title: Abnormal Bone Mechanical and Structural Properties in Adolescent Idiopathic Scoliosis: A Study with Finite Element Analysis and Structural Model Index.
abstract: Previous studies found adolescent idiopathic scoliosis (AIS) is associated with low bone mineral density (BMD) and abnormal bone quality, whilst the association between AIS and their bone strength is unknown. From high-resolution peripheral quantitative computed tomography-generated images, bone mechanical properties can be evaluated with finite element analysis (FEA), and trabecular rod-plate configuration related to trabecular bone strength can be quantified by structure model index (SMI). This study aimed to compare trabecular configuration and bone mechanical properties between AIS and the controls. 95 AIS girls aged 12-14 years and 97 age- and gender-matched normal controls were recruited. Bilateral femoral necks and non-dominant distal radius were scanned by dual-energy X-ray absorptiometry for areal BMD and HR-pQCT for SMI and FEA, respectively. Subjects were further classified into osteopenic and non-osteopenic group based on their areal BMD. Bone mechanical properties (stiffness, failure load and apparent modulus) were calculated using FEA. Linear regression model was used for controlling age, physical activity and calcium intake. AIS was associated with lower failure load and apparent modulus after adjusting for age, whereas AIS was associated with lower apparent modulus after adjusting for all confounders. Osteopenic AIS was associated with more rod-like trabeculae when compared with non-osteopenic AIS, whereas no difference was detected between osteopenic and non-osteopenic controls. This might be the result of abnormal regulation and modulation of bone metabolism and bone modelling and remodelling in AIS which will warrant future studies with a longitudinal design to determine the significance of micro-architectural abnormalities in AIS.
authors.affiliation: Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Shatin, Hong Kong, China.|Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, Hong Kong and Nanjing, China.
authors.forename: K Y
authors.initials: KY
authors.lastname: Cheuk
authors.affiliation: Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Shatin, Hong Kong, China.|Department of Orthopaedics and Traumatology, Bone Quality and Health Centre, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: T Y
authors.initials: TY
authors.lastname: Zhu
authors.affiliation: Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Shatin, Hong Kong, China.|Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, Hong Kong and Nanjing, China.|Department of Orthopaedics and Traumatology, Bone Quality and Health Centre, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: F W P
authors.initials: FW
authors.lastname: Yu
authors.affiliation: Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Shatin, Hong Kong, China.|Department of Orthopaedics and Traumatology, Bone Quality and Health Centre, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: V W Y
authors.initials: VW
authors.lastname: Hung
authors.affiliation: Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, Hong Kong and Nanjing, China.|Lee Hysan Clinical Research Laboratories, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: K M
authors.initials: KM
authors.lastname: Lee
authors.affiliation: Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Shatin, Hong Kong, China.|Department of Orthopaedics and Traumatology, Bone Quality and Health Centre, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: L
authors.initials: L
authors.lastname: Qin
authors.affiliation: Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Shatin, Hong Kong, China.|Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, Hong Kong and Nanjing, China.|Department of Orthopaedics and Traumatology, Bone Quality and Health Centre, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: J C Y
authors.initials: JC
authors.lastname: Cheng
authors.affiliation: Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Shatin, Hong Kong, China. tplam@ort.cuhk.edu.hk.|Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, Hong Kong and Nanjing, China. tplam@ort.cuhk.edu.hk.|Department of Orthopaedics and Traumatology, Bone Quality and Health Centre, The Chinese University of Hong Kong, Shatin, Hong Kong, China. tplam@ort.cuhk.edu.hk.
authors.forename: T P
authors.initials: TP
authors.lastname: Lam
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D001696:Biomechanical Phenomena; D015519:Bone Density; D001851:Bone Diseases, Metabolic; D001842:Bone and Bones / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D016022:Case-Control Studies; D002648:Child; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000503:physiopathology*
keywords: Adolescent idiopathic scoliosis; Bone mechanical properties; Finite element analysis; Osteopenia; Rod-plate configuration; Structure model index