title: Extent of physeal involvement in Legg-Calvé-Perthes disease.
abstract: OBJECTIVE
  The growth plate involvement (GPI) index is reportedly a reliable predictor of final radiographic outcome in Legg-Calvé-Perthes disease (LCPD). We determined whether (1) the GPI index was associated with the lateral pillar classification, (2) the GPI index could predict the final radiographic outcome, and (3) the geometry of proximal femur was affected by presence of physeal involvement.
  
  
  METHODS
  We reviewed 47 patients with unilateral LCPD who were treated conservatively. The mean duration of follow-up was 9.5 years (range, five to 13 years). The affected hips were categorized into those with and without physeal involvement. Herring classifications were determined and the GPI indices were estimated at the stage of maximum fragmentation. The Stulberg classification, leg length discrepancy (LLD), articulotrochanteric distance (ATD) index, neck-shaft angle (NSA), neck width and height were determined at skeletal maturity.
  
  
  RESULTS
  The GPI indices were lower in Herring groups A and B (p < 0.001) and Stulberg classes I and II (p = 0.002), and these values were increased in the Herring group B/C and C and Stulberg classes III, IV and V. However, the age of onset, LLD and ATD index at skeletal maturity were not associated with the GPI index. The NSA of the affected hips with physeal involvement was significantly different compared to that of unaffected hips (p < 0.001).
  
  
  CONCLUSIONS
  The GPI index could be used to determine the extent of physeal involvement in LCPD, and might be considered one of the prognostic values of radiographic development in patients with LCPD who are treated conservatively.
authors.affiliation: Institute for Rare Diseases and Department of Orthopaedic Surgery, Korea University Medical Center, Guro Hospital, 148 Gurodong-ro, Guro-gu, Seoul, 152-703, South Korea, kwpark77@gmail.com.
authors.forename: Kwang-Won
authors.initials: KW
authors.lastname: Park
authors.forename: Chastity Amor
authors.initials: CA
authors.lastname: Rejuso
authors.forename: Rey-An Nino
authors.initials: RA
authors.lastname: Garcia
authors.forename: Tae-Wan
authors.initials: TW
authors.lastname: Kim
authors.forename: Hae-Ryong
authors.initials: HR
authors.lastname: Song
mesh_terms: D000328:Adult; D000368:Aged; D002675:Child, Preschool; D004838:Epiphyses / Q000000981:diagnostic imaging*; D005260:Female; D006132:Growth Plate / Q000000981:diagnostic imaging*; D006621:Hip Joint / Q000000981:diagnostic imaging; D006801:Humans; D007870:Leg Length Inequality / Q000000981:diagnostic imaging; D007873:Legg-Calve-Perthes Disease / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011859:Radiography; D012189:Retrospective Studies