Despite high success rates of hip and knee arthroplasty, up to 20% of patients report moderate-to-severe pain (NRS \> 3) persisting beyond the expected healing period. This investigator-initiated, descriptive cohort study will re-invite approximately 100 consenting patients with persistent postoperative pain-identified from a pool of \ 7 000 respondents-to complete standardized assessments of neuropathic (DN4), nociplastic (IASP criteria + Fibromyalgia Survey Questionnaire) and nociceptive (KOOS/HOOS pain domains) pain. Primary outcomes are the prevalence of potential nociplastic pain and the proportion experiencing significant pain in two or more mechanistic categories. Secondary analyses will compare baseline vs. re-evaluated DN4 scores, FSQ and KOOS/HOOS distributions, and examine differences between patients with and without possible neuropathic pain. Findings will inform targeted pre- and postoperative pain management strategies.