Assessment and characterization of back pain and biopsychosocial influences in lower limb amputation: scoping review.

Back pain affects over half of individuals with lower limb amputation, yet research findings on associated factors remain fragmented. In view of the evolution of pain science in the general population, this fragmentation likely stems from significant variability in the identification, characterization, and classification of pain, as well as inconsistent assessment of associated biopsychosocial factors. This scoping review aims to examine how back pain is currently identified, assessed, classified, and characterized in people with lower-limb amputation, to determine the gaps and inconsistencies that could impede standardization and evidence synthesis. Six electronic databases were searched for studies involving major unilateral acquired lower limb amputation. Two independent reviewers screened articles and extracted data using standardized forms in Covidence. Synthesis focused on identification, classification, reporting of back pain-related biopsychosocial variables, and assessment strategies. Sixty-seven studies were included, predominantly cross-sectional (69%). Although pain intensity was frequently assessed, methods were binary (yes/no), and the use of mechanistic classification and biopsychosocial factors was sparse. Measurement strategies were highly heterogeneous, with standardized frameworks used in only 4 studies. This scoping review reveals a profound discrepancy between contemporary pain science approaches and current pain practice methodologies for the lower limb amputation population. Significant diagnostic gaps persist because of inconsistent classification of pain mechanisms and a void in reporting biopsychosocial variables. Prioritizing standardized frameworks and a population-specific core outcome set is essential to bridge the translational gap. These advancements will improve research quality and facilitate more targeted, evidence-based clinical care for this complex population.