The Reliability of Maitland's Irritability Judgments in Patients with Low Back Pain

Maitland's construct of musculoskeletal pain irritability is widely used by physical therapists but has not been defined to the extent that its measurement properties can be tested. The purpose of this study was to examine the inter-rater reliability of physical therapists' irritability judgments during application to patients with low back pain (LBP). Eighty patients with LBP received two consecutive examinations at their initial clinic visit by two physical therapists. Patients reported pain location and intensity prior to each evaluation. Therapists judged subjects' LBP as irritable or non-irritable. Inter-rater agreement of physical therapist irritability judgments was moderate (kappa = 0.44, prevalence-adjusted kappa = 0.50). This level of reliability of therapists' LBP irritability judgments may be improved upon by development of an operational definition of pain irritability. Further research is needed to identify measures appropriate for inclusion in an operational definition of pain irritability and to assess the value of making pain irritability judgments in evidence-based physical therapy practice.