Identifying Directional Preference: A Scoping Review and Thematic Analysis of Variability and Application in Musculoskeletal Pain Research.

Objective: The objective of this review was to identify and describe the varying definitions and operational criteria used to characterize directional preference in musculoskeletal care research.

Data sources: A scoping review was conducted using 6 electronic databases (PubMed, CINAHL, Embase, SPORTDiscus, Web of Science, and Cochrane Library) from inception through May 2024.

Study selection: Studies were included if they involved adults with musculoskeletal conditions and used the term "directional preference" in their methodology or reporting.

Data extraction and synthesis: Data were extracted on terminology, definitions, and operational criteria. Definitions were thematically categorized. Expert consultation with 18 clinicians and researchers was also conducted to evaluate consensus on key components. The review followed PRISMA-ScR guidelines.

Main outcome(s) and measure(s): Primary outcomes included the number and type of directional preference definitions and expert perspectives on essential definitional elements.

Results: Out of 15,390 records screened, 149 studies met the inclusion criteria. These studies exhibited considerable variability, with 111 unique definitions categorized into 8 distinct themes. Notably, 22% of studies failed to define directional preference, and 15% incorrectly equated it with centralization. Expert consultation (n = 18) highlighted substantial variability in the perceived importance of different definition components, with "response to repeated and/or sustained movements" emerging as the most consistently prioritized criterion. Despite these insights, no consensus on a definition was reached, complicating research interpretation and clinical guideline formulation.

Conclusions and relevance: There is substantial inconsistency in the definition and operationalization of directional preference across the musculoskeletal literature, which impairs research synthesis and clinical translation. Symptom change in response to repeated or sustained movement may serve as a foundation for a standardized definition. Future consensus-driven efforts, such as Delphi studies, are needed to establish a clear and consistent definition to support improved research quality and clinical application.