A 14% Rate of Surgery in Modern Rigo Chêneau Bracing for Adolescent Idiopathic Scoliosis: In-Brace Correction and Brace Wear Contribute to Treatment Success

PURPOSE: Rigo Chêneau-style orthoses (RCSOs) have gained popularity for treating adolescent idiopathic scoliosis (AIS) due to their emphasis on 3-dimensional correction. However, previous studies lack objective measures of brace wear compliance and have not described in-brace correction (IBC) thresholds associated with treatment success. This study evaluated the relationship between IBC, brace wear, and treatment outcomes in AIS patients treated with RCSOs. METHODS: A retrospective review at a single academic institution included skeletally immature patients aged 10 to 18 years with AIS and a major curve of 20 to 40 degrees, who underwent full-time RCSO treatment with thermal wear-time sensors. Patients were followed until skeletal maturity or progression to surgery. Treatment success was defined as a change of ≤5 degrees in the major curve at the latest follow-up. Multivariable logistic regression identified predictors of treatment success. RESULTS: Fifty patients (45 females, 90%) were included, with 36 (72%) classified as Sanders stage 3 and a mean age at brace initiation of 12.4±1.2 years (range: 10.1 to 15.5). The mean baseline major curve was 31±5 degrees with an IBC of 55±20%. The mean brace wear was 11.7±3.6 hours per day. At a mean follow-up of 3.0±0.9 years (range: 1.1 to 5.3), 43 patients (86%) avoided surgery and 36 (72%) met criteria for treatment success, with a mean major curve of 32±12 degrees. Greater IBC (60% vs. 40%, P<0.001) and brace wear (12.4 vs. 10.0 h, P=0.034) were associated with treatment success in univariate analysis, with IBC remaining an independent predictor in multivariable analysis (P=0.013). An IBC ≥45% was associated with treatment success (AUC=0.79). Patients achieving ≥45% IBC (n=33) demonstrated significantly higher success rates (88% vs. 41%, P<0.001) and lower rates of progression to surgery (6% vs. 29%, P=0.037). CONCLUSIONS: In this study, which included objective compliance data, 3-dimensional RCSO bracing in AIS was associated with high rates of treatment success. Greater IBC and brace wear were associated with improved outcomes, with IBC emerging as the primary independent predictor of success. An IBC of 45% was associated with improved outcomes and may represent a clinically meaningful target in modern 3-dimensional bracing. LEVEL OF EVIDENCE: Level IV.