Blood level changes in total knee arthroplasty with and without a tourniquet

Marco Felipe Francisco Honorato de Barros, Evandro Junior Christovam Ribeiro, Rafael Gomes Dias

To evaluate the difference between the total blood loss in patients undergoing primary total knee arthroplasty with and without the use of tourniquet. A retrospective cohort study, with analysis of medical records of patients undergoing primary total knee arthroplasty in 2015, with and without the use of a tourniquet. Comparison was performed of hemoglobin (HB) and hematocrit (HT) variation in the complete blood count (CBC) during the pre- and post-operative period between the two groups. There were 117 patients undergoing primary total knee arthroplasty included, minimum age of 33 and maximum of 86 years, with a mean of 67 years. 64.1% of the surgeries used a tourniquet and 35.9% did not. The mean preoperative HB in Group 1 was 13.08 and 12.97 in Group 2 (p = 0.435). The mean postoperative HB in Group 1 was 11.64 and 10.93 in Group 2 (p = 0.016). The variation of HB in Group 1 was 1.44 and 2.04 in Group 2 (p = 0.025). The mean preoperative HT in Group 1 was 38.96 and 39.01 in Group 2 (p = 0.898). The mean postoperative HT in Group 1 was 34.47 and 32.19 in Group 2 (p = 0.005). The variation of HT in Group 1 was 4.49 and 6.82 in Group 2 (p = 0.001). A total of 21 patients received transfusions RCC (red cell concentrates), as a result of HB below 8 g/dL or clinical symptoms, respectively, representing seven of Group 1 (9.3% of total intra-group) and 14 of Group 2 (33.3% of total intra-group), with p = 0.001. In patients undergoing primary total knee arthroplasty using a tourniquet, a lower variance in the hematimetric indices was observed and fewer blood transfusions were necessary.