Predicting Postoperative Sagittal Plane Alignment of the Foot Using Intraoperative Simulated Weightbearing Lateral Imaging During Flatfoot Reconstructive Surgery: A Short-Term Retrospective Analysis

Abstract

The sagittal plane relationship of the hindfoot and midfoot joints is a primary determinant of proper alignment in flatfoot reconstructive surgery as assessed both clinically and on postoperative weightbearing (WB) lateral radiographs. The traditional approach to intraoperative radiographic imaging allows for accurate assessment of fixation placement but only a crude evaluation of final sagittal plane alignment. Surgeons employ various methods in an attempt to load the foot during lateral imaging. Skepticism exists regarding the ability of simulated WB fluoroscopy to predict the final outcome, and evidence is lacking to support this practice. A retrospective investigation was performed assessing the correlation of Meary's angle, calcaneal inclination angle, and calcaneal-1st metatarsal angle as demonstrated on intraoperative simulated WB lateral foot imaging to 10- week postoperative full WB lateral radiographs. A consistent simulated WB imaging protocol was used with 46 consecutive cases of flatfoot reconstruction in this analysis of secular trends. The average change in Meary's angle between intraoperative simulated WB and postoperative full WB was -1.09° with 89% of cases within ±5°. The average change in calcaneal-1st metatarsal angle between intraoperative simulated WB and full WB was -2.61° with 85% of cases within ±5°. The average change in calcaneal inclination angle between intraoperative simulated WB and full WB was -2.62° with 88% of cases within ±5°. These findings confirm the clinical utility of intraoperative simulated WB lateral imaging as a useful tool in predicting the postoperative sagittal plane alignment of the midfoot and rearfoot in patients undergoing flatfoot reconstructive surgery.