Moderate evidence supports that the use of a tourniquet in total knee arthroplasty (TKA) decreases intraoperative blood loss.

Rationale
With regard to pain, two high quality studies (Liu 2014 and Ledin 2012) and another moderate quality study (Ejaz 2014) showed decreased pain in the no tourniquet group in the very early postoperative period that was not significant after four days (Ledin 2012 and Liu 2014) and eight weeks (Ejaz 2014) respectively.
 
One high quality study (Ledin 2012) and one moderate quality (Aglietti 2000) found increased intraoperative blood loss in the no tourniquet patients. However, Ledin 2012 found no increased total bleeding when hemoglobin dilution was measured and Aglietti 2000 found no difference when overall total blood loss was tabulated.
 
One high quality study (Liu 2014) showed better quadriceps function in the no tourniquet group but equivalent Oxford Knee Scores and range of motion. One moderate quality (Ejaz 2014) study demonstrated better Knee Injury and Osteoarthritis Outcomes (KOOS) subscores and early range of motion to week eight postoperatively in the no tourniquet group, where differences then became statistically insignificant.
 
  1. Aglietti,P., Baldini,A., Vena,L.M., Abbate,R., Fedi,S., Falciani,M. Effect of tourniquet use on activation of coagulation in total knee replacement. Clin Orthop Relat Res. 2000/2; 371: 169-177
  2. Ejaz,A., Laursen,A.C., Kappel,A., Laursen,M.B., Jakobsen,T., Rasmussen,S., Nielsen,P.T. Faster recovery without the use of a tourniquet in total knee arthroplasty. Acta Orthopaedica 2014/8; 4: 422-426
  3. Ledin,H., Aspenberg,P., Good,L. Tourniquet use in total knee replacement does not improve fixation, but appears to reduce final range of motion. Acta Orthop 2012/10; 5: 499-503
  4. Liu,D., Graham,D., Gillies,K., Gillies,R.M. Effects of tourniquet use on quadriceps function and pain in total knee arthroplasty. Knee Surg Relat Res 2014/12; 4: 207-213