title: Development of the osseous and cartilaginous acetabular index in normal children and those with developmental dysplasia of the hip: a cross-sectional study using MRI.
abstract: The purpose of this study was to investigate   the development of the osseous acetabular index (OAI) and cartilaginous   acetabular index (CAI) using MRI. The OAI and CAI were measured   on the coronal MR images of the hip in 81 children with developmental   dysplasia of the hip (DDH), with a mean age of 19.6 months (3 to   70), and 241 normal control children with a mean age of 5.1 years   (1 month to 12.5 years). Additionally the developmental patterns   of the OAI and CAI in normal children were determined by age-based   cross-sectional analysis. Unlike the OAI, the normal CAI decreased rapidly from a mean   of 10.17° (sd 1.60) to a mean of 8.25° (sd 1.90) within   the first two years of life, and then remained constant at a mean   of 8.04° (sd 1.65) until adolescence. Although no difference   in OAI was found between the uninvolved hips in children with unilateral   DDH and normal hips (p = 0.639), the CAI was significantly different   between them both (p < 0.001). The normal CAI has fully formed at   birth, and is maintained constantly throughout childhood. The CAI   in the unaffected hips in children with unilateral DDH is also mildly   dysplastic.
authors.affiliation: Shengjing Hospital of China Medical University, Department of Pediatric Orthopaedics, No.36 Sanhao Street, Heping District, Shenyang City, China.
authors.forename: L Y
authors.initials: LY
authors.lastname: Li
authors.forename: L J
authors.initials: LJ
authors.lastname: Zhang
authors.forename: Q W
authors.initials: QW
authors.lastname: Li
authors.forename: Q
authors.initials: Q
authors.lastname: Zhao
authors.forename: J Y
authors.initials: JY
authors.lastname: Jia
authors.forename: T
authors.initials: T
authors.lastname: Huang
mesh_terms: D000077:Acetabulum / Q000254:growth & development*; D002356:Cartilage / Q000254:growth & development*; D002648:Child; D002675:Child, Preschool; D002681:China; D003430:Cross-Sectional Studies; D005260:Female; D006618:Hip Dislocation, Congenital / Q000503:physiopathology*; D006621:Hip Joint / Q000254:growth & development / Q000503:physiopathology*; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male