REST AND MOVEMENT PAIN HIP AND KNEE REPLACEMENT

ObjectiveThere is limited information about the extent to which the association between pre-operative and chronic post-operative pain is mediated via pain-on-movement or pain-at-rest. We explored these associations in patients undergoing total hip (THR) and total knee (TKR) replacement.Methods322 and 316 patients receiving THR and TKR respectively were recruited into in a single centre UK cohort (APEX) study. Pre-operative, acute post-operative and 12-month pain severity was measured using self-reported pain instruments. The association between pre-operative / acute pain and chronic post-operative pain was investigated using structural equation modelling (SEM).ResultsPatients with high levels of pre-operative pain were more likely to report chronic pain after THR (β=0.195; p=0.02) and TKR (β=0.759; p<0.0001). Acute post-operative pain-on-movement was not associated with chronic pain after TKR or THR after adjusting for pre-operative pain, however acute pain-at-rest was associated with chronic pain after T...