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

OBJECTIVE: To evaluate the difference between the total blood loss in patients undergoing primary total knee arthroplasty with and without the use of tourniquet. METHODS: 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. RESULTS: 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. CONCLUSION: 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.