Pain Trajectories and Influencing Factors After Total Joint Arthroplasty: A Longitudinal Data Analysis.

OBJECTIVES: This study aims to explore postoperative pain trajectories in patients undergoing total joint arthroplasty (TJA) and to identify patterns of pain change and their influencing factors. METHODS: We used convenience sampling to select 374 patients with total joint arthroplasty at a Grade A tertiary hospital. Among them, 304 completed perioperative pain assessments from before surgery to postoperative day 90. Latent class growth model (LCGM) was used to distinguish subgroups of pain trajectories, and multivariate logistic regression was applied to analyze the influencing factors. RESULTS: LCGM identified three pain trajectory groups: rapid remission (n=39, 12.83%), gradual remission (n=223, 73.36%), and basically stable (n=42, 13.82%). Multivariate analysis showed that, compared with gradual remission, preoperative pain duration >3 months was negatively associated with rapid remission trajectory (odds ratio [OR]=0.18, 95% confidence interval [CI]: 0.04-0.84, P=0.029). Compared with rapid remission, a lower preoperative WOMAC score (OR=0.96, 95%CI: 0.94-0.99, P=0.003) and POD7 nonopioid combination analgesia (OR=25.90, 95%CI: 2.49-269.71, P=0.006) were independent predictors of the basically stable trajectory. DISCUSSION: There are three heterogeneous trajectories of postoperative pain after TJA. We recommend implementing stratified interventions based on key factors, including the preoperative WOMAC score, preoperative pain duration, and time-specific postoperative analgesic regimens, providing a new approach to precise analgesia.