IntroductionTotal knee arthroplasty is a highly effective treatment for end-stage knee osteoarthritis, and it is usually performed under spinal or general anaesthesia with or without a surgical tourniquet. Some debate about the preferred mode of anaesthesia regarding patient outcomes remains. The aim of this study, which compares general and spinal anaesthesia with and without a tourniquet on the outcomes of total knee arthroplasty, is to determine the optimal type of anaesthesia regimen and assess the effect of a tourniquet on the patient’s recovery following total knee arthroplasty.Methods and analysisThis study is a randomised, controlled, parallel-group, four-arm study comparing spinal and general anaesthesia with and without a tourniquet in 400 patients undergoing fast-track total knee arthroplasty, with a 12-month follow-up. The primary outcome is cumulative intravenous oxycodone consumption by patient-controlled analgesia during the first 24 postoperative hours. Secondary outcomes include postoperative nausea and vomiting, the length of hospital stay, the duration of the surgery, blood loss, demand for surgical unit resources, complications, readmissions, postoperative knee function, range of motion, health-related quality of life, prolonged pain and mortality.Ethics and disseminationThis study’s protocol is in accordance with the declaration of Helsinki. The results of this study will be disseminated in international peer-reviewed journals.Trial registration number NCT03364088; Pre-results.

Background: We investigated the effects of spinal and general anaesthesia and surgical tourniquet on acute pain and early recovery after total knee arthroplasty (TKA). Methods: Patients (n¼413) were randomised to four parallel groups: spinal anaesthesia with or without tourniquet, and general anaesthesia with or without tourniquet. The primary outcome was patient-controlled i.v. oxycodone consumption over 24 postoperative hours. Results: Results from 395 subjects were analysed. Median i.v. oxycodone consumption did not differ between the four groups (spinal anaesthesia without [36.6 mg] and with tourniquet [38.0 mg], general anaesthesia without [42.3 mg] and with tourniquet [42.5 mg], P¼0.42), between spinal (37.7 mg) and general anaesthesia (42.5 mg) groups (median difference e3.1, 95% confidence interval [CI] e7.4 to 1.2, P¼0.15) and between tourniquet and no-tourniquet groups (40.0 vs 40.0 mg, median difference e0.8, CI e5.1 to 3.5, P¼0.72). Vomiting incidence was higher with spinal than with general anaesthesia (21% [42/200] vs 13% [25/194], CI 1.05 to 3.1, P¼0.034). The mean haemoglobin decrease was greater without than with tourniquet (e3.0 vs e2.5 g dl À1 , mean difference e0.48, CI e0.65 to e0.32, P<0.001). No differences were observed in pain, pain management, incidences of blood transfusions, in-hospital complications, or length of hospital stay. Conclusions: For TKA, spinal and general anaesthesia with or without tourniquet did not differ in 24-h postoperative opioid consumption, pain management, blood transfusions, in-hospital complications, and length of hospital stay. Vomiting incidence was higher in the spinal than in the general anaesthesia group. Tourniquet use caused smaller decreases in haemoglobin levels. Clinical trial registration: EudraCT 2016-002035-15.