Note: This abstract has been published in the proceeding of 14th annual meeting of the North American Spine Society (October 1999, Chicago). The abstract will also be presented at ISSLS annual meeting (April 2000, Australia) and McKenzie North American Conference (June 2000, Orlando).

"Purpose: The purpose of this study was to investigate inter-examiner agreement with the McKenzie assessment process in determining diagnostic syndromes, sub-syndromes, detection, and relevance of the sagittal and frontal plane deformities. Because classification in older patients with concomitant illnesses can become more difficult, patients were divided into two groups, those 55 years of age or older and those under 55.

Methods: Consenting patients with low back pain with or without leg pain presenting for care were simultaneously assessed by two physical therapists trained in the McKenzie evaluation system (Occasion 1). The therapists were randomly assigned as assessor and observer and then reversed roles for a second post-treatment examination of each patient (Occasion 2). Patients received treatment from physical therapists not involved in the reliability study. Examiners were required to document conclusions regarding the appropriate McKenzie syndrome, sub-syndrome, and the outcomes of the specific mechanical tests. Agreement was estimated by kappa using Landis and Koch’s guidelines where values exceeding 0.4 represent acceptable inter-examiner reliability.

Results: Forty-five subjects, mean age = 47.2 years, with acute, subacute, or chronic low back pain, were examined on Occasion 1, with 34 undergoing Occasion 2 examination. Kappas for selection of the syndrome categories were 0.70 and 0.92 and for the derangement sub-syndromes 0.96 and 0.87 on Occasion 1 & 2 respectively. For specific tests, i.e. presence of lateral shift, relevance of lateral shift, relevance of lateral component, and deformity in the sagittal plane, Occasion1 kappas were .52, .85, .95 and 1.00 and Occasion 2 kappas were .58, 1.00, .91 and 1.00, respectively. Because classification can become more difficult with older patients due to concomitant illnesses, patients were divided into two groups, those 55 years of age or older and those under 55. Consistent with this hypothesis, inter-examiner agreements on syndrome categories in patients under 55 years of age were higher, and in fact perfect, with kappas = 1.0.

Conclusion: High inter-examiner reliability was found with these two therapists, one credentialled and one a diplomat with the McKenzie Institute International".