Immediate in-brace correction and 1-year radiographic stability after a hybrid textile brace for adolescent idiopathic scoliosis: a retrospective cohort study

PURPOSE: brace (VNTC, Seoul, Republic of Korea) is a hybrid spinal orthosis designed to prevent curve progression in adolescent idiopathic scoliosis (AIS). Given that AIS often involves both structural deformity and flexibility-dependent components, evaluating brace effects requires assessing curve flexibility in addition to Cobb angle magnitude. This study examined the immediate in-brace correction and its long-term follow-up outcomes. METHODS: This retrospective study analyzed data from participants aged 9-17 years, diagnosed with AIS. Pre-brace standing and supine radiographs were used to assess curve flexibility. In-brace standing radiographs were taken on the day of application. Follow-ups at 6 months and 1 year recorded Cobb angles. RESULTS: Among 108 patients (82 girls and 26 boys), 75 were followed for 6 months and 58 for 1 year. The mean age at brace application was 13.4 ± 1.7 years, and the mean Risser grade was 2.8 ± 1.5. The mean Cobb angles of the primary curve were 24.7 ± 9.6° (supine) and 32.7 ± 10.3° (standing), indicating a degree of flexibility component averaging 8.1 ± 4.8°, corresponding to 25.4 ± 14.3% of standing scoliosis angle. Immediate correction of the flexible component averaged 68.6 ± 34.7%. At 6 months, 14.7% showed improvement, 69.3% stabilization, and 16.0% progression. At 1 year, 17.2% of evaluable patients showed improvement and 51.7% stabilization, while 31.0% demonstrated progression exceeding 5°. Flexibility was significantly associated with immediate in-brace correction (r = 0.39, p < 0.001). CONCLUSION: The hybrid textile brace was associated with significant immediate radiographic correction, particularly in flexible curves. Baseline flexibility is informative in anticipating the immediate corrective response, whereas the uncontrolled design precludes conclusions regarding long-term clinical effectiveness.