title: Biomechanical investigation of the classic metaphyseal lesion using an immature porcine model.
abstract: OBJECTIVE
  The classic metaphyseal lesion is highly associated with abuse in infants. Classic metaphyseal lesions, also referred to as corner or bucket-handle fractures, are fractures through the metaphyseal region of the long bones near the growth plate. Knowledge of the biomechanics and mechanisms necessary to produce a classic metaphyseal lesion may provide insight into the injury causation associated with this unique fracture type. Thus, the purpose of this study was to investigate loading conditions necessary to create a classic metaphyseal lesion using an immature porcine model.
  
  
  METHODS
  Twenty-four pelvic limb specimens from 7-day-old and 3-day-old piglets were tested in lateral bending (varus and valgus) using an electromechanical testing machine. All specimens were loaded dynamically in four-point bending at a rate of 100 inches/min. Microcomputed tomography was performed on specimens before and after testing. Pre- and posttest CT images were compared to assess whether fracture had occurred.
  
  
  RESULTS
  Fractures resembling classic metaphyseal lesions were identified in 12 of the 24 specimens. Microcomputed tomography images revealed trabecular disruptions visually similar to classic metaphyseal lesions in children.
  
  
  CONCLUSIONS
  Metaphyseal fractures, consistent with clinical classic metaphyseal lesions, resulted from a single loading event delivering varus or valgus bending to the stifle (knee). A classic metaphyseal lesion is a unique type of fracture with specific morphologic characteristics. Therefore, we suggest using the term "classic metaphyseal fracture" in lieu of classic metaphyseal lesion to improve precision of terminology.
authors.affiliation: 1 Department of Engineering Fundamentals, University of Louisville, Louisville, KY.
authors.forename: Angela
authors.initials: A
authors.lastname: Thompson
authors.forename: Gina
authors.initials: G
authors.lastname: Bertocci
authors.forename: Kim
authors.initials: K
authors.lastname: Kaczor
authors.forename: Craig
authors.initials: C
authors.lastname: Smalley
authors.forename: Mary Clyde
authors.initials: MC
authors.lastname: Pierce
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001696:Biomechanical Phenomena; D004195:Disease Models, Animal; D004838:Epiphyses / Q000000981:diagnostic imaging / Q000293:injuries*; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013314:Stress, Mechanical; D013552:Swine; D055114:X-Ray Microtomography
keywords: biomechanics; child abuse; classic metaphyseal lesion; microcomputed tomography; pediatric fracture