Wearable kinesthetic system for joint knee flexion-extension monitoring in gait analysis

In this paper we investigated on the possibility of using a wearable kinesthetic system for monitoring flexion-extension of the knee joint during deambulation. The final goal was to provide an unobtrusive technique to identify the clinical stage of the recovery process of patients affected by venous ulcer. These patients have great difficulty in walking depending on the severity level of disease and after a surgical operation they usually progressively improve up to recover their normal walking capability. Typically, they are monitored by means of invasive instrumentation. On the contrary, our wearable system is comfortable and non-invasive for the patient. A preliminary pilot test was performed in order to discriminate healthy subjects with a normal walk, from injured subjects. Two discriminating criteria, based on the flexion-extension excursion and its variance, respectively, were envisaged. The latter parameter resulted more effective. In order to determine the discrimination threshold an experimental ROC curve was traced. Finally sensitivity and specificity of the test were experimentally computed.