Biological Link Between Anxiety and Outcomes Post Knee Arthroplasty

This study aims to investigate the potential biological mechanisms linking preoperative anxiety and depression with poorer patient-reported outcomes following total knee or hip replacement surgery. Specifically, we are exploring whether psychological distress is associated with increased local joint inflammation (synovitis) and whether this may mediate reduced functional recovery. Biological samples (including synovial fluid, synovial tissue, and fat pad) will be collected intraoperatively from routine surgical waste, and additional blood samples will be analysed for routine blood tests (FBC, Renal function tests, Liver function tests) and inflammatory markers (CRP, ESR, IL-6, CD solubles). We will correlate these findings with validated psychological and functional outcome measures collected pre- and postoperatively. Recruitment and Consent: Patients scheduled for elective knee or hip replacement at the Robert Jones and Agnes Hunt Orthopaedic Hospital will be screened for eligibility by a clinician as part of the care team. Eligible patients will receive a patient information sheet and consent form by post ahead of their routine preoperative clinic visit. A telephone call will follow to confirm interest. Final written informed consent will be obtained by a trained research nurse at the preoperative assessment clinic. Participants may decline or withdraw from the study at any time without affecting their standard clinical care. Risks, Burdens, and Benefits: The risks associated with participation are minimal. All tissue samples will be collected during routine surgery while the patient is under general anaesthesia, using tissue that would otherwise be discarded. A small additional blood sample (20 ml) will be collected on the day of surgery using the same venepuncture as for routine bloods, and a follow-up sample (approx. 15 ml) will be withdrawn at the routine 3-month clinic visit. The risks of blood withdrawal are minimal such as discomfort or bruising. However, a senior trained staff will withdraw all the blood tests to minimise any potential risks. Questionnaires on anxiety and depression might cause mild emotional discomfort; appropriate safeguarding procedures are in place, and GP referrals will be made for participants scoring above clinical thresholds. Participants will be informed of their blood test results related to inflammation, where clinically appropriate. Confidentiality and Data Security: All identifiable information will be stored securely, in accordance with the Data Protection Act 1998 and current NHS policies. Each participant will be assigned a unique study ID. Identifiable data will be kept separate from research data and stored in encrypted, password-protected files. Only authorised research staff will have access. Biological samples sent for external analysis (IL-6 and CD solubles in Sheffield Hospital) will be fully anonymised. Use and Storage of Samples: The institution holds appropriate approvals under the Human Tissue Act to store and use human biological samples. Any remaining samples may be stored securely in the RJAH Arthritis Research Centre laboratory for future ethically approved research. No genetic testing will be performed. Samples may be transported to partner laboratories within the UK for specific assays, using NHS-compliant logistics. Ethical and Organisational Oversight: This is a single-site, low-risk observational study embedded within routine NHS care. There are no additional clinic visits or interventions. Ethical, data protection, and sample handling issues have been reviewed and addressed through standard NHS research governance procedures, and the study has received peer review and 'agreement in principle' from all relevant support departments.