title: Femoral morphology and epiphyseal growth plate changes of the hip during maturation: MR assessments in a 1-year follow-up on a cross-sectional asymptomatic cohort in the age range of 9-17 years.
abstract: OBJECTIVE
  The goal of this prospective study was to characterize the morphology and physeal changes of the femoral head during maturation using MRI in a population-based group of asymptomatic volunteers.
  
  
  METHODS
  Sixty-four pupils (127 hips) of 331 pupils from a primary and high school were asked to take part in this study and were willing to participate. 3T MRI of the hip was obtained at baseline and 1-year follow-up. With these images, we analyzed the femoral morphology and epiphyseal changes related to age, status of the physis, and location on the femur.
  
  
  RESULTS
  The radius of the femoral head and neck increased with age, as expected, (p < 0.001). The epiphyseal extension increased significantly with age (p < 0.05), but epiphyseal tilt and alpha angle showed no differences (p > 0.05). Building groups by using the epiphyseal status, we found that the epiphyseal extension had the highest changes in the "open" group and almost stopped in the "closed" group. The tilt angle did not change significantly (p > 0.05). Significant smaller alpha-angles were found in the "closed" group, however, these were in a normal range in all of them. Correlated to the position, the highest alpha-angle values were located in anterior-superior and superior-anterior position.
  
  
  CONCLUSIONS
  Our data can be used as normative values, which can be compared to patients or cohorts with certain risk factors (e.g., professional athletes), this will offer the chance to detect and understand pathological changes.
authors.affiliation: Department of Orthopedic Surgery, University of Bern, Bern, Switzerland. philipp.kienle@gmail.com
authors.forename: Karl-Philipp
authors.initials: KP
authors.lastname: Kienle
authors.forename: Johannes
authors.initials: J
authors.lastname: Keck
authors.forename: Stefan
authors.initials: S
authors.lastname: Werlen
authors.forename: Young-Jo
authors.initials: YJ
authors.lastname: Kim
authors.forename: Klaus-Arno
authors.initials: KA
authors.lastname: Siebenrock
authors.forename: Tallal Charles
authors.initials: TC
authors.lastname: Mamisch
mesh_terms: D000293:Adolescent; D002648:Child; D003430:Cross-Sectional Studies; D004838:Epiphyses / Q000254:growth & development*; D005260:Female; D005270:Femur Head / Q000254:growth & development*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011446:Prospective Studies; D012016:Reference Values