Cortical bone thickness of the distal radius predicts the local bone mineral density

Florian Schmidutz; Christoph Schopf; Shuang G Yan; Marc-Daniel Ahrend; Christoph Ihle; Christoph Sprecher

doi:10.1302/2046-3758.1012.BJR-2020-0271.R1

Cortical bone thickness of the distal radius predicts the local bone mineral density

Bone Joint Res. 2021 Dec;10(12):820-829. doi: 10.1302/2046-3758.1012.BJR-2020-0271.R1.

Authors

Florian Schmidutz^{1

2

3}, Christoph Schopf², Shuang G Yan^{2

4}, Marc-Daniel Ahrend^{1

3}, Christoph Ihle³, Christoph Sprecher¹

Affiliations

¹ AO Research Institute Davos, Davos, Switzerland.
² Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation, University of Munich (LMU), Munich, Germany.
³ Department of Trauma and Reconstructive Surgery, Eberhard Karls University Tübingen, BG Unfallklinik Tübingen, Tübingen, Germany.
⁴ Department of Orthopaedic Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, China.

PMID: 34927444
PMCID: PMC8696524
DOI: 10.1302/2046-3758.1012.BJR-2020-0271.R1

Abstract

Aims: The distal radius is a major site of osteoporotic bone loss resulting in a high risk of fragility fracture. This study evaluated the capability of a cortical index (CI) at the distal radius to predict the local bone mineral density (BMD).

Methods: A total of 54 human cadaver forearms (ten singles, 22 pairs) (19 to 90 years) were systematically assessed by clinical radiograph (XR), dual-energy X-ray absorptiometry (DXA), CT, as well as high-resolution peripheral quantitative CT (HR-pQCT). Cortical bone thickness (CBT) of the distal radius was measured on XR and CT scans, and two cortical indices mean average (CBTavg) and gauge (CBTg) were determined. These cortical indices were compared to the BMD of the distal radius determined by DXA (areal BMD (aBMD)) and HR-pQCT (volumetric BMD (vBMD)). Pearson correlation coefficient (r) and intraclass correlation coefficient (ICC) were used to compare the results and degree of reliability.

Results: The CBT could accurately be determined on XRs and highly correlated to those determined on CT scans (r = 0.87 to 0.93). The CBTavg index of the XRs significantly correlated with the BMD measured by DXA (r = 0.78) and HR-pQCT (r = 0.63), as did the CBTg index with the DXA (r = 0.55) and HR-pQCT (r = 0.64) (all p < 0.001). A high correlation of the BMD and CBT was observed between paired specimens (r = 0.79 to 0.96). The intra- and inter-rater reliability was excellent (ICC 0.79 to 0.92).

Conclusion: The cortical index (CBTavg) at the distal radius shows a close correlation to the local BMD. It thus can serve as an initial screening tool to estimate the local bone quality if quantitative BMD measurements are unavailable, and enhance decision-making in acute settings on fracture management or further osteoporosis screening. Cite this article: Bone Joint Res 2021;10(12):820-829.

Keywords: CT scans; Cortical bone; Cortical index; Fracture; Osteoporosis; Pearson correlation coefficient; bone mineral density (BMD); bone quality; distal radius; dual-energy X-ray absorptiometry; osteoporotic bone; pQCT; radiography.