Introduction: During the last decades the number of published randomized clinical trials in lower back pain has accumulated. For some interventions considerable numbers of trials are available. Trials have been shown to vary substantially regarding their quality.

Objective: To assess the methodological quality of published randomized clinical trials into the efficacy of commonly used interventions in lower back pain.

Methods: Review of criterium-based meta-analyses. Computer aided search of published randomized clinical trials (RCTs) into efficacy of spinal manipulation and mobilization, exercise therapy, back schools, bed rest, orthoses and traction therapy. Additional screening of journals not covered by Medline and Embase. Assessment of the methodological quality using a set of predefined criteria.

Results: 69 different RCTs were identified. Methodological scores varied between 16-82 points (maximum was 100 points). Methodological quality tends to be associated with the outcomes of the studies. Methodological shortcomings are frequently found; e.g. small samples sizes, no description of the randomization procedure, no description of dropouts, no placebo-control group and the lack of blinded outcome assessments.

Discussion: Although a considerable number of randomized clinical trials have been carried out evaluating the efficacy of interventions in lower back pain, the methodological quality appears to be disappointingly low. Future trials are clearly needed, but much more attention should be paid to the methods of such studies.