The role of isolated gastrocnemius and combined Achilles contractures in the flatfoot.

In the absence of bony deformity, ankle equinus is generally the result of shortening within the gastrocnemius-soleus complex. Restriction of ankle dorsiflexion as a proxy for equinus contracture has been linked to increased mechanical strains and resultant foot and ankle pathology for a long time. This entity has many known causes, and data suggest it can manifest as either an isolated gastrocnemius or combined (Achilles) contracture. Numerous disorders of the foot and ankle have been linked with such "equinus disease", and although some of these relationships remain controversial, a reasonably convincing relationship between equinus contracture and the development of flatfoot exists. What is still perhaps most misunderstood is the temporal association between these two pathologies, and hence higher levels of evidence are needed in the future to define more precisely the interplay between flatfoot deformity and gastrocnemius-soleus tightness.