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

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.

KEYWORDS:

• McKenzie Method
• Mechanical Diagnosis and Therapy
• low back pain
• adolescents
• young adults
• provisional classification
• inter-rater reliability

Supplemental Material

Supplemental data for this article can be accessed here.

Acknowledgments

We would like to thank Eduardo Correa, Dimitri Dragutan, and Kalem Kachur for being the assessors in this study. We would like to thank Dr Noemi Dahan-Oliel and the members of the Rehabilitation Services Department at the Shriners Hospitals for Children-Canada for their support during this study. We would also like to thank Richard Rosedale for his guidance and feedback for this study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Role of the funding source

This study was funded by a grant from the Professional Order of Physiotherapy Quebec. The study sponsors did not play a role in the study design, collection, analysis and interpretation of data, in the writing of the manuscript, and in the decision to submit the manuscript for publication.

Additional information

Notes on contributors

Monica Chan

Monica Chan, BSc, MScA(PT), Cert. MDT, is a physical therapist at the Shriners Hospitals for Children-Canada. Her research interests are MDT, Orthopedics, and Musculoskeletal Care.

Michael Dyck

Michael Dyck, BScPT, Dip. MDT is a probationary faculty member of the McKenzie Institute Canada. He provides educational courses on Mechanical Diagnosis and Therapy for which he does receive a teaching fee. He is also a physical therapist at Active Solution Physiotherapy. His research interests are MDT, Orthopedics, and Musculoskeletal Care.

Gloria Thevasagayam

Gloria Thevasagayam, BScPT, is a physical therapist at the Shriners Hospitals for Children-Canada. Her research interests are MDT, Orthopedics, and Musculoskeletal Care.

Rita Yap

Rita Yap, BScPT, MSc, is a physical therapist at the Shriners Hospitals for Children-Canada. Her research interests are MDT, Orthopedics, and Musculoskeletal Care.

Jean Ouellet

Jean Ouellet, MD, is the Clinical Director of Scoliosis and Spine Surgery and orthopedic surgeon at the Shriners Hospital for Children-Canada. His research interests are Scoliosis Animal Models and Spine, Biomechanics, Disc Cell Biology, and Bone Anabolic Agents.

Shawn M Robbins

Shawn M Robbins, BScPT, PhD, is an Associate Professor at McGill University, School of Physical and Occupational Therapy. His research utilizes biomechanical and clinical measures to assess orthopedic health conditions and their treatment in both clinic and laboratory settings.