Screening to identify postoperative pain and cross-sectional associations between factors identified in this process with pain and function, three months after total knee replacement

ObjectivesDescribe the screening and recruitment process of a randomised trial and evaluate associations with knee pain and function three months after total knee replacement (TKR).MethodsTo screen for a multi-centre trial, 5036 patients were sent an Oxford Knee Score (OKS) questionnaire 10 weeks post-TKR. Patients who reported pain in their replaced knee (≤14 on OKS pain component), completed a second OKS 12 weeks post-TKR. Those still experiencing pain 12 weeks post-TKR completed a detailed questionnaire 13 weeks post-TKR. These data were used to characterise pain in a cross-sectional analysis. Multivariable regression was performed, identifying factors associated with pain and function at 13 weeks post-TKR. Results We received OKS questionnaires from 3058/5063 (60%) TKR patients, 907/3058 (30%) reported pain in their replaced knee 10-weeks post-operatively. By 12-weeks, 179/553 (32%) patients reported improved pain (OKS>14). At 13-weeks, 192/363 (53%) who completed a detailed questionnaire reported neuropathic pain, 94/362 (26%) reported depression symptoms and 95/363 (26%) anxiety symptoms. More severe pain at 13-weeks post-operatively was associated with poorer general health, poorer physical health, more pain worry and lower satisfaction with surgery outcome. More severe functional limitation was associated with higher levels of depression, more pain worry, lower satisfaction with surgery outcome and higher pain acceptance.ConclusionsScreening after TKR identified people with pain. We identified several potential targets (physical and mental health outcomes, acceptance of pain and quality of life) for tailored intervention to improve outcomes for patients. Trials of multidisciplinary interventions are now needed.