An Exploration of Maitland's Concept of Pain Irritability in Patients with Low Back Pain

Maitland's construct of musculoskeletal pain irritability is widely used by physical therapists for making decisions about the vigor of examination and treatment, but this construct has not been defined to the extent that its measurement properties can be tested. The purposes of this study were to 1) determine if physical therapists utilize low back pain (LBP) irritability judgments to make treatment decisions, 2) identify LBP characteristics appropriate for an LBP irritability construct, and 3) develop a measurement construct of LBP irritability. Physical therapists evaluated and treated 183 subjects with LBP. The therapists judged the subjects' LBP as irritable or non-irritable, and recorded treatments provided at the initial visit. A principal-components analysis (PCA) was performed on 14 patient-reported LBP characteristics to identify potential components of a measurement construct of LBP irritability. The therapists' irritability judgments were found to be associated with the types of treatments prescribed. Five dimensions of LBP irritability were identified by the PCA from the 14 LBP characteristics considered. Four of these dimensions were associated with the therapists' LBP irritability judgments. The Roland-Morris Disability Questionnaire, presence of distal symptoms, and forward bending tolerance were found to have a stronger association with the irritability judgments than the dimensions of irritability identified in this study. Validated measures of LBP characteristics in current clinical use may adequately capture Maitland's concept of irritability.