The hindfoot and its relation to rotational deformities of the forefoot.

The movements occurring at the various joints of the foot are complex, and since deformities can arise at each joint, classification of the deformities of the foot can be confusing. The position of the hindfoot can be conveniently described using the relationship of the long axis of the calcaneus to the long axis of the tibia. The position of the forefoot can then be related to that of the hindfoot. Rotation of the forefoot occurs as a result of relative movements of the talus and calcaneus and is a noticeable feature of the valgus or flat foot. Various types of valgus foot are recognized, e.g., calcaneovalgus, equinovalgus or "vertical talus," and so-called "postural" valgus. A variation is described in which the hindfoot is valgus by definition, when the patient is standing, but in which after correction the talus moves into an abnormally horizontal position relative to the calcaneus and the forefoot assumes a position of marked supination, almost appearing to stand on its lateral edge. This deformity has been observed in paralytic conditions and also in an idiopathic form. It may be correctable if detected early but if allowed to progress may result in a persistent deformity, producing discomfort and excessive shoe wear. In the late stage correction of the hindfoot may, if the rotational component is not recognized, result in an unacceptable forefoot position.