Skeletal immaturity, IGF-I and IGFBP-3 serum concentrations in Legg-Calvé-Perthes disease (skeletal immaturity, IGF-I and IGFBP-3 in LCPD).

Abstract

Skeletal immaturity is a major feature in Legg-Calvé-Perthes disease (LCPD). Evaluation of growth hormone concentration, somatomedin activity, or insulin-like growth factor I (IGF-I) concentration revealed inconsistent results. Recently, IGF-binding protein 3 (IGFBP-3) was found normal in relation to chronological age in LCPD patients. In this study IGF-I and IGFBP-3 were measured in the serum of 23 children with unilateral LCPD and in 23 sex and age matched controls. IGF-I and IGFBP-3 were measured with radioimmunoassays, using an IGF binding site-blocked assay for IGF-I. The results were related to the chronological age in all and to the bone age in 19 of the patients. Bone age was retarded in 16 of 19 patients with a delay of one year or more in twelve children (mean 14.75, range 2-35 months). Chronological age and bone age related IGF-I and IGFBP-3 serum concentrations were predominantly within the normal ranges and did not differ significantly from the matched controls. IGF-I and IGFBP-3 serum levels showed a high correlation, which was similar in LCPD (r = 0.7; p < 0.0001) and in the control group (r = 0.8; p < 0.0001). Our data confirm that most children with LCPD are skeletally immature. However, IGF-I measured with IGF-II-blocked IGFBP binding sites, and IGFBP-3 serum concentrations analysed with respect to bone age show no evidence for a disturbance of the hypothalamo-pituitary-somatomedin axis in these children.