Subtalar arthroereisis with calcaneal stop screw for symptomatic flexible flatfoot in children A prospective case series

Symptomatic flexible flatfoot in children and adolescents can cause pain, functional limitations, and reduced quality of life. Subtalar arthroereisis with the calcaneal stop screw (CSS) is a minimally invasive surgical option; however, prospective data on combined radiographic and clinical outcomes using validated pediatric instruments are limited. This study aimed to evaluate the radiographic and clinical outcomes of CSS in children with symptomatic flexible flatfoot. In this prospective case series, 60 children and adolescents (42 boys, 18 girls; mean age 11.8 ± 1.9 years) with symptomatic flexible flatfoot who underwent CSS arthroereisis were enrolled. Radiographic parameters (calcaneal pitch angle, talar inclination angle, and Costa-Bartani angle) were measured on weight-bearing radiographs. Clinical outcomes were assessed using the Oxford Ankle Foot Questionnaire for Children (OxAFQ-C), a validated pediatric instrument. Assessments were performed preoperatively and at six weeks, three, six, and twelve months postoperatively. Linear mixed models were used for statistical analysis to account for repeated measures. All radiographic parameters improved significantly at 12 months postoperatively (p < 0.001 for all). The calcaneal pitch angle increased from 12.7° ± 3.0° to 18.3° ± 3.3°, the talar inclination angle decreased from 27.9° ± 5.8° to 20.3° ± 2.7°, and the Costa-Bartani angle decreased from 135.2° ± 5.4° to 125.9° ± 4.8°. OxAFQ-C scores also improved significantly across all domains (p < 0.001 for all), with all improvements substantially exceeding previously reported minimal clinically important difference thresholds. Concomitant percutaneous Achilles tendon lengthening was performed in 12 patients (20%). No major complications were observed. Subtalar arthroereisis with the calcaneal stop screw appears to be a safe and effective minimally invasive procedure for symptomatic flexible flatfoot in children and adolescents, leading to significant improvements in both radiographic alignment and clinical outcomes at one year postoperatively. Longer-term comparative studies are warranted to confirm the durability of these results. Level IV, therapeutic case series This study was registered as a prospective case series with the Iranian Registry of Clinical Trials (IRCT20250817066885N1).