Wider considerations following evaluation of the STAR care pathway for patients with painful knee replacement

present the results of a randomised controlled trial (RCT) investigating the clinical and cost-effectiveness of the Support and Treatment After Replacement (STAR) care pathway compared with usual care on pain severity and pain interference after total knee replacement. The first point of note for this new RCT is the research question and design—the trial is an excellent example of a pragmatic, pathway-based design (ie, a management or package-of-care comparison) rather than the standard head-to-head comparison of two highly prescriptive and specific treatments. This is a fairly new approach to testing the efficacy of complex interventions and one that usefully accounts for real-world variation in treatment content and fidelity. It is likely we will see more of these types of comparisons, as it is increasingly recognised that RCTs with tightly-defined, complex treatments—along with the mixed fidelity associated with these treatments—are difficult to conduct and interpret and, sadly, can be unrepresentative of patients in real-world practice.

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Clarification and understanding of this lack of representativeness also assists the research community on defining what an intervention (for an RCT) really is. A colleague highlighted that physiotherapy (or any such broad therapeutic treatment label) is too vague a term to be of any real use in defining treatment for RCTs, as it refers only to a profession or to a global notion of an intervention. Unlike assessments of prescribed drugs, for example, treatments involving behaviour modifications, practitioner skill and experience, and high content and delivery heterogeneity (as described in this study

) are not helped by such general labels.