Postoperative Medial Cuneiform Position is Correlated with Patient-Reported Outcomes Following Cotton Osteotomy for Reconstruction of the Stage II Adult Acquired Flatfoot Deformity

CATEGORY: Hindfoot, Midfoot/Forefoot INTRODUCTION/PURPOSE: During reconstruction of the stage II adult acquired flatfoot deformity (AAFD), residual supination of the midfoot is often addressed with an opening wedge medial cuneiform (Cotton) osteotomy after adequate correction of the hindfoot valgus deformity. The purpose of this study was to determine if there was a correlation between postoperative alignment of the medial cuneiform using the previously described cuneiform articular angle (CAA) on lateral radiographs and postoperative patient-reported outcomes using the Foot and Ankle Outcome Score (FAOS). METHODS: Sixty-three feet in 61 patients with stage II AAFD who underwent a Cotton osteotomy as part of a flatfoot reconstruction were included the study. The CAA, medial arch sag angle (MASA), and lateral talo-first metatarsal (Meary’s) angles were measured on postoperative weightbearing lateral radiographs at a minimum of 40 weeks postoperatively. Pearson’s correlation analysis was used to determine if there was an association between postoperative radiographic angles and FAOS at a minimum of 24 months postoperatively. Patients were also divided into mild plantarflexion (CAA> or =-2 degrees) and moderate plantarflexion (CAA<-2 degrees) groups, and Wilcoxon rank-sum tests were used to identify whether there were differences in clinical outcomes between the two medial cuneiform positions. A postoperative CAA of -2 degrees was chosen because it is two standard deviations from the average postoperative CAA following a flatfoot reconstruction (Castaneda et al. FAI 2012). RESULTS: Postoperative CAA was significantly positively correlated with the postoperative FAOS symptoms (r=.27, P=.03), daily activities (r=.29, P=.02), sports activities (r=.26, P=.048), and quality of life (r=.28, P=.02) subscales. A positive correlation indicates that higher postoperative FAOS scores are associated with a decreased amount of plantarflexion of the medial cuneiform (i.e. a more positive CAA). Patients in the mild plantarflexion group had statistically and clinically better outcomes compared with the moderate plantarflexion group in the FAOS symptoms (P=.04), daily activities (P =.04), and sports activities (P=.01) subscales (Figure 1). Graft size was correlated with postoperative CAA (r =-.30, P = .02) but not correlated with any postoperative FAOS subscale (all P values > .40). CONCLUSION: Our study suggests that the surgeon should avoid excessive plantarflexion of the medial cuneiform and use the Cotton osteotomy judiciously as part of a flatfoot reconstruction for stage II AAFD.