title: Superior versus anteroinferior plating of the clavicle revisited: a mechanical study.
abstract: OBJECTIVE
  This study was designed to compare bone-implant stiffness of two fixation techniques on a sawbone model of a clavicle fracture.
  
  
  METHODS
  Twenty-four preosteotomized synthetic left clavicles (Sawbones Worldwide, Vashon, WA) were divided into four groups based on type of fixation: standard 3.5-mm pelvic reconstruction plate in the superior position; standard 3.5-mm pelvic reconstruction plate in an anteroinferior position; 3.5-mm locking pelvic reconstruction plate in a superior position; and a 3.5-mm locking pelvic reconstruction plate in an anteroinferior position. Three nondestructive cyclic mechanical tests were performed in random order: axial, torsion, and four-point bend.
  
  
  RESULTS
  No significant difference was found in axial (P = 0.61) or torsional stiffness (internal rotation, P = 0.46 or external rotation, P = 0.49) among all groups. No significant difference occurred in bending rigidity (four-point bending test) with type of plate (P = 0.41), but when the plate was placed anteroinferiorly, bending rigidity was significantly higher (P < 0.001) than in the superior position.
  
  
  CONCLUSIONS
  Placing the plate anteroinferiorly on the clavicle provides a more stable construct in terms of bending rigidity with no detriment in axial and torsional stiffness compared with placing the plate superiorly. We believe that anteroinferior plating is preferred as a result of the increase in bending rigidity together with other advantages, including avoidance of neurovascular compromise, the use of longer screws, and decreased hardware prominence.
authors.affiliation: Orthopaedic Trauma Service, Hospital for Special Surgery, New York, NY 10021, USA.
authors.forename: George
authors.initials: G
authors.lastname: Partal
authors.forename: Kathleen N
authors.initials: KN
authors.lastname: Meyers
authors.forename: Nicholas
authors.initials: N
authors.lastname: Sama
authors.forename: Eric
authors.initials: E
authors.lastname: Pagenkopf
authors.forename: Paul B
authors.initials: PB
authors.lastname: Lewis
authors.forename: Ariel
authors.initials: A
authors.lastname: Goldman
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Wright
authors.forename: David L
authors.initials: DL
authors.lastname: Helfet
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D002968:Clavicle / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods; D006801:Humans; D016268:Internal Fixators; D008953:Models, Anatomic; D012784:Shoulder Fractures / Q000601:surgery*