Background: Early tourniquet release (before wound closure) in total knee arthroplasty [TKA] has been advocated to have
advantages over late release (after skin closure), but the early release can significantly increase perioperative blood loss. To reduce intra-operative blood loss, a new technique called "intermittent early tourniquet release [IETR]" has been developed.

Objective: To compare intra- and post-operative blood loss between IETR and conventional early tourniquet release [CETR] techniques in primary TKA.

Materials and Methods: A prospective randomized controlled trial was conducted with 28 patients aged over 50 years who had been diagnosed with primary knee osteoarthritis and who were scheduled
to undergo primary cemented TKA involving application of a pneumatic tourniquet. In all cases, after cementation of the prosthesis, the tourniquet was released. For patients randomized to the IETR group, the tourniquet was then re-inflated to the previous pressure (without re-exsanguination) one minute after the initial release. The tourniquet was again released after 2 minutes of second re-inflated. Tourniquets were not re-inflated after the initial releasein
patients in the CETR group. Intra- and post-operative blood loss was measured in addition to measurement of hemoglobin and hematocrit levels 24 hours post-operatively. Estimated blood volume loss [BVL] was also calculated.

Results: Pre-operative characteristics in both groups were similar. Following the operation, there was no significant difference between the IETR and CETR groups in intra-operative blood loss (mean
difference -1.0, 95% CI -51.7, 49.8), post-operative blood loss (mean difference -5.2, 95% CI -218.9, 208.5). Estimated BVL and decreases in hemoglobin and hematocrit level were not significantly smaller in the IETR group (mean difference (69.64, 95% CI -92.1, 231.3, p = 0.384), (0.3, 95% CI -0.1, 0.8, p = 0.148) and (1.5, 95% CI -0.1, 3.0, p = 0.070), respectively). In addition, there was no difference in either the number of blood transfusions or in the incidence of tourniquet-related complications.

Conclusion: The IETR technique helps reduce estimated post-operative BVL and decreases in hemoglobin and hematocrit levels compared to the CETR technique, although the differences are not
statistically significant. Re-inflation of the tourniquet after initial deflation does, however, improve surgical field visualization, facilitating cauterization of bleeding blood vessels and results in no increase in tourniquet-related complications.

Keywords: Total knee arthroplasty, Early tourniquet release, Intra-operative blood loss