The contemporary practice of orthopaedic surgery requires an evidence-based approach to support all medical and surgical interventions. In this essay, the author expresses a forthright, personal and somewhat prejudiced appeal to retain the legitimacy of clinical decision making in conditions that are rare, contain multiple variables, have a solution that generally works or has an unpredictable course.

Cite this article: Bone Joint J 2014;96-B:1002–4.

Randomised controlled trials represent the gold standard in the evaluation of outcome of treatment. They are needed because differences between treatment effects have been minimised and observational studies may give a biased estimation of the outcome. However, conducting this kind of trial is challenging. Several methodological issues, including patient or surgeon preference, blinding, surgical standardisation, as well as external validity, have to be addressed in order to lower the risk of bias. Specific tools have been developed in order to take into account the specificity of evaluation of the literature on non-pharmacological intervention. A better knowledge of methodological issues will allow the orthopaedic surgeon to conduct more appropriate studies and to better appraise the limits of his intervention.