title: The biomechanical effect of the distal interosseous membrane on distal radioulnar joint stability: a preliminary anatomic study.
abstract: OBJECTIVE
  The distal interosseous membrane (DIOM) is a secondary stabilizer of the distal radioulnar joint (DRUJ) and has a considerably variable morphology. The purpose of this study was to investigate whether innate DRUJ stability is influenced by the anatomic variation of the DIOM.
  
  
  METHODS
  Ten fresh-frozen cadaver upper extremities were used in this study. The humerus and the ulna were affixed rigidly to a custom-made apparatus, with the elbow in 90° of flexion. Testing was performed by translating the radius in volar and dorsal directions relative to the ulna, with a 20-N applied force in neutral forearm alignment, 60° pronation, and 60° supination. Total translation of the radius was measured as DRUJ laxity. After the experiment, we investigated anatomic variation of the DIOM, especially regarding the existence of the distal oblique bundle (DOB), which is a notably thick fiber within the DIOM. We compared the DRUJ stability between the groups with and without the DOB.
  
  
  RESULTS
  The DOB was found in 4 of 10 specimens. The group with a DOB demonstrated a significantly greater DRUJ stability in the neutral position than the group without a DOB. In pronated and supinated forearm positions, no significant difference in DRUJ stability was obtained between the groups with and without a DOB.
  
  
  CONCLUSIONS
  Innate DRUJ stability in the neutral forearm position was greater in the group with a DOB than in those without a DOB.
  
  
  CONCLUSIONS
  This study suggests that considerable variation exists in DRUJ laxity and that it partially depends on anatomical variations of the DIOM.
authors.affiliation: Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kitamura
authors.forename: Hisao
authors.initials: H
authors.lastname: Moritomo
authors.forename: Sayuri
authors.initials: S
authors.lastname: Arimitsu
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Berglund
authors.forename: Kristin D
authors.initials: KD
authors.lastname: Zhao
authors.forename: Kai-Nan
authors.initials: KN
authors.lastname: An
authors.forename: Marco
authors.initials: M
authors.lastname: Rizzo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007593:Joint Instability / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011884:Radius / Q000033:anatomy & histology / Q000502:physiology*; D016059:Range of Motion, Articular; D014457:Ulna / Q000033:anatomy & histology / Q000502:physiology*; D014955:Wrist Joint / Q000033:anatomy & histology / Q000502:physiology*