title: Variability in knee laxity in anterior cruciate ligament deficiency using a mechanized model.
abstract: OBJECTIVE
  To establish normative values for the magnitude of anterior tibial translation (ATT) in the Lachman and pivot shift tests in the intact and anterior cruciate ligament (ACL)-deficient states, and to explore whether a correlation in ATT magnitude exists between the Lachman and pivot shift tests.
  
  
  METHODS
  Twenty-six fresh frozen cadaveric hip-to-toe specimens were used. Mechanized testing was performed to simulate both a Lachman and pivot shift test with the ACL intact. Tests were repeated after sectioning the ACL. ATT was recorded using a computer navigation system. Difference in ATT after sectioning was calculated for each specimen.
  
  
  RESULTS
  For the Lachman, mean lateral compartment ATT in the intact knee was 5.3 mm (SD = 2.8 mm). After sectioning the ACL, translation increased to 11.4 mm (SD = 3.9 mm; P < 0.05). For the mechanized pivot shift, mean lateral compartment ATT in the intact knee was -0.2 mm (SD = 2.6 mm). After sectioning the ACL, translation increased to 8.2 mm (SD = 3.1 mm; P < 0.05). No correlation in the magnitude of ATT was found between the intact and ACL-deficient knees for either the Lachman or pivot shift tests, or between both tests (Cronbach's α < 0.7).
  
  
  CONCLUSIONS
  No correlation was found between the Lachman and pivot shift test in both the intact and ACL-deficient knee. This suggests that the Lachman cannot be used as a surrogate for the pivot shift as the magnitude of the Lachman did not predict the magnitude of the pivot shift.
authors.affiliation: Hospital for Special Surgery, 535 E 70th Street, New York, NY 10021, USA. courtneykdawson@gmail.com
authors.forename: Courtney K
authors.initials: CK
authors.lastname: Dawson
authors.forename: Eduardo M
authors.initials: EM
authors.lastname: Suero
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Pearle
mesh_terms: D000328:Adult; D000368:Aged; D016118:Anterior Cruciate Ligament / Q000503:physiopathology / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D002102:Cadaver; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis / Q000503:physiopathology*; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010808:Physical Examination / Q000379:methods*