Height velocity curves in female patients with idiopathic scoliosis

Following identification of peak height velocity (PHV) by a recent study as a possible prognostic factor for curve progression in patients with idiopathic scoliosis (IS), the aim of this study was to investigate PHV curves in Japanese female patients with IS. The study subjects were 20 skeletally immature IS patients who were followed until maturity. The mean age and the mean pubertal status at the initial visit were 9.8 years and 24 months before menarche, respectively, with a follow-up period of 5.2 years. Height measurements were recorded at each visit, and HV was calculated as the change in height (cm) divided by the time interval (yr.) between visits of 6 to 12 months. The PHV, age at PHV (APHV), height at PHV (HPHV), and final height (FH) were determined. Patient HV curves were plotted using their HV data, and growth periods (GPs) were calculated from the curves. PHVs and GPs of study patients were compared to standard data from unaffected girls. The median values and interquartile ranges in PHV, APHV, HPHV, and FH were 8.5 cm/yr. (7.9-9.7), 11.8 yr. (11.2-12.1), 153.2 cm (150.1-155.8), and 160.1 cm (157.4-162.4), respectively. The median GP was 27 months. The PHV and GP values in IS female patients were higher and shorter than those in unaffected girls. These findings indicate that the patterns of height velocity curves in IS patients are different from those in unaffected girls, suggesting that curve progression in IS patients is associated with the magnitude of PHV and duration of GP. Recently, we have developed an HV reader to easily and quickly identify the present HV in patients with scoliosis, applicable for the clinical setting or school screening. We conclude that risk assessments of curve progression in patients with IS should include HV along with measures of skeletal maturity such as the Risser sign and/or digital skeletal age using hand X-rays.