Are preoperative psychological factors associated with chronic postoperative pain after total knee arthroplasty: a systematic review.

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.