First Metatarsal Length Change and Clinical Outcomes After Osteotomy for Mild-to-Moderate Incongruent Hallux Valgus: A Retrospective Cohort Study.

Abstract

Radiographic correction after hallux valgus surgery may not fully explain clinical outcomes, and first metatarsal length change may be an additional structural factor associated with function. To evaluate the association between postoperative first metatarsal length change and clinical outcomes after distal Turan (Lindgren-Turan) and proximal medial open-wedge osteotomies for mild-to-moderate incongruent hallux valgus. Retrospective cohort study (Level 3). Fifty patients who underwent isolated distal Turan (Lindgren-Turan) or proximal medial open-wedge osteotomy for mild-to-moderate incongruent hallux valgus were retrospectively analyzed. Outcomes were assessed preoperatively and at final follow-up using weight-bearing radiographs, VAS, the American Orthopaedic Foot and Ankle Society (AOFAS) score, and the EQ-5D summed descriptive score. The primary analysis evaluated the association between first metatarsal length change and postoperative AOFAS score, with an exploratory adjusted regression model. Mean follow-up was 38 months. Significant postoperative improvement was observed in hallux valgus angle, intermetatarsal angle, VAS, AOFAS, and EQ-5D score. Greater positive first metatarsal length change was associated with lower postoperative AOFAS score (rho = -0.401, p = 0.004), persisting in the adjusted model (B = -0.50 per mm, p = 0.003), and with less AOFAS improvement (rho = -0.361, p = 0.010). No significant association was observed with angular parameters or angular correction. First metatarsal length change was associated with postoperative function and may add information beyond angular measurements. Because it was closely related to surgical technique and not randomized, it should be interpreted as a procedure-associated structural marker rather than a causal effect. 3.