Inter-rater Reliability of the McKenzie Method of Mechanical Diagnosis and Therapy for the Provisional Classification of Low Back Pain in Adolescents and Young Adults

Abstract

ABSTRACT Objective To investigate the inter-rater reliability of Mechanical Diagnosis and Therapy (MDT)-trained Diplomats in classifying adolescents and young adults with lumbar pain. Methods Forty-three participants (mean age 15 ± 2 years) with lumbar pain, with or without lower extremity symptoms, were assessed simultaneously by three MDT Diploma holders and classified into one of three groups: 1) Derangement, 2) Dysfunction, 3) Postural/OTHER. Inter-rater reliability was calculated using the Fleiss kappa statistics with 95% confidence intervals (CI). Analyses were repeated with the younger (11 to 15 years old) and older (16 to 21 years old) age groups. Results There was moderate reliability (Fleiss kappa = 0.50, 95% CI = 0.45 to 0.54) for the entire sample, which was statistically significant (p < 0.001). There was good reliability in older participants (Fleiss kappa = 0.63, 95% CI = 0.57 to 0.70), but poor reliability in younger participants (Fleiss kappa = 0.33, 95% CI = 0.27 to 0.39). There was 100% agreement in classifications among assessors for 70% of participants. Discussion The MDT system has moderate reliability when classifying lumbar pain in adolescents and young adults. Future reliability studies may include a balanced group for classifications or a second session.