Fracture discrimination capability of ulnar flexural rigidity measured via cortical bone mechanics technology: study protocol for the Stronger study

Osteoporosis is characterized by low bone mass and structural deterioration of bone tissue, leading to bone fragility (i.e., weakness) and an increased risk for fracture. The current standard for assessing bone health and diagnosing osteoporosis is dual-energy x-ray absorptiometry (DXA), which quantifies areal bone mineral density (BMD), typically at the hip and spine. However, DXA-derived BMD assesses only one component of bone health and is notably limited in evaluating bone strength, a critical factor in fracture resistance. Although multifrequency vibration analysis can quickly and painlessly assay bone strength, there has been limited success in advancing a device of this nature. Recent progress has resulted in the development of Cortical Bone Mechanics Technology (CBMT), which conducts a dynamic 3-point bending test to assess the flexural rigidity (EI) of ulnar cortical bone. Data indicates that ulnar EI accurately estimates ulnar whole bone strength and provides unique and independent information about cortical bone compared to DXA-derived BMD. Consequently, CBMT has the potential to address a critical unmet need: better identification of patients with diminished bone strength who are at high risk of experiencing a fragility fracture. However, the clinical utility of CBMT-derived EI has not yet been demonstrated. We have designed a clinical study to assess the accuracy of CBMT-derived ulnar EI in discriminating post-menopausal women who have suffered a fragility fracture from those who have not. These data will be compared to DXA-derived peripheral and central measures of BMD obtained from the same subjects. In this article, we describe the study protocol for this multi-center fracture discrimination study (The STRONGER Study).