Effect of the Modified Lapidus Procedure for Hallux Valgus on Foot Width

Background: Despite the importance of shoe wear to patients with hallux valgus (HV), few studies have investigated changes in foot width following surgery in this population. The purpose of our study was to determine if the modified Lapidus procedure would effectively decrease foot width in patients with HV. Methods: Thirty-one feet (19 left, 12 right) in 30 patients (29 females, 1 male) who underwent a modified Lapidus procedure in combination with a modified McBride and Akin osteotomy for treatment of HV were included in the study. All patients had preoperative and at least 5-month postoperative imaging, consisting of both weightbearing radiographs and computed tomography (WBCT) scans, which were used to measure bony and soft tissue foot widths pre- and postoperatively by 2 independent observers. Results: Intraclass correlation coefficients (ICCs) demonstrated high interobserver reliability (all ICCs >0.90). Bony foot width decreased significantly, by a mean of 8.9 mm (9.1%) on radiographs and 7.9 mm (8.4%) on WBCT scans (P < .001). The soft tissue foot width also decreased significantly, by a mean of 6.9 mm (6.3%) on radiographs and 6.7 mm (6.4%) on WBCT scans (P < .001). Changes in the hallux valgus angle and intermetatarsal angle correlated with changes in bony foot width on WBCTs (both r > 0.4, P < .02). Conclusions: The modified Lapidus procedure in combination with a modified McBride and Akin osteotomy resulted in statistically significant changes in both bony and soft tissue foot width. Patients should be counseled that foot width decreases, on average, by 0.5 to 1 cm.