Effectiveness of a locking plate in preserving midcalcaneal length and positional outcome after Evans calcaneal osteotomy: a retrospective pilot study.

When using the Evans calcaneal osteotomy for repair of a calcaneovalgus deformity, lengthening of the lateral column of the foot is the method by which the procedure acts to correct the deformity. Therefore, maintaining the length is a priority. In our experience, substantial length is lost soon after surgery using the traditional nonfixated procedure. To test this hypothesis, a retrospective study was undertaken in which we compared the calcaneal length before and after the Evans procedures in 22 patients treated without fixation and 13 patients in whom the graft was fixated with a small locking plate to bridge the osteotomy and reduce the compressive forces on the graft. Within the first 10 days after surgery, the increase in calcaneal length from the preoperative length was 6.3 mm in the nonfixated group and 6.8 mm in the fixated group (p = .54 for the 0.5-mm difference). At 12 weeks after surgery, the mean amount of shortening from the value observed at 1 week was 2.45 (range 0 to 6) mm in the nonfixated group and 1.0 (range 0 to 3) mm in the internal fixation group (p = .48). Also, at 12 weeks, distal calcaneal migration or dorsal anterior calcaneal displacement of more than 3 mm occurred in 5 patients (23%) in the nonfixated group and 1 patient (8%) in the fixated group (p = .04). Our results suggest that locking plates do preserve the correction obtained with the Evans calcaneal osteotomy.