The quantitative evaluation of anterior drawer test using an electromagnetic measurement system

The anterior drawer test (ADT) is the gold standard examination for the diagnosis of anterior talofibular ligamentinsufficiency,although there is noquantitative evaluation of ADT that is generally usable and reliable.An electromagnetic sensor (EMS)has been used to quantitatively evaluate joint kinematics, and has a high potential to be applied to the ankle joint. The aim of this study was to validatethe EMS measurement of the ADTin comparison to the fluoroscopic evaluationand to evaluate the reproducibility of the EMS measurement.Six feet were included,and an examinerperformed the ADT5 times for each foot while the anterior translation of the ankle jointwas quantitative evaluatedusing EMS and fluoroscope simultaneously. The anterior translation of the ankle joint during the ADT in EMS and in fluoroscope was 8.1 +/- 5.7 mm and 3.6 +/- 2.4 mm.Astrong correlation was observed between the measurements using EMS and fluoroscope (p < 0.01, the correlation coefficient = 0.91). Another 20 feet were included, and three examiners performed the ADT five times for each foot with the EMS measurement. The intra and inter-examiner reliability was 0.99 and 0.89.The EMS could quantify the anterior translation during the ADT which corresponds to fluoroscopic evaluation.