Hybrid minimally invasive correction for flexible flatfeet in young adults: a prospective cohort study

TL;DR

A new surgical approach combining two procedures improves foot alignment and function in young adults with flexible flatfeet.

Contribution

A hybrid minimally invasive technique combining MDCO and STA is proposed for treating moderate to severe flexible flatfeet.

Findings

Significant radiological improvements were observed in talo-navicular coverage and talo-calcaneal angles after surgery.

AOFAS scores improved from an average of 62.69 preoperatively to 94.19 at three years postoperatively.

12.5% of patients experienced sinus tarsi pain, and 9.3% required removal of the arthroereisis implant.

Abstract

Introduction: This study aims to assess the functional and radiological outcomes of combining minimally invasive medial displacing calcaneal osteotomy (MDCO) with subtalar arthroereisis (STA) for the treatment of symptomatic planovalgus feet in young adults. Methods: A single-centre, prospective cohort study was conducted between November 2015 and February 2022. The study included a total of 32 patients with flexible flatfoot who were treated with subtalar arthroereisis combined with medialising calcaneal osteotomy with at least three years of follow-up. Radiographic evaluation included talar coverage angle, AP talo-first metatarsal (T1MT), AP talo-calcaneal, lateral talo-first metatarsal, and calcaneal pitch angles. Function was assessed by the AOFAS score. Results: Angles and scores were compared preoperatively and at the third-year follow-up. The mean talo-navicular coverage angle TNCA reduced from 32.72° (±8.33) preoperatively to 8.84° (±5.70) at the last follow-up. The mean AP T1MT improved from 21.59° (±8.47) preoperatively to 7.78° (±4.03) at three years postoperatively. Meary’s angle decreased from 20.84° (±7.14) preoperatively to 4.78° (±3.20) following the correction. The mean preoperative AOFAS score was 62.69 (±9.26), and significantly improved to 94.19 (±3.80) at the last follow-up. Four feet experienced sinus tarsi pain (12.5%), and three patients (9.3%) needed removal of the arthroereisis implant. Conclusions: The combination of MDCO and STA holds significant promise for treating flexible flatfeet in adolescents and young adults, particularly in cases of moderate to severe deformity. This combination demonstrates a synergistic interaction, with the STA implant providing internal bracing to support MDCO and reducing stresses over the medial arch by preventing hyper-pronation. Simultaneously, the MDCO reinforces the reconstruction, achieving the necessary increased correction in moderate to severe flatfoot cases, while also reducing stresses over the STA implant.

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