title: Anterolateral Drawer Versus Anterior Drawer Test for Ankle Instability: A Biomechanical Model.
abstract: BACKGROUND
  The addition of unconstrained internal rotation to the physical examination could allow for detection of more subtle degrees of ankle instability. We hypothesized that a simulated anterolateral drawer test allowing unconstrained internal rotation of the ankle would provoke greater displacement of the lateral talus in the mortise versus the anterior drawer test.
  
  
  METHODS
  Ten cadaveric lower extremities were tested in a custom apparatus designed to reproduce the anterior drawer test and the anterolateral drawer test, in which the ankle was allowed to internally rotate about the intact deep deltoid ligament while being subluxed anteriorly. Specimens were tested intact and with anterior tibiofibular ligament sectioned. A differential variable reluctance transducer was used to measure lateral talar displacement with anterior forces of 25 and 50 N.
  
  
  RESULTS
  No significant differences in talar displacement or ankle rotation were noted in intact specimens between the groups. Among sectioned specimens, significantly more talar displacement (25 N [6.5 ± 1.7 mm vs 3.8 ± 2.4 mm] and 50 N [8.7 ± 0.9 mm vs 4.5 ± 2.5 mm], P < .001) and ankle rotation (25 N [13.9 ± 8.0 degrees vs 0.0 ± 0.0 degrees] and 50 N [23.7 ± 5.8 degrees vs 0.0 ± 0.0 degrees], P < .001) were found in the anterolateral drawer versus anterior drawer group.
  
  
  CONCLUSIONS
  In an ankle instability model, the anterolateral drawer test provoked almost twice the lateral talus displacement found with the anterior drawer test.
  
  
  CONCLUSIONS
  Allowing internal rotation of the ankle while testing for ankle instability may allow the examiner to detect more subtle degrees of ankle instability.
authors.affiliation: Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore, Maryland.
authors.forename: Adam G
authors.initials: AG
authors.lastname: Miller
authors.affiliation: Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore, Maryland.
authors.forename: Stuart H
authors.initials: SH
authors.lastname: Myers
authors.affiliation: Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore, Maryland.
authors.forename: Brent G
authors.initials: BG
authors.lastname: Parks
authors.affiliation: Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore, Maryland lyn.camire@medstar.net.
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Guyton
mesh_terms: D000369:Aged, 80 and over; D000843:Ankle Joint / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D002102:Cadaver; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008954:Models, Biological; D010808:Physical Examination / Q000379:methods*
keywords: ankle; anterior drawer; anterolateral drawer; biomechanics; instability