Subtalar arthroereisis in pediatric flexible flat foot: Functional and radiographic results with 5 years of average follow-up.

The aim of this retrospective study is to evaluate the clinical-functional and radiographic results in pediatric patients with painful and disabling Flexible Flat Foot (FFF) refractory to conservative treatment who underwent percutaneous subtalar arthroereisis with a Maxwell Brancheau Arthroereisis® (MBA) implant. Patients aged 8-14 years old with a minimum follow-up of 24 months were included. A pre and postoperative radiographic evaluation was carried out analyzing Meary's angle, internal Moreau-Costa-Bartani´s angle, Talar declination angle, Calcaneal Pitch, Kite's angle, Talar-1st metatarsal angle, and Talonavicular coverage angle. In those patients with more than 5 years of follow-up, the development of subtalar osteoarthritis was evaluated. A clinical-functional evaluation was carried out using the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot rating scale. Pre and postoperative pain was evaluated using the visual analog scale (VAS). Postoperative complications were described. Fourteen patients (19 feet) met the inclusion criteria. The mean age at surgery was 12 years old with a mean follow-up of 68.26 months. All radiographic angles improved significantly. No signs of subtalar osteoarthritis were identified. The mean pre and postoperative pain according to VAS was 7.05 and 0.77 respectively. The mean pre and postoperative AOFAS was 75.42 and 97.05 respectively. One female patient had persistent pain in both feet (VAS = 4). However, she was able to do sports and daily life activities without restrictions. None of the implants needed to be removed due to intolerance or pain. Subtalar arthroereisis seems to be effective to improve the clinical-functional and radiographic parameters in moderate pediatric FFF.