Blood Loss in Total Knee Arthroplasty: A Meta-analysis of 4 Different Tourniquet Protocols

Context: Decreasing perioperative blood loss using a tourniquet during primary total knee arthroplasty (TKA) is a standard practice but there is still no consensus on ideal technique. Objective: We classified and compared the effect of 4 different tourniquet protocols used in primary TKA. Data Sources: Pub Med and Embase search was performed the term ‘Tourniquet Blood loss Knee replacement' to identify original articles. Study Selection: All the original articles that compared two or more different protocols of tourniquet usage during primary TKA were included. All studies which had an additional variable that would affect perioperative hemoglobin level were excluded. Data Extraction: Change in the mean hemoglobin level perioperatively when using a specific type of tourniquet was calculated in each study. By combining the results of all studies on each particular type of tourniquet usage, the weighted mean and its variance, standard error, standard deviation and 95% CI were calculated. Results: 16 studies with a total of 1126 patients were included in metaanalysis. The results of type 2a, type 2b and type 3 techniques of tourniquet usage during primary TKA were essentially comparable. Type 2a, type 2b and type 3 techniques of tourniquet usage were found to have the lowest mean change in the perioperative hemoglobin level and a non overlapping 95% confidence interval of the mean change in the perioperative hemoglobin level compared to type 0 technique of tourniquet usage. Type 1 technique of tourniquet usage had the broadest 95% confidence interval indicating significant individual outliers compared to the rest of the techniques of tourniquet usage during primary TKA. Conclusion: Type 2a, type 2b and type 3 techniques of tourniquet usage are superior to type 0 and type 1 techniques of tourniquet usage in patients undergoing primary TKA.