title: Role of the interosseous membrane and annular ligament in stabilizing the proximal radial head.
abstract: OBJECTIVE
  The purpose of our study was to determine the relative contributions of the annular ligament, proximal band, central band, and distal band of the interosseous membrane in preventing dislocation of the proximal radius.
  
  
  METHODS
  In part 1 of the study, 8 forearms were loaded transversely with the forearm intact, and the central band, proximal band, and annular ligament were sequentially sectioned to determine the percentage contribution of each structure in preventing transverse radial displacement. In part 2, 12 forearms were cyclically supinated and pronated while optical sensors measured radial and ulnar motion. Transverse radial head motion was computed as the distal band, central band, and proximal band (and annular ligament) were sequentially sectioned.
  
  
  RESULTS
  In part 1, there was no significant difference in the percentage contribution of each structure in preventing radial transverse displacement. In part 2, only after sectioning of the central band did significant radial head displacement occur. Greater displacements occurred in supination than in pronation. Dislocation of the proximal radius occurred in 2 arms after sectioning of all 3 structures.
  
  
  CONCLUSIONS
  Under pure transverse displacement, the central band, annular ligament, and proximal band equally contributed to stabilizing the radius. However, during forearm rotation, the central band contributed more to radial head stability than the annular ligament and proximal band. Our study contributes to our knowledge of forearm biomechanics, demonstrating the importance of the central band in providing proximal radial head stability. Forceful supination should be avoided after surgical procedures designed to stabilize the radial head.
authors.affiliation: Department of Orthopedic Surgery, SUNY Upstate Medical University, Syracuse, NY, USA.
authors.forename: Ashley
authors.initials: A
authors.lastname: Anderson
authors.affiliation: Department of Orthopedic Surgery, SUNY Upstate Medical University, Syracuse, NY, USA. Electronic address: wernerf@upstate.edu.
authors.forename: Frederick W
authors.initials: FW
authors.lastname: Werner
authors.affiliation: Department of Orthopedic Surgery, SUNY Upstate Medical University, Syracuse, NY, USA.
authors.forename: Emily R
authors.initials: ER
authors.lastname: Tucci
authors.affiliation: Department of Orthopedic Surgery, SUNY Upstate Medical University, Syracuse, NY, USA.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Harley
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D002102:Cadaver; D004551:Elbow Joint / Q000503:physiopathology*; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000503:physiopathology / Q000517:prevention & control*; D008023:Ligaments, Articular / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D019637:Orthopedic Procedures / Q000379:methods*; D011884:Radius / Q000601:surgery*; D000092464:Elbow Injuries
keywords: Radial head dislocation; annular ligament; interosseous membrane