Anterior talocrural joint laxity: diagnostic accuracy of the anterior drawer test of the ankle.
STUDY DESIGN
Prospective, blinded, diagnostic-accuracy study.


OBJECTIVES
To investigate the diagnostic accuracy of the ankle anterior drawer test (ADT) to detect anterior talocrural joint laxity in adults with a history of lateral ankle sprain.


BACKGROUND
The ADT is used to manually detect anterior talocrural joint laxity following lateral ankle sprain injury; however, the diagnostic accuracy of this test has not been established.


METHODS
Sixty-six subjects with a history of lateral ankle sprain were examined with the ADT. Anterior talocrural joint laxity was measured digitally from ultrasound images of the talofibular interval during performance of the ADT. In addition, anterior talocrural joint laxity was measured digitally in 20 control subjects to establish a reference standard. ADT results were defined as "positive" or "negative," based on this and a second reference standard established from the literature.


RESULTS
The group with a history of lateral ankle sprain had a mean ± SD anterior talocrural joint laxity of 3.36 ± 3.25 mm, compared with 0.17 ± 1.87 mm in the control group. Thirty-five of 66 (53%) subjects demonstrated anterior talocrural joint laxity at a reference standard of 2.3 mm or greater, and 24 (36%) at a reference standard of 3.7 mm or greater. Sensitivity of the ADT was 0.74 (95% confidence interval [CI]: 0.58, 0.86) and 0.83 (95% CI: 0.64, 0.93) at the 2.3 mm or greater and 3.7 mm or greater reference standards, respectively. Specificity of the test was 0.38 (95% CI: 0.24, 0.56) and 0.40 (95% CI: 0.27, 0.56), respectively. Positive likelihood ratios were 1.2 and 1.4, whereas the negative likelihood ratios were 0.66 and 0.41, respectively.


CONCLUSION
The ADT provides limited ability to detect excessive anterior talocrural joint laxity; however, it may provide useful information when used in side-to-side ankle comparisons and in conjunction with other physical exam procedures, such as palpation.


LEVEL OF EVIDENCE
Diagnosis, level 3b.