Purpose: The purposes of this study were to: 1) investigate the inter-rater and intra-rater reliability of use of the Flexicurve for measurement of spinal length (L), thoracic (TL) and lumbar length (LL), thoracic (TW) and lumbar width (LW), and 2) quantify measurement error and minimal detectable change at the 95% CI (MDC95) for the same measurements.
Methods: Flexicurve measurements of the thoracolumbar spine were recorded by two examiners in standing. Intra-class correlation coefficients were calculated to determine the intra- and inter-rater reliability. Measurement error and MDC95 were calculated to determine length and width measurements that would constitute real change in spinal curvature.
Results: Thoracolumbar length (L) measurements had the highest degree of intra-rater reliability (0.93), while TL, TW, LL, LW showed moderate to good intra-rater reliability (0.61-0.80). Inter-rater reliability for all measurements was moderate (0.58-0.72). Measurement error was moderate to high for TW, LL, and LW (15-25%), and low for L and TL (1-6%). The %MDC95 for TW, LL, and LW found in this study was high (>40%), but was low for L (3.5%).
Conclusion: Thoracolumbar length measurement with the Flexicurve showed good intra-rater reliability, low measurement error, and low MDC95 and may be a useful measure in clinical practice.