The effects of medial and lateral displacement calcaneal osteotomies on ankle and subtalar joint pressure distribution.

We compared the pressure distribution in the ankle and posterior facet of the subtalar joint following 1 cm medial and lateral displacement calcaneal osteotomies to the pressure distribution in the intact foot. Six cadaver specimens were loaded in neutral alignment while pressure measurements were recorded. A 1-cm medial displacement osteotomy shifted the average center of force in the ankle 1.0 mm medially (p = 0.36) while a lateral displacement osteotomy shifted the center of force 1.1 mm laterally (p = 0.42). There was also a slight shift in the percentage of pressure toward the side of the talus to which the calcaneus was shifted. For the lateral displacement osteotomy, the pressure increased 4.0% in the lateral-most quadrant (p = 0.05), while the medial osteotomy increased the pressure 1.3% in the medial quadrant (p = 0.30). In the subtalar joint, a medial displacement osteotomy shifted the pressure distribution slightly medially (5.9%, p = 0.06) and more anteriorly (9.6%, p = 0.02) while the distribution was shifted laterally (5.9%, p = 0.17) and anteriorly (5.6%, p = 0.03) with a lateral displacement osteotomy. These shifts of percentage of pressure between quadrants of the joints were slight-less than 5% in the ankle and less than 10% in the subtalar joint. Significant translation of the calcaneal tuberosity appears to have only a small effect on pressure distribution in the ankle and posterior facet of the subtalar joint in a weighted cadaver model.