Fear of movement/(re)injury, disability and participation in acute low back pain.

Fear of movement/(re)injury and its associated avoidance behavior have shown to be strongly associated with functional disability in chronic low back pain. In acute low back pain disability, the role of pain-related fear has received little research attention so far. Measures of pain-related fear such as the Tampa Scale for Kinesiophobia (TSK) are increasingly being used in primary care. The aim of the present study was: (1). to further investigate the factor structure of the TSK in a population of acute low back pain (LBP) patients in primary care by means of a confirmatory factor analysis (CFA); (2). to examine the relationship between fear of movement/(re)injury and disability, as well as participation in daily and social life activities in 615 acute LBP patients seen by general practitioners and physical therapists in primary care settings; and (3). to examine whether disability mediates the association between pain-related fear and participation. CFA, and a subsequent explorative factor analysis on the TSK revealed a two-factor model. The factors consisted of items associated with 'harm', and items representing the 'avoidance of activity'. Both constructs were significantly associated with disability and participation. Additionally, and in contrast to what is often observed in chronic pain, disability, and to a lesser degree participation, were also associated with pain intensity. Finally, the association between pain-related fear, pain intensity and participation was indeed mediated by disability. The results suggest that early on in the development of LBP disability, the successful reduction of pain-related fear and disability might foster increased participation in daily and social life activities.