title: Correlation between wrist loads and the distal radius volar tilt angle.
abstract: BACKGROUND
  Based on the phenomenon of bone adaptation to mechanical stimuli (Wolff's law) this study investigates a previously unreported correlation between the maximum wrist joint reaction force and the volar tilt angle of the distal radius.
  
  
  METHODS
  Free body analysis of the sagittal-plane forces acting on the supinated distal radius during lifting and radiographic measurements in thirty normal wrists are used to analyse the correlation between the theoretically calculated maximum wrist joint reaction force and the radiographically measured volar tilt angle.
  
  
  RESULTS
  Non-statistically significant difference (p=0.33, 95% confidence interval -0.64 degrees to 0.22 degrees) and statistically significant correlation (R(2)=0.74, r=0.86, p<0.001) between the angle of the maximum wrist force and the volar tilt angle of the distal radius and inverse relationship between the volar tilt angle and the magnitude of the maximum wrist force (R(2)=0.71, r=-0.84, P<0.001) were found.
  
  
  CONCLUSIONS
  The radiographically measured volar tilt angle of the distal radius appears not to differ significantly from the theoretically calculated angle of the maximum wrist joint reaction force, a possible explanation for the phylogenetical development of the volar tilt angle. Also, an inverse relationship between the volar tilt angle and the magnitude of the maximum joint reaction force was observed suggesting that wrists characterized by a low volar tilt angle may be subjected during lifting activities to maximum joint reaction forces up to 50% higher than those in wrists with a high volar tilt and emphasising the importance of accurate restoration of the volar tilt during treatment of all distal radius fractures.
authors.affiliation: Department of Orthopaedic Surgery, University of Bristol, Bristol BS2 8HW, UK. mail@ioanniskarnezis.gr
authors.forename: Ioannis A
authors.initials: IA
authors.lastname: Karnezis
mesh_terms: D000328:Adult; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D011187:Posture / Q000502:physiology*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D011884:Radius / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000502:physiology*; D013223:Statistics as Topic; D013314:Stress, Mechanical; D019415:Torque; D016474:Weight-Bearing / Q000502:physiology*; D014955:Wrist Joint / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000502:physiology*