New method of diagnosis for chronic ankle instability: comparison of manual anterior drawer test, stress radiography and stress ultrasound.

PURPOSE: To diagnose chronic ankle instability, clinicians frequently use manual anterior drawer test and stress radiography. However, both exams can yield incorrect results and do not reveal the extent of ankle instability. The use of stress ultrasound during a manual anterior drawer stress procedure might enable the diagnosis of chronic ankle instability. METHODS: Seventy-three patients with chronic ankle pain or laxity after remote ankle sprain were included. The study population included 41 males and 32 females. The mean age of the patients at the time of the operation was 29 years. A standardized physical examination (manual anterior drawer test), stress radiography and stress ultrasonography were performed to assess the anterior talofibular ligament (ATFL). Ultrasound images were taken in the resting position and the maximal anterior drawer position. The statistical significance of stress ultrasound among the three groups according to manual anterior drawer test and a specific degree (5 mm) of anterior translation of stress radiography were analysed. Correlation coefficients between stress ultrasound, stress radiography and manual anterior drawer test were calculated. RESULTS: There was a significant difference for ATFL length (ATFL stress) and ATFL ratio (ATFL stress/ATFL resting) among the three groups (both p < 0.001). However, there was no significant difference for anterior translation of stress radiography among three groups according to manual anterior drawer test (p = 0.159). There was a significant difference for ATFL length (ATFL stress) and ATFL ratio between two groups with 5-mm anterior translation of stress radiography (p = 0.002 and p = 0.011, respectively). The mean value of grade of manual anterior drawer test between the two groups also differed (p = 0.021). There was a moderately positive linear relationship between stress ultrasound and manual anterior drawer test. Also, there was a positive linear relationship between stress ultrasound and stress radiography. CONCLUSION: The results suggest that the value of ATFL length (ATFL stress) and ATFL ratio of stress ultrasound could be used for diagnosis of chronic ankle instability in addition to manual anterior drawer test and stress radiography.