Abstract
BACKGROUND: Hallux abductus valgus (HAV) is a common, complex forefoot deformity with significant clinical and functional implications. While minimally invasive surgery (MIS) often results in better recovery and improved cosmetic outcomes, adjunctive procedures such as zig-zag tenotomy of the extensor hallucis longus (EHL) tendon remain poorly documented. This study aims to evaluate the clinical, structural, and functional outcomes of MIS with and without EHL tenotomy in patients with moderate to severe HAV. METHODS: This was a prospective, randomized, controlled, single-blind clinical trial conducted in a private clinic in Alicante, Spain, between February 2024 and June 2025. Adults aged 20-90 years with moderate/severe HAV and hallux hyperextension were randomized (ABBA sequence, concealed by independent investigator) to MIS with zig-zag EHL tenotomy (n = 25) or MIS without tenotomy (n = 21). Both groups underwent Reverdin-Isham and Akin osteotomies plus adductor tenotomy. PRIMARY OUTCOME: change in the hallux valgus angle (HVA) at 12 months. SECONDARY OUTCOMES: changes in PASA, IMA, DASA, MPA, IPA, mean and peak plantar pressure (static baropodometry, S-Plate®), and AOFAS score. Intra- and intergroup differences were analyzed using t-tests and repeated-measures ANOVA, reporting p-values and effect sizes (Cohen's d, 95% CI). RESULTS: Of 49 patients assessed, 46 were randomized (4 men, 42 women; mean age 62.0 ± 13.6 years). At 12 months, both groups improved significantly in HVA: tenotomy group - 18.2° (95% CI - 21.9 to - 14.5; d = 1.73; p < 0.001) vs. no-tenotomy - 16.9° (95% CI - 21.5 to - 12.3; d = 1.83; p < 0.001), with no significant between-group difference. The tenotomy group showed greater reductions in PASA (- 5.68°, d = 1.12), IMA (- 4.16°, d = 1.30), and IPA (- 12.17°, d = 1.20). Mean plantar pressure increased significantly only in the tenotomy group (+ 18.7 g/cm(2); p = 0.04). Peak plantar pressure remained unchanged in both groups. AOFAS scores improved significantly and similarly in both groups (time*group interaction, p = 0.38). CONCLUSIONS: In moderate/severe HAV, adding zig-zag EHL tenotomy to MIS may provide additional benefits in radiographic correction and plantar load redistribution without impairing functional recovery. These findings support its use in complex deformities or high tendon tension, though longer-term follow-up is needed to assess stability and recurrence. TRIAL REGISTRATION: ClinicalTrials.gov ID NCT06243471 (Feb 2024).