This is the era of Evidence-based Medicine. Sufficient time has passed to allow the scientific scrutiny to be applied to the various assessment and treatment methods available to patients. Though further studies are forthcoming and are necessary to build a full evidence base, there are many studies published in peer reviewed journals that support various aspects of the McKenzie Approach of MDT. This approach continues to be the most researched physical therapy based method available. The following is the selection of some of the most important studies on the approach to date with an explanation of their significance.
It is fundamentally important that any system of assessment and treatment have two key components of the assessment-
1. reliability and
2. diagnostic validity
Reliability means that two different examiners will agree on the assessment findings and come to the same conclusion when assessing each patient. Since treatment decisions rely exclusivey on the patient assessment this is critical. The following two studies demonstrate that the McKenzie Approach, when applied by Credentialled therapists, has very good agreement.
- Kilpikoski S, Airaksinen O, Kankaanpaa M, Leminen P, Videman T, Alen M.; Interexaminer reliability of low back pain assessment using the McKenzie method. Spine; Apr 15;27(8):E207-14, 2002.
- Ramjou H, Kramer JF, Yamada R; Intertester reliability of the McKenzie evalutation in assessing patients with mechanical low-back pain. J Orth & Sports Phys Ther; Ju;30(7):368-383, 2000.
The second part of the diagnostic process is the accuracy of the assessment when compared to a diagnostic standard. The following two studies demonstrate the accuracy of key findings in the McKenzie assessment and their relation to diagnostic injection. These are the first studies to our knowledge to find any physical examination process can accurately predict injection findings.
- Donelson R, Aprill C, Medcalf R, Grant W.; A prospective study of centralization of lumbar and referred pain. A predictor of symptomatic discs and anular competence. Spine; May 15;22(10):1115-22, 1997.
- Laslett M, Young SB, Aprill CN, McDonald B.; Diagnosing painful sacroiliac joints: A validity of a McKenzie evaluation and sacroiliac provocation texts. Aust J Physiother; 49(2):89-97, 2003.
- Skytte L, May S, Peterson P; Centralization: its prognostic value in patients with referred symptoms and sciatica Spine; 30:E293-E299, 2005
- Werneke M, Hart DL; Centralization phenomenon as a prognostic factor for chronic low back pain and disability Spine; Apr 1;26(7):758-65, 2001.
- Werneke MW, Hart DL; Categorizing patients with occupational low back pain by use of the Quebec Task Force Classification system versus pain pattern classification procedures: discriminant and predictive validity Phys Ther; 84:243-253, 2004.
- Long A, Donelson R, Fung T; Does it matter which exercise? A randomized control trial of exercises for low back pain. Spine; 29:2593-2602, 2004.
In this study, we have a clear endorsement for the value of subclassifying our patients using a McKenzie assessment, establishing directional preference and giving our patients specific exercises based upon these findings, which will significally affect patient outcomes in regard to, among other things ... pain, function and medication use.
This is probably one of, if not the, most important MDT study to date. It certainly helps us to justify the MDT assessment and the specific interventions based on individual patients presentations. It shows that it is what we do with our patients that determine their outcom. It is not simply that centralizers have a superior outcome with any treatment provided. The treatment must match the assessment findings or the results are inferior.
- Alexander AH, Jones AM, Rosenbaum Jr D H:; Nonoperative Managment of Herniated Nucleus Pulposus: Patient Selection by the Extension Sign-Long term Follow-up. Orthopaedic Review; 21;181-188, 1992.
- Larsen K, Weidick F, Leoboeuf-Yde C.; Can passive prone extensions of the back prevent back problems?: a randomized. controlled intervention trial of 314 military conscripts. Spine; Dec 15;27(24):2747-52, 2002.