Fibrinolytic activity in human legs in tourniquet ischemia

Tranexamic Acid in Foot and Ankle Surgery: A Topical Review and Value Analysis

Tranexamic acid (TXA) has become a commonly used perioperative intervention in total joint arthroplasty, shoulder and knee arthroscopy, and spinal procedures in order to minimize blood loss, hematoma formation, hemarthrosis, and wound healing complications. There is a potential role for TXA use in foot and ankle procedures, with limited studies suggesting a potential benefit in minimizing postoperative wound complications and blood loss without an increased risk of thromboembolic events. In light of the profound clinical and financial impact of TXA use in other orthopaedic subspecialties and the early successes in foot and ankle surgery, we aim to provide more information about TXA and its use in foot and ankle surgery. Therefore, the purpose of this review is to perform a comprehensive literature review on the topic of TXA use in foot and ankle procedures in order to describe the pertinent available literature on the use of TXA in orthopaedic surgery and its implications specifically in foot and ankle surgery. It is our aim to identify potential benefits and shortcomings in the available evidence on TXA use for foot and ankle surgery in hopes to (1) best inform foot and ankle surgeons where beneficial and safe and (2) inspire further research on this topic as it relates to clinical management for foot and ankle patients.Levels of Evidence: Level IV.

Tourniquet and tranexamic acid use in total knee arthroplasty

Background

There is no consensus on how tourniquet and tranexamic acid (TXA) use in total knee arthroplasty (TKA) affect blood transfusion rates and total blood loss. We compared outcome measures and transfusion rates after TKA, with and without the use of tourniquet and TXA.

Methods

A retrospective study of 477 consecutive patients undergoing primary TKA between 2008 and 2013 was performed. There were 243 in the tourniquet-assisted (TA) and 234 in the tourniquet-unassisted (TU) group. Operative times, hemoglobin levels, blood transfusion rates, complications, and length of stay were assessed. Subanalysis was performed on those patients receiving and not receiving TXA within the TU group.

Results

Mean operative duration was 66.4 minutes in the TA group and 87.5 minutes in the TU group (P < .0001). Mean postoperative drop in hemoglobin was greater in TU group (3.1 g/dL vs 2.8 g/dL, P = .002). The transfusion rate was 9.5% in TA compared with 11.5% in TU patients (P = .46) with comparable mean units transfused (2.6 vs 2.2, P = .30). There was no difference in wound infection (P = .82) and total complication rates (P = .27) between groups. Those patients given TXA had a lower hemoglobin drop (2.6 g/dL vs 3.3 g/dL, P = .04) with similar transfusion (13.3% vs 11%, P = .61) and complication (P = .95) rates.

Conclusions

TU TKA had a greater operative duration and postoperative drop in hemoglobin than TA TKA. However, transfusion rates were similar between groups. TXA use reduced the operative decrease in hemoglobin with no effect on complication or transfusion rates.

Level of Evidence

Level III, retrospective cohort study.

The effects of a tourniquet used in total knee arthroplasty: a meta-analysis

Background

The purpose of this research is to evaluate the effects of a tourniquet in total knee arthroplasty (TKA).

Methods

The study was done by randomized controlled trials (RCTs) on the effects of a tourniquet in TKA. All related articles which were published up to June 2013 from Medline, Embase, and Cochrane Central Register of Controlled Trails were identified. The methodological quality of the included studies was assessed by the Physiotherapy Evidence Database (PEDro) scale. The meta-analysis was performed using Cochrane RevMan software version 5.1.

Results

Thirteen RCTs that involved a total of 689 patients with 689 knees were included in the meta-analysis, which were divided into two groups. The tourniquet group included 351 knees and the non-tourniquet group included 338 knees. The meta-analysis showed that using a tourniquet in TKA could reduce intraoperative blood loss (weighted mean difference (WMD), -198.21; 95% confidence interval (CI), -279.82 to -116.60; P < 0.01) but did not decrease the calculated blood loss (P = 0.80), which indicates the actual blood loss. Although TKA with a tourniquet could save the operation time for 4.57 min compared to TKA without a tourniquet (WMD, -4.57; 95% CI, -7.59 to -1.56; P < 0.01), it had no clinical significance. Meanwhile, the use of tourniquet could not reduce the possibility of blood transfusion (P > 0.05). Postoperative knee range of motion (ROM) in tourniquet group was 10.41° less than that in the non-tourniquet group in early stage (≤10 days after surgery) (WMD, -10.41; 95% CI, -16.41 to -4.41; P < 0.01). Moreover, the use of a tourniquet increased the risk of either thrombotic events (risk ratio (RR), 5.00; 95% CI, 1.31 to 19.10; P = 0.02) or non-thrombotic complications (RR, 2.03; 95% CI, 1.12 to 3.67; P = 0.02).

Conclusions

TKA without a tourniquet was superior to TKA with a tourniquet in thromboembolic events and the other related complications. There were no significant differences between the two groups in the actual blood loss. TKA with a tourniquet might hinder patients' early postoperative rehabilitation exercises.

The arterial tourniquet: pathophysiological consequences and anaesthetic implications

The arterial tourniquet is widely used in upper and lower extremity surgery and in intravenous regional anaesthesia. The local and systemic physiological effects and the anaesthetic implications are reviewed. Localised complications result from either tissue compression beneath the cuff or tissue ischaemia distal to the tourniquet. Systemic effects are related to the inflation or deflation of the tourniquet. Safe working guidelines for the application of an arterial tourniquet have not been clearly defined.

Effects of hypoxia and acidosis on vascular plasminogen activator release in the pig ear perfusion system

The influence of hypoxia and acidosis on the release of vascular plasminogen activator was studied in the isolated perfused pig ear. Perfusion with deoxygenated or acid solutions led to significant increases in plasminogen activator release (p less than 0.001); acid solutions of pH 6.7 were more effective than those of pH 6.9. Perfusions with lactate and AMP, two metabolic products which might act as mediators of fibrinolytic stimulation during hypoxia, resulted in moderate increases of plasminogen activator in the effluent (p less than 0.01).