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Maquer et al. ISV: not a good clinical surrogate for trabecular bone score


A previous study had suggested that using trabecular bone score (TBS) to estimate vertebral fracture risk in patients with osteoporosis was not feasible because TBS does not correlate with vertebral strength. Here, Maquer et al. use a similar experimental set-up plus two more realistic load scenarios to explore further.

In addition to the classic endplate embedding technique used by Roux et al., the authors also loaded 62 human lumbar vertebrae via intervertebral discs to mimic the in vivo situation and via a ball joint to induce anterior wedge failure. Areal bone mineral density (aBMD) and the initial slope of the variogram (ISV) used to derive TBS were obtained from HR-pQCT scans performed before testing. The authors assessed how aBMD and ISV were related to TBS and also apparent failure stress and failure load.

Although aBMD significantly correlated with failure load and apparent failure stress in all three set ups, ISV did not. The authors conclude that ISV is not a good clinical surrogate for vertebral strength, no matter how it is measured.

Editor’s comment: A paper difficult to read but with a rigorous experimental approach showing that aBMD remains the greatest contributor of experimentally tested vertebral strength, whereas ISV, a surrogate of TBS makes very little significant contribution. These results confirm previous studies and question the real nature of the bone strength parameters, if any, estimated by TBS.

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