Are Children Suffering From Congenital Pseudarthrosis of the Tibia Associated With Bone Quality Decreased?

Abstract

Background: Congenital pseudarthrosis of the tibia (CPT) is a rare and difficult to treat congenital disease in neonates. Our team's previous study found that exosomes derived from serum of children with CPT can reduce the effect of bone formation. In this study, we used ultrasound bone densitometry to detect the bone quality between children with CPT and those non-metabolic disease children, to determine the bone strength of children with CPT. Methods: A total of 37 CPT children and 40 children without the bone metabolic disease (control group) were recruited in our hospital. The ultrasonic bone densitometer was used to examine the bilateral calcaneus of the subjects. According to the measurement results, we collected the broadband ultrasonic attenuation (BUA), sound transmission velocity (SOS), quantitative ultrasound index (QUI), bone strength index(STI) and bone mineral density estimation(BMDe) values. For the intergroup analysis, t test was used to determine the differences of various quantitative measurements. Multivariable regression was used to examine the associations between quantitive ultrasound measurements differences and age, body mass index (BMI), neurofibromatosis type 1 (NF1) and CPT Crawford type. Intra-class correlation coefficient (ICC) was calculated to estimate intra- and inter-rater agreements. Results: Seventy-four calcaneus scans from CPT patients (23 boys and 14 girls) and 80 calcaneus scans (24 boys and 16 girls) from the control. The CPT patients exhibited significantly lower SOS (1368.75±136.78 m/s), STI (7.2319±38.6525), QUI (8.2532±56.1720) and BMDe (-0.0241±0.3552 g/cm3) than the control (SOS: 1416.02±66.15 m/s, STI: 7.96±16.884, QUI: 28.8299±25.461, BMDe: 0.0180±0.1610 g/cm3). Multiple linear regression revealed that SOS, STI, QUI was statistically significant and negatively correlated with CPT Crawford classification.Conclusions: We found the incidence of decreased bone quality in CPT group was higher than that in the non-bone metabolic disease group. This phenomenon was not related to NF1 while related to CPT Crawford classification, which suggested that the higher grade of the CPT Crawford classification, the lower the bone strength and the higher the risk of fracture.