Anatomy and Biomechanics of Cavovarus Deformity.

A high longitudinal plantar arch, varus position of the heel, forefoot equinus, and pronation of the first ray are characteristic of a cavovarus deformity. Forefoot-driven and hindfoot-driven deformities are distinguished based on pathomechanics. In first ray strong plantarflexion, the forefoot touches the ground first. This leads to compensatory varus heel, lock of the midfoot, reduction of the flexible phase, and decrease in shock absorption. In hindfoot-driven cavovarus deformity, the subtalar joint may compensate for varus deformities above the ankle joint. Overload of the lateral soft tissue structures and degenerative changes may occur in longstanding cavovarus deformity.