Opioid use and dosage following knee arthroplasty (KA) has not been reported for subgroups with persistent moderate pain versus rapidly improving mild pain, externally validated from prior work. We determined if opioid use and dosage varied for persons classified into these externally validated subgroups. A secondary purpose determined if bodily pain scores associated with outcome subgroup. This was a secondary analysis of a prospective no-effect randomized clinical trial conducted on 384 participants with pain catastrophizing and scheduled for KA. Data were collected preoperatively and at 2-, 6- and 12-months following surgery. Two-piece latent class growth curve analyses applied previously validated pain outcomes to determine subgroup outcome trajectories for proportion of opioid users and oral morphine equivalent (OME) dosages. Substantial trajectory separation was found for opioid use and OME. Specifically, average OME dosage for the persistent moderate pain subgroup was more than double that for the other outcome subgroup. Average preoperative opioid daily OME dosage for 170 patients reporting opioid use was 24.94 (95% CI = 20.52, 29.38). Bodily pain was consistently higher for the persistent moderate pain subgroup compared to the other subgroup. Outcome subgroups in patients with pain catastrophizing demonstrated substantial differences in opioid use and dosage and were predicted by high pain catastrophizing, more bodily pain and changes in bodily pain over time. The persistent moderate pain subgroup is at greater risk of opioid use and greater opioid dosages and should be targeted for preoperative screening and interventions to reduce opioid use and potential opioid misuse. PERSPECTIVE: More frequent and higher opioid dosage following knee arthroplasty was found for the persistent moderate pain subgroup compared to the other subgroup. Patients with persistent pain had worse catastrophizing, contralateral and ipsilateral lower extremity pain, low back pain and whole body pain compared to the rapidly improving mild pain subgroup.
Copyright © 2023. Published by Elsevier Inc.