius BMD and femoral neck BMD is small. But women with isolated osteoporosis at the radius had biochemical and microarchitecture deterioration that were similar to women with hip osteoporosis.

Conclusion: Future research should address the clinical implications of isolated osteoporosis at the radius and whether treatment is warranted.