Combined Minimally Invasive Chevron-Akin and Distal Minimally Invasive Metatarsal Osteotomy for Hallux Valgus and Metatarsalgia: 12-Month Outcomes and High Radiographic Recurrence in a Dual-Center Study

Abstract

Background:

Minimally invasive techniques for forefoot surgery, including the minimally invasive chevron-Akin (MICA) and distal minimally invasive metatarsal osteotomy (DMMO), have demonstrated favourable outcomes in the treatment of hallux valgus and central metatarsalgia, respectively. Combining these 2 procedures in a single surgical session aims to address multiple deformities concurrently, although potential biomechanical interactions may affect long-term stability. This study investigates the clinical and radiographic outcomes of patients undergoing simultaneous MICA and DMMO, with a focus on hallux valgus recurrence.

Methods:

This retrospective, dual-international-centre study included 100 feet from 98 patients who underwent concomitant MICA and DMMO (2nd–4th metatarsals) between 2019 and 2023 at 2 specialized minimally invasive surgery (MIS) centers. Inclusion criteria were symptomatic hallux valgus with central metatarsalgia unresponsive to conservative treatment and a minimum 12-month follow-up. Radiographic outcomes (hallux valgus angle [HVA], intermetatarsal angle [IMA]) and patient-reported outcomes (Patient-Reported Outcomes Measurement Information System [PROMIS], visual analog scale [VAS]) were assessed preoperatively and postoperatively at 3 and 12 months. Radiographic recurrence was defined as HVA >20 degrees at 12-month follow-up.

Results:

Significant improvements were observed in radiographic parameters, with the mean IMA decreasing from 14.65 degrees preoperatively to 9.8 degrees at 3 months and 10.1 degrees at 12 months (95% CI: 8.1-14, P = .028), and the mean HVA decreasing from 39.6 degrees to 16.8 degrees and 22.6 degrees at the respective time points (95% CI: 12-41, P = .024). Despite significant radiographic improvements, recurrence (HVA > 20 degrees) was observed in 75 of 100 feet (75%), although the degree of recurrence was mild (mean HVA 22.6 degrees at 12 months vs 16.8 degrees at 3 months). PROMIS physical function scores improved from 42.3 ± 6.2 to 59.9 ± 4.8 at 3 months and 71.4 ± 5.1 at 12 months (95% CI: 25.6-32.6, P = .011), with a 12-month gain of 29.1 points, surpassing the Minimal Clinically Important Difference (MCID) of 4.5 to 6.0. PROMIS pain interference scores decreased from 63.5 ± 5.7 to 48.2 ± 6.1 and 39.6 ± 5.4 (95% CI: −27.4 to −20.4, P = .021), whereas PROMIS pain intensity improved from 6.9 ± 1.1 to 4.3 ± 1.3 and 2.1 ± 1.0 (95% CI: −5.3 to −4.2, P = .023). VAS pain scores also declined from 7.3 to 2.3 (95% CI: 1-5, P = .021). All PROMIS changes exceeded their respective MCID thresholds.

Complications included delayed DMMO union in 1% of osteotomies and superficial wound infections in 4% of patients. Symptomatic hardware removal occurred in 10% of patients, and persistent metatarsalgia in 6%.

Conclusion:

Simultaneous MICA and DMMO procedures result in substantial improvements in radiographic alignment and patient-reported outcomes, despite a high rate of mild radiographic recurrence at 12 months. The inconsistency between radiographic recurrence and patient satisfaction may be explained by pain relief and functional gains. Nevertheless, surgeons should recognize the substantially elevated risk of hallux valgus recurrence possibly related to biomechanical destabilization from concurrent DMMO and consider whether staged procedures may be more appropriate. Further long-term studies are needed to assess the durability of correction and refine patient selection criteria.