title: Comparison of two manual tests for ankle laxity due to rupture of the lateral ankle ligaments.
abstract: BACKGROUND
  Assessment of ankle laxity can be both subjective and difficult, especially in less-experienced hands. The commonly-practiced anterior drawer test can mislead practitioners in the diagnosis of ankle instability due to subtalar joint motion. A manual stress test, focusing on tibiotalar translation, may be required.
  
  
  OBJECTIVE
  To evaluate the validity, reliability, and diagnostic accuracy of the modified manual stress test--the anterolateral drawer test (ALDT)--compared with the original anterior drawer test (ADT) in two groups of examiners with different levels of experience.
  
  
  METHODS
  A cadaveric study was performed at University Research Laboratory. Nine below the- knee specimens were randomized into three groups to simulate different degrees of lateral ligament injury. Two groups of examiners (Group A was four athletic training students; Group O was four senior orthopaedic trainees) performed ADT and ALDT while direct anatomical measurement (DAM) of tibiotalar translation was used as a reference under controlled load (Telos device). Ankle translation from DAM, ADT, and ALDT was recorded in millimeters. Measurements were compared using a paired t-test. Pearson correlation was used to determine linear relationship between groups. Inter- and intra-rater reliability was identified using ICC (intraclass correlation coefficient). The diagnostic threshold was determined by a receiver operating characteristic curve.
  
  
  RESULTS
  Both groups of examiners demonstrated excellent intra-observer reliability (0.94 for ADT and 0.80 for ALDT) and fair-to-good inter-observer reliability (0.52 for ADT and ALDT). There was no difference in the mean of measurement between group A and group O except for the ALDT on intact specimens (P = 0.01) and the ADT on the ATFL+CFL cut specimens (P = 0.02). Correlation with the DAM was superior in the ALDT (r = 0.73) compared to the ADT (r = 0.57). When using 4 mm or more as a diagnostic threshold, sensitivity and specificity (respectively) were found to be 100% and 66.67% for the ADT and 100% and 66.67% for the ALDT.
  
  
  CONCLUSIONS
  For diagnosis of ankle ligament injuries, this cadaveric study demonstrated high sensitivity, reliability and correlation with the gold standard using ADLT, regardless of the examiner's experience.
authors.affiliation: Department of Orthopaedic, Faculty of Medicine Chiang Mai University Hospital, Chiang Mai, Thailand.
authors.forename: Tanawat
authors.initials: T
authors.lastname: Vaseenon
authors.forename: Yubo
authors.initials: Y
authors.lastname: Gao
authors.forename: Phinit
authors.initials: P
authors.lastname: Phisitkul
mesh_terms: D000368:Aged; D000843:Ankle Joint; D002102:Cadaver; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis*; D017844:Lateral Ligament, Ankle / Q000293:injuries*; D008297:Male; D008875:Middle Aged; D012421:Rupture
keywords: Ankle instability; ankle laxity; ankle ligament; anterior drawer test; anterolateral drawer test