Rein S, et al. - Researchers performed sonographic investigation of the anterior talofibular ligament and the calcaneofibular ligament in 16 patients with functional ankle instability (FAI) and 16 controls under neutral and standardized stress conditions of 15 kp with a TELOS device. In clinical investigation, the FAI group showed significantly higher rate of a positive anterior drawer and talar tilt, significantly increased supination of the right ankle joint and increased plantarflexion of the left ankle joint compared with controls. In both ligaments in the FAI group, sonographic observations revealed significantly higher rates of inhomogeneity and hypo-echogenicity. In the FAI group, they observed significantly longer anterior talofibular ligament under stress conditions, and significantly longer calcaneofibular ligament under both neutral and stress conditions. Twenty-two percent of the FAI group showed peritendinous edema of the peroneal tendons vs 6% of controls.