Correlation of postoperative midfoot position with outcome following reconstruction of the stage II adult acquired flatfoot deformity

Background: No studies investigating the effect of the midfoot (talonavicular joint) position on clinical outcomes following flatfoot reconstruction have been performed. The purpose of our study was to determine whether a postoperative abducted or adducted forefoot alignment, as determined from anteroposterior (AP) radiographs, was associated with a difference in outcomes using the Foot and Ankle Outcome Score (FAOS).

Methods: Midfoot abduction was defined on postoperative AP radiographs, evaluated at a mean of 1.9 years in 55 patients from the authors' institution who underwent flatfoot reconstruction for a stage II adult acquired flatfoot deformity (AAFD), as a lateral incongruency angle greater than 5 degrees, a talonavicular uncoverage angle greater than 8 degrees, and a talo-first metatarsal angle greater than 8 degrees based on previously reported measurements. Patients with 2 or more measurements in the abduction category were classified as the abduction group (n = 30); those with 1 or fewer measurements in the abduction category were placed in the adduction group (n = 25). The preoperative and postoperative FAOS values with a mean follow-up of 3.1 years were compared using Wilcoxon rank-sum tests.

Results: Patients corrected to a position of adduction showed significantly lower improvement in the FAOS daily activities (P = .012) and quality of life subscales (P = .046). The mean improvement in subscale scores for the adducted group was lower for pain (P = .052) and sports activities (P = .085) but did not reach statistical significance. No significant difference in the FAOS symptoms subscale (P = .372) between groups was found.

Conclusion: Correction of the talonavicular joint to a position of adduction following a stage II AAFD was associated with decreased patient outcomes in daily activities and quality of life compared with an abducted position. These results suggest that overcorrection to a position of midfoot adduction leads to a lesser amount of individual patient improvement in reconstruction of a stage II AAFD.