Who develops chronic pain after an acute lower limb injury? A longitudinal study of children and adolescents.

Prevention of chronic pain is a major challenge in this area of clinical practice. To do this, we must be able to understand who is most at risk of developing chronic pain after an injury. In this study, we aimed to identify risk factors of chronic pain onset, disability, and pain interference after a lower limb musculoskeletal injury in children and adolescents between 8 to 16 years of age. We assessed biopsychosocial factors including age, sex, pubertal status, anxiety, depression, fear of pain, pain worry, adverse life events, and sleep in children. We also assessed risk factors in parents including parent anxiety, depression, parent pain catastrophising, and protective behaviours. Logistic and hierarchical linear regressions identified risk factors assessed immediately postinjury for outcomes assessed at 3 months postinjury. Fourteen percent (17/118 children) reported chronic pain 3 months after injury. There were significant between-group differences in children with and without chronic pain at baseline. Children with chronic pain reported higher pain intensity, disability, pain interference, child depression, fear of pain, and catastrophic thinking about their pain. Regressions showed child depression and fear of pain at baseline independently predicted chronic pain onset at 3 months, parent protectiveness predicted child pain interference at 3 months, and child depression, poor sleep, parent anxiety and pain catastrophising predicted disability. Most children recover after a lower limb injury, but a minority develop chronic pain predicted by important psychosocial risk factors, which could be addressed to prevent the onset of treatment-resistant chronic pain and disability.