Radiographic Measurement of Ankle Lateral Stability in Normal Korean Adults / 대한족부족관절학회지

ABSTRACT

PURPOSE: Anterior drawer and varus stress test are commonly used for radiologic evaluation of chronic lateral ankle instability. However, there are controversies regarding the method of measurement and the normal value. This study was performed to investigate radiologic normal values in normal Korean adults and to analyze differences by age and gender. MATERIALS AND METHODS: Sixty Korean adults were recruited and divided in three groups (20 in their twenties, 20 in their thirties, 20 in their forties). There were 10 males and 10 females in each group. The selection criteria were no history of ankle injury and no evidence of instability on physical examination. Radiologic measurement of varus talar tilt and anterior talar translation were performed through anterior and varus stress radiographs using Telos device (150N force). The measurement was repeated twice by three researchers, and intraobserver reproducibility and interobserver reliability were analyzed. The average talar tilt and anterior talar translation were obtained. RESULTS: Talar tilt and anterior talar translation on ankle stress radiographs had good intraobserver reproducibility and interobserver reliability. Talar tilt was average 3.7degrees and 5.1degrees in male and female of twenties of age, 3.9degrees and 4.8degrees in their thirties, 3.4degrees and 4.5degrees in their forties. Anterior talar translation was average 3.5 mm and 4.2 mm in their twenties, 4.1 mm and 3.8 mm in their thirties, 3.6 mm and 4.1mm in their forties. There was no significant difference in talar tilt and anterior talar translation by age. However, there was significant difference in talar tilt by gender. CONCLUSION: Normal range of talar tilt angle in Korean adults was below 8.3degrees, and normal range of anterior talar translation was below 7.6 mm. It seems to be able to serve as a good reference for radiologic evaluation and for treatment of chronic lateral ankle instability.