Alterated ligamento-muscular reflex pattern after stimulation of the anterior talofibular ligament in functional ankle instability.

PURPOSE: Ligamento-muscular reflex pattern following stimulation of the anterior talofibular ligament (ATFL) was examined. METHODS: The peroneus longus (PL), the tibialis anterior (TA), and tibialis posterior (TP) muscles were investigated in sixteen patients with functional ankle instability (FAI) and 16 age- and gender-matched controls. The ATFL was stimulated with a fine wire electrode while electromyographic (EMG) activities were recorded during isometric foot contraction of 20% maximal force in plantarflexion, dorsiflexion, supination and pronation. The complete measurement was repeated after a peroneal block anesthesia. RESULTS: Statistically significant changes in post-stimulus EMG activity were observed in all three muscles and all four tested foot positions. In supination, the PL showed no reactions in both groups before and after anesthesia. The post-stimulus inhibition of the TA seen after 80 and 180 ms disappeared in controls after anesthesia. The TP had similar inhibitory responses in both groups. CONCLUSION: Ligamento-muscular reflex pattern is alterated in FAI. While early reactions are essential in protecting the ankle joint in sudden movements, the later responses indicate a supraspinal control of neuromuscular stability of the ankle joint. Proprioceptive rehabilitation of the PL, TA, and TP is crucial in FAI to compensate for post-traumatic ligamentomuscular reflex deficiencies. LEVEL OF EVIDENCE: II.

Ultrasound Analysis of Lateral Ankle Ligaments in Functional Ankle Instability.

The anterior talofibular ligament and the calcaneofibular ligament were sonographically investigated in 16 patients with functional ankle instability (FAI) and 16 controls under neutral and standardized stress conditions of 15 kp with a TELOS device. Clinical investigation revealed a significantly higher rate of a positive anterior drawer and talar tilt (p <0.001, respectively), significantly increased supination (p = 0.047) of the right ankle joint and increased plantarflexion (p = 0.009) of the left ankle joint in the FAI group compared with controls. Significantly higher rates of inhomogeneity and hypo-echogenicity were sonographically observed in both ligaments in the FAI group (p < 0.05, respectively). The anterior talofibular ligament was significantly longer under stress conditions, and the calcaneofibular ligament was significantly longer under both neutral and stress conditions in the FAI group (p < 0.05, respectively). Peritendinous edema of the peroneal tendons was found in 22% of the FAI group and 6% of controls.