Yang KG, Lee WYW, Hung ALH, et al. - In girls having adolescent idiopathic scoliosis (AIS), reduced cortical bone density and bone mechanical strength with increased bone turnover markers were evident at peak height velocity (PHV). PHV coupled with reduced cortical and finite element analysis parameters may afford the link to the earlier documented finding that low bone mineral density (BMD) could contribute as one of the prognostic factors for curve progression that mostly happens during PHV in AIS.

• This analysis involved 396 AIS girls in two separate cohorts.

• Girls at thumb ossification composite index (TOCI)-4 were found to have numerically the highest height velocity (0.71 ± 0.24 cm/month) corresponding to the PHV.

• Lower cortical volumetric BMD, cortical thickness and apparent modulus were evident in participants at TOCI-4 vs (a) those at TOCI-1–3 and (b) those at TOCI-8.

• Higher concentrations of C-terminal telopeptide of type 1 collagen and procollagen type 1 N-terminal propeptide were detected in participants at TOCI-4, vs those at TOCI-8.