Impact of forefoot width variation on clinical and functional outcomes following the Lapidus procedure

Purpose: This study aimed to evaluate the effect of variations in bony and soft tissue foot widths on clinical and functional outcomes after hallux valgus correction with the Lapidus procedure.

Methods: Forty-three feet in 35 patients with a mean follow-up of 18.5 months undergoing the LP were reviewed. Clinical and functional data were assessed with the VAS for pain, AOFAS Scale, LEFS and SF-12 health survey, which is divided into physical and mental health composite scales (PCS-12 and MCS-12). Radiographic analysis of forefoot width was based on bony and soft tissue limits. Intermetatarsal-angle and HV-angle were also assessed.

Results: Bony width changed significantly from 95.5 mm to 84.2 mm (11.8%) and soft tissue width from 107.12 mm to 100.84 mm (5.86%) (p < 0.001). IMA and HVA improved significantly. Significant clinical and functional improvements were observed, except in MCS-12. In simple linear regression, correlation was found between variations of bony width with Δ-AOFAS and Δ-PCS-12, meaning that as the forefoot narrows, their values increase (p = 0.02 and p = 0.005, respectively). It was also related to Δ-IMA, meaning that the forefoot narrows as these parameters improve (p < 0.001 and p < 0.001). Soft tissue width was related to Δ-PCS-12 and Δ-AIM. In multiple linear regression, the strongest correlation was between bony width variation and Δ-IMA (p = 0.029, r² = 0.22).

Conclusion: Forefoot narrowing was correlated with improved clinical and functional outcomes, as measured by AOFAS and PCS-12. In addition, correction of the radiographic parameters, mainly IMA, reflected on a significant decrease in the forefoot width.