title: Coxa magna quantification using MRI in Legg-Calve-Perthes disease.
abstract: BACKGROUND
  The idiopathic avascular necrosis of the femoral epiphysis characterizes the Legg-Calve-Perthes disease in pediatric osteoarticular pathologies. The coxa magna, more frequently observed, corresponds to an enlargement and deformation of the femoral head. The volume extension induces a subluxation of the hip, which is a bad prognosis for the healthy function of the joint.
  
  
  METHODS
  The aim of the study was to quantify the coxa magna in Legg-Calve-Perthes disease using magnetic resonance imaging. Twenty-five patients with unilateral Legg-Calve-Perthes disease were included in the clinical protocol and the volume properties of cartilaginous epiphyseal head were quantified using custom-made image processing software.
  
  
  RESULTS
  Difference in cartilage volume between healthy hips and pathological ones were significant. Excepting one patient, we observed a statistically significant volume increase for the pathological hip, the mean value being +13%.
  
  
  CONCLUSIONS
  Our results confirmed the effective three-dimensional properties of the coxa magna, which is clearly associated to a negative prognosis for the future of the joint. To our knowledge, the volume quantification of coxa magna has not been established before. The non-radiant MRI associated to three-dimensional investigation could potentially improve the clinical follow up of children to adapt the non-invasive treatment and to plan the surgery if necessary.
authors.affiliation: Children Hospital, Orthopedic Pediatric Department, Toulouse, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Sales de Gauzy
authors.forename: Jérôme
authors.initials: J
authors.lastname: Briot
authors.forename: Pascal
authors.initials: P
authors.lastname: Swider
mesh_terms: D002358:Cartilage, Articular / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D005270:Femur Head / Q000473:pathology*; D025981:Hip Injuries; D006621:Hip Joint / Q000473:pathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007873:Legg-Calve-Perthes Disease / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male