title: Physeal growth arrest by excessive compression: histological, biochemical, and micro-CT observations in rabbits.
abstract: BACKGROUND
  Compressive force across the growth plate may cause retardation and even arrest of physeal growth. The purpose of this study was to investigate histologic changes, metabolic changes in terms of glycosaminoglycan (GAG) concentration, and contrast-enhanced micro-computed tomography (CEMCT) findings of physeal cartilage in a rabbit model of physeal damage caused by excessive compression.
  
  
  METHODS
  Compressive forces were applied via external fixators for two weeks to the growth plates of distal femurs and proximal tibiae of right hind-legs in 8-week-old rabbits. Left hind-legs remained intact and were used as controls. Forty-four bone specimens containing growth plates of distal femurs or proximal tibiae were harvested one week (n = 12) and four weeks (n = 32) after surgery, and examined for histologic findings (H&E staining) and GAGs quantification in physeal cartilage. After incubation in an ionic contrast material for 48 hours, specimens were scanned by CEMCT, and the pixel values of physeal cartilage were measured.
  
  
  RESULTS
  CEMCT showed a thin, highly attenuated line parallel to the growth plate in compressed specimens harvested at four weeks after surgery, which was found to be transversely connected trabecular bone. In these specimens, GAG content in physeal cartilage was significantly lower, and CEMCT pixel values of physeal cartilage were significantly higher than in the specimens from the contralateral control side.
  
  
  CONCLUSIONS
  Excessive compressive force applied to growth plates produces altered histologic features and metabolic function in terms of decreased GAG content in physeal cartilage, changes that can be demonstrated by CEMCT.
authors.affiliation: Department of Orthopedic Surgery, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Won Joon
authors.initials: WJ
authors.lastname: Yoo
authors.forename: Jung-Eun
authors.initials: JE
authors.lastname: Cheon
authors.forename: Hye Ran
authors.initials: HR
authors.lastname: Lee
authors.forename: Tae-Joon
authors.initials: TJ
authors.lastname: Cho
authors.forename: In Ho
authors.initials: IH
authors.lastname: Choi
mesh_terms: D000818:Animals; D006132:Growth Plate / Q000000981:diagnostic imaging / Q000254:growth & development* / Q000378:metabolism / Q000473:pathology*; D008297:Male; D011312:Pressure; D011817:Rabbits; D055114:X-Ray Microtomography