The effect of the Risser stage on bracing outcome in adolescent idiopathic scoliosis

Background: To determine the influence of the Risser sign on the need for surgery in children wearing orthoses for the treatment of adolescent idiopathic scoliosis (AIS), data on compliance with brace wear were collected and analyzed. Methods: One hundred and sixty-eight patients were prospectively enrolled at the timethat brace wear had been prescribed and were followed until the cessation of bracing or the need for surgery. Inclusion criteria were a curve magnitude between 25° and 45°; a Risser stage of 0, 1, or 2; and, if female, <1 year post menarche at the time of brace prescription. Compliance was measured using thermal monitors. Results: The prevalence of surgery, or progression to a curve magnitude of ≥50°, was 44.2% for patients at Risser stage 0 (n = 120), 6.9% for patients at Risser stage 1 (n = 29), and 0% for patients at Risser stage 2 (n = 19). Brace wear averaged 11.3, 13.4, and 14.2 hours per day for the Risser stage-0, 1, and 2 groups, respectively. While the groups had no difference in initial curve magnitude (p = 0.11), more patients at Risser stage 0 had progression to surgery than did patients at Risser stage 1 or stage 2 despite bracing (p < 0.0001). Twenty-six (41.9%) of 62 Risser stage-0 patients who wore braces ≥12.9 hours per day had progression to surgery. Ten patients at Risser stage 0 with closed triradiate cartilage wore braces ≥18 hours per day, and none underwent surgery. In comparison, 7 of 10 patients at Risser stage 0 with open triradiate cartilage and similar daily brace wear underwent surgery. Of 9 patients at Risser stage 0 with open triradiate cartilage who wore braces ≥12.9 hours daily for curves measuring <30°, 7 had a nonsurgical outcome. Conclusions: Patients at Risser stage 0 are at risk for surgery despite brace wear. In these patients, 12.9 hours of daily wear-the number of hours linked with a successful outcome in the BRAIST (Bracing in Adolescent Idiopathic Scoliosis Trial)-did not prevent surgery. Patients with open triradiate cartilage were at highest risk, especially those with curves of ≥30°. Risser stage-0 patients should be prescribed a minimum of 18 hours of brace wear. Bracing should be initiated for curves of <30° in patients at Risser stage 0, especially those with open triradiate cartilage. Level of Evidence: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.