Safety and feasibility evaluation of tourniquets for total knee replacement (SAFE-TKR): study protocol.

INTRODUCTION: This study is designed to determine whether a full randomised controlled trial (RCT) examining the clinical effectiveness and safety of total knee replacement surgery with or without a tourniquet is warranted and feasible.

METHOD AND ANALYSIS: Single centre, patient-blinded and assessor-blinded RCT. A computer-generated randomisation service will allocate 50 participants into one of two trial treatments, surgery with or without a tourniquet. The primary objective is to estimate recruitment, crossovers and follow-up of patients. All patients will have an MRI scan of their brain preoperatively and day 1 or 2 postoperatively to identify ischaemic cerebral emboli (primary clinical outcome). Oxford Cognitive Screen, Montreal Cognitive Assessment and Mini-Mental State Examination will be evaluated as outcome tools for measuring cognitive impairment at days 1, 2 and 7 postoperatively. Thigh pain, blood transfusion requirements, venous thromboembolism, revision surgery, surgical complications, mortality and Oxford knee and five-level EuroQol-5D scores will be collected over 12 months. Integrated qualitative research study : 30 trial patients and 20 knee surgeons will take part in semistructured interviews. Interviews will capture views regarding the pilot trial and explore barriers and potential solutions to a full trial. Multicentre cohort study : UK National Joint Registry data will be linked to Hospital Episode Statistics to estimate the relationship between tourniquet use and venous thromboembolic event, length of hospital stay, risk of revision surgery and death. The study will conclude with a multidisciplinary workshop to reach a consensus on whether a full trial is warranted and feasible.

ETHICS AND DISSEMINATION: National Research Ethics Committee (West Midlands-Edgbaston) approved this study on 27 January 2016 (15/WM/0455). The study is sponsored by University of Warwick and University Hospitals Coventry and Warwickshire. The results will be disseminated via high-impact peer-reviewed publication.

TRIAL REGISTRATION NUMBER: ISRCTN20873088; Pre-results.