Calcaneal osteotomy in the treatment of adult acquired flatfoot deformity.

Calcaneal osteotomies are an essential part of our current armamentarium in the treatment of AAFD. Soft tissue correction or bony realignment alone have failed to adequately correct the deformity; therefore, both procedures are used simultaneously to achieve long-term correction. Medial displacement and lateral column lengthening osteotomies in isolation or in combination and the Malerba osteotomy have been employed along with soft tissue balancing to good effect by various authors. The goal is to create a stable bony configuration with adequate soft tissue balance to maintain dynamic equilibrium in the hindfoot. In “pronatory syndromes,” the relation of the osteotomy to the posterior subtalar facet modifies the biomechanics of the hindfoot in different ways. Anterior calcaneal osteotomies correct deformities in the transverse plane (forefoot abduction), whereas posterior tuberosity osteotomies result in “varization” of the calcaneus and correct the frontal plane deformity. The choice of osteotomy depends on the plane of the dominant deformity. If the subtalar axis is more horizontal than normal, transverse plane movement is cancelled out and the frontal plane eversion–inversion is predominant. The patient presents with marked hindfoot valgus without significant forefoot abduction. Conversely, if the subtalar axis is more vertical than normal, transverse plane movement is predominant and the patient presents with forefoot abduction and instability of the medial midtarsal joints, although without significant hindfoot valgus. In this situation, a lateral column lengthening procedure is recommended to decrease the uncovering of the talar head and improve the height of the arch while correcting the forefoot abduction. With a predominant frontal plane deformity, medialization of the calcaneal tuberosity is used to displace the calcaneal weight bearing axis medially, aligning it with the tibial axis and restoring the function of the gastrosoleus as a heel invertor. An essential prerequisite for this is the absence of arthritis affecting the subtalar joint. The Achilles tendon may need to be lengthened at the same time.