Purpose: To examine whether psychological factors are associated with chronic postoperative pain ≥12 months after total knee arthroplasty (TKA), given that ∼10% of patients report persistent pain despite otherwise successful surgery, and psychological influences are proposed contributors. Methods: A systematic review was conducted following PRISMA guidelines, including adults undergoing primary or revision TKA with postoperative pain assessed at a minimum of one year. Searches were performed in MEDLINE and Embase. Risk of bias was evaluated using the Newcastle-Ottawa scale. The protocol was registered with PROSPERO (CRD42024620401). Due to substantial heterogeneity in the studies, findings were synthesised narratively. Results: Thirty-seven studies met eligibility criteria. Twelve psychological factors were assessed across studies, most frequently depressive symptoms, pain catastrophising, and anxiety. Results were inconsistent, and no psychological factor showed a reproducible association with long-term postoperative pain across studies. Expectations were the only factor consistently associated with pain outcomes, while self-efficacy showed no association. Other factors, such as kinesiophobia and psychological distress, were examined in too few studies to support firm interpretation. Most studies demonstrated a moderate risk of bias, primarily due to reliance on self-reported measures and lack of non-exposed comparison cohorts. Conclusion: Substantial heterogeneity across studies limits firm conclusions regarding the influence of psychological factors on chronic postoperative pain one year after TKA. Patient expectations may play a meaningful role, whereas self-efficacy appears unrelated. Overall, most patients experienced pain improvement regardless of psychological profile. Standardised assessment methods are needed to clarify these associations and guide clinical practice.
Heegaard et al. (Wed,) studied this question.