The psychometric properties of the Roland Morris disability questionnaire for patients with chronic mechanical low back pain

Abstract

Purpose: Functional status measures are currently not widelyused in South Africa to facilitate clinical decision-making or document treatment outcomes for patients with low back pain (LBP). This study investigated the internal consistency and clinical utility of a back-specific functional status measure, the Roland Morris Disability Questionnaire (RMDQ), and determined its ability to confirm the need for spinal fusion surgery. Method: Aretrospective, descriptive design was used with 42 patients with chronic mechanical low back pain who consulted a private Orthopaedic surgeon in Cape Town over a one year  period. All patients completed the RMDQ prior to their consultation. On completion of the medical examination, a rating for surgery was determined for each patient. The completed questionnaires were analysed using Statistical Package for the Social Sciences (SPSS). Results: The mean RMDQ score was 8.6 (N=42; median=9.0; range=2-21). Cronbach’s alpha showed a high internal consistency between items (.92). A categorical principal component analysis (CATPCA) identified two distinct dimensions in the RMDQ. Item reduction improved the internal consistency and thus the construct validity of the RMDQ. There was a low correlation between the surgeon’s rating for surgery and RMDQ scores (r=.40; P