What is the clinical evidence base for McKenzie therapy in management of back pain?
Studies were identified using a computer-based literature search of 7 databases: MEDLINE, EMBASE, DARE, CINAHL, PEDro, the Cochrane Register of Clinical Trials (CENTRAL), and the Cochrane Database of Systematic Reviews. Search terms included McKenzie therapy, McKenzie treatment, and McKenzie method. Studies published before September 2003 were eligible.
To be included in the review, each study had to fulfill the following criteria: (1) the study was a randomized or quasi-randomized controlled trial, (2) the subjects' primary complaint was nonspecific low back pain or neck pain with or without radiation to the extremities, (3) the authors investigated the efficacy of the McKenzie method/McKenzie treatment in comparison with no treatment, sham treatment, or another treatment, (4) individualized patient treatment and treatment were specified according to McKenzie principles, and (5) the authors reported at least one of the outcome measures of pain, disability, quality of life, work status, global perceived effect, medication use, medical visits, or recurrence. Studies were included with no language restriction and with subjects of all age groups, of either sex, and with any duration of symptoms. Studies were excluded if subjects had any of the following spinal conditions: cauda equina syndrome, cord compression, infection, fracture, neoplasm, inflammatory disease, pregnancy, any form of headache, whiplash-associated disorders, vertigo/dizziness, or vertebrobasilar insufficiency.
Data were independently extracted from each study by 2 investigators using a standardized data extraction form. The standardized data extraction form and experience level of the investigators were not included in the review. In studies with more than 2 treatment groups, the treatment contrast of more relevance to current Australian physiotherapy was selected. Data were also extracted for short-, intermediate-, and long-term follow-up based on the criteria suggested by the Cochrane Back Review Group. Short-term follow-up was defined as less than 3 months from onset of treatment. Intermediate-term follow-up was defined as at least 3 months and less than 12 months from onset of treatment. Long-term follow-up was defined as equal to or greater than 12 months. All eligible studies were rated for methodologic quality using the PEDro scale. The PEDro scale is a checklist that examines the "believability and the interpretability of trial quality."(1) The 11-item checklist yields a maximum score of 10 if all criteria are satisfied. The first item on the scale (Eligibility Criteria) is not scored. The PEDro scores were extracted from the PEDro database. If a study had not been entered into the database and scored, it was reviewed and scored by an experienced PEDro rater.
Normalized data for pain and disability were given possible total scores of 100. The article's scores on the PEDro scale were average, ranging from 4 to 8 of 10. The most common flaw in the methods, which occurred in all 6 studies, was the failure to blind both the patient and therapist. Four of the 6 did not blind the researcher interpreting the data. For both pain and disability at short-term (<3 months) follow-up, individual study results for low back pain favored McKenzie therapy compared with the following: nonsteroidal anti-inflammatory drugs, educational booklet, back massage with back care advice, strength training with therapist supervision, spinal mobilization, or general mobility exercises. Trends favored McKenzie therapy at intermediate-term (3-12 months) follow-up for pain and disability, as well as work absences. The McKenzie treatment group in the cervical spine study had less pain and disability at both short- and intermediate-term follow-up than did the exercise group, although the effect sizes were small. The same McKenzie treatment group tended to have fewer health care contacts in the ensuing 12 months than the comparison exercise group. The results suggest that McKenzie therapy provides a reduction in short-term pain (mean reduction of 8.6 on a 100-point scale) compared with the therapies mentioned above. A second (sensitivity) analysis was conducted to include data from 3 studies that were initially excluded because of lack of individualized treatment. The sensitivity analysis was used to determine if the exclusion of these studies would significantly alter the conclusion of the review. Instead, the sensitivity analysis strengthened the evidence supporting the notion that McKenzie therapy is more effective in short-term pain relief than other therapies (reduction of 11.4 on a 100-point scale).
This review provides evidence that McKenzie therapy results in a decrease in short-term (<3 months) pain and disability for low back pain patients compared with other standard treatments, such as nonsteroidal anti-inflammatory drugs, educational booklet, back massage with back care advice, strength training with therapist supervision, and spinal mobilization. No statistical differences were found between McKenzie therapy and other therapies at intermediate-term (3-12 months) follow-up. Data are insufficient on long-term (>12 months) outcomes or outcomes other than pain and disability (eg, quality of life). To date, no authors have compared McKenzie therapy with placebo or no treatment. Also, few data are available on the McKenzie method and its effect on neck pain. Future researchers should focus on these issues.