Evans Calcaneal Osteotomy: Assessment of Multiplanar Correction.

Flatfoot deformity consists of collapse of the medial arch, forefoot abduction, increased talonavicular uncoverage, and hindfoot valgus. Although numerous soft tissue and bony procedures have been proposed to correct each plane of deformity, there is a lack of objective data in the literature quantifying the amount of structural correction. The purpose of this study was to quantify the multiplanar deformity correction of the lateral column lengthening osteotomy (Evans) on hindfoot alignment through objective, reproducible, radiographic measurements. We retrospectively reviewed 45 Evans calcaneal osteotomy procedures in 24 female (53%) and 21 male (47%) feet performed on 40 patients (5 bilateral). The mean follow-up was 53 weeks (range, 32-116). The mean age at the time of surgery was 35 years (range, 11-73). Statistically significant improvement in radiographic alignment was found in the calcaneal inclination angle, tibial-calcaneal angle, tibial-calcaneal position, and the anteroposterior talo-first metatarsal angle (p < .0001 for all). Although a direct correlation between graft size and degree of angular correction was not observed, it should be noted the calcaneal graft size (mean, 11.8 mm) and the amount of hindfoot valgus correction (mean, 12.6°) appear to be clinically related. The results of this study support that the Evans calcaneal osteotomy corrects the hindfoot alignment in 3 planes as evidenced by our multiplanar radiographic measurements.