Preoperative Planning and Intraoperative Technique for Accurate Translation of a Distal First Metatarsal Osteotomy

Abstract

We used preoperative radiographic and intraoperative anatomic measurements to predict and achieve, respectively, the precise amount of capital fragment lateral translation required to restore anatomic balance to the first metatarsophalangeal joint. Correlation was used to relate the amount of capital fragment translation and operative reduction of the first intermetatarsal angle (IMA), hallux abductus angle (HAA), tibial sesamoid position (TSP), metatarsus adductus angle, and first metatarsal length. The mean capital fragment lateral translation was 5.54 ± 1.64 mm, and the mean radiographic reductions included a first IMA of 5.04° ± 2.85°, an HAA of 9.39° ± 8.38°, and a TSP of 1.38 ± 0.9. These changes were statistically (p < .001) and clinically (≥32.55%) significant. The mean reduction of the metatarsus adductus angle was 0.66° ± 4.44° and that for the first metatarsal length was 0.33 ± 7.27 mm, and neither of these were statistically (p = .5876 and 0.1247, respectively) or clinically (≤3.5%) significant. Pairwise correlations between the amount of lateral translation of the capital fragment and the first IMA, HAA, and TSP values were moderately positive and statistically significant (r = 0.4412, p = .0166; r = 0.5391, p = .0025; and r = 0.3729, p = .0463; respectively). In contrast, the correlation with metatarsus adductus and the first metatarsal shortening were weak and not statistically significant (r = 0.2296, p = .2308 and r = −0.2394, p = .2109, respectively). The results of our study indicate that predicted preoperative and executed intraoperative lateral translation of the capital fragment correlates with statistically and clinically significant reductions in the first IMA, HAA, and TSP.