Acute pain trajectories and the persistence of post-surgical pain: a longitudinal study after total hip arthroplasty.

Abstract

The aim of this study was to explore acute movement-evoked postoperative pain intensity trajectories over the first 5days after total hip arthroplasty (THA) and to examine how these pain trajectories are associated with pain-related outcomes 6weeks and 6months later. A total of 150 adult patients [72 women (48.0%); mean age60.0 ± 9.2 (standard deviation) years] completed pain questionnaires preoperatively, several times daily postoperatively until hospital discharge, and 6weeks and 6months after surgery. Results showed that the best model had four different acute postoperative pain trajectories and a significant quadratic term. The trajectories varied in terms of initial pain intensity levels and rates of decline/increase in pain over the first 4 postoperativedays. Significant predictors of pain trajectory membership were preoperative pain disability and anxiety as well as cumulative morphine consumption 24h following surgery. Pain trajectories were significantly associated with levels of pain intensity and anxiety at 6weeks but not at 6months postoperatively. This study showed that during the postoperative period patients differed in terms of pain intensity profiles and that these differences were associated with outcomes for up to 6weeks following surgery. Pain trajectories were not predictive of persistent postoperative pain status at 6months. Nonetheless, these results highlight the importance of patient heterogeneity in acute postoperative pain and pain-related outcomes months after THA.