The Hidden Costs of a Bloodless Field: A Systematic Review of the Complications of Tourniquet Use in Total Knee Arthroplasty.

Pneumatic tourniquets are widely used in total knee arthroplasty (TKA) to improve visualization and cement fixation, yet their potential harms remain debated. This study systematically evaluated complications associated with tourniquet use in primary TKA, focusing on wound complications as the primary outcome and venous thromboembolism (VTE), pain, quadriceps dysfunction, transfusion, and systemic adverse events as secondary outcomes. MEDLINE (Medical Literature Analysis and Retrieval System Online), Embase, and Cochrane Controlled Register of Trials (CENTRAL) were searched from January 2000 to July 2025. Eligible randomized controlled trials (RCTs) compared (i) tourniquet vs no tourniquet, (ii) full-duration vs limited/timed use, or (iii) alternative pressure strategies. Two reviewers independently screened, extracted data, and assessed risk of bias (RoB 2). Random-effects meta-analyses were performed where appropriate. Certainty of evidence was appraised using GRADE (Grading of Recommendations, Assessment, Development, and Evaluations). Twenty-six reports (25 unique RCT datasets; 3,183 patients, 2001-2024) were included. Across 1,940 patients in 15 RCT comparisons, tourniquet use showed a non-significant trend toward more wound complications (risk ratio (RR) 1.31, 95%CI 0.73-2.36; moderate certainty, I²=20.9%). VTE across 2,144 patients in 15 RCTs showed no significant difference (RR 1.09, 95%CI 0.72-1.64; low certainty). Transfusion in three RCTs (199 patients) showed no clear difference (RR 0.45, 95%CI 0.19-1.04; low certainty). Six RCTs (~500 patients) consistently reported greater early pain and quadriceps dysfunction with tourniquet. Rare but serious adverse events (e.g., compartment syndrome, vascular injury) were documented. In primary TKA, routine full-duration tourniquet use does not reduce VTE or transfusion requirements, is associated with early pain and quadriceps dysfunction, and may increase wound morbidity. Pressure-optimised or selective approaches may mitigate harms while preserving technical benefits. Routine use should be reconsidered in favour of tailored strategies.