Intertester reliability of judgments of the presence of trigger points in patients with low back pain

The purpose of this study was to determine the intertester reliability of assessments of the presence of trigger points in the region of the lumbar spine of patients with low back pain (LBP). A total of six trigger points described by Travell and Simons were studied. The trigger point examination procedures described by Travell and Simons were used by 12 physical therapists. Randomly paired therapists examined 50 patients for 197 trigger points. The Kappa coefficient, percent agreement, the observed proportion of positive agreement (Ppos), and the observed proportion of negative agreement (Pneg) were used to describe reliability. Kappa values ranged from .29 to .38. Percent agreement ranged from 76% to 79%. Ppos ranged from .43 to .52. The low Kappa and Ppos values suggest different therapists are unable to reliably determine when a trigger point is present in a patient with LBP. This study suggests the usefulness of examining for the presence of trigger points in patients with LBP should be questioned.