Interobserver reliability of scoliometer measurements of rotational deformity in adolescent idiopathic scoliosis

Assessment of rotational deformity of spinal curvature is an important meth od of evaluating curves and in following the progression of adolescent idio pathic scoliosis. An evaluation of the interobserver reliability of scoliom eter measurements was performed. We also iinvestigated whether interobserve r reliability varied with the magnitude of the Cobb angle. Three clinicians . measured the axial rotation of thoracic and lumbar curves in degrees on f ifty patients with adolescent idiopathic scoliosis during the same office v isit The Cobb angles were measured on the same day. Correlations were made by determining a: Pearson correlation coefficient. Agreement between the ra ters was good with coefficients ranging from .83 to .89 (average = .86). Th e interobserver variability was 1.3 degrees and was not dependent on the ma gnitude of the Cobb angle. Correlation between degrees of rotation and Cobb angle was, poor for each of the raters with average coefficient .55. These results demonstrate that interobserver reliability in use of the Scoliomet er is good, not excellent. They also confirm that rotational deformity has no relation to the sagittal curve. The Scoliometer is a useful augmentation device in evaluating and planning treatment in scoliosis, but is not relia ble in long term tracking of progression when used by multiple observers.