The relationship between compliance of physiotherapeutic scoliosis specific exercises and curve regression with adolescent idiopathic scoliosis: a retrospective, age- and sex-matched case-control study

Abstract

Introduction: Physiotherapeutic scoliosis specific exercise (PSSE) reduces Cobb angles of patients with mild to moderate adolescent idiopathic scoliosis (AIS) through an appropriate exercise compliance (EC), but avoiding overtreatment is crucial. Research Question: To determine the requisite EC of PSSE for achieving curve regression; to analyze whether the apical translation (AT), apical wedging (AW), and apical rotation (AR) of the major curve improve with regression effect. Methods: Between 2019 and 2021, a total of 2072 patients with AIS were treated with either bracing or PSSE at our scoliosis clinic. Of those, 763 patients undertook only PSSE for a consecutive 6-month. This resulted 426 patients, namely 213 with curve regression and 213 age- / sex-matched with curve stabilization/ deterioration at the 6-month, were eligible for regression analysis to detect the relationship between EC and regression effect at the 6-month; receiver operating characteristic (ROC) curve analysis and Youden’s index were applied to identify the threshold of EC leading to curve regression at the 6-month. The AT, AW, and AR of the major curve were compared before and after 6-month PSSE to investigate the radiographic parameters that improved with regression effect. Results: EC was correlated with regression effect (odds ratio: 19.9, 95% confidence interval: 11.3–35.0, p < 0.001) and the cutoff threshold of EC was 4.4 h/week for 6 months to realize such an effect. AT was improved by 47.6% with curve regression, in which 152 cases remained curve regression whereas 61 cases presented curve stabilization and no case progressed into the operative threshold at the 1.5-year follow-up. Conclusions: A 6-month PSSE protocol of 4.4 hours per week was potentially leading to curve regression in treating mild to moderate scoliosis. An improvement in AT of the major curve was observed with the regression effect. Discussion: Studies demonstrated the ability of PSSE to reduce the Cobb angle; it is thus crucial to determine the EC realizes such a reduction. In addition, the effects of PSSE in changing vertebral monography remain unknown, understanding these effects can help researchers discover how PSSE remodels deformed vertebrae. This study defined the cutoff threshold of EC leading to curve regression and revealed that AT improved with the curve regression.