Trabecular Bone Score: Where are we now?

The Trabecular Bone Score is a rather new index obtained at the lumbar spine at the same time as a real bone mineral density. It was developed to reflect bone microarchitecture. It was proposed to be easily used in everyday practice as a surrogate of bone strength. Our aim was to review 1. technical points such as correlations between Trabecular Bone Score and bone microarchitectural parameters, Trabecular Bone Score and bone strength, the effects of dual-energy X-ray absorptiometry image spatial resolution, age, macroarchitecture, body mass index, and osteoarthritis, on Trabecular Bone Score, and 2. evidences to use Trabecular Bone Score for separating individuals with fragility fractures from controls, predicting fragility fractures, and for longitudinally monitoring changes related to treatments. Correlations between Trabecular Bone Score and bone microarchitectural parameters vary widely across bone sites, microarchitectural parameters, and study designs. In vivo, the Trabecular Bone Score explains little of the variance in trabecular microarchitectural parameters. We emphasize that it is a texture parameter. The Trabecular Bone Score is reduced in patients with fragility fracture. Several retrospective and prospective studies have shown its discriminative ability regarding the fracture risk. When combining the areal Bone mineral Density and Trabecular Bone Score, the Trabecular Bone Score remains a predictor of fracture but not the areal Bone Mineral Density. However in prospective studies, the best predictor of fracture remains hip areal bone mineral density. Due to the lack of evidence, we recommend not to use Trabecular Bone Score for following patients treated by anti-osteoporotic drugs.

Usefulness of bone density measurement in fallers.

The objective of this systematic literature review is to discuss the latest French recommendation issued in 2012 that a fall within the past year should lead to bone mineral density (BMD) measurement using dual-energy X-ray absorptiometry (DXA). This recommendation rests on four facts. First, osteoporosis and fall risk are the two leading risk factors for nonvertebral fractures in postmenopausal women. Second, BMD measurement using DXA supplies significant information on the fracture risk independently from the fall risk. Thus, when a fall occurs, the fracture risk increases as BMD decreases. Third, osteoporosis drugs have been proven effective in preventing fractures only in populations with osteoporosis defined based on BMD criteria. Finally, the prevalence of osteoporosis is high in patients who fall and increases in the presence of markers for frailty (e.g., recurrent falls, sarcopenia [low muscle mass and strength], limited mobility, and weight loss), which are risk factors for both osteoporosis and falls. Nevertheless, life expectancy should be taken into account when assessing the appropriateness of DXA in fallers, as osteoporosis treatments require at least 12months to decrease the fracture risk. Another relevant factor is the availability of DXA, which may be limited due to geographic factors, patient dependency, or severe cognitive impairments, for instance. Studies are needed to better determine how the fall risk and frailty should be incorporated into the fracture risk evaluation based on BMD and the FRAX® tool.