Abstract
BACKGROUND: Identifying prognostic factors for outcomes after joint replacement could improve the provision of stratified care. This systematic review evaluated whether social support is a prognostic factor for better patient-reported outcomes after total hip replacement (THR) and total knee replacement (TKR). METHODS: MEDLINE, Embase and PsycINFO were searched from inception to April 2019. Cohort studies evaluating the association between social support and patient-reported outcomes at three months or longer after THR or TKR were included. Data were extracted from study reports. Study quality was assessed using the QUIPS tool. Data were synthesized using meta-analysis and narrative synthesis. The review was registered on PROSPERO (CRD42016041485). FINDINGS: Searches identified 5,810 articles and 56 studies with data from 119,165 patients were included. In meta-analysis, the presence of social support had a beneficial effect on long-term post-operative WOMAC (mean difference 2.88; 95% CIs 1.30; 4.46) and Oxford Knee Score (0.29; 0.12, 0.45). Social support measured using a validated questionnaire was found to be associated with WOMAC pain (0.04; 0.00, 0.08) but not WOMAC function (-0.01; -0.12, 0.11). The presence of social support had a positive association with some SF-36 subscales but not others. For all outcomes, results of narrative synthesis were inconsistent. INTERPRETATION: There is evidence that social support is a prognostic factor for some outcomes after joint replacement. Development and evaluation of complex interventions to improve social support and social integration is warranted. FUNDING: This study was supported by the NIHR Biomedical Research Centre at University Hospitals Bristol NHS Foundation Trust and the University of Bristol.