• Journal of Korean Orthopaedic Sports Medicine
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• v.10 no.1
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• pp.35-40
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• 2011

Purpose: This study was performed to evaluate the diagnostic usefulness of ankle stress radiograph for evaluation of chronic lateral ankle instability. Materials and Methods: Among patients undergoing the modified-Brostrom procedure, 42 cases with complete rupture of the anterior talofibular ligament were enrolled in this study. Sixty Korean adults (120 cases) were recruited as the control group. Radiologic measurement of talar tilt and anterior talar translation was performed through stress radiographs using Telos device. We obtained the normal range of Korean adults, and used as a standard value for judgment of mechanical instability. We analyzed the sensitivity, specificity, positive and negative prediction value of ankle stress radiograph. Results: On ankle stress radiograph, normal range of talar tilt angle and anterior talar translation was below $8.3^{\circ}$, below 7.6mm. Talar tilt angle on varus stress radiograph showed 57% of sensitivity, 97% of specificity, 89% of positive and 86% of negative prediction value. Anterior talar translation on anterior drawer stress radiograph showed 69% of sensitivity, 97% of specificity, 91% of positive and 90% of negative prediction value. Conclusion: Ankle stress radiograph had a good specificity, positive and negative prediction value for the evaluation of mechanical instability. However it underestimated the mechanical instability of ankle joint. It must be remembered that normal stress radiograph does not exclude ankle instability.