title: Posterior cruciate ligament and posterolateral corner deficiency results in a reverse pivot shift.
abstract: BACKGROUND
  As measured via static stability tests, the PCL is the dominant restraint to posterior tibial translation while the posterolateral corner is the dominant restraint to external tibial rotation. However, these uniplanar static tests may not predict multiplanar instability. The reverse pivot shift is a dynamic examination maneuver that may identify complex knee instability.
  
  
  OBJECTIVE
  In this cadaver study, we asked whether (1) isolated sectioning or (2) combined sectioning of the PCL and posterolateral corner increased the magnitude of the reverse pivot shift and (3) the magnitude of the reverse pivot shift correlated with static external rotation or posterior drawer testing.
  
  
  METHODS
  In Group I, we sectioned the PCL followed by structures of the posterolateral corner. In Group II, we sectioned the posterolateral corner structures before sectioning the PCL. We performed posterior drawer, external rotation tests, and mechanized reverse pivot shift for each specimen under each condition and measured translations via navigation.
  
  
  RESULTS
  Isolated sectioning of the PCL or posterolateral corner had no effect on the reverse pivot shift. Conversely, combined sectioning of the PCL and posterolateral corner structures increased the magnitude of the reverse pivot shift. The magnitude of the reverse pivot shift correlated with the posterior drawer and external rotation tests.
  
  
  CONCLUSIONS
  Combined sectioning of the PCL and posterolateral corner was required to cause an increase in the magnitude of the mechanized reverse pivot shift. The reverse pivot shift correlated with both static measures of stability.
  
  
  CONCLUSIONS
  Combined injury to the PCL and posterolateral corner should be considered in the presence of a positive reverse pivot shift.
authors.affiliation: Department of Orthopaedic Surgery, David Geffen School of Medicine, University of California Los Angeles, 10945 Le Conte Avenue, PVUB #33-55 H, Los Angeles, CA 90095, USA. fpetrigliano@mednet.ucla.edu
authors.forename: Frank A
authors.initials: FA
authors.lastname: Petrigliano
authors.forename: Clayton G
authors.initials: CG
authors.lastname: Lane
authors.forename: Eduardo M
authors.initials: EM
authors.lastname: Suero
authors.forename: Answorth A
authors.initials: AA
authors.lastname: Allen
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Pearle
mesh_terms: D000328:Adult; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis* / Q000503:physiopathology; D007719:Knee Joint / Q000503:physiopathology*; D008875:Middle Aged; D010808:Physical Examination; D016119:Posterior Cruciate Ligament / Q000503:physiopathology* / Q000601:surgery; D012399:Rotation; D013977:Tibia / Q000503:physiopathology