HR-pQCT With Finite Element Analysis Reliable for Estimating Bone Strength, Microarchitecture During Pubertal Growth

The combination of high-resolution peripheral quantitative computed tomography (HR-pQCT) with computational finite element analysis (FEA) is a reliable, noninvasive method for assessing bone strength development and microarchitecture during pubertal growth, according to study results published in the Journal of Bone and Mineral Research.

The researchers noted that there is not much prospective data in the literature regarding HR-pQCT for assessment of bone strength and microarchitecture development in children and adolescents.

In this study, they aimed to quantify annual changes in bone strength and microarchitecture properties, define and characterize changes in precision errors for pediatric bone strength, and estimate the recommended monitoring time intervals for characterizing bone development at the distal radius and tibia.

The cross-sectional study enrolled developing children age 8 to 14 years recruited from 2 public schools and community programs. The researchers enrolled 65 participants with baseline HR-pQCT data: 38 participated in the 1-year follow-up (mean age, 10.6 ± 1.7 years), 32 participated in the precision study (mean age, 11.3 ± 1.6 years), and 5 participated in both studies.

The study results indicated that at the distal radius and tibia, bone strength estimates increased across all FEA outcomes. Over 1 year, failure load increased by 16% and stiffness increased by 21% at the distal radius, with increases of 12% and 16%, respectively, at the tibia.

The increased bone strength most likely stems from increased bone size, specifically increased cortical thickness measures, which increased between 4% and 10%. Cortical porosity decreased by 19.6% and 6.6% at the distal radius and tibia, respectively. These changes exceeded precision errors of all bone strength outcomes, which were ≤6.8% at the distal radius and ≤5.1% at the tibia, indicating cortical consolidation at the distal ends of the growing radius and tibia.

Estimated monitoring time intervals for HR-pQCT and FEA indicated bone strength outcomes can be monitored annually at both the distal radius and tibia. Monitoring time intervals for bone strength outcomes at the distal radius ranged between 0.5 and 1.1 years and at the distal tibia between 0.6 and 1.5 years. However, there were a few impractically long monitoring time intervals at the distal radius (634 years for cortical bone area and infinity for trabecular bone volume fraction) as there were no annual changes in these outcomes.

The researchers noted that there were a few limitations associated with this study, including its small sample size, short follow-up, homogeneous ethnicity, and inability to scan the exact same anatomical site during follow-up because of bone growth.

The investigators concluded that they have “characterized and contrasted annual changes to corresponding precision errors, as well as defined [monitoring time intervals] for bone strength, microarchitecture, and other properties at the distal radius and tibia when using pediatric HR-pQCT imaging combined with FEAs.”

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Reference

Bunyamin A, Björkman K, Kawalilak C, et al. Reliability of annual changes and monitoring time intervals for bone strength, size, density, and microarchitectural development at the distal radius and tibia in children: a 1-year HR-pQCT follow-up [published online February 7, 2019]. J Bone Miner Res. doi:1002/jbmr.3693