Value of thumb ossification composite index for predicting peripubertal growth potential in girls with adolescent idiopathic scoliosis

Abstract

Objective: To evaluate the predictive value of thumb ossification composite index (TOCI) for growth potential in female adolescent idiopathic scoliosis (AIS) patients and to analyze its correlation with several other indicators of growth potential. Methods: A retrospective review was conducted on 45 girls with AIS who underwent standard bracing treatment between October 2006 and August 2013 in Nanjing Drum Tower Hospital. All patients were regularly followed up with an interval of 3-6 months until brace weaning. At each visit, the following data were collected and recorded: chronologic age, stage of menses, standing height, Cobb angle of main curve, TOCI score, digital skeletal age (DSA) score and radius, ulna and small bones (RUS) score. The height velocity (HV) at each visit were calculated. The correlations analysis between TOCI and other indicators including DSA scores and RUS scores were studied. Results: The average age at initial visit was (10.9±1.3) years. The mean age of menarche was (12.6±1.3) years. The mean peak height velocity (PHV) was (7.5±1.5) cm/year and the mean age of PHV was (12.0±0.9) years. A total of 71.8% AIS girls attained their PHV at TOCI 5. The Spearman correlation analysis showed that TOCI was highly correlated with the DSA and RUS scores (r=0.95 and 0.96, both P<0.001). Chi-square test showed that TOCI 5 accurately predicted the occurrence of PHV (Cramer V=0.531, P=0.007). Conclusion: The TOCI 5 indicates high HV and high growth potential in AIS patients with bracing treatment. TOCI can thus serve as a good indicator for growth potential in braced AIS girls.