Matheus O Almeida, Alessandra Narciso Garcia, Luciola C Menezes Costa, Maurits W van Tulder, Chung-Wei Christine Lin, Luciana AC Machado

There is widespread agreement amongst clinicians that people with non-specific low back pain (NSLBP) comprise a heterogeneous group and that their management should be individually tailored. One treatment known by its tailored design is the McKenzie method (e.g. an individualized program of exercises based on clinical clues observed during assessment). To evaluate the effectiveness of the McKenzie method in people with (sub)acute non-specific low back pain. We searched CENTRAL, MEDLINE, Embase and two trials registers up to 15 August 2022. We included randomized controlled trials (RCTs) investigating the effectiveness of the McKenzie method in adults with (sub)acute (less than 12 weeks) NSLBP. We used standard methodological procedures expected by Cochrane. This review included five RCTs with a total of 563 participants recruited from primary or tertiary care. Three trials were conducted in the USA, one in Australia, and one in Scotland. Three trials received financial support from non-commercial funders and two did not provide information on funding sources. All trials were at high risk of performance and detection bias. None of the included trials measured adverse events. McKenzie method versus minimal intervention (educational booklet; McKenzie method as a supplement to other intervention - main comparison) There is low-certainty evidence that the McKenzie method may result in a slight reduction in pain in the short term (MD -7.3, 95% CI -12.0 to -2.56; 2 trials, 377 participants) but not in the intermediate term (MD -5.0, 95% CI -14.3 to 4.3; 1 trial, 180 participants). There is low-certainty evidence that the McKenzie method may not reduce disability in the short term (MD -2.5, 95% CI -7.5 to 2.0; 2 trials, 328 participants) nor in the intermediate term (MD -0.9, 95% CI -7.3 to 5.6; 1 trial, 180 participants). McKenzie method versus manual therapy There is low-certainty evidence that the McKenzie method may not reduce pain in the short term (MD -8.7, 95% CI -27.4 to 10.0; 3 trials, 298 participants) and may result in a slight increase in pain in the intermediate term (MD 7.0, 95% CI 0.7 to 13.3; 1 trial, 235 participants). There is low-certainty evidence that the McKenzie method may not reduce disability in the short term (MD -5.0, 95% CI -15.0 to 5.0; 3 trials, 298 participants) nor in the intermediate term (MD 4.3, 95% CI -0.7 to 9.3; 1 trial, 235 participants). McKenzie method versus other interventions (massage and advice) There is very low-certainty evidence that the McKenzie method may not reduce disability in the short term (MD 4.0, 95% CI -15.4 to 23.4; 1 trial, 30 participants) nor in the intermediate term (MD 10.0, 95% CI -8.9 to 28.9; 1 trial, 30 participants). Based on low- to very low-certainty evidence, the treatment effects for pain and disability found in our review were not clinically important. Thus, we can conclude that the McKenzie method is not an effective treatment for (sub)acute NSLBP.