Displacement of the anterior process of the calcaneus after Evans calcaneal osteotomy

The Evans calcaneal osteotomy is an invaluable tool in the correction of pediatric collapsing pes planovalgus. It has traditionally been performed without the use of fixation. Recently, however, fixation of the Evans osteotomy has been proposed to prevent displacement. A retrospective radiographic study was performed of 33 patients (50 feet) to examine the amount of displacement of the anterior process after performing the Evans osteotomy without fixation. The anterior process height was measured digitally from the radiographs on the lateral view preoperatively, at approximately 6 weeks postoperatively, and at the final follow-up visit. The patients were followed up to a mean of 30.57 (range, 6 to 107) weeks postoperatively. The anterior process showed a statistically significant dorsal displacement of 1.21 mm (95% confidence interval 0.29, 2.12, P = .0001) at 6 weeks postoperatively. This had diminished to an insignificant dorsal displacement of 0.57 mm (95% confidence interval -0.21, 1.34, P = .148) at the final follow-up visit. Clinically and statistically significant improvements in the calcaneal inclination and talar declination angles were observed in the early and late postoperative periods. None of the patients experienced a postoperative complication that required a return to the operating room.