title: The stabilizing effect of the distal interosseous membrane on the distal radioulnar joint in an ulnar shortening procedure: a biomechanical study.
abstract: BACKGROUND
  The importance of the stabilizing effect of the distal interosseous membrane on the distal radioulnar joint, especially in patients with a distal oblique bundle, has been described. The purpose of this study was to evaluate the stability of the distal radioulnar joint after an ulnar shortening osteotomy and to quantify longitudinal resistance to ulnar shortening when the osteotomy was proximal or distal to the ulnar attachment of the distal interosseous membrane. These relationships were characterized for forearms with or without a distal oblique bundle.
  
  
  METHODS
  Ten fresh-frozen cadavers were used. A transverse osteotomy and ulnar shortening was performed proximal (proximal shortening) and distal (distal shortening) to the ulnar attachment of the distal interosseous membrane. Distal radioulnar joint laxity was evaluated as the volar and dorsal displacements of the radius relative to the fixed ulna with 20 N of applied force. Testing was performed under controlled 1-mm increments of ulnar shortening up to 4 mm, with the forearm in neutral alignment, 60° of pronation, and 60° of supination. Resistance to ulnar shortening was quantified as the slope of the load-displacement curve obtained by displacing the distal ulnar segment proximally.
  
  
  RESULTS
  In proximal shortening, significantly greater stability of the distal radioulnar joint was obtained with even 1 mm of shortening compared with the control, whereas distal shortening demonstrated significant improvement in stability of the distal radioulnar joint only after shortening of ≥4 mm in all rotational positions. Significantly greater stability of the distal radioulnar joint was achieved with proximal shortening than with distal shortening and in specimens with a distal oblique bundle than in those without a distal oblique bundle. The longitudinal resistance to ulnar shortening was significantly greater in proximal shortening than in distal shortening. The stiffness in proximal shortening was not affected by the presence of a distal oblique bundle in the distal interosseous membrane.
  
  
  CONCLUSIONS
  Ulnar shortening with the osteotomy carried out proximal to the attachment of the distal interosseous membrane had a more favorable effect on stability of the distal radioulnar joint compared with distal osteotomy, especially in the presence of a distal oblique bundle.
authors: Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN 55905, USA.
authors: Sayuri
authors: S
authors: Arimitsu
authors: Hisao
authors: H
authors: Moritomo
authors: Takashi
authors: T
authors: Kitamura
authors: Lawrence J
authors: LJ
authors: Berglund
authors: Kristin D
authors: KD
authors: Zhao
authors: Kai-Nan
authors: KN
authors: An
authors: Marco
authors: M
authors: Rizzo
mesh_terms: D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D002102:Cadaver; D002358:Cartilage, Articular / Q000601:surgery*; D016267:External Fixators; D005260:Female; D005542:Forearm / Q000502:physiology / Q000601:surgery; D006801:Humans; D007593:Joint Instability / Q000517:prevention & control*; D016014:Linear Models; D008297:Male; D010027:Osteotomy / Q000379:methods*; D016059:Range of Motion, Articular / Q000502:physiology; D013718:Tensile Strength; D014457:Ulna / Q000601:surgery*; D014955:Wrist Joint / Q000601:surgery*