title: The effects of ACL injury on knee proprioception: a meta-analysis.
abstract: BACKGROUND
  It is suggested the anterior cruciate ligament (ACL) plays a significant role in knee proprioception, however, the effect of ACL injury on knee proprioception is unclear. Studies utilising the two most common measurement techniques, joint position sense and threshold to detect passive motion, have provided evidence both for and against a proprioceptive deficient following ACL injury.
  
  
  OBJECTIVE
  The objective of the study was to undertake a meta-analysis investigating the effects of ACL injury, treated conservatively or by reconstruction, on proprioception of the knee, measured using joint position sense and/or threshold to detect passive movement techniques.
  
  
  METHODS
  Seven databases were searched from their inception to September 2013 using the subject headings 'anterior cruciate ligament, proprioception, postural sway, joint position sense, balance, equilibrium or posture' to identify relevant studies.
  
  
  METHODS
  PRISMA guidelines were followed as much as possible. Studies that investigated the effect of ACL injury on either knee joint kinaesthesia or position sense were included in this review.
  
  
  METHODS
  Two reviewers independently extracted data using a standardised assessment form. Comparisons were made using a fixed effect model with an inverse variance method using Review Manager Software (V5.1).
  
  
  RESULTS
  Patients with ACL injury have poorer proprioception than people without such injuries (SMD=0.35°; P=0.001 and SMD=0.38°; P=0.03) when measured using joint position sense and threshold to detect passive motion techniques respectively. Patients had poorer proprioception in the injured than uninjured leg (SMD=0.52°; P<0.001) and the proprioception of people whose ACL was repaired was better than those whose ligament was left unrepaired (SMD=-0.62°; P<0.001).
  
  
  CONCLUSIONS
  Heterogeneity of measurement techniques and lack of psychometric details.
  
  
  CONCLUSIONS
  ACL injuries may cause knee proprioception deficits compared to uninjured knees and control groups. Although differences were statistically significant, the clinical significance of findings can be questioned. Clinical practitioners using joint position sense or threshold to detect passive motion techniques need to consider the reliability and validity of data provided.
authors.affiliation: Faculty of Health and Sciences, Department of Medical and Sport Sciences, University of Cumbria, Fusehill Street, Carlisle CA1 2HH, UK. Electronic address: Nicola.Relph@Cumbria.ac.uk.
authors.forename: N
authors.initials: N
authors.lastname: Relph
authors.affiliation: School of Health Science, Frederick Rd Campus, University of Salford, Salford M6 6PU, UK.
authors.forename: L
authors.initials: L
authors.lastname: Herrington
authors.affiliation: Stroke & Vascular Research Centre, School of Nursing, Midwifery & Social Work, Jean McFarlane Building, University of Manchester, Oxford Rd, Manchester M13 9PL, UK.
authors.forename: S
authors.initials: S
authors.lastname: Tyson
mesh_terms: D016118:Anterior Cruciate Ligament / Q000503:physiopathology* / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology* / Q000601:surgery; D011434:Proprioception / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology
keywords: Anterior cruciate ligament (ACL); Joint position sense; Knee proprioception; Threshold to detect passive motion