The Dyna Ankle is primarily used to treat lateral ligament ruptures, but it is also very suitable for the treatment of medial ligament ruptures. Distortion of the upper ankle with lateral ligament rupture usually occurs as a result of excessive plantar flexor supination strain. The talofibular anterior ligament is always affected, so relieving strain on this outer ligament is important for treatment. The dynamic ankle orthosis Dyna Ankle was developed for functional treatment and places the foot in a position with slight pronation and dorsal extension. Plantar flexion and supination are restricted through a dynamic restraint, while the degree of pronation and dorsal extension motion is unrestricted.