Spring Ligament Instability.

The crucial role of the spring ligament complex within the pathologic process that leads to flatfoot deformity has evolved recently. There has been improvement in the anatomic knowledge of the spring ligament and understanding of its complex relationship to the deltoid complex and outstanding advances in biomechanics concepts related to the spring ligament. Optimization of flatfoot treatment strategies are focused on a renewed interest in the spring ligament and medial soft tissue reconstruction in concert with bony correction to obtain an adequate reduction of the talonavicular deformity and restoration of the medial longitudinal arch.