title: The assessment of postural control and the influence of a secondary task in people with anterior cruciate ligament reconstructed knees using a Nintendo Wii Balance Board.
abstract: BACKGROUND
  Postural control impairments may persist following anterior cruciate ligament (ACL) reconstruction. The effect of a secondary task on postural control has, however, not been determined. The purpose of this case-control study was to compare postural control in patients following ACL reconstruction with healthy individuals with and without a secondary task.
  
  
  METHODS
  45 patients (30 men and 15 women) participated at least 6 months following primary ACL reconstruction surgery. Participants were individually matched by age, gender and sports activity to healthy controls.
  
  
  METHODS
  Postural control was measured using a Nintendo Wii Balance Board and customised software during static single-leg stance and with the addition of a secondary task. The secondary task required participants to match the movement of an oscillating marker by adducting and abducting their arm.
  
  
  METHODS
  Centre of pressure (CoP) path length in both medial-lateral and anterior-posterior directions, and CoP total path length.
  
  
  RESULTS
  When compared with the control group, the anterior-posterior path length significantly increased in the ACL reconstruction patients' operated (12.3%, p=0.02) and non-operated limbs (12.8%, p=0.02) for the single-task condition, and the non-operated limb (11.5%, p=0.006) for the secondary task condition. The addition of a secondary task significantly increased CoP path lengths in all measures (p<0.001), although the magnitude of the increase was similar in both the ACL reconstruction and control groups.
  
  
  CONCLUSIONS
  ACL reconstruction patients showed a reduced ability in both limbs to control the movement of the body in the anterior-posterior direction. The secondary task affected postural control by comparable amounts in patients after ACL reconstruction and healthy controls. Devices for the objective measurement of postural control, such as the one used in this study, may help clinicians to more accurately identify patients with deficits who may benefit from targeted neuromuscular training programs.
authors.affiliation: Musculoskeletal Research Centre, Faculty of Health Sciences, La Trobe University, Melbourne, Victoria, Australia.
authors.forename: Brooke E
authors.initials: BE
authors.lastname: Howells
authors.forename: Ross A
authors.initials: RA
authors.lastname: Clark
authors.forename: Clare L
authors.initials: CL
authors.lastname: Ardern
authors.forename: Adam L
authors.initials: AL
authors.lastname: Bryant
authors.forename: Julian A
authors.initials: JA
authors.lastname: Feller
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Whitehead
authors.forename: Kate E
authors.initials: KE
authors.lastname: Webster
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D016118:Anterior Cruciate Ligament / Q000502:physiology*; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D011184:Postoperative Period; D004856:Postural Balance / Q000502:physiology*; D011434:Proprioception / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D020127:Recovery of Function / Q000502:physiology; D018910:Video Games